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1.	Rögnvaldsson, Thorsteinn, 1963-, et al. (författare) ARC13 – Assessment of Research and Coproduction : Reports from the assessment of all research at Halmstad University 2013 2014 Rapport (populärvet., debatt m.m.)abstract During 2013, an evaluation of all the research conducted at Halmstad University was carried out. The purpose was to assess the quality of the research, coproduction, and collaboration in research, as well as the impact of the research. The evaluation was dubbed the Assessment of Research and Coproduction 2013, or ARC13. (Extract from Executive Summary)
2.	Andersson, Åsa, Professor, 1960-, et al. (författare) Effects on serum protein levels from one bout of high intensity interval training in individuals with axial spondyloarthritis and controls Annan publikation (övrigt vetenskapligt/konstnärligt)abstract Background: Axial spondyloarthritis (axSpA) is a chronic inflammatory disease primarily affecting the axial skeleton causing pain, inflammation, and stiffness. Individuals with axSpA are at greater risk of developing cardiovascular disease, which can be counteracted by physical activity. High-intensity interval training (HIIT) has been shown to improve cardiovascular health, but the effect on disease activity and the level of inflammation in axSpA has been less studied. With the aim of investigating how levels of inflammatory cytokines, myokines, and protein markers for bone metabolism are acutely affected by one bout of HIIT, we studied serum from individuals with axSpA and healthy controls (HC).Methods: Ten participants with axSpA and 11 age- and sex-matched HC performed a single HIIT bout on a cycle ergometer: 4x4 minutes intervals with three minutes active rest in between. Blood samples were taken before and one hour after the HIIT bout. Serum proteins (IL-6, IL-17, IL-18, TNFa, CXCL-10, VEGF-A, BDNF, DKK-1, osteoprotegerin, osteocalcin, osteopontin, BMP-7, CRP) were analyzed with a Luminex system or ELISA. Descriptive data are presented as mean with standard deviation. A two-way ANOVA was used for comparisons.Results: A main effect from baseline to one hour post HIIT showed that both groups had a significant increase in serum levels (pg/ml) of IL-6: axSpA 2.2 (3.0) to 3.2 (1.8) and HC 0.4 (0.4) to 1.9 (2.0), p=0.03. VEGF-A (pg/ml) was significantly lower in the axSpA group: 159 (138) vs. HC 326 (184), p=0.03, but was not affected by the HIIT bout. BMP-7 (ng/ml) increased in both groups after the HIIT: axSpA 61.6 (13.1) to 75.2 (20.0) and HC 64.6 (20.8 to 75.0 (17.8), p<0.001. For the other proteins analyzed, there were no significant differences in serum concentrations between individuals with axSpA and HC, or within the two groups before and after one bout of HIIT.Conclusions: One acute bout of HIIT significantly increases the serum concentrations of IL-6 and BMP-7 after 1 hour in both individuals with axSpA and HC.© Research Square 2024
3.	Andersson, Åsa, Professor, 1960-, et al. (författare) Serum Protein Response To A Single High-Intensity Interval Training Bout – Comparison Between Individuals With Spondyloarthritis And Healthy Controls 2022 Ingår i: Annals of the Rheumatic Diseases. - London : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 81:Suppl 1, s. 780-781 Tidskriftsartikel (refereegranskat)abstract Axial spondyloarthritis (axSpA) is a chronic inflammatory disease affecting mainly the axial skeleton. To decrease the risk of cardiovascular comorbidity, aerobic training is recommended as a part of disease management in patients with axSpA. High-intensity interval training (HIIT) interventions are, in addition to other recommended treatments, believed to positively affect the disease activity (1). However, the knowledge about the acute effects of HIIT on the inflammatory process at the molecular level is less studied. Understanding the acute HIIT effects on cytokines and additional serum proteins in axSpA is important for further long-term HIIT interventions and recording of the effect of HIIT on the axSpA disease profile.ObjectivesTo study the acute effects on serum proteins, such as cytokines, myokines, and inflammatory- and bone-related proteins, in response to a single bout of HIIT, and to compare the levels between baseline and post-HIIT in patients with axSpA and healthy controls (HC).MethodsThe pilot study included twenty-one participants (10 female, 11 male), mean (SD) age 40 (7) years, ten with axSpA, and eleven age and sex matched HC, who performed a single HIIT on a cycle ergometer consisting of 4x4 minutes interval (90% heart rate, HR-max) with three minutes active rest in between (70% of HR-max). Disease activity (BASDAI, 0-10) in patients with axSpA was 1.6 (0.8). Health status EuroQol (EQ5D, 0-1) were 0.87 (0.11) for axSpA, and 0.93 (0.10) for HC. The groups were well matched with no difference in baseline data for weight, BMI, EQ5D, blood pressure or aerobic capacity.Blood samples were taken before (baseline) and one hour after the single HIIT. The following serum proteins were analyzed on a Luminex MAGPIX System (Luminex corporation, Austin, TX USA): Interleukin (IL)-6, IL-17, IL-18, TNFαAGPIX System (Luminex corporatiosteoprotegerin, osteocalcin, osteopontin, and FGF-23. A three-way analysis of variance (ANOVA) was used to detect differences between groups, between sexes, and before and after a HIIT bout in a 2(group)2(sex)2(time) design. For main effects or interactions significant at p≤0.05, simple effect t-tests were used to determine the specific effects.ResultsA group main effect (p=0.048) showed that the serum level of IL-6 was increased one hour after the HIIT session primarily in the HC, 0.4 pg/ml (SD±0.4) at baseline vs. post-HIIT 1.8 (2.0). The concentration of the cytokines/chemokine IL-17, IL-18, TNFα group main effect (p=0.048) showed that the serum level of IL-6 was increased one hour after the HIIT session primarily in30) in VEGF-A showed that the axSpA group had significantly lower VEGF-A at baseline, 159 pg/ml (138) vs 326 (184) in the control group (which might be due to anti-inflammatory medication). A sex main effect (p=0.029) was observed from baseline to post-HIIT for the bone hormone osteocalcin, with a more pronounced decrease of serum osteocalcin in women with axSpA, 14.0 ng/ml (8.3) vs. post HIIT 13.2 (6.9). Moreover, the level of the multifunctional protein osteopontin was significantly lower (sex main effect, p=0.021) in women, 10.7 ng/ml (7.0) vs. men 20.4 (10.1), post-HIIT.ConclusionThis pilot study shows that one bout of HIIT influences the expression of proteins involved in inflammation and metabolism, and that sex is an important factor in the response to HIIT. The results should be followed up in longer intervention studies including higher numbers of participants.References[1]Sveaas, S. H. et al. (2019). High intensity exercise for 3 months reduces disease activity in axial spondyloarthritis (axSpA): a multicentre randomised trial of 100 patients. British journal of sports medicine, 54(5), 292-297.Disclosure of InterestsÅsa Andersson: None declared, Emma Haglund Consultant of: Novartis, Emma Berthold: None declared, Elisabeth Mogard Consultant of: Novartis, Anna Torell: None declared, M Charlotte Olsson: None declared
4.	Gerhardt, Karin, et al. (författare) Nog nu, politiker – ta klimatkrisen på allvar 2022 Ingår i: Aftonbladet. - Stockholm : Aftonbladet Hierta. ; 25 August Tidskriftsartikel (populärvet., debatt m.m.)
5.	Torell, Anna, 1967-, et al. (författare) Effects of a digital-based high-intensity interval training (HIIT) intervention in individuals with axial spondyloarthritis – a randomized controlled pilot study (RCT) 2023 Ingår i: Annals of the Rheumatic Diseases - The EULAR journal 2023. ; , s. 1049-1049 Konferensbidrag (refereegranskat)abstract Background: Physical exercise is an important treatment for individuals with axial spondyloarthritis (axSpA). Although high-intensity training (HIT) has been shown to reduce disease symptoms and risk of comorbidity without exacerbating disease activity (1), compliance tends to decrease over time. Increased knowledge is needed on how to optimize and tailor individual exercise programs for continued regular exercising and improved health.Objective: To study the effects of HIT on aerobic capacity, body composition, disease activity, physical function, health status and fatigue in individuals with axSpA after a 12-week intervention supported by digital coaching.Methods: Twenty-two individuals (women, n=12), recruited from two rheumatology clinics in southern Sweden, were randomized to a HIT intervention group (HG; n=11) or a control group (CG; n=11). The HG completed three HIT sessions/week, including two interval training sessions (4x4 min), in self-selected activities for 12 weeks. The individuals in the HG were individually coached and had regular support from a physical therapist primarily by digital coaching. The CG continued exercising as usual. Assessment of aerobic capacity (VO2max), body composition (BMI and visceral fat area [cm2]), disease activity (CRP [µg/ml], BASDAI, 0-10 best-worst), physical function (BASFI, 0-10 best-worst), health status (EQ5D, 0-1 worst-best, ASAS health index [ASAS-HI], 0-17 best-worst), and fatigue (fatigue severity scale [FFS], 0-7 best-worst) were sampled at baseline and after 12 weeks. Mean and standard deviation (SD) were used for descriptive statistics. Repeated measures analysis of variance (ANOVA) was used to investigate effect of group (HGCG) and time (PREPOST), with a post-hoc analysis using t-tests when ANOVA indicated a significant difference in main effects or interactions. A significance level of p≤0.05 was used. Fisher´s exact test was used to study the effects over time for CRP (as dichotomized variable, > or < 4 µg/ml).Results: Results presented are part of an ongoing RCT based on 19 individuals (women n=11) that have completed the 12-week follow-up analyses. The participants mean (SD) age was 48 (10) years, BMI 25 (4), VO2max 37 (6) mlO2/kg/min, and BASDAI 2.6 (0.3). No differences were present between the HG (n=9) and the CG group (n=10) at baseline for the studied variables. After 12 weeks of HIT an ANOVA interaction (p<0.05 showed that HG increased their VO2max (6.4 [3.6] mlO2/kg/min; p<0.001) but CG did not. For BMI, visceral fat area, disease activity (BASDAI), physical function (BASFI), fatigue (FFS) no differences in main effects or interactions were found (p>0.05). Health status (EQ5D) showed an ANOVA time main effect (p=0.007) where the HG increased their health status (0.10 [0.06] units; p=0.02) after 12-weeks, but CG did not. For health status measured with ASAS-HI no differences between groups were found. For dichotomized CRP-values no differences were found in either of the group’s pre-post. Conclusions: This pilot RCT shows that after 12 weeks of digital-based HIT intervention, the HG increased their aerobic capacity and EQ5D health status compared to CG, while body composition, disease activity, physical function, and fatigue did not show any significant differences between the groups. References(1) Sveaas SH, Bilberg a, Berg IJ, Provan SA, Rollefstad S, Semb AG, et al. high intensity exercise for 3 months reduces disease activity in axial spondyloarthritis (axSpA): a multicentre randomised trial of 100 patients. Br J Sports med. 2019
6.	Torell, Anna, 1967-, et al. (författare) Effects of a digital-based high-intensity training intervention in individuals with axial spondyloarthritis – a randomized controlled pilot study (RCT) 2023 Ingår i: Annals of the Rheumatic Diseases. - London : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 82:Suppl 1, s. 1049-1049 Tidskriftsartikel (refereegranskat)
7.	Brorsson, Sofia, et al. (författare) Grip force and muscle activity are associated with kinematics in the golf swing 2012 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 44:Suppl. 2, s. 474-474 Konferensbidrag (refereegranskat)
8.	Brorsson, Sofia, et al. (författare) Unilateral Strength Training With Maximal Velocity Improves Lower Body Power Outcome And Movement Velocity 2012 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 44:Suppl. 2, s. 671-671 Konferensbidrag (refereegranskat)
9.	Ek, Staffan, et al. (författare) Relative Age Effect of Sport Academy Adolescents, a Physiological Evaluation 2020 Ingår i: Sports. - Basel : MDPI. - 2075-4663. ; 8:1 Tidskriftsartikel (refereegranskat)abstract The relationship between birth quarter distribution and physiological characteristics related to athletic skills, in adolescent sport academy students has not been fully investigated. In a cross-sectional study, we recruited 86 boys and 52 girls aged 12-14 years during their first term at a sport academy school. We measured body size, cardiac size, pulmonary function, body composition, lower body power, cardiorespiratory fitness parameters, and running endurance by standard methods and analyzed these estimates in relation to birth quarter by ANOVA. Birth quarter distribution in our cohort was compared with birth quarter distribution in the same ages in the whole of Sweden and analyzed by logistic regression. The academy had an overrepresentation of students born in the first quartile of the year compared to those born in the last quartile (odds ratio 2.3 (95% CI: 1.1-4.7)). When comparing the physiological characteristics between birth quarters, uniformity is prominent since out of 26 performed physiological and anthropometric tests only four showed statistically significant group differences. We thus believe that the selection process to the sport academy favours athletes with higher chronological age, i.e., a so-called relative age effect is present. © 2020 MDPI (Basel, Switzerland).
10.	Frandsen, Björn, 1988-, et al. (författare) Hip and Trunk Muscle Electromyography Differences Between Bilateral and Unilateral Bodyweight Resistance Exercises 2015 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract IntroductionIn sports, force production and movement are predominantly generated in a unilateral weight-bearing stance. Therefore, unilateral resistance training may possibly elicit more sport-specific strength gains compared to traditional bilateral strength training. Hip- and trunk- muscles stabilize the pelvis and trunk to maintain proper technique and posture in resistance training and are thought to play a central role in sports performance as well as injury prevention. Hip- and trunk- muscle activity increases as the body weight balance change from a bilateral to a unilateral stance. Little research has examined the magnitude of change in muscle activation differences between bilateral and unilateral stance in lower body exercises.AimThe aim of this study was to examine the electromyographic (EMG) activity in hip and trunk muscles in three bodyweight exercises performed in a bilateral and a unilateral stance.Methods14 healthy, young adults participated in a single session, single-group, observational study. Manual muscle testing was used to attain a maximal voluntary isometric contraction (MVC) value for gluteus medius, gluteus maximus, rectus abdominis, and erector spinae. EMG measurements (4 channel ME6000, MegaWin Software, Kuopio, Finland) were taken during performance of squat, bridge, and plank exercises in both a bilateral and a unilateral stance.ResultsIn all three exercises, EMG activity (presented as magnitude of change) was greater in the unilateral stance compared to the bilateral stance (p< 0.05), for the muscles gluteus medius (squat 478%, bridge 204%, plank 285%) and gluteus maximus (squat 371%, bridge 172%, plank 233%). In addition, in plank, EMG activity was greater in unilateral stance compared to the bilateral stance (p< 0.05) in rectus abdominis (120%) and erector spinae (127%). In the squat and bridge, no differences were identified in EMG activity for rectus abdominis and erector spinae between the bilateral and the unilateral stance.DiscussionNearly all unilateral exercises activated the hip muscles (gluteus medius, gluteus maximus) more than double compared to the same exercises performed bilaterally. In particular, gluteal muscle activity during the unilateral squat was more than 3.5 fold greater as compared to the bilateral stance. This greater magnitude of change in the unilateral squat might be explained by the single contact point with the ground in the squat, whereas the bridge and plank exercises include more ground contact points even in their unilateral stance. A unilateral training program including squat exercises might be beneficial for developing hip strength which is of great importance in sports performance.
11.	Helland, Christian, et al. (författare) Training Strategies to Improve Muscle Power : Is Olympic-style Weightlifting Relevant? 2017 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, PA : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 49:4, s. 736-745 Tidskriftsartikel (refereegranskat)abstract INTRODUCTION: This efficacy study investigated the effects of (1) Olympic-style weightlifting (OWL), (2) motorized strength and power training (MSPT), and (3) free weight strength and power training (FSPT) on muscle power.METHODS: Thirty-nine young athletes (20±3 yr.; ice hockey, volleyball and badminton) were randomized into the three training groups. All groups participated in 2-3 sessions/week for 8 weeks. The MSPT and FSPT groups trained using squats (two legs and single leg) with high force and high power, while the OWL group trained using clean and snatch exercises. MSPT was conducted as slow-speed isokinetic strength training and isotonic power training with augmented eccentric load, controlled by a computerized robotic engine system. FSPT used free weights. The training volume (sum of repetitions x kg) was similar between all three groups. Vertical jumping capabilities were assessed by countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), and loaded CMJs (10-80 kg). Sprinting capacity was assessed in a 30 m sprint. Secondary variables were squat 1-repetition-maximum, body composition and quadriceps thickness and architecture.RESULTS: OWL resulted in trivial improvements, and inferior gains compared to FSPT and MSPT for CMJ, SJ, and DJ. MSPT demonstrated small, but robust effects on SJ, DJ and loaded CMJs (3-12%). MSPT was superior to FSPT in improving 30 m sprint performance. FSPT and MSPT, but not OWL, demonstrated increased thickness in the vastus lateralis and rectus femoris (4-7%).CONCLUSION: MSPT was time-efficient and equally or more effective than FSPT training in improving vertical jumping and sprinting performance. OWL was generally ineffective and inferior to the two other interventions. Copyright © 2016 by the American College of Sports Medicine.
12.	Horwath, Oscar, et al. (författare) Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players. 2019 Ingår i: Journal of Science and Medicine in Sport. - Chatswood : Elsevier. - 1440-2440 .- 1878-1861. ; 22:7, s. 821-826 Tidskriftsartikel (refereegranskat)abstract OBJECTIVES: To determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players.DESIGN: Experimental, randomized trial.METHODS: Twenty-two resistance-trained ice hockey players (18±1year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n=11) or traditional resistance training (TRAD; n=11). Participants underwent supervised progressive resistance training for 8 weeks (2-3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement.RESULTS: Similar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11-17%, P<0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P=0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P=0.01) and rectus femoris muscles (P=0.03).CONCLUSIONS: Both modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players. © 2019 Sports Medicine Australia
13.	Khan, Taha, 1983-, et al. (författare) A Novel Method for Classification of Running Fatigue Using Change-Point Segmentation 2019 Ingår i: Sensors. - Basel : MDPI. - 1424-8220. ; 19:21 Tidskriftsartikel (refereegranskat)abstract Blood lactate accumulation is a crucial fatigue indicator during sports training. Previous studies have predicted cycling fatigue using surface-electromyography (sEMG) to non-invasively estimate lactate concentration in blood. This study used sEMG to predict muscle fatigue while running and proposes a novel method for the automatic classification of running fatigue based on sEMG. Data were acquired from 12 runners during an incremental treadmill running-test using sEMG sensors placed on the vastus-lateralis, vastus-medialis, biceps-femoris, semitendinosus, and gastrocnemius muscles of the right and left legs. Blood lactate samples of each runner were collected every two minutes during the test. A change-point segmentation algorithm labeled each sample with a class of fatigue level as (1) aerobic, (2) anaerobic, or (3) recovery. Three separate random forest models were trained to classify fatigue using 36 frequency, 51 time-domain, and 36 time-event sEMG features. The models were optimized using a forward sequential feature elimination algorithm. Results showed that the random forest trained using distributive power frequency of the sEMG signal of the vastus-lateralis muscle alone could classify fatigue with high accuracy. Importantly for this feature, group-mean ranks were significantly different (p < 0.01) between fatigue classes. Findings support using this model for monitoring fatigue levels during running. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
14.	Kroos, G., et al. (författare) Gene expression of angiogenic factors in muscle tissue during age-related development of hypertension in spontaneously hypertensive rats 2008 Ingår i: Abstracts 25th Conference of the European Society for Microcirculation. - Basel : S. Karger. - 9783805586368 ; , s. 120-120 Konferensbidrag (refereegranskat)abstract Essential hypertension has been associated with capillary rarefaction but little is known about the cellular mechanisms underlying this process. We examined the gene expression of angiogenic factors during age-related development of hypertension in spontaneously hypertensive rats (SHR). Wild-type Wistar Kyoto (WKY) rats served as controls. White gastrocnemius muscle was obtained and blood pressure was monitored at 5, 10 and 15 weeks of age. In the SHR group, systolic blood pressure increased from 5 to 10 and 15 weeks of age and the levels were higher than in the WKY group at 10 and 15 weeks (~70%; P<0.05). The mRNA content for MMP-2 was overall lower (P<0.05) in SHR compared to WKY. VEGFmRNA increased (p<0.05) from 5 to 10 weeks in SHR and there was a general increase (P<0.05) in the VEGF receptor flt-1. There was a trend for a lower content of eNOS and CYP 2C11 in the SHR than in WKY group. There were no alterations in the mRNA content of KDR, AMP 5'- nucleotidase, or Cytochrome P450 4A. The results show that the age-related development of hypertension from 5 to 15 weeks in SHR rats is not associated with major changes in mRNA content of the herein included angiogenic factors.
15.	Larsson, Jonas, 1968-, et al. (författare) Cardiorespiratory responses of load carriage in female and male soldiers 2022 Ingår i: Applied Ergonomics. - Oxford : Elsevier. - 0003-6870 .- 1872-9126. ; 101 Tidskriftsartikel (refereegranskat)abstract PurposeTo investigate the effect of sex and load carriage on cardiorespiratory responses to high intensity exercise in male and female soldiers.MethodsSoldiers (9 women, 9 men) performed a graded treadmill test until exhaustion with no load (NL) and combat-gear with body armor (CG). Cohen's d effect sizes, paired t-tests and ANOVA were used to study differences between conditions. A mixed linear regression model analyzed the relationship between heart rate (HR) and oxygen uptake (V̇O2) with load and between sexes.ResultsWearing CG resulted in, for both sexes, a decreased time to exhaustion (−11 min), lower V̇O2peak (L/min) ES = 0.56; VO2peak (mL//kg/min) ES = 2.44, both p < 0.001, a net decrease in minute ventilation (ES = 3.53) and no change in HRmax. No sex-difference were present except for absolute V̇O2peak. The VO2 and HR relationship showed a cardiorespiratory reduction wearing CG vs. NL. Added load was equal between sexes, although female soldiers' CG relative to body mass was higher (25%) than male soldiers’ (20%), p < 0.01.ConclusionWearing CG reduces soldiers’ cardiorespiratory capacity and exercise performance level, although the reduction cannot be explained solely based on the added load of CG, instead CG seems to restrict the capacity to fully ventilate. No sex differences were found in relative cardiorespiratory responses to wearing CG compared to NL.
16.	Larsson, Jonas, 1968-, et al. (författare) Cardiovascular Effects of Load Carriage in Soldiers; A Pilot Study 2019 Ingår i: Book of Abstracts of the 24th Annual Congress of the European College of Sport Science – 3rd - 6th July 2019, Prague – Czech Republic. - : European College of Sport Science. - 9783981841428 ; , s. 422-423 Konferensbidrag (refereegranskat)abstract Introduction: Previous studies have shown that risk of physical fatigue increases if prolonged average work intensity exceeds 50% of oxygen uptake (VO2). In order to avoid persistent fatigue in a work setting, it is important to conduct suitable work capacity analyses. In physically demanding jobs where wearing protective gear and/or external load is mandatory, monitoring of cardiovascular demands through heart rate (HR) is one way to track the workers’ relative effort. There are limited studies examining effects of load carrying on cardiovascular capacity where it appears that VO2peak differ when soldiers and firefighters are tested with work-related equipment/clothing compared to light clothing. The aim of this pilot study was to investigate effects of load (combat gear) on HR, VO2 and muscle oxygen saturation (SmO2) compared to no load in soldiers during a graded treadmill protocol.Methods: Eight volunteer army soldiers (1 woman, 7 men) performed a graded treadmill test until exhaustion. All soldiers performed the test twice, once with light clothes and no load (NL) and once with added load, their personal combat gear (CG), with at least 48 h between sessions. The treadmill protocol stages included supine and standing positions, followed by marching speeds of 5.4 km/h and 8 km/h at 0 incline (all 5 min) immediately followed by a set marching speed of 8 km/h with a starting incline of 2 % increasing the incline 2 % every third minute until voluntary exhaustion. Measurements of HR, VO2 and SmO2 were collected continuously and the last 30 s of each stage were averaged and used for statistical analyses (paired t-tests).Results: The mean added load for all soldiers with CG was 16.8 ± 1.1 kg. All soldiers completed at least 6 stages (range 6-11 stages) with both NL and CG, where time to exhaustion with NL was longer (19.1 ± 3.2 min) compared to CG (9.1 ± 2.9 min; p <0.01). Submaximal HR and VO2 were both significantly higher with CG compared to NL (at absolute intensities) at all marching speeds all soldiers completed (5.4 km/h 0 % grade - 8 km/h 4% grade; all p<0.05). For SmO2, marching with CG compared to NL resulted in increased muscle oxygen utilization, at submaximal stages 8 km/h 0% -4% grade (all p<0.05). For values at maximal effort the CG had a significantly lower VO2peak (3.7 ± 0.5 L/min) compared to NL (4.1 ± 0.6 L/min, p <0.01), whereas there was no difference in HRpeak or the lowest value of SmO2 between CG (193.1 ± 7.2 bpm; 42.4 ± 30.3%) and NL (195.4 ± 8.9 bpm; 47.0 ± 29.2%).Conclusions: This pilot study suggests that assessment of aerobic capacity in soldiers should be conducted with combat gear to help determine their actual work capacity during combat and other load carrying tasks. These results suggest that if soldiers’ work performance is determined without added load it overestimates their aerobic capacity (VO2peak) in tasks wearing combat gear, which might lead to added fatigability and deleterious effect on performance.
17.	Larsson, Jonas, et al. (författare) Cardiovascular responses of load carriage in female and male soldiers 2020 Ingår i: 5th International Congress on Soldiers Physical Performance. ; , s. 260-260 Konferensbidrag (refereegranskat)
18.	Larsson, Jonas, 1968-, et al. (författare) Development and application of a questionnaire to self-rate physical work demands for ground combat soldiers 2020 Ingår i: Applied Ergonomics. - Oxford : Elsevier. - 0003-6870 .- 1872-9126. ; 83 Tidskriftsartikel (refereegranskat)abstract Purpose: The aim of the present study was to identify the most physically demanding work tasks for Swedish ground combat soldiers through the development and application of a questionnaire survey. This is the first in a series of studies aiming to describe the development process and validation of physical selection standards in the Swedish armed forces.Methods: Based on procedural documentation, combat manuals and job analyses, a questionnaire was developed that defined and rated the perceived physical strain of 30 work tasks for ground combat soldiers. To assess validity, an expert focus group was used and psychometric analysis performed. The questionnaire was then distributed to 231 ground combat soldiers, of whom 165 responded (71%).Results: The questionnaire was validated in three steps to achieve face and content validity, and internal consistency was acceptable (Chronbach's alpha ≥0.95). Of the 30 work tasks included in the survey, transport of wounded was rated as the most demanding task for both aerobic capacity and strength. Other highly demanding tasks for aerobic capacity included combat movement (low/high crawl), dismounted attack in close country, urban and rough terrain and carrying heavy loads. There were no gender differences for either aerobic or strength demands in the top five most challenging tasks based on proportions.Conclusions: This study identified the most physically demanding tasks performed in the Swedish ground combat forces. Almost all the physically demanding tasks found in the present study contain elements of lifting and carrying, which require muscular strength and muscular endurance, with no gender differences. © 2019 Elsevier Ltd. All rights reserved.
19.	Larsson, Jonas, 1968-, et al. (författare) Physiological Demands and Characteristics of Movement During Simulated Combat 2023 Ingår i: Military medicine. - New York, NY : Oxford University Press. - 0026-4075 .- 1930-613X. ; 188:11-12, s. 3496-3505 Tidskriftsartikel (refereegranskat)abstract INTRODUCTION: Military tasks place considerable physiological demands on the soldier. It is therefore important to know the energy expenditure of soldiers while solving tasks in different environments. The purpose of this study was to describe the cardiorespiratory demands of certain movements and activities on ground combat soldiers during military field operations using body sensors and simulated combat.MATERIALS AND METHODS: Movement characteristics and cardiorespiratory responses were assessed in 42 soldiers (three women) in the Swedish Army. The different posts assessed were commander, combat engineer, driver, and gunner. The military field exercises examined were urban operations and retrograde operations in rough terrain. Measurements included (1) body mass, (2) heart rate (HR) including maximal (HRmax), (3) velocity, (4) accelerations/decelerations, and (5) distance moved. Maximal aerobic capacity (V̇O2peak, mL·kg-1·min-1) was tested in a laboratory setting when wearing combat gear and body armor.RESULTS: There was a weak positive correlation (r = 0.41 and 0.28, both P < .05) between VO2peak and percentage of time over 40% and 50% of maximal aerobic capacity during simulated combat. No differences were found for the different posts in time spent over 40% or 50% of maximal aerobic capacity and 76% of their HRmax (P > .05). Wearing combat gear and additional load while solving tasks resulted in mean HR varying between 98 and 111 beats·min-1, corresponding with 50-57% of the soldiers HRmax. Studying all exercises, mean HR was 105 ± 11 beats min-1, 54 ± 5% of HRmax corresponding to light work intensity. Soldiers performed between 2.8 and 4.9 accelerations/min in the different exercises. A significant correlation between V̇O2peak (mL kg-1 min-1) and acceleration and m/min were found, implying that soldiers with good aerobic capacity were able to cope better with tasks requiring quick movements.CONCLUSION: Conducting military operations in urban terrain and retrograde operations in rough terrain strains ground combat soldiers' cardiorespiratory system, with work intensities close to 40% of maximal aerobic capacity in 15-33% of mission time. Tasks with external load carriage include change of direction, accelerations, bounds, and jumping over obstacles, and physical fitness tests should replicate this. Findings in this study also add objective data to the physiological demands of work performed by combat soldiers while conducting urban operations and retrograde operations in rough terrain. These findings could be used to develop a model for classifying work demands for ground combat forces. © The Association of Military Surgeons of the United States 2022.
20.	Larsson, Jonas, 1968-, et al. (författare) Self-rated physical work demands for ground combat soldiers 2018 Ingår i: PES 2018 3rd International Conference on Physical Employment Standards, University of Portsmouth, United Kingdom, 17-19 July 2018. ; , s. 31-31 Konferensbidrag (refereegranskat)abstract Introduction: Military tasks are physically demanding, and the ability to achieve and maintain the physical capacity required to perform all military tasks are important. Previous studies in other countries have identified the most physically demanding work tasks to be carrying, lifting heavy loads, and digging. The aim of the present study was to identify the most physically demanding work tasks for Swedish ground combat soldiers and to study gender differences in perceived difficulty of the tasks.Methods: Based on procedural documentation, field manuals and job analyses, a questionnaire was developed that defined 30 work tasks for ground combat soldiers. To assess face and content validity, an expert focus group was used. The questionnaire was distributed to 231 ground combat soldiers, 165 of whom responded (71.4%), rating the perceived physical strain of the identified work tasks.Results: Of the 30 item work tasks included in the survey, five were selected as the most physically demanding. Transport of wounded was rated as the most demanding task both for aerobic endurance and strength. Other highly demanding tasks for aerobic capacity were low/high crawl, dismounted attack in close country, urban and rough terrain, and carrying heavy loads. For muscle strength demands there were a total of 11 different work task ranked for hand-, arm-, leg-, and core strength although many of them only occurred in one of the areas of interest. Carrying heavy loads were ranked in second place except for leg and core strength there it was in third place, instead high and low crawl was ranked very strenuous for leg and core strength. Care of wounded were ranked high for hand strength but not so hard for the rest of the areas.Conclusions: Swedish ground combat soldiers rate many tasks as physically demanding. Almost all the identified tasks were physically challenging and contains elements of lifting and carrying, which demand personnel’s muscular strength and muscular endurance capabilities for the soldiers. There were no significant differences in ranked physical requirements between male and female soldiers although they sometimes ranked the tasks in different order.
21.	Larsson, Jonas, 1968-, et al. (författare) Swedish soccer coaches' experiences and application of physical training in male elite soccer : A qualitative content analysis study 2021 Ingår i: Scandinavian Sport Studies Forum. - Malmö : Malmö University. - 2000-088X. ; 12, s. 159-181 Tidskriftsartikel (refereegranskat)abstract In elite soccer, training becomes more systematic and soccer clubs try to optimise their physiological training programs. Previous research has investigated many aspects of soccer, but research into the coaches’ own experiences and continuous improvement of physical training is lacking. The aim of this study was to describe the coaches’ experiences and their application of physical training in male elite soccer. The design of the study was explorative and based on a qualitative content analysis with an abductive approach based on a custom version of the four-step quality model—the plan-do-check-act (PDCA) cycle. Fifteen elite soccer coaches in Sweden were interviewed. The result showed that physical training in male elite soccer is an ongoing continuously improvement process that contains four different categories: 1) planning, containing gained experiences, teamwork, and lack of resources; 2) executing with different training methods, weekly rotation, and individual training; 3) evaluating containing monitor training load and physiological testing, and 4) improving with search for knowledge and long-term development. The coaches try to absorb new knowledge and continuously improve their training methods, although lack of resources sometimes does not allow them to introduce new training methods.
22.	Malmborg, Julia, 1988-, et al. (författare) Daily Musculoskeletal Pain Affects Health And Sports Performance Negatively In Youth Athletes 2017 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, PA : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 49, s. 972-972 Tidskriftsartikel (refereegranskat)abstract In sports, musculoskeletal pain (MSP) is often studied from the perspective of sport specific injuries, why little is known about the prevalence of daily or multisite MSP that does not affect participation in sports. It is also unclear if daily or multisite MSP is a risk factor for worse health-related quality of life (HRQoL) and worse sports performance in youth athletes.PURPOSE: To study how HRQoL and sports performance is affected by daily MSP in youth athletes that are able to participate in sports.METHODS: 136 Swedish youth athletes attending a sport school (13 to 14 years, boys n=83, girls n=53) completed the EQ-5D measuring HRQoL (range 0 to 1, worst to best), a pain questionnaire including current pain (yes/no), pain in 18 body regions (never to rarely/monthly to weekly/more than once a week to almost daily), and pain intensity in the last week (0 to 10, best to worst), anthropometric measures to estimate biological age, and sports performance tests (grip strength, 20 meter sprint, and countermovement jump(CMJ)).RESULTS: 109 to 117 of the 136 students answered the different pain questions. 53 of 113 (47%) reported current MSP, and 28 of 109 (26%) experienced MSP ‘more than once a week to almost daily’ from one or more body regions (frequent MSP group), while 28% (n=30) stated ‘never to rarely’ in MSP (no MSP group). Boys in the frequent MSP group reported worse HRQoL, higher pain intensity, performed worse in all sports performance tests, and had a younger biological age than boys in the no MSP group. Girls in the frequent MSP group reported worse HRQoL and higher pain intensity than the girls in the no MSP group. No other differences were found (table).CONCLUSIONS: Every other youth athlete attending a sport school reported current MSP and one out of four reported almost daily MSP. MSP affects HRQoL negatively in both boys and girls, and sports performance negatively in boys. The prevalence of MSP in youth athletes is concerning since pain in younger ages may predict pain in adult ages.© 2017 American College of Sports Medicine
23.	Malmborg, Julia, 1988-, et al. (författare) Health status, physical activity, and orthorexia nervosa : A comparison between exercise science students and business students 2017 Ingår i: Appetite. - Amsterdam : Elsevier. - 0195-6663 .- 1095-8304. ; 109, s. 137-143 Tidskriftsartikel (refereegranskat)abstract Orthorexia nervosa is described as an exaggerated fixation on healthy food. It is unclear whether students in health-oriented academic programs, highly focused on physical exercise, are more prone to develop orthorexia nervosa than students in other educational areas. The aim was to compare health status, physical activity, and frequency of orthorexia nervosa between university students enrolled in an exercise science program (n = 118) or a business program (n = 89). The students completed the Short Form-36 Health Survey (SF-36), the International Physical Activity Questionnaire (IPAQ), and ORTO-15, which defines orthorexia nervosa as a sensitive and obsessive behavior towards healthy nutrition. The SF-36 showed that exercise science students scored worse than business students regarding bodily pain (72.8 vs. 82.5; p = 0.001), but better regarding general health (83.1 vs. 77.1; p = 0.006). Of 188 students, 144 (76.6%) had an ORTO-15 score indicating orthorexia nervosa, with a higher proportion in exercise science students than in business students (84.5% vs. 65.4%; p = 0.002). Orthorexia nervosa in combination with a high level of physical activity was most often seen in men in exercise science studies and less often in women in business studies (45.1% vs. 8.3%; p < 0.000). A high degree of self-reporting of pain and orthorexia nervosa in exercise science students may cause problems in the future, since they are expected to coach others in healthy living. Our findings may be valuable in the development of health-oriented academic programs and within student healthcare services. © 2016 Elsevier Ltd
24.	Malmborg, Julia, PhD, 1988-, et al. (författare) Musculoskeletal pain in adolescent sportschool students – a two-year follow-up 2021 Konferensbidrag (refereegranskat)
25.	Malmborg, Julia, 1988-, et al. (författare) Pain and its association to health, orthorexia nervosa, sports performance, and physical maturity in sport school adolescents 2017 Ingår i: Proceedings of the Nordic Sport Science Conference – ‘The Double-Edged Sword of Sport: Health Promotion Versus Unhealthy Environments’. - Halmstad : Halmstad University Press. ; , s. 56-57 Konferensbidrag (refereegranskat)
26.	Malmborg, Julia, 1988-, et al. (författare) Risk Factors for Persistence and Development of Frequent Musculoskeletal Pain in Adolescent Athletes 2020 Ingår i: Annals of the Rheumatic Diseases. - London : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 79:Suppl 1, s. 206-206 Tidskriftsartikel (refereegranskat)abstract Physical activity has a positive impact on health, but adolescent athletes often report musculoskeletal pain (MP) which is negative in the aspect of sustaining physical activity over time. There is a lack of longitudinal assessments of MP and potential risk factors, such as timing of physical maturation, in adolescent athletes.Objectives:To identify risk factors associated with the persistence or development of frequent MP at a 2-year follow-up in adolescent sport school students.Methods:Fourteen-year-old sport school students (n=233) were invited to participate in this 2-year longitudinal study. Self-reports of MP was assessed as frequency, distribution, and intensity, and health status by EQ-5D. Physical maturation was calculated by the Mirwald equation (height, weight, and sitting height) (1), and categorized as early (>1 year), average (±1 year), or late (<–1 year). Students were grouped at baseline and follow-up into infrequent (never to monthly) or frequent (weekly to daily) MP groups. Logistic regression analysis was used to study associations between frequent MP at follow-up and baseline variables.Results:131 students (79 boys and 52 girls) were included in the study. Development or persistence of frequent MP at follow-up (n=61) was associated with being a girl, late physical maturation (only boys were categorized as late), non-contact sports participation, frequent MP at baseline, and reporting ≥2 MP sites at baseline. Students with a better health status at baseline were less likely to belong to the frequent MP group at follow-up (Table).Conclusion:Frequent MP is common in sport school students. MP in young athletes may become a future health problem and there is a need for recognition and interventions by coaches and health services to prevent MP from becoming persistent.References:[1]Mirwald, R. L., Baxter-Jones, A. D., Bailey, D. A., & Beunen, G. P. (2002). An assessment of maturity from anthropometric measurements.Med Sci Sports Exerc, 34(4), 689-694.Table.Associations between background variables at baseline and frequent MP at follow-up based on crude logistic regression analysis controlling each variable for sex.Baseline variablesModelInfrequent MP vs. Frequent MPOR(95% CI; p-value)SexBoys1.00Girls2.76(1.34–5.68; p<0.01)Physical maturationAverage (±1 year)1.00Early (>1 year)0.41(0.05–3.65; p=0.42)Late (<–1 year)3.83(1.13–12.95; p=0.03)Sport categoriesContact1.00Non-contact5.16(2.07–12.88; p<0.001)MP groupsInfrequent1.00Frequent2.74(1.31–5.72; p<0.01)MP intensity last week (NRS 0–10, best to worst)1.15(0.98–1.35; p=0.10)Number of MP sites01.0012.32(0.71–7.58; p=0.16)≥22.87(1.32–6.25; p<0.01)EQ-5D (0.00–1.00, worst to best)0.03(0.001–0.58; p=0.02)Disclosure of Interests:None declared
27.	Malmborg, Julia S., 1988-, et al. (författare) Musculoskeletal pain and its association with health status, maturity, and sports performance in adolescent sport school students: a 2-year follow-up 2022 Ingår i: Bmc Sports Science Medicine and Rehabilitation. - London : Springer Science and Business Media LLC. - 2052-1847. ; 14:1 Tidskriftsartikel (refereegranskat)abstract Background Musculoskeletal pain and its risk factors are rarely assessed in studies on adolescent athletes. The aim was to identify risk factors at baseline that were associated with the persistence or development of musculoskeletal pain at a two-year follow-up in adolescent sport school students, and to study cross-sectional associations at follow-up between musculoskeletal pain and sports performance. Methods Sport school students (79 boys and 52 girls, aged 14 years at baseline) were divided into infrequent (never-monthly) or frequent (weekly-almost daily) pain groups, based on frequency of pain using a pain mannequin. Logistic regression analyses were performed to study longitudinal associations between frequent pain at follow-up and baseline variables: pain group, number of regions with frequent pain, health status by EQ-5D, maturity offset (pre, average, or post peak height velocity), and sports (contact or non-contact). Linear regression analyses were used to study cross-sectional associations between pain groups and 20-m sprint, agility T-test, counter-movement jump, and grip strength at follow-up. Results were stratified by sex. Results A higher percentage of girls than boys reported frequent pain at follow-up (62% vs. 37%; p = 0.005). In boys, frequent pain at follow-up was associated with being pre peak height velocity at baseline (OR 3.884, CI 1.146-13.171; p = 0.029) and participating in non-contact sports (OR 3.429, CI 1.001-11.748; p = 0.050). In girls, frequent pain at follow-up was associated with having frequent pain in two or more body regions at baseline (OR 3.600, CI 1.033-12.542; p = 0.044), having a worse health status at baseline (OR 3.571, CI 1.026-12.434; p = 0.045), and participating in non-contact sports (OR 8.282, CI 2.011-34.116; p = 0.003). In boys, frequent pain was associated with worse performances in 20-m sprint and counter-movement jump, but not in agility T-test and grip strength. Conclusions Baseline risk factors for having frequent pain at follow-up were late maturation in boys, frequent pain and worse health status in girls, and participation in non-contact sports in both sexes. Boys with pain performed worse in sports tests. Coaches and school health-care services should pay attention to the risk factors and work towards preventing pain from becoming persistent.
28.	Malmborg, Julia S, 1988-, et al. (författare) Musculoskeletal pain and its association with maturity and sports performance in 14-year-old sport school students 2018 Ingår i: BMJ Open Sport & Exercise Medicine. - London : BMJ. - 2055-7647. ; 4:1 Tidskriftsartikel (refereegranskat)abstract Objectives In youth sports, musculoskeletal pain is often studied from the standpoint of sports injuries, but little is known about pain conditions in which athletes still participate. The aim was to study the frequency of pain and associations with maturity offset, health status and sports performance in 14-year-old sport school students. Methods Cross-sectional design. One hundred and seventy-eight students (108 boys and 70 girls) completed anthropometric measures for maturity offset (height, weight and sitting height), questionnaires (pain mannequin and EQ-5D for health status) and sports performance tests (sprint, agility, counter-movement jump and grip strength). Differences between groups were analysed with Student's t-test and analysis of covariance. Results Thirty-one students (18.6%) reported infrequent pain, 85 (50.9%) frequent pain and 51 (30.5%) constant pain. Students in the constant pain group had worse health status than those in the infrequent pain group. Boys with constant pain (n=27) had a lower mean maturity offset (-0.38 vs 0.07 years; p=0.03) than boys with infrequent pain (n=22), and pain was associated with worse sports performance. There was no difference in maturity or sports performance between girls with constant pain (n=24) and girls with infrequent pain (n=9). Conclusion Musculoskeletal pain is common in sport school students and coincides with worse health status and with a younger biological age in boys. The high prevalence of pain should be acknowledged by coaches and student healthcare workers in order to promote a healthy and sustainable development in young athletes.
29.	Malmborg, Julia S, 1988-, et al. (författare) Worse health status, sleeping problems, and anxiety in 16-year-old students are associated with chronic musculoskeletal pain at three-year follow-up 2019 Ingår i: BMC Public Health. - London : Springer Science and Business Media LLC. - 1471-2458. ; 19:1 Tidskriftsartikel (refereegranskat)abstract Background: Chronic musculoskeletal pain is common in adolescents, and it has been shown that adolescents with pain may become young adults with pain. Pain often coincides with psychosomatic symptoms in adults, but little is known about longitudinal associations and predictors of pain in adolescents. The aim was to investigate chronic musculoskeletal pain and its associations with health status, sleeping problems, stress, anxiety, depression, and physical activity in 16-year-old students at baseline, and to identify risk factors using a three-year follow-up. Methods: This was a longitudinal study of 256 students attending a Swedish upper secondary school. Questionnaires regarding chronic musculoskeletal pain and distribution of pain (mannequin), health status (EQ-5D3 L), sleeping problems (Uppsala Sleep Inventory), stress symptoms (single-item question), anxiety and depression (Hospital Anxiety and Depression Scale), and physical activity (International Physical Activity Questionnaire) were issued at baseline and follow-up. Student's t-test and chi2 test were used for descriptive statistics and logistic regression analyses were used to study associations between chronic pain and independent variables. Results: Fifty-two out of 221 students at baseline (23.5%) and 39 out of 154 students at follow-up (25.3%) were categorized as having chronic musculoskeletal pain. Chronic musculoskeletal pain at follow-up was separately associated with reporting of an EQ-5D value below median (OR 4.06, 95% CI 1.83-9.01), severe sleeping problems (OR 3.63, 95% CI 1.69-7.82), and possible anxiety (OR 4.19, 95% CI 1.74-10.11) or probable anxiety (OR 3.82, 95% CI 1.17-12.48) at baseline. Similar results were found for associations between chronic musculoskeletal pain and independent variables at baseline. In multiple logistic regression analysis, chronic musculoskeletal pain at baseline was a predictor of chronic musculoskeletal pain at follow-up (OR 2.99, 95% CI 1.09-8.24, R-2 = 0.240). Conclusion: Chronic musculoskeletal pain at baseline was the most important predictor for reporting chronic musculoskeletal pain at the three-year follow-up, but a worse health status, severe sleeping problems, and anxiety also predicted persistence or development of chronic musculoskeletal pain over time. Interventions should be introduced early on by the school health services to promote student health.
30.	Malmborg, Julia, 1988-, et al. (författare) Sleeping Problems and Anxiety is Associated to Chronic Multisite Musculoskeletal Pain in Swedish High School Students 2018 Ingår i: Annals of the Rheumatic Diseases. - London : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 77:Suppl. 2, s. 226-226 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract Background: The relationship between chronic multisite musculoskeletal pain (CMP) and sleep is complex, where pain can lead to sleeping problems and lack of sleep can intensify the pain perception. Most previous studies relates to adults, but adolescents may also suffer from CMP, and there is a need for more knowledge regarding the relationships between CMP and sleeping problems, stress, anxiety, depression, and health status.Objectives: To study background factors associated to CMP in first year Swedish high school students.Methods: First year Swedish high school students (n=296) were invited to complete questionnaires on chronic pain (mannequin with 18 body regions), sleeping problems (Uppsala Sleep Inventory, four items scored from 1–5), stress (ELO questions, scored from 1–5), anxiety and depression (Hospital Anxiety and Depression Scale, scored from 0–21), health status (EQ-5D, scored from 0 to 1, worst to best) and physical activity (International Physical Activity Questionnaire, categorised into low, moderate and high levels). Stress and sleeping items were dichotomized into 1–3 points (best) vs 4–5 points (worst). Individuals scoring at least severe problems (4 points) at one or more sleeping items were classified as having severe sleeping problems. HADS were categorised as non-cases (0–7), possible7–10 and probable cases (11–21 points). Students were grouped as having CMP (pain present in ≥3 regions) or not (no chronic pain or chronic pain in 1–2 regions). Multiple logistic regression analyses (adjusted for sex) with CMP as dependent variable were performed in SPSS, version 24.Results: 254 students (86% of total sample, 87 boys and 167 girls) with a mean age of 16.1 (SD 0.6) years participated in the study. CMP was present in 25 (9.8%) students with no differences between boys and girls (8.0% vs 10.8%; p=0.488). Having CMP was associated with reporting severe sleeping problems (OR 2.49, 95% CI: 1.06 to 5.81, p=0.035) with initiating sleep, maintaining sleep, early morning awakenings and/or not feeling restored after sleep in comparison to the other students. Students with CMP were more likely to be categorised as probable cases for anxiety (OR 3.06, 95% CI: 1.09 to 8.61, p=0.034), but there were no associations for possible cases for anxiety (OR 1.15, 95% CI: 0.38 to 3.51, p=0.800), possible cases (OR 2.03, 95% CI: 0.63 to 6.54), or probable cases for depression (OR 3.35, 95% CI: 0.33 to 33.83). There was a nearly significant association between stress and belonging to the CMP group (OR 2.31, 95% CI: 0.97 to 5.53, p=0.059). A higher self-reported health status was associated to a lower likelihood for CMP (OR 0.04, 95% CI: 0.01 to 0.27, p=0.001). Distribution of physical activity levels of low, moderate and high was not significantly associated to having CMP in comparison with not having it.Conclusions: One in ten high school students fulfilled criteria for having chronic multisite musculoskeletal pain. CMP was associated to sleeping problems, anxiety, and a worse health status. The results from this study may be used by school health-care professionals in their preventive work to promote student’s health.Disclosure of Interest: None declared
31.	Olsson, Charlotte M., 1967-, et al. (författare) Electromyographic Analysis of Left and Right Side Gluteus Medius in Unilateral and Bilateral Bodyweight Exercises 2017 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, PA : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 49:5S, s. 464-465 Tidskriftsartikel (refereegranskat)
32.	Olsson, Charlotte M., 1967-, et al. (författare) Sex-Differences In Bench Press Muscle Activation With Pre-Exhaustion Of Triceps Brachii 2018 Ingår i: Conference Abstracts. ; , s. 67-68 Konferensbidrag (refereegranskat)abstract Purpose: Pre-exhaustion is a resistance training method which activates a stronger single-joint muscle to momentary exhaustion directly before a multi-joint exercise including the pre-exhausted muscle. This results in greater recruitment of muscles in the multi-joint exercise to further increase muscle strength. The pre-exhaustion method in bench press has mainly been studied in men and it is uncertain if sex-differences exists. Men are stronger than women in absolute strength, especially in the upper body but if this holds true for upper body relative strength is debated. The purpose was to investigate muscle activity by surface electromyography (EMG) between women and men in bench press with and without pre-exhaustion of triceps brachii (TB) and to compare relative strength in 10RM bench press between the sexes.Methods: 15 women and 15 men in their 20s with weight lifting experience were recruited to the study. During the first session body composition and 10 repetition maximum (10RM) bench press were determined Participants performed both protocol A and B in a cross-over design on separate days. Protocol A began with 10 RM bench press, five minutes recovery, pre-exhaustion exercise (triceps extensions to failure) immediately followed by a second round of bench press with the same 10RM load as before pre-exhaustion. Protocol B started with triceps extensions to failure immediately before bench press at their before established 10RM, five minutes of recovery then they performed 10RM bench press again. IN both protocols, EMG electrodes were attached to TB), pectoralis major (PM) and deltoideus anterior (DA). EMG values were normalized to maximum voluntary isometric contraction (MVIC) and expressed as % MVIC.Results: Bench press only EMG activity in %MVIC was similar between women and men, but analysis of variance (TB interaction p=0.02) showed that women had higher %MVIC in TB after pre-exhaustion whereas muscle activity decreased in men compared to bench press without pre-exhaustion. Yet, the number of repetitions completed in bench press after pre-exhaustion of TB were the same (women 4.3 ± 2.6 vs men 3.8 ± 2.2; p=0.55). As expected, in 10RM weight men (64.0 ± 7.1 kg) were stronger than women (37.1 ± 6.5 kg; p<0.01), however when related to fat free mass no difference was evident in relative strength between women and men.Conclusion: Men and women have similar muscle activation patterns during a 10RM bench press, but TB pre-exhaustion followed by a bench press appears to have a greater effect on TB activation in women compared to men. Absolute strength was greater in men, but normalized to fat free mass women and men had similar upper body relative strength.
33.	Olsson, M. Charlotte, 1967-, et al. (författare) Bench press muscle activation with triceps brachii pre-exhaustion in females and males 2019 Ingår i: Journal of Sports Sciences. - Abingdon : Routledge. - 0264-0414 .- 1466-447X. ; 37:Supp1, s. 71-72 Tidskriftsartikel (refereegranskat)
34.	Olsson, M Charlotte, 1967-, et al. (författare) Electromyography Muscle Activity in Unilateral and Bilateral Squats with Relative Loads 2015 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract IntroductionUnilateral strength training is becoming popular as a complement to bilateral training particularly in athletes active in sports performed primarily on one leg. Some studies have shown improved performance after unilateral compared to bilateral strength training, however the underlying cause for this improvement is unclear. The aim of this study was to compare electromyography (EMG) muscle activity in unilateral and bilateral squats performed with 80% of 1repetition maximum (RM) performed in a smith machine.MethodsParticipants in the study were 12 healthy women and men (mean age 25±2 years) with previous weight-lifting experience. EMG activity was measured during the concentric phase in the muscles vastus lateralis, biceps femoris, gluteus medius and erector spinae during A) a maximal voluntary isometric contraction (MVIC), B) 1RM squat (90 degree knee flexion) bilaterally and unilaterally, and C) 3 repetitions 80% of 1RM for both the unilateral and bilateral stance, where each squat was performed at a set speed with the aid of a metronome.ResultsEMG activities, calculated as percent of MVIC, in thigh and hip muscles (vastus lateralis, biceps femoris, gluteus medius) were significantly higher (p<0.01 for all) in the unilateral compared to the bilateral stance. The highest increase in EMG activity was in the gluteus medius where the unilateral squat elicited a 2.9 increase compared to bilateral stance. Unilateral stance muscle activation was in vastus lateralis 1.2 times higher and in biceps femoris 1.5 times higher compared to the bilateral stance. For the trunk muscle erector spinae, the opposite was apparent. EMG activity was 0.6 times lower (p<0.01) when the squat was performed unilaterally compared to bilaterally.DiscussionEven when the load is made relative to the 1RM for each stance the muscles in especially the gluteus medius but also vastus lateralis and biceps femoris is activated to a higher degree when performed unilaterally which could be a partial explanation as to why the unilateral stance can be beneficial to include in a strength training regime despite the absolute load being lower.
35.	Olsson, M Charlotte, 1967-, et al. (författare) Lower body electromyography muscle activity differences between unilateral and bilateral squats with relative loads 2014 Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, United States : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 46:5S, s. 962-963 Tidskriftsartikel (refereegranskat)
36.	Parker, James, 1980- (författare) A multi-disciplinary approach to studying performance among high-level golfers : physiological and biomechanical aspects 2018 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract In competitive golf, the player’s ability to hit the ball a long distance affects the score in a positive way. Swing kinematics is considered an important factor in driver performance; one way of improving swing kinematics is through strength and power training. Subsequently, high-level golfers and their coaches often explore novel ways of increasing the distance of a shot, in particular driver carry distance (CD). This licentiate thesis presents two studies with the overall aim of studying how swing kinematic and physical characteristics are associated with driver performance among intercollegiate golf players. The studies report swing kinematics associated with driver performance (study 1) and the impact of isokinetic rotational training on driver performance and swing kinematic variables (study 2).The methods used were (1) a cross-sectional correlation study (n=15) and (2) an open trial intervention study (n=20). The studies investigated (1) the relationship between golf swing kinematics and driver performance, and (2) the impact of strength training on swing kinematics and driver performance variable.The results show variables that were distinctive for the club head speed (CHS) were mainly during the downswing: greater X-factor stretch; and higher pelvis peak speed. Whilst, factors distinctive to the regression model for CD were mainly at impact: reduced thorax rotation; and greater thorax lateral bend. Nine weeks of isokinetic training increased seated rotational force and power, peak arm speed and arm acceleration, ball speed, and CD more compared to isotonic training. Even though isokinetic training did not increase CHS, it did result in greater CD.This licentiate thesis contributes to the understanding of which variables influence driver performance, in particular CD, among high-level golfers. Segmental interactions (pelvis-thorax), lead arm speed and acceleration, isokinetic and isotonic training. These results may guide training interventions aiming to improve driver and golf performance among high-level golfers, particularly those with a background of strength training. Future studies could investigate how the interaction between swing kinematics, clubhead trajectory, and driver performance variables differ between male and female golfers.
37.	Parker, James, 1980-, et al. (författare) A One Year Study on Changes in Flexibility and Stability Characteristics in Elite Golfers 2011 Annan publikation (övrigt vetenskapligt/konstnärligt)abstract The results from this study show that training strategies can lead to improved flexibility and stability in golfers during the off season, however maintaining these improvements, particularly flexibility, during the in-season is not as easy. Decreased flexibility on the left side leads to reduced ROM to manage deceleration of forces produced in the golf swing that probably lead to an increased risk of injury. Significant improvements can be made after no more than 3 months of training, including flexibility and stability training. Technique training may be more successful if it follows a period of concentrated physical training. During the in-season, emphasis ought to be on maintaining ROM by effective implementation of stretching programs.
38.	Parker, James, 1980-, et al. (författare) Are There Stretch Shortening Cycle like Actions in the Shoulder and Torso in Upper Body Striking Actions 2013 Konferensbidrag (övrigt vetenskapligt/konstnärligt)
39.	Parker, James, 1980-, et al. (författare) Differences in kinematics and driver performance in elite female and male golfers 2022 Ingår i: Sports Biomechanics. - Abingdon : Routledge. - 1476-3141 .- 1752-6116. ; 21:6, s. 731-747 Tidskriftsartikel (refereegranskat)abstract The aim of this study was to compare swing kinematic differences between women and men and investigate which variables predict clubhead speed (CHS) and carry distance (CD) whilst accounting for individual variation. Methods: Swing kinematics and driver performance data were collected on 20 (10 women) elite golfers (HCP 0.7 ± 1.4). We used Bayesian T-test for between sex comparison of swing kinematics and Bayesian Analysis of covariance (ANCOVA) to produce general linear models for CHS and carry distance for elite female and male golfers separately. Results: There was strong evidence that the driver performance variables CHS and CD were decreased in women compared to men, and two kinematic variables; time to arm peak speed downswing and angular wrist peak speed were slower in women. The ANCOVAs identified very strong to overwhelming evidence that participant as a fixed factor was a determinant of CHS for both women and men but was not a determinant of CD. Conclusion: when looking to enhance driver performance among high-level golfers, coaches should be aware that variables that determine CHS and CD differ among women and men and if the aim is to improve CHS coaches should not forget the importance of individual swing characteristics. © 2019 Parker, Hellström & Olsson. Published by Informa UK Limited, trading as Taylor & Francis Group.
40.	Parker, James, 1980-, et al. (författare) Effects of 8 Weeks of Isokinetic Training on Power, Golf Kinematics, and Club Head Speed In Elite Golfers 2015 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Introduction: Elite competitive golfers commonly use physical conditioning as a way of improving playing results. Multiple studies have investigated the use of different training methods for improving performance but few studies have investigated the use of isokinetic power training as a way of improving swing kinematics and/or club head speed (CHS). The specific objective of the study was to investigate if eight weeks of isokinetic power training was more effective than traditional power training in improving swing kinematics and CHS.Methods: 20 competitive elite golfers (handicap better than -3.1), 13 men and 7 women, (age 22±2 years) were tested for lower body power (countermovement jump and loaded vertical squat jump 20,40 & 60kg), rotational power (seated upper body rotational power at 10% of body weight; bw) and golf swing kinematics (pelvis, thorax and lead arm peak rotational velocities using electromagnetic motion capture system; Polhemus Inc. USA ) and club head speed (doppler-radar launch monitor system; Flightscope, South Africa), Participants were split into a control (CTL) group (n=10) who continued with the regular strength and power training and an intervention (IK) group (n=10) performing isokinetic power training in the isokinetic 1080Quantum system (1080Motion, Sweden) during 8 weeks. The intervention focused on barbell squat (22kg at 0.5 ms-1) and standing rotation (10% body weight at 1 ms-1).Statistical analysis: a 2 (between; groups) x 2 (within; time) ANOVA assessed any differences in power, club and swing kinematics.Results: Statistically significant improvements were observed in both the IK and CTL group for rotational power (p<0.001), CHS (p=0.025), and peak arm speed (p=0.001). There were no significant differences in countermovement jump height, peak power during squats, peak pelvis speed, or peak thorax speed following the intervention period.Discussion: After 8 weeks of power training, both rotational power and peak arm speed improved as did the performance measure of CHS in both the IK and CTL group. However no significant changes were found between the two groups. In conclusion, there was no evidence suggesting that isokinetic training, as performed in this study, is neither detrimental, nor more effective, than traditional strength training when it comes to increasing CHS in golf performance.
41.	Parker, James, 1980-, et al. (författare) Effects of nine weeks isokinetic training on power, golf kinematics, and driver performance in pre-elite golfers 2017 Ingår i: BMC Sports Science, Medicine and Rehabilitation. - London : BioMed Central. - 2052-1847. ; 9 Tidskriftsartikel (refereegranskat)abstract BackgroundIt has previously been shown that isotonic strength training can improve driver performance among golfers, though few studies have investigated effects of strength training on swing kinematics together with driver performance. In this study we investigated whether isokinetic rotational training could improve driver performance and swing kinematic variables amongst elite golfers.MethodsTwenty competitive pre-elite golfers (handicap better than −3.0), 13 men and 7 women, were split into two groups, one group received the isokinetic power training (IK) alongside their normal isotonic pre-season strength-training and the other group continued with their normal isotonic pre-season strength-training regime (IT). The IK group completed 12 sessions of isokinetic power training on a standing rotation exercise (10% body weight at 1 m/s) and barbell squat (25 kg plus 10% body weight at 0.5 m/s). The IT group continued with their normal isotonic pre-season strength-training regime. Participants were tested for rotational power, lower body power, golf swing kinematics, and driver performance before and after a nine-week training period.ResultsAfter the nine-week training period both the IK and the IT groups increased their dominant side rotational force and power (effect sizes between 0.50–0.96) and magnitude based inference indicated that IK had a likely (> 80%) more beneficial increase in dominant side rotational force and power. For swing kinematics, IK had a likely (> 80%) more beneficial improvement in lead arm speed and acceleration compared to the IT group. For driver performance, IK had a possible (65%) beneficial effect on ball speed and likely (78%) beneficial effect on carry distance when compared to IT, whereas neither of the groups improved club head speed.ConclusionIn the present study on pre-elite golfers we found that 9 weeks of isokinetic training increased seated rotational force and power, peak arm speed and arm acceleration, ball speed, and carry distance more compared to isotonic training. Even though isokinetic training did not increase CHS, it did result in greater carry distance. © The Author(s). 2017
42.	Parker, James, 1980-, et al. (författare) Relationships between golf swing kinematics and driver performance in elite golfers Annan publikation (övrigt vetenskapligt/konstnärligt)abstract Swing kinematics and driver performance are considered important factors in golf performance. In golf research clubhead speed (CHS) is commonly used as the driver performance measure, whereas carry distance (CD) is less investigated and together with final ball position determine the success of a drive. The aim of this study was to investigate which kinematic factors of the pelvis, thorax, and lead arm explain CHS and/or CD. Swing kinematics data on 15 elite golfers were collected using an electromagnetic 3-D system and a doppler-radar launch monitor system. Variables that emerged as important for both CHS and CD were: reduced pelvis rotation top of backswing (TOB); reduced X-factor TOB; and more thorax lateral bend TOB, along with greater thorax peak speed during the downswing. Variables that were distinctive for the CHS model were mainly during the downswing: greater X-factor stretch; and higher pelvis peak speed. Finally, factors distinctive to the regression model for CD were: reduced thorax rotation; and greater thorax lateral bend. Implications from the results suggest whilst greater peak pelvis speed and x-factor stretch effect CHS they do not significantly influence CD. Likewise, the variables unique to CD do not significantly influence CHS but may be a technical attributes which allow for more optimal clubhead delivery leading to improved CD.
43.	Parker, James, 1980-, et al. (författare) The Relationship of the Lead Arm, Upper Torso, and Pelvis with Driver Club Head Speed Among Elite Golf Players 2015 Ingår i: International Journal of Golf Science. - Champaign, IL : Human Kinetics. - 2168-7595 .- 2168-7609. ; 4:Suppl., s. S73-S75 Tidskriftsartikel (refereegranskat)
44.	Parker, James, 1980-, et al. (författare) The Variability in Kinematics and Carry in a Longitudinal Intra-individual Study of Elite Golfers 2016 Ingår i: Abstracts. ; , s. 47-48 Konferensbidrag (refereegranskat)abstract Purpose: To hit further and with high accuracy is important for success in the long game in golf. Even for very accomplished golfers a certain degree of between shot variance is evident even when trying to consistently repeat a successful shot. The consistency is determined by the biomechanics of the golfer, which influences club head speed (CHS) and position, and initial ball launch conditions, which in combination with environmental factors determine shot outcome. Previous research has identified several biomechanical variables associated with variance in CHS, including thorax rotation speed and lead arm speed (LAS). Pilot data from our laboratory have indicated moderate non-significant relationship between CHS and carry in elite male golfers when studied over time. Thus, the aim of this study was to explore the relationship between peak speed of the pelvis, thorax, and lead upper arm and carry over time, investigating both within and between session variability in elite male golfers.Methods: Six elite male golfers (handicap range -3 to +0.5) (age range 21-23 years) were included in this study. The golfers were studied on four separate occasions over a year. Each test occasion included a golf specific warm-up of the golfers’ choice, then subjects were instructed to hit five balls with their driver and use the swing that was as ‘normal ‘as possible. Data on swing kinematics was collected using a four sensor electromagnetic motion capture system at 120Hz (Polhemus Inc. USA). Nine landmarks were digitized to define segment lengths, orientations and joint axes. CHS and carry were collected using a launch monitor (Trackman3e, v.3.2, Trackman, Denmark). The swing events were determined from sensors on the club; top of backswing was determined when the club changes direction from backswing to downswing. Impact was determined when the clubhead reaches the horizontal position equivalent to where it was at address. Angular velocities and displacements of the pelvis, thorax, and lead arm were calculated using standard biomechanics principles in conjunction with advanced motion measurement software (AMM 3D, USA). No data smoothing techniques were used before data analysis. IBM SPSS v.22 was used to analyse the data through hierarchical multilevel modelling (MLM). First a baseline model without predictors was run, then MLM was repeated with predictors where the ﬁrst level of the data contained carry and kinematic data from each shot (within session level). At the second level, the carry scores were nested within sessions and analysed between sessions. Lastly, at the third level, the sessions were nested within players (between players). Carry was used as outcome variable and kinematics as predictor variables with a probability level of 0.05.Results: Initially MLM baseline model for carry only, was tested) without predictors. The results showed a statistical significant intercept (Estimate = 226.24, p<.001). Intraclass correlations (ICC) suggested that 32.5% of the variance in carry were present within sessions (level 1), whilst 38.0% were attributed to differences in carry between sessions (level 2). Results from the second MLM generated an improved model fit (-2 LL & BIC) where peak speeds of the pelvis, thorax, and lead upper arm were included as fixed effect covariates on level 1. The result showed that peak LAS was a statistically significant predictor of carry (β=.17, p=.001) whereas peek speed of neither thorax (β=-.04, p=.364) nor pelvis (β=.02, p=.673) had any statistically significant relationship with carry.Discussion: The present study found that 32.5% of variation in shot consistency can be explained at the within session level (influenced by for example variance in centeredness of impact), and 38% of variation in shot consistency can be explained at the between session level (influenced by for example environmental factors). Furthermore, LAS was the only significant predictor of within session variance in carry. Our results indicated peak LAS speed as a predictor of within session variance in carry and this is partly supported by previous research who found golfers with higher arm speed had higher ball velocity than golfers with lower arm speed(Healy et al., 2011). However, results from our pilot study differ from previous research which reports a relationship between peak thorax speed and driver performance. The difference could be due to our results being based on longitudinal data at intra-individual level, whereas previous studies have used a cross-sectional study design, different analysis methods and reported at an inter-individual level. In conclusion, our preliminary data show that within session LAS is a predictor of carry distance when the objective is shot consistency. Practitioners may consider training strategies to optimize arm speed when improve driving consistency among elite golfers. ReferencesHealy, A., Moran, K. A., Dickson, J., Hurley, C., Smeaton, A. F., O'Connor, N. E., . . . Chockalingam, N. (2011). Analysis of the 5 iron golf swing when hitting for maximum distance. Journal of sports sciences, 29(10), 1079-1088.
45.	Ražanskas, Petras, 1987-, et al. (författare) Predicting Blood Lactate Concentration and Oxygen Uptake from sEMG Data during Fatiguing Cycling Exercise 2015 Ingår i: Sensors. - Basel : MDPI. - 1424-8220. ; 15:8, s. 20480-20500 Tidskriftsartikel (refereegranskat)abstract This article presents a study of the relationship between electromyographic (EMG) signals from vastus lateralis, rectus femoris, biceps femoris and semitendinosus muscles, collected during fatiguing cycling exercises, and other physiological measurements, such as blood lactate concentration and oxygen consumption. In contrast to the usual practice of picking one particular characteristic of the signal, e.g., the median or mean frequency, multiple variables were used to obtain a thorough characterization of EMG signals in the spectral domain. Based on these variables, linear and non-linear (random forest) models were built to predict blood lactate concentration and oxygen consumption. The results showed that mean and median frequencies are sub-optimal choices for predicting these physiological quantities in dynamic exercises, as they did not exhibit significant changes over the course of our protocol and only weakly correlated with blood lactate concentration or oxygen uptake. Instead, the root mean square of the original signal and backward difference, as well as parameters describing the tails of the EMG power distribution were the most important variables for these models. Coefficients of determination ranging from R2 = 0:77 to R2 = 0:98 (for blood lactate) and from R2 = 0:81 to R2 = 0:97 (for oxygen uptake) were obtained when using random forest regressors.
46.	Ražanskas, Petras, et al. (författare) Predicting physiological parameters in fatiguing bicycling exercises using muscle activation timing 2017 Ingår i: Biomedical Signal Processing and Control. - Amsterdam : Elsevier. - 1746-8094 .- 1746-8108. ; 35, s. 19-29 Tidskriftsartikel (refereegranskat)abstract This article is concerned with a novel technique for prediction of blood lactate concentration level and oxygen uptake rate from multi-channel surface electromyography (sEMG) signals. The approach is built on predictive models exploiting a set of novel time-domain variables computed from sEMG signals. Signals from three muscles of each leg, namely, vastus lateralis, rectus femoris, and semitendinosus were used in this study. The feature set includes parameters reflecting asymmetry between legs, phase shifts between activation of different muscles, active time percentages, and sEMG amplitude. Prediction ability of both linear and non-linear (random forests-based) models was explored. The random forests models showed very good prediction accuracy and attained the coefficient of determination R2 = 0.962 for lactate concentration level and R2 = 0.980 for oxygen uptake rate. The linear models showed lower prediction accuracy. Comparable results were obtained also when sEMG amplitude data were removed from the training sets. A feature elimination algorithm allowed to build accurate random forests (R2 > 0.9) using just six (lactate concentration level) or four (oxygen uptake rate) time-domain variables. Models created to predict blood lactate concentration rate relied on variables reflecting interaction between front and back leg muscles, while parameters computed from front muscles and interactions between two legs were the most important variables for models created to predict oxygen uptake rate.© 2017 Elsevier Ltd.
47.	Razanskas, Petras, et al. (författare) Time Domain Features of Multi-channel EMG Applied to Prediction of Physiological Parameters in Fatiguing Bicycling Exercises 2015 Ingår i: Frontiers in Artificial Intelligence and Applications. - Amsterdam : IOS Press. - 0922-6389 .- 1879-8314. ; 278, s. 118-127 Tidskriftsartikel (refereegranskat)abstract A set of novel time-domain features characterizing multi-channel surface EMG (sEMG) signals of six muscles (rectus femoris, vastus lateralis, and semitendinosus of each leg) is proposed for prediction of physiological parameters considered important in cycling: blood lactate concentration and oxygen uptake. Fifty one different features, including phase shifts between muscles, active time percentages, sEMG amplitudes, as well as symmetry measures between both legs, were defined from sEMG data and used to train linear and random forest models. The random forests models achieved the coefficient of determination R2 = 0:962 (lactate) and R2 = 0:980 (oxygen). The linear models were less accurate. Feature pruning applied enabled creating accurate random forest models (R2 >0:9) using as few as 7 (lactate) or 4 (oxygen) time-domain features. sEMG amplitude was important for both types of models. Models to predict lactate also relied on measurements describing interaction between front and back muscles, while models to predict oxygen uptake relied on front muscles only, but also included interactions between the two legs. © 2015 The authors and IOS Press. All rights reserved.
48.	Sundström, Tomas, et al. (författare) Five Weeks of Plyometric Training Improve Vertical Jump Height in Female Handball Players During In-Season 2010 Ingår i: Nordic Conference 2010. - Odense : University of Southern Denmark. ; , s. 112-113 Konferensbidrag (refereegranskat)abstract Introduction: Handball is a sport requiring many different physical qualities in order to perform well, one of which is good jumping ability. For handball players available time to enhance power during in-season is often restricted due to an already high training load emphasizing other aspects of the sport than jumping ability. Therefore, one aim of this study was to examine if a small amount of additional plyometric training during in-season, combining drop jumps and box jumps, could give significant improvements in vertical jump height in female handball players after five weeks of training. Generally, vertical jump height is evaluated with two-legged tests, however, the question arises if the tests are relevant in sports that predominantly use several steps and one-leg jumps such as handball. A second aim of this study was thus to develop, evaluate and validate a handball-specific test performed on one leg.Methods: Two Swedish female handball-teams playing in the third division were recruited. Players from one team made up the intervention-group (n = 9) and players from the other team functioned as the control-group (n = 4). Plyometric training was added to the regular handball training session twice per week during five weeks, lasting approximately 15 minutes per session, consisting of two sets of eight repetitions of drop jumps and box jumps respectively, while the control-group continued their training as normal. Jumping performance was evaluated through the squat jump test (SJ), countermovement jump test (CMJ) and the handball-specific one leg jump test (OLJ) developed for this study in order to offer a more sport-specific evaluation tool when testing sports that predominantely jump on one leg.Results: The intervention-group improved their jumping height significantly with 2,7 cm in the SJ, 3,6cm in the CMJ and 3,6 cm in the OLJ (p < 0,01 for all). The control-group had an opposite trend with diminishing results in all three jumps, -1,5 cm in the SJ (p < 0,05), -1,7 cm in the CMJ (p < 0,05) and -0,9 cm in the OLJ (not significant). The one-legged jump test (OLJ) correlated well with both SJ (r= 0,79, p <0,01 ), and CMJ (r=0,75, p < 0,01).Discussion: The present study found significant improvements in jumping height after only five weeks of plyometric training for female handball players. Interestingly, the intervention-group improved to the same extent in both the one and the two-leg jumps test, which might be explained by the accumulation of handball specific training drills performed on one-leg, together with the two-legged plyometric exercises. The same assumption could also explain why the control-group showed no change in the one-leg jump test between the pre and post-tests, but displayed significant lower scores in the two-legged jumping tests after 5 weeks with only regular handball training.Conclusion: The improvements seen in this study with a small amount of additional plyometric training is relevant for coaches that need to provide gains in jumping performance during in-season when there is not a lot of time for additional training. Moreover, an evaluation test needs to be as specific as possible to the performance in the sport. The one-leg vertical jump test, developed in this study, could be a first step to a future handball-test that better resembles the jumping performance in handball than already established two-leg jumping tests.
49.	Söderström Malmborg, Julia, 1988- (författare) Pain and health in adolescents and young adults – pieces of a puzzle 2020 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Background: Musculoskeletal pain is a burden for the individual and for society, and it has a negative impact on overall health. The biological, psychological, and social factors that govern pain and health form a complex puzzle to put together. Musculoskeletal pain conditions may be alleviated by physical activity, but a too high level of physical activity may also increase the risk of pain. Youth athletes may be especially vulnerable to developing pain due to factors related to training load and physical maturity. Being physically active and maintaining a healthy diet is associated with better health, but if carried out to excess these health behaviours may become unhealthy. Our understanding of musculoskeletal pain and health in adolescents and young adults needs to be developed, both in individuals involved in sports and exercise and in the general population.Aim: The overall aim was to study musculoskeletal pain and its relationship to various health-related factors in adolescents and young adults enrolled in sport or general education programmes.Methods: Study I was a cross-sectional study on university students (aged 19–29) from an exercise science programme (n = 118) and a business programme (n = 89), assessing health status, physical activity, and orthorexia nervosa (an exaggerated fixation on healthy food). Study II was a cross-sectional study (n = 178), and Study III a 2-year longitudinal (n = 131) study on sport school students (aged 14 at baseline), assessing musculoskeletal pain, health status, physical maturity, and sports performance. Study IV was a 3-year longitudinal study on students from a general upper secondary school (n = 256, aged 16 at baseline), assessing chronic musculoskeletal pain, health status, physical activity, sleep, stress, anxiety, and depression.Results: In Study I, compared to business students, exercise science students reported more pain, but better general health. A high level of physical activity in combination with orthorexia nervosa was most prevalent in men from the exercise science programme. In Studies II and III, pain was common in sport school students. At baseline, boys with constant pain were not as physically mature as boys with infrequent pain. Students with constant pain reported a worse health status than students with infrequent pain. At follow-up, frequent pain, frequent pain in two or more body regions, and a worse health status at baseline were identified as risk factors for having frequent pain at follow-up in girls. For boys, late physical maturation at baseline was a risk factor. Involvement in non-contact sports was also an identified risk factor over time in both sexes. Pain was associated with a worse sports performance in boys at both baseline and follow-up. In Study IV, chronic musculoskeletal pain was common in students from a general upper secondary school. A worse health status, severe sleeping problems, anxiety, and chronic musculoskeletal pain at baseline were associated with reporting chronic musculoskeletal pain at follow-up.Conclusions: Pain was prevalent, and also persistent, in adolescents and young adults, irrespective of attending sport or general education programmes. Pain is a biopsychosocial phenomenon and must be treated as such. Pain should be frequently monitored, and treatment should be introduced early on to prevent pain from becoming persistent.
50.	Verikas, Antanas, 1951-, et al. (författare) Electromyographic Patterns during Golf Swing : Activation Sequence Profiling and Prediction of Shot Effectiveness 2016 Ingår i: Sensors. - Basel : MDPI AG. - 1424-8220. ; 16:4 Tidskriftsartikel (refereegranskat)abstract This study analyzes muscle activity, recorded in an eight-channel electromyographic (EMG) signal stream, during the golf swing using a 7-iron club and exploits information extracted from EMG dynamics to predict the success of the resulting shot. Muscles of the arm and shoulder on both the left and right sides, namely flexor carpi radialis, extensor digitorum communis, rhomboideus and trapezius, are considered for 15 golf players (∼5 shots each). The method using Gaussian filtering is outlined for EMG onset time estimation in each channel and activation sequence profiling. Shots of each player revealed a persistent pattern of muscle activation. Profiles were plotted and insights with respect to player effectiveness were provided. Inspection of EMG dynamics revealed a pair of highest peaks in each channel as the hallmark of golf swing, and a custom application of peak detection for automatic extraction of swing segment was introduced. Various EMG features, encompassing 22 feature sets, were constructed. Feature sets were used individually and also in decision-level fusion for the prediction of shot effectiveness. The prediction of the target attribute, such as club head speed or ball carry distance, was investigated using random forest as the learner in detection and regression tasks. Detection evaluates the personal effectiveness of a shot with respect to the player-specific average, whereas regression estimates the value of target attribute, using EMG features as predictors. Fusion after decision optimization provided the best results: the equal error rate in detection was 24.3% for the speed and 31.7% for the distance; the mean absolute percentage error in regression was 3.2% for the speed and 6.4% for the distance. Proposed EMG feature sets were found to be useful, especially when used in combination. Rankings of feature sets indicated statistics for muscle activity in both the left and right body sides, correlation-based analysis of EMG dynamics and features derived from the properties of two highest peaks as important predictors of personal shot effectiveness. Activation sequence profiles helped in analyzing muscle orchestration during golf shot, exposing a specific avalanche pattern, but data from more players are needed for stronger conclusions. Results demonstrate that information arising from an EMG signal stream is useful for predicting golf shot success, in terms of club head speed and ball carry distance, with acceptable accuracy. Surface EMG data, collected with a goal to automatically evaluate golf player’s performance, enables wearable computing in the field of ambient intelligence and has potential to enhance exercising of a long carry distance drive.

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