| 1. |
- Aagaard, Philip, et al.
(författare)
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Early Repolarization in Middle-Age Runners-Cardiovascular Characteristics.
- 2014
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 46:7, s. 1285-1292
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study aimed to assess the prevalence and patterns of early repolarization (ER) in middle-age long-distance runners, its relation to cardiac structure and function, and its response to strenuous physical activity. Methods: Male first-time cross-country race participants >45 yr were assessed pre-and postrace by medical history and physical examination, 12-lead ECG, vectorcardiography, blood tests, and echocardiography. ER was defined either as ST elevation or J wave and categorized according to localization and morphology. Results: One hundred and fifty-one subjects (50 +/- 5 yr) were evaluated before the race, and 47 subjects were evaluated after the race. Altogether, 67 subjects (44%) had ER. Subjects with versus without ER had a lower resting HR (56 +/- 8 vs 69 +/- 9 bpm, P = 0.02), lower body mass index (24 +/- 2 vs 25 +/- 3 kg.m(-2), P < 0.001), higher training volume (3.0 +/- 2.6 vs 2.1 +/- 2.7 h.wk(-1), P = 0.03), and faster 30-km running times (194 +/- 28 vs 208 +/- 31 min, P = 0.01). Vectorcardiography parameters in subjects with ER showed more repolarization heterogeneity: vector gradient (QRS-T-area) (120 +/- 25 vs 92 +/- 29 mu Vs, P < 0.001), T-area (105 +/- 18 vs 73 +/- 23 mu Vs, P < 0.001), and T-amplitude (0.63 +/- 0.13 vs 0.53 +/- 0.16 mm, P < 0.001); these parameters were inversely related to HR (r = -0.37 to -0.48, P < 0.001). ER disappeared in 15 (75%) of 20 subjects after the race. Conclusions: ER is a common finding in middle-age male runners. This ECG pattern, regardless of morphology and localization, is associated with normal cardiac examinations including noninvasive electrophysiology, features of better physical conditioning, and disappears after strenuous exercise in most cases. These findings support that ER should be regarded as a common and training-related finding also in middle-age physically active men.
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| 2. |
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| 3. |
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| 4. |
- Aagaard, Per, 1957, et al.
(författare)
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Preparticipation Evaluation of Novice, Middle-Age Long-Distance Runners.
- 2013
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Ingår i: Medicine and science in sports and exercise. - 0195-9131 .- 1530-0315. ; 45:1, s. 130-137
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Tidskriftsartikel (refereegranskat)abstract
- Abstract PURPOSE: To assess the cardiovascular health and risk profile in middle-aged males making an entry to participate for their first time in a long-distance race. METHODS: Male first-time participants ≥45 years in the world's largest cross-country running race, the Lidingöloppet, were evaluated with a medical history and physical exam, European risk-SCORE, 12-lead ECG, echocardiography and blood tests. Further diagnostic work-up was performed when clinically indicated. RESULTS: Of 265 eligible runners, 153 (58%, age 51±5 y) completed the study. While the 10-year fatal cardiovascular event risk was low (SCORE: 1% (IQR: 0 - 1%)), mild abnormalities were common, e.g. elevated blood-pressure (19%), left ventricular hypertrophy (6%), elevated LDL cholesterol (5%). ECG changes compatible with "athlete's heart" were present in 82%, e.g. sinus bradycardia (61%) and/or early repolarization (32%). ECG changes considered training-unrelated were found in 24%, e.g. prolonged QTc: 13%; left axis deviation: 5.3%; left atrial enlargement: 4%). In 14 runners (9%) additional diagnostic work-up was clinically motivated, and 4 (2%) were ultimately discouraged from vigorous exercise due to QTc intervals >500 ms (n=2), symptomatic atrioventricular block (n=1), and a cardiac tumor (n=1). The physician exam and the ECG identified 12 of the 14 subjects requiring further evaluation. CONCLUSIONS: Cardiovascular evaluation of middle-aged men, including a physician exam and a 12-lead ECG, appears useful to identify individuals requiring further testing prior to vigorous exercise. The additional yield of routine echocardiography was small.
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| 9. |
- Ahokas, Essi K., et al.
(författare)
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Nocturnal Heart Rate Variability in Women Discordant for Hormonal Contraceptive Use
- 2023
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 55:7, s. 1342-1349
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The aim of this study was to investigate within-cycle differences in nocturnal heart rate (HR) and heart rate variability (HRV) in naturally menstruating women (NM) and women using combined hormonal contraceptives (CU) or progestin-only hormonal contraceptives (PU).Methods Physically active participants were recruited into three groups: NM (n = 19), CU (n = 11), and PU (n = 12). Participants’ HR and HRV (with Bodyguard 2 HRV monitor), and blood hormones were monitored during one menstrual cycle (MC) (NM-group) or for 4 weeks (CU and PU-groups). Estradiol, progesterone, and luteinizing hormone were analyzed from fasting blood samples collected four times in the NM (M1 = bleeding, M2 = follicular phase, M3 = ovulation, and M4 = luteal phase) and PU groups (M1 = lowest E2; M2 = M1 + 7 days; M3 = M1 + 14 days; M4 = M1 + 21 days) and twice in the CU group (active and inactive pill phases). After every blood sample, nightly HR and HRV were recorded and examined as an average from two nights.Results Hormonal concentrations differed (p < 0.05) between MC phases in the NM- and PU-groups, but not (p ≥ 0.116) between the active and inactive phases in the CU-group. In the NM- and PU-groups, some of the HRV values were higher, while in the NM-group, HR was lower during M2 compared to M3 (p < 0.049) and M4 (p < 0.035). In the CU-group, HRV values (p = 0.014-0.038) were higher, and HR was lower (p = 0.038) in the inactive phase compared to the first week of the active phase.Conclusions The MC and hormonal cycle phases influence autonomic nervous system balance, which is reflected in measurements of nocturnal HR and HRV. This should be considered when monitoring recovery in physically active individuals.
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| 10. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Effects of Aerodynamic Drag and Drafting on Propulsive Force and Oxygen Consumption in Double Poling Cross-Country Skiing
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 54:7, s. 1058-1065
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to investigate the effects of aerodynamic drag and drafting on propulsive force (FPROP), drag area (CDA), oxygen cost (V˙O2), metabolic rate (Ė), and heart rate (HR) during roller skiing on a treadmill in a wind tunnel using the double poling technique. A secondary aim was to investigate the effects of wind versus no-wind test conditions on the same physiological parameters. Methods Ten subjects of each gender participated in the experiments. One pair of skiers of the same gender roller skied simultaneously in line with the air flow; the distance between the skiers was 2.05 m. Each pair was tested as follows: I) with wind, leading; II) with wind, drafting; and III) without wind. The treadmill inclination was 0° throughout the tests. For the wind conditions, the air velocity was similar to the treadmill belt speed: 3 to 7 m·s-1 for men and 3 to 6 m·s-1 for women. Results Drafting resulted in significantly (P < 0.05) lower FPROP,CDA, V˙O2, and Ė, compared with leading, for both genders at racing speed but not at lower speeds, whereas HR was only affected for the male skiers at racing speed. The test without wind resulted in significantly lower FPROP, V˙O2, and Ė at all tested speeds compared with the tests with wind present, whereas HR was lower only at higher speeds. Conclusions At racing speed, but not at lower speeds, the positive effects of drafting behind a skier during double poling were obvious and resulted in a lower FPROP, CDA, V˙O2, Ė, and HR. Tests without wind present put even lower demands on the skiers' physiology, which was also evident at lower speeds.
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| 11. |
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| 12. |
- Anderson, Cheryl B, et al.
(författare)
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Validation of the PDPAR as an adolescent diary : effect of accelerometer cut points
- 2005
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 37:7, s. 1224-1230
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate the validity of the Previous Day Physical Activity Recall (PDPAR) as a physical activity diary in adolescents using two accelerometer intensity classifications.METHODS: One hundred eighth graders (47 boys, 53 girls) used the PDPAR as a daily diary and wore MTI accelerometers for four consecutive days. Measured time spent in moderate (> or = 3 METs) and vigorous (> or = 6 METs) activity was based on two published MTI cut-point limits (that of Freedson et al./Trost et al. and that of Puyau et al.). Spearman rank order correlations and Bland-Altman plots were used to examine agreement between MTI and PDPAR diary estimates of activity.RESULTS: MTI estimates of mean minutes per day of total moderate to vigorous physical activity (MVPA) were 65.2 (+/-43.2) using the Freedson et al./Trost et al. cutoffs and 17.5 (+/-18.5) using those of Puyau et al., while students self-reported 105.1 (+/-80.1) min.d(-1). Significant relationships were observed between the diary and MTI for total MVPA using either the Freedson et al./Trost et al. (r = 0.42) or Puyau et al. (r = 0.41) cutoff as well as raw counts (r = 0.44). Plots showed reasonable agreement between the diary and Freedson et al./Trost et al. MTI estimates of MVPA for daily totals of < or = 60 min, but the Puyau et al. estimates were consistently lower. Diaries overestimated activity as time increased when compared to either MTI cut point, especially on vigorous activity.CONCLUSIONS: Time estimates of MVPA differed by assessment tool, but diary estimates showed adequate association with the MTI. Diaries reflected intensity-specific activity, corresponding most closely with the Freedson et al./Trost et al. classification of moderate, but substantially overestimated vigorous activity regardless of cut-point method. This is likely due to the measurement characteristics of the PDPAR, which classifies activities in 30-min blocks, as well as the nature of common activities in which high levels of intensity are not sustained.
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| 13. |
- Andersson, Erik, 1984-, et al.
(författare)
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Metabolic responses and pacing strategies during successive sprint skiing time trials
- 2016
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 48:12, s. 2544-2554
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To examine the metabolic responses and pacing strategies during the performance of successive sprint time trials (STTs) in cross-country skiing. METHODS: Ten well-trained male cross-country skiers performed four self-paced 1300-m STTs on a treadmill, each separated by 45 min of recovery. The simulated STT course was divided into three flat (1°) sections (S1, S3 and S5) involving the double poling sub-technique interspersed with two uphill (7°) sections (S2 and S4) involving the diagonal stride sub-technique. Treadmill velocity and V˙O2 were monitored continuously and gross efficiency was used to estimate the anaerobic energy supply. RESULTS: The individual trial-to-trial variability in STT performance time was 1.3%, where variations in O2 deficit and V˙O2 explained 69% (P < 0.05) and 11% (P > 0.05) of the variation in performance. The first and last STTs were equally fast (228 ± 10 s), and ~ 1.3% faster than the second and the third STTs (P < 0.05). These two fastest STTs were associated with a 14% greater O2 deficit (P < 0.05), while the average V˙O2 was similar during all four STTs (86 ± 3% of V˙O2max). Positive pacing was used throughout all STTs, with significantly less time spent on the first than second course half. In addition, metabolic rates were substantially higher (~_30%) for uphill than for flat skiing, indicating that pacing was regulated to the terrain. CONCLUSIONS: The fastest STTs were characterized primarily by a greater anaerobic energy production, which also explained 69% of the individual variation in performance. Moreover, the skiers employed positive pacing and a variable exercise intensity according to the course profile, yielding an irregular distribution of anaerobic energy production.
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| 14. |
- Andersson, Eva, et al.
(författare)
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Trunk muscle strength in athletes.
- 1988
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 20:6, s. 587-93
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Tidskriftsartikel (refereegranskat)abstract
- Maximal voluntary strength of the trunk muscles was measured in 57 male elite athletes (soccer players, wrestlers, tennis players, and gymnasts), 14 female elite gymnasts, and in a normal group of 87 conscripts. Mean ages in the different groups ranged from 18-22 yr. An isokinetic (constant velocity) technique was used to record maximal torque produced by trunk and hip muscles during flexion, extension, and lateral flexion over the range of motion. The constant angular velocities used were 15 deg.s-1 and 30 deg.s-1, respectively. Isometric strength was measured in a straight body position (0 deg. of flexion). The measurements were made with the subjects in a horizontal position with the pivot point at the hip and at the lumbar (L2-L3) level. All male athlete groups showed higher peak torque values than the normals. The differences were largest in hip extension and trunk flexion. The male gymnasts also showed significantly higher peak values in hip flexion as compared to all other categories. There was no difference in strength per kg body weight between female gymnasts and untrained males, except in trunk extension. The position for peak torque occurred earlier in the movements for the athletes, especially for the gymnasts in extension movements and for the tennis players in flexion movements. In isometric contractions essentially the same strength differences were present as in the slow isokinetic contractions. In lateral flexion wrestlers and tennis players showed significantly higher strength in movements toward the nondominant side. Thus, differences were present between the athletes and the normals, some of which appeared to be sport specific and related to long-term systematic training.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 15. |
- Andersson, Helena M., et al.
(författare)
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Neuromuscular fatigue and recovery in elite female soccer : effects of active recovery
- 2008
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 40:2, s. 372-380
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the time course of recovery from neuromuscular fatigue and some biochemical changes between two female soccer matches separated by an active or passive recovery regime. METHODS: Countermovement jump (CMJ), sprint performance, maximal isokinetic knee flexion and extension, creatine kinase (CK), urea, uric acid, and perceived muscle soreness were measured in 17 elite female soccer players before, immediately after, 5, 21, 45, 51, and 69 h after a first match, and immediately after a second match. Eight players performed active recovery (submaximal cycling at 60% of HRpeak and low-intensity resistance training at < 50% 1RM) 22 and 46 h after the first match. RESULTS: In response to the first match, a significant decrease in sprint performance (-3.0 +/- 0.5%), CMJ (-4.4 +/- 0.8%), peak torque in knee extension (-7.1 +/- 1.9%) and flexion (-9.4 +/- 1.8%), and an increase in CK (+ 152 +/- 28%), urea (15 +/- 2), uric acid (+ 11 +/- 2%), and muscle soreness occurred. Sprint ability was first to return to baseline (5 h) followed by urea and uric acid (21 h), isokinetic knee extension (27 h) and flexion (51 h), CK, and muscle soreness (69 h), whereas CMJ was still reduced at the beginning of the second match. There were no significant differences in the recovery pattern between the active and passive recovery groups. The magnitude of the neuromuscular and biochemical changes after the second match was similar to that observed after the first match. CONCLUSION: The present study reveals differences in the recovery pattern of the various neuromuscular and biochemical parameters in response to a female soccer match. The active recovery had no effects on the recovery pattern of the four neuromuscular and three biochemical parameters.
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| 16. |
- Apró, William, et al.
(författare)
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Amino Acid-induced S6K1 Activity In Human Skeletal Muscle Is Mediated By Increased mTor/Rheb Interaction : 128 June 1, 11: 15 AM - 11: 30 AM.
- 2016
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Ingår i: Medicine And Science In Sports And Exercise 2016 May; Vol. 48 (5S Suppl 1), pp. 17.. - : Ovid Technologies (Wolters Kluwer Health). ; 48:5 Suppl 1, s. 17-
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Konferensbidrag (refereegranskat)abstract
- Cell culture studies have shown that amino acids activate mTORC1 signaling by increasing the interaction between mTOR and its essential activator Rheb. However, the existence of this mechanism in human skeletal muscle remains to be determined.PURPOSE: To determine if increased mTORC1 signaling in response to amino acids in human skeletal muscle is due to an increased interaction between mTOR and Rheb.METHODS: Eight well trained men performed resistance exercise on two separate occasions. In connection with the exercise, subjects were supplemented with flavored water (Pla) and essential amino acids (EAA) in a double-blind, randomized cross-over design. Muscle biopsies were taken in the vastus lateralis muscle before, immediately after and 90 and 180 min post exercise. Activity of the mTORC1 pathway was assessed by a radiolabeled in-vitro kinase assay for its immediate downstream target S6K1. Protein-protein interactions were determined by western blot following co-immunoprecipitation of mTOR with Rheb. Co-immunoprecipitation was performed on pooled muscle samples from three of the eight subjects.RESULTS: Activity of S6K1 remained unchanged immediately after exercise in both trials. However, at 90 min post exercise, S6K1 activity increased by approximately 2- and 8-fold (p<0.05) from baseline the Pla and EAA trials, respectively. At the 180 min time point, S6K1 activity remained elevated in both trials being approx. 3-fold higher in the Pla trial and 5-fold higher (p<0.05) in the EAA trial. The fold-change in mTOR and Rheb interaction largely resembled the activity pattern of S6K1 in both trials; in the Pla trial the fold-change was 0.9, 1.3 and 1.4 while in the EAA trial the fold-change was 1.6, 2.9 and 1.9 immediately after, 90 min after and 180 min after exercise, respectively.CONCLUSIONS: The large increase in S6K1 activity following EAA intake appears to be mediated by an increased interaction between mTOR and its proximal activator Rheb. This is the first time this mechanism has been demonstrated in human skeletal muscle.
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| 17. |
- Apró, William, 1980-, et al.
(författare)
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Endurance Exercise Does Not Impair mTOR Signalling After Resistance Exercise : D-58 Thematic Poster - Skeletal Muscle Cell Signaling: JUNE 2, 2011 3:15 PM - 5:15 PM: ROOM: 304
- 2011
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 43:5, s. 52-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Resistance exercise is known to stimulate muscle hypertrophy and this effect is mainly mediated by the mammalian target of rapamycin (mTOR) pathway. In contrast, endurance exercise results in a divergent phenotypic response which to a large extent is mediated by adenosine monophosphate-activated protein kinase (AMPK). Research indicates that molecular interference may exist, possibly through an inhibitory effect on mTOR signalling by AMPK, when these two modes of exercise are combined. PURPOSE: To investigate the impact of subsequent endurance exercise on resistance exercise induced mTOR signalling. METHODS: In a randomized and cross-over fashion, ten male subjects performed either heavy resistance exercise (R) or heavy resistance exercise followed by endurance exercise (RE) on two separate occasions. The R protocol consisted of thirteen sets of leg press exercise with 3 minutes of recovery allowed between each set. In the RE session, resistance exercise was followed by 15 minutes recovery after which 30 min of cycling was initiated at an intensity equal to 70 % of the subjects' maximal oxygen consumption. Muscle biopsies were collected before, 1 and 3 hours after resistance exercise in both trials. Samples were analyzed for several signalling proteins in the mTOR pathway using western blot technique. RESULTS: Phosphorylation of mTOR increased approx. twofold at 1 h post resistance exercise and remained elevated at the 3 h time point (p< 0.01) with no difference between the two trials. Phosphorylation of p70S6k, a downstream target of mTOR, was increased about 6-and18-fold at 1 h and 3 h post resistance exercise (p< 0.01). There was no difference in p70S6k phosphorylation at any time point between the two trials. Phosphorylation of the eukaryotic elongation factor eEF2 was decreased 3- to 4-fold at both time points post resistance exercise (p< 0.01) with no difference between trials. Phosphorylation of AMPK was unchanged at the 1 h time point but decreased approximately 30 % from pre-exercise values in both trials at 3 h post resistance exercise (p< 0.01). CONCLUSIONS: The signalling response following heavy resistance exercise is not blunted by subsequent endurance exercise. Supported by the Swedish National Centre for Research in Sports.
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| 18. |
- Arvidsson, Daniel, 1974, et al.
(författare)
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Energy Cost in Children Assessed by Multisensor Activity Monitors
- 2009
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Ingår i: Medicine & Science in Sports & Exercise. - : American College of Sports Medicine. - 0195-9131 .- 1530-0315. ; 41:3, s. 603-611
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The SenseWear Pro2 Armband (SWA; BodyMedia, Inc., Pittsburg, PA), the Intelligent Device for Energy Expenditure and Activity (IDEEA; Minisun LLC, Fresno, CA), and the ActiReg (AR; PreMed AS, Oslo, Norway) were compared with indirect calorimetry to determine the ability of these devices to assess energy cost in children during resting and different physical activities. Methods: Fourteen children, 11–13 yr old, wore the SWA, the IDEEA, and the AR during resting, sitting, stationary bicycling, jumping on a trampoline, playing basketball, stair walking, and walking/running along a 50-m track. The Oxycon Mobile portable metabolic system (VIASYS Healthcare, Conshohocken, PA) was used as the criterion method for energy cost. Results: For resting and sitting, the three activity monitors showed comparable results, but none of them accurately assessed energy cost for stationary bicycling, jumping on a trampoline, or playing basketball. The IDEEA was the only activity monitor that accurately assessed energy cost for stair walking. Also, the IDEEA showed a close estimate of energy cost across the walking and the running intensities, whereas the SWA accurately assessed energy cost for slow to normal walking but showed increased underestimation of energy cost with increasing speed. The AR overestimated energy cost during walking and during slow running but did not respond to increasing running speed. Conclusions: To be able to capture children’s physical activity, all three activity monitors need to be further developed. Overall, the IDEEA showed the highest ability to assess energy cost in this study, but SWA may be more feasible for use in children under free-living conditions.
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| 19. |
- Arvidsson, Daniel, 1974, et al.
(författare)
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Energy cost of physical activities in children : Validation of SenseWear Armband
- 2007
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Ingår i: Medicine & Science in Sports & Exercise. - : American College of Sports Medicine. - 0195-9131 .- 1530-0315. ; 39:11, s. 2076-2084
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To examine the validity of SenseWear Pro2 Armband in assessing energy cost of physical activities in children, and to contribute with values of energy costs in an overview of physical activities in children. METHODS: Energy cost was assessed by SenseWear Pro2 Armband in 20 healthy children, 11-13 yr, while lying down resting, sitting playing games on mobile phone, stepping up and down on a step board, bicycling on a stationary bike, jumping on a trampoline, playing basketball, and walking/running on a treadmill at the speeds 2, 3, 4, 5, 6, 7, 8, and 10 km x h(-1). During these activities, energy cost was also assessed from VO2 and VCO2 measured by Oxycon Mobile portable metabolic system, which was used as criterion method. RESULTS: The difference in energy cost between SenseWear Pro2 Armband and Oxycon Mobile was -0.7 (0.5) (P < 0.001) for resting, -2.0 (0.9) (P < 0.001) for playing games on mobile phone, -6.6 (2.3) (P < 0.001) for stepping on the step board, -12.0 (3.7) (P < 0.001) for bicycling, -2.7 (11.9) (P = 0.34) for jumping on the trampoline, and -14.8 (6.4) kJ x min(-1) (P < 0.001) for playing basketball. The difference in energy cost between SenseWear Pro2 Armband and Oxycon Mobile for increasing treadmill speed was 1.3 (3.1) (P = 0.048), 0.1 (2.9) (P = 0.82), -1.2 (2.6) (P = 0.049), -1.6 (3.2) (P = 0.044), -3.1 (3.7) (P = 0.0013), -4.9 (3.7) (P < 0.001), -5.3 (3.7) (P < 0.001), and -11.1 (3.5) kJ x min(-1) (P < 0.001). CONCLUSIONS: SenseWear Pro2 Armband underestimated energy cost of most activities in this study, an underestimation that increased with increased physical activity intensity. A table of energy costs (MET values) of physical activities in children measured by indirect calorimetry is presented as an initiation of the creation of a compendium of physical activities in children
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| 20. |
- Arvidsson, Daniel, et al.
(författare)
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Neighborhood Walkability, Income, and Hour-by-Hour Physical Activity Patterns.
- 2013
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Ingår i: Medicine & Science in Sports & Exercise. - 1530-0315. ; 45:4, s. 698-705
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate both the mean daily physical activity and the hour by hour physical activity pattern across the day using accelerometry, and how they are associated with neighborhood walkability and individual income. METHODS: Moderate physical activity (MPA) was assessed by accelerometry in 2,252 adults in the City of Stockholm, Sweden. Neighborhood walkability (residential density, street connectivity, land use mix) was objectively assessed within 1,000m network buffers around the participants´ residence and individual income was self-reported. RESULTS: Living in a high walkability neighborhood was associated with more mean daily MPA compared with living in a low walkability neighborhood on weekdays and weekend days. Hour by hour analyses showed that this association appeared mainly in the afternoon/early evening during weekdays, while it appeared across the middle of the day during weekend days. Individual income was associated with mean daily MPA on weekend days. On weekdays, the hour by hour analyses showed that high income was associated with more MPA around noon and in late afternoon/early evening, while low income was associated with more MPA at the hours before noon and in the early afternoon. During the weekend, high income was more consistently associated with higher MPA. CONCLUSIONS: Hour by hour accelerometry physical activity patterns provides a more comprehensive picture of the associations between neighborhood walkability and individual income and physical activity and the variability of these associations across the day.
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| 21. |
- Arvidsson, Daniel, et al.
(författare)
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Physical Activity and Concordance between Objective and Perceived Walkability.
- 2012
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Ingår i: Medicine & Science in Sports & Exercise. - 1530-0315. ; 44, s. 280-287
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:: To investigate concordance between objective and perceived neighborhood walkability, their associations with self-reported walking and objective physical activity, and sociodemographic characteristics of individuals in neighborhoods with objectively assessed high walkability who misperceive it as low. METHODS:: In 1,925 individuals aged 20-66 years, recruited from administrative areas in the city of Stockholm, Sweden, of both high and low neighborhood walkability, objective neighborhood walkability was assessed within a 1,000m radius of each individual's residential address using Geographic Information Systems (GIS). Perceived walkability was based on the Neighborhood Environment Walkability Scale (NEWS). Walking was assessed using the International Physical Activity Questionnaire (IPAQ), and total physical activity and moderate-to-vigorous physical activity (MVPA) by an accelerometer (ActiGraph). Sociodemographic characteristics were self-reported. RESULTS:: Objective and perceived neighborhood walkability agreed in 67.0% of the individuals, with kappa=0.34 (95% CI: 0.30-0.38). One-third of the individuals in neighborhoods with objectively assessed high walkability misperceived it as low. This non-concordance was more common among older and married/cohabiting individuals. After adjustment for sociodemographic characteristics, high objective neighborhood walkability was associated with 35.0 (95% CI: 14.6-64.6) and 10.5 (95% CI: -5.2-28.5) more minutes/week of walking for transportation and leisure, respectively, and 2.8 (95% CI: 0.9-5.0) more minutes/day of MVPA. High perceived neighborhood walkability was associated with 41.5 (95% CI: 15.8-62.9) and 21.8 (95% CI: 2.8-40.0) more minutes/week of walking for transportation and leisure, respectively, and 1.7 (95% CI: -0.3-3.7) more minutes/day of MVPA. CONCLUSIONS:: Objective and perceived neighborhood walkability both contribute to the amount of walking and objective physical activity. Both measures of neighborhood walkability may be important factors to target in interventions aiming at increasing physical activity.
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| 22. |
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| 23. |
- Berg, H E, et al.
(författare)
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Involvement of eccentric muscle actions in giant slalom racing.
- 1995
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 27:12, s. 1666-70
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Tidskriftsartikel (refereegranskat)abstract
- Joint angular movements and muscle activation (EMG), were determined in male elite racers while performing the giant slalom. Movement cycles averaged 3.5 +/- 0.6 s (left plus right turn), and knee angle ranged 66-114 degrees (180 degrees = straight leg). Knee extensor muscle use was dominated (rectified EMG; P < 0.05) by the leg controlling the outside (downhill) ski during the turn. Time spent while decreasing knee angle (eccentric muscle action) of outside leg averaged 1.0 +/- 0.2 s. This phase was longer (P < 0.05) than the average push-off (concentric muscle action) phase of 0.5 +/- 0.1 s. Moreover, EMG activity of the outside leg during eccentric muscle actions exceeded (P < 0.05) that of concentric actions and was similar to that attained during maximum isometric knee extension in laboratory tests. Knee and hip angular movement ranged 20-50 degrees. Average joint velocities equalled 20-40 degrees.s(-1) during the turning phase. Thus, competitive giant slalom skiing is dominated by slow eccentric muscle actions performed at near maximum voluntary force. Because of their greater ability to generate force, eccentric muscle actions may be warranted or even required to resist the G-forces induced during the turn phase.
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| 24. |
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| 25. |
- Berg, H. E., et al.
(författare)
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Muscle control in elite alpine skiing
- 1999
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 31:7, s. 1065-1067
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to determine whether muscle control may be influenced by accelerative forces brought about by the downhill displacement of body mass in combination with the sharp turns during alpine skiing. METHODS: Sixteen elite skiers performed either super G (SG), giant slalom (GS), slalom (SL), or freestyle mogul (FM) skiing. Knee and hip joint angles and electromyographic (EMG) activity of the knee extensors were recorded. RESULTS: During the course of a turn, the minimum (deepest stance position) knee angle of the outside (main load-bearing) leg ranged from 60 degrees to 100 degrees, where the smallest angle was obtained in the FM event. Among the traditional alpine disciplines, smaller knee angles were obtained in the high-speed events (i.e., knee angle: SG CONCLUSIONS: We believe these results have important implications for the design of specific training models.
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| 26. |
- Bergh, U, et al.
(författare)
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Maximal oxygen uptake "classical" versus "contemporary" viewpoints.
- 2000
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 32:1, s. 85-8
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Tidskriftsartikel (refereegranskat)abstract
- In two articles Timothy Noakes proposes a new physiological model in which skeletal muscle recruitment is regulated by a central "govenor," specifically to prevent the development of a progressive myocardial ischemia that would precede the development of skeletal muscle anaerobiosis during maximal exercise. In this rebuttal to the Noakes' papers, we argue that Noakes has ignored data supporting the existing hypothesis that under normal conditions cardiac output is limiting maximal aerobic power during dynamic exercise engaging large muscle groups.
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| 27. |
- Bergman, Frida, Medicine doktor, 1984-, et al.
(författare)
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Increasing Physical Activity In Office Workers - An RCT Of Treadmill Workstations
- 2018
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Ingår i: Medicine & Science in Sports & Exercise. - : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 50:5, s. 47-47
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: Our primary hypothesis was that an intervention with treadmill workstations would increase time spent walking. Secondary hypotheses were a decrease in time spent sitting with a concomitant increase in time spent standing and in light intensity physical activity (LPA) leading to positive effects on body measurements and body composition.METHODS: The intervention group received a treadmill workstation at their office desk during 13 months. Daily time spent sitting, standing and walking and number of steps was measured with activPAL®. Daily time in LPA and MVPA was measured with Actigraph®. Body weight, BMI and waist circumference were measured according to standardized protocols. Dual X-ray Absorptiometry was used to estimate body composition. Mixed models was used for the statistical analysis, with group, day of week (weekday/ weekend), time point and gender as fixed effects and age as a covariate. p<0.05 was considered significant.RESULTS: Eighty participants were included. The intervention group significantly increased their time spent walking at all follow-ups, with a difference at 13 months of 22 minutes (p<0.01) and 1645 steps per day (p<0.05), respectively, versus controls. Concomitantly, they decreased their MVPA with 13 minutes per day (p<0.001) at weekdays at 13 months versus baseline. We also found a decrease in LPA with 19 minutes per day (p<0.05), and of 17 minutes per day for MVPA (p<0.001) at 13 months versus baseline at weekends. The control group increased their time spent sitting with 25 minutes per day (p<0.05) and decreased the time spent standing with 35 minutes per day at weekdays (p<0.001) compared to baseline. There was also a decrease in LPA with 14 minutes per day (p<0.01) and in MVPA with 6 minutes per day (p<0.01) versus baseline during weekdays, with a decrease in sitting time with 36 minutes (p<0.05) at weekends. There were no significant changes in body measurements or body composition.CONCLUSION: It is possible to increase daily walking time by introducing treadmill workstations at offices. A decreased MVPA within the intervention group may contribute to lack of effects on body measurements and body composition. It is therefore important that future interventions aim at both reducing sedentary time as well as increasing, or at least remaining, MVPA levels.
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| 28. |
- Björklund, Glenn, 1972-, et al.
(författare)
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Biomechanical influenced differences in O2 extraction in diagonal skiing: arm versus leg
- 2010
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Ingår i: Medicine & Science in Sports & Exercise. - : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 42:10, s. 1899-1908
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Tidskriftsartikel (refereegranskat)abstract
- Biomechanically Influenced Differences in O-2 Extraction in Diagonal Skiing: Arm versus Leg. Med. Sci. Sports Exerc., Vol. 42, No. 10, pp. 1899-1908, 2010. Purpose: This study aimed to determine whether the differences in oxygen extraction and lactate concentration in arms and legs during cross-country skiing are related to muscle activation or force production and how these differences are influenced by a reduction in exercise intensity. Methods: Nine well-trained male cross-country skiers (age = 22 +/- 3 yr, (V) over dotO(2max) = 5.3 +/- 0.3 L.min(-1) and 69 +/- 3 mL.kg(-1).min(-1)) performed diagonal skiing on a treadmill for 3 min at 90% followed by 6 min at 70% of (V) over dotO(2max). During the final minute of each workload, arterial, femoral, and subclavian venous blood was collected for determination of blood gases, pH, and lactate. EMG was recorded from six upper-and lower-body muscles, and leg and pole forces were measured. Cardiorespiratory variables were monitored continuously. Results: Oxygen extraction in the legs was higher than that in the arms at both 90% and 70% of (V) over dotO(2max) (92% +/- 3% vs 85% +/- 6%, P < 0.05 and 90% +/- 3% vs 78% +/- 8%, P < 0.001). This reduction with decreased workload was more pronounced in the arms (-9.8% +/- 7.7% vs -3.2% +/- 3.2%, P < 0.01). EMGRMS for the arms was higher, and pole ground contact time was greater than the corresponding values for the legs (both P < 0.01). At both intensities, the blood lactate concentration was higher in the subclavian than that in the femoral vein but was lowered more in the subclavian vein when intensity was reduced (all P < 0.001). Conclusions: The higher muscle activation (percentage of maximal voluntary isometric contraction) in the arms and the longer ground contact time of the poles than the legs contribute to the lower oxygen extraction and elevated blood lactate concentration in the arms in diagonal skiing. The better lactate recovery in the arms than that in the legs is aided by greater reductions in muscle activation and pole force when exercise intensity is reduced.
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| 29. |
- Bjørnsen, Thomas, et al.
(författare)
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Type 1 Muscle Fiber Hypertrophy after Blood Flow-restricted Training in Powerlifters.
- 2019
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Ingår i: Medicine and science in sports and exercise. - 1530-0315. ; 51:2, s. 288-298
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the effects of blood flow restricted resistance exercise (BFRRE) on myofiber areas (MFA), number of myonuclei and satellite cells (SC), muscle size and strength in powerlifters. METHODSSeventeen national level powerlifters (25±6 yrs [mean±SD], 15 men) were randomly assigned to either a BFRRE group (n=9) performing two blocks (week 1 and 3) of five BFRRE front squat sessions within a 6.5-week training period, or a conventional training group (Con; n=8) performing front squats at ~70% of one-repetition maximum (1RM). The BFRRE consisted of four sets (first and last set to voluntary failure) at ~30% of 1RM. Muscle biopsies were obtained from m. vastus lateralis (VL) and analyzed for MFA, myonuclei, SC and capillaries. Cross sectional areas (CSA) of VL and m. rectus femoris (RF) were measured by ultrasonography. Strength was evaluated by maximal voluntary isokinetic torque (MVIT) in knee extension and 1RM in front squat.BFRRE induced selective type I fiber increases in MFA (BFRRE: 12% vs. Con: 0%, p<0.01) and myonuclear number (BFRRE: 17% vs. Con: 0%, p=0.02). Type II MFA was unaltered in both groups. BFRRE induced greater changes in VL CSA (7.7% vs. 0.5%, p=0.04), which correlated with the increases in MFA of type I fibers (r=0.81, p=0.02). No group differences were observed in SC and strength changes, although MVIT increased with BFRRE (p=0.04), whereas 1RM increased in Con (p=0.02).Two blocks of low-load BFRRE in the front squat exercise resulted in increased quadriceps CSA associated with preferential hypertrophy and myonuclear addition in type 1 fibres of national level powerlifters.
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| 30. |
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| 31. |
- Bolger, Claire, et al.
(författare)
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Hyperpnea-Induced Bronchoconstriction and Urinary CC16 Levels in Athletes
- 2011
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Ingår i: Medicine & Science in Sports & Exercise. - 1530-0315. ; 43:7, s. 1207-1213
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Tidskriftsartikel (refereegranskat)abstract
- BOLGER, C., E. TUFVESSON, M. SUE-CHU, G. DEVEREUX, J. G. AYRES, L. BJERMER, and P. KIPPELEN. Hyperpnea-Induced Bronchoconstriction and Urinary CC16 Levels in Athletes. Med. Sci. Sports Exerc., Vol. 43, No. 7, pp. 1207-1213, 2011. Purpose: Exercise-induced bronchoconstriction (EIB) is a common condition in both individuals with asthma and otherwise healthy elite athletes. Although excessive water loss by peripheral airways during hyperpnea is regarded as the initial trigger for EIB, the cascade of events that follows remains unclear. Our goal was to establish whether transient disruption of the airway epithelial barrier occurs after a short period of hyperpnea of dry air in athletes with EIB. Methods: Urinary concentration of the pneumoprotein Clara cell (CC16) was used as an assumed biomarker of lung epithelial cell damage or dysfunction. Samples were collected at baseline and for 90 min after an 8-min eucapnic voluntary hyperpnea (EVH) test in 50 female individuals (28 athletes and 22 untrained). Results: Nineteen subjects (10 athletes) demonstrated a sustained bronchoconstriction after EVH (mean +/- SE forced expiratory volume in the first second (FEV1) fall from baseline = 23.4% +/- 2.6%). The remaining subjects had a negative challenge result with an FEV1 fall of 5.9% +/- 0.6%. An increase (P < 0.001) in urinary CC16 concentration was noticed after EVH in all but one subject, with no group difference (median CC16 increase before to after challenge: athletes EVH- 0.083 ng.mu mol(-1), athletes EVH+ 0.223 ng.mu mol(-1), untrained EVH- 0.074 ng.mu mol(-1), untrained EVH+ 0.571 ng.mu mol(-1); P > 0.05). Conclusions: Urinary levels of CC16 are increased after EVH in all individuals (trained and untrained, with and without EIB) suggestive of dehydration-induced perturbation of the distal respiratory epithelium during episodes of hyperventilation.
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| 32. |
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| 33. |
- Boon, Hanneke, 1981-, et al.
(författare)
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Substrate Source Use in Older, Trained Males after Decades of Endurance Training
- 2007
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Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, PA : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 39:12, s. 2160-2170
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to compare substrate source use in older, long-term exercising, endurance-trained males with sedentary controls. METHODS: [U-C]palmitate and [6,6-H2]glucose tracers were applied to assess plasma free fatty acid (FFA) and glucose oxidation rates, and to estimate muscle- and/or lipoprotein-derived triacylglycerol (TG) and muscle glycogen use. Subjects were 10 long-term exercising, endurance-trained males and 10 sedentary controls (age 57 +/- 1 and 60 +/- 2 yr, respectively). Muscle biopsy samples were collected before and after exercise to assess muscle fiber type-specific intramyocellular lipid and glycogen content. RESULTS: During exercise, plasma palmitate Ra, Rd, and Rox were significantly greater in the trained subjects compared with the controls (Ra: 0.36 +/- 0.02 and 0.25 +/- 0.02; Rd: 0.36 +/- 0.03 and 0.24 +/- 0.02; Rox: 0.31 +/- 0.02 and 0.20 +/- 0.02 mmol.min, respectively, P < 0.01). This resulted in greater plasma FFA and total fat oxidation rates in the trained versus sedentary subjects (P < 0.001). Muscle- and/or lipoprotein-derived TG use contributed 10 +/- 2 and 11 +/- 3% in the trained and control groups, respectively (NS). No significant net changes in muscle fiber lipid content were observed. CONCLUSIONS: Older, endurance-trained males oxidize more fat during moderate-intensity exercise than do sedentary controls. This greater total fat oxidation rate is attributed to a higher plasma FFA release, uptake, and oxidation rate. In contrast, intramyocellular triacylglycerol does not seem to represent a major substrate source during 1 h of moderate-intensity exercise in older trained or sedentary men. ©2007 The American College of Sports Medicine.
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| 34. |
- Branth, Stefan, et al.
(författare)
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Energy turnover in a sailing crew during offshore racing around the world
- 1996
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 28:10, s. 1272-1276
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Tidskriftsartikel (refereegranskat)abstract
- Energy turnover during offshore sailing was studied in 11 male crew members of one team during the first three legs of the 1993-1994 Whitbread Round The World Race. The effect of racing on the energy balance of the crew members was studied by anthropometric measurements and dietary intake as calculated from food inventories before and after each leg. Energy turnover, calculated from dietary intake and release of endogenous energy as a result of changes in body composition, was higher than expected (about 18-20 MJ·d-1). These findings were confirmed using the doubly labeled water technique in six crew members during the third leg, in which mean energy turnover was found to be 19.3 MJ·d-1. Changes in body weight and composition indicated a negative energy balance during all legs.
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| 35. |
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| 36. |
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| 37. |
- Bugge, Anna, et al.
(författare)
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Effects of a 3-year intervention: The Copenhagen School Child Intervention Study.
- 2012
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Ingår i: Medicine & Science in Sports & Exercise. - 1530-0315. ; 44:7, s. 1310-1317
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: This study assessed short and long term effects of a 3-year controlled school-based physical activity (PA) intervention on fatness, cardiorespiratory fitness (VO2peak) and cardiovascular disease (CVD) risk factors in children. METHODS: The study involved 18 schools (10 intervention and 8 controls) and included a follow-up 4 years after the end of intervention. The analyses included 696, 6-7 yrs old children at baseline, 612 at post-intervention (age 9.5 yrs) and 441 at follow-up (age 13.4 yrs). The intervention consisted of a doubling of the amount of physical education (from 90 to 180 min/week), training of PE-teachers, and upgrading of physical education and playing facilities. Anthropometrics and systolic blood pressure (SBP) were measured. VO2peak was directly measured and PA assessed using accelerometry. Fasting blood samples were analyzed for CVD risk factors. A composite risk score was computed from z-scores of SBP, triglycerides, ratio of total cholesterol to high-density lipoproteins cholesterol, homeostatic model assessment (HOMA-score), skinfolds, and inverse VO2peak. RESULTS: The HOMA-score of intervention group boys had a smaller increase from baseline to post-intervention compared to control boys (p = 0.004). From baseline to follow-up intervention group boys had a smaller increase in SBP compared to control boys (p=0.010). There were no other significant differences between groups. CONCLUSION: This 3-years school-based PA intervention caused positive changes in SBP and HOMA-score in boys, but not in PA, VO2peak, fatness and the other measured CVD risk factors. Our results indicate that a doubling of physical education and providing training and equipment may not be sufficient to induce mayor improvements in CVD risk factors in a normal population.
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| 38. |
- Bäcklund, Catharina, 1971-, et al.
(författare)
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Validity of an armband measuring energy expenditure in overweight and obese children
- 2010
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Ingår i: Medicine & Science in Sports & Exercise. - : The American College of Sports Medicine. - 0195-9131 .- 1530-0315. ; 42:6, s. 1154-1161
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To examine the ability of the SenseWear Pro2 Armband (SWA) to accurately assess energy expenditure in free-living overweight or obese children during a two-week period, by comparison with energy expenditure measured using the doubly labeled water (DLW) method. A second aim was to examine which software version, Innerview Professional 5.1 or Sensewear Professional 6.0, are the most appropriate for use together with SWA in overweight and obese children. Method: A random sample of 22 healthy, overweight or obese children (11 girls and 11 boys) aged 8-11 years was recruited from an ongoing intervention study. Energy expenditure in free-living conditions was simultaneously assessed with the SWA and DLW methods during a 14-day period. All data from the SWA were analyzed using InnerView Professional software versions 5.1 (SWA 5.1) and 6.1 (SWA 6.1). Results: An accurate estimation in energy expenditure was obtained when SWA 5.1 was used, showing a non-statistically significant difference corresponding to 17 (1200) kJ[middle dot]d-1 compared with the energy expenditure measured using the DLW method. However, when SWA 6.1 was used a statistically significant (18%) underestimation of energy expenditure was obtained, corresponding to 1962 (1034) kJ[middle dot]d-1 compared with the DLW method. Conclusion: The SWA together with software version 5.1, but not 6.1, is a valid method for accurately measuring energy expenditure at group level of free-living overweight and obese children.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Carlsson, Sofia, et al.
(författare)
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Genetic effects on physical activity : results from the Swedish Twin Registry
- 2006
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 38:8, s. 1396-1401
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of this study was to investigate the genetic effects on leisure-time physical activity using data from the Swedish Twin Registry. METHODS: We investigated 13,362 twin pairs (5334 monozygotic and 8028 dizygotic pairs) aged 14-46 yr. Information on leisure-time physical activity was obtained by questionnaire. Correlations and odds ratios of physical activity were calculated for males, females, and monozygotic and dizygotic twins, respectively. Structural equation modeling was used to estimate the contribution of genetic effects as well as common and nonshared environmental factors on leisure-time physical activity. RESULTS: About one third of the twins reported that they exercised regularly (26% in females and 39% in males). The correlations of physical activity were twice as high in monozygotic compared with dizygotic twins, suggesting the presence of genetic effects. The variation in physical activity due to heritage was 57% (95% confidence interval (CI) = 0.49-0.63) in males and 50% (95% CI = 0.49-0.55) in females. The common environmental influence on physical activity was very small compared with the influence from environmental factors unique to the individual. CONCLUSIONS: Our study establishes heredity as an important component behind individual differences in physical activity in adult men and women. This may be one reason behind difficulties in convincing people to adopt an active lifestyle. Still, this study shows that there is a substantial influence on physical activity from environmental factors unique to the individual.
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| 43. |
- Ceci, Ruggero L., et al.
(författare)
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Health Promotion Intervention On Rural Roads In Sweden : A Case Study Of Cycling Safety
- 2017
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Ingår i: Medicine & Science in Sports & Exercise. - : LIPPINCOTT WILLIAMS & WILKINS. - 0195-9131 .- 1530-0315. ; 49:5 S, s. 229-229
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden, as well as in many countries in Scandinavia and in northern Europe, there is a growing trend to allocate the daily exercise routines to cycling and walking in the form of work commuting. This has led to an increase of bikers with light race bikes and garment for race bike training along the roads and streets of major cities. One crucial factor is the safety of the bikers on the public roads with mixed traffic. If the cyclist had control over the distance between themselves and the motor vehicle/object, how much space would they give themselves? To investigate how road safety factors such as proximity to vehicles passing the bikers on a rural roads a study was conducted.The experiment was conducted in an indoor athletics arena at Lugnet stadium in Falun where 48 participants were assigned to one of three groups. Group one with a balanced order of the object-proximity variable (n = 24); group two with the object-proximity variable ordered closest first and moving outward from the track (n = 12); and group three with object-proximity variable ordered furthest away first and moving inward towards the track (n = 12). The participants were donned with a bicycle helmet with a GoPro camera, a second camera was attached to the handlebars. Independent variables were object proximity to the bicycle lane (cm) measured from the center of the lane; dependent variables were lateral position in cm to moving objects, cycling speed and heart rate.The preliminary results suggest that bicycle lane must be at least 140 cm broad to accommodate a ‘comfortable’ passing distance (for the cyclist). The equivalent passing speeds equates to a car speed of approximately 40 km/h. If the car speeds were higher, the bicycle lane will need to be broader.
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Cornish, Rahchell S, et al.
(författare)
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Effect of caffeine on exercise capacity and function in prostate cancer survivors.
- 2015
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 47:3, s. 468-75
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study aimed to examine the acute effect of caffeine on exercise capacity, exercise-related fatigue, and functional performance in prostate cancer survivors.METHODS: In this randomized, placebo-controlled, double-blind crossover study, 30 prostate cancer survivors (age, 70.3 ± 7.7 yr; body mass, 80.5 ± 13.0 kg; mean ± SD) consumed 6.04 ± 0.16 mg·kg(-1) of anhydrous caffeine or a placebo 1 h before completing a battery of exercise capacity and functional performance tests. Testing sessions were separated by 3-4 wk. Immediate fatigue and perceived exertion were measured directly pre- and postexercise at both testing sessions.RESULTS: Caffeine increased exercise capacity by 7.93 s (+3.0%; P = 0.010); however, postexercise fatigue and perception of exertion were comparable with the placebo session (P = 0.632 and P = 0.902, respectively). Increases in isometric grip strength trended toward significance in both dominant (+2.9%; P = 0.053) and nondominant (+2.1%; P = 0.061) hands in the caffeine trial compared with placebo. Caffeine ingestion did not result in improvements in performance for any of the remaining functional measures, including the timed up-and-go test, repeated chair stands, 6-m fast walk, and 6-m backward tandem walk. Systolic blood pressure and HR were significantly increased (P = 0.006 and P = 0.040, respectively) upon completion of the testing battery when compared with placebo.CONCLUSIONS: Consumption of caffeine 1 h before exercise induced improvements in exercise capacity and muscular strength in prostate cancer survivors. However, there was no change in exercise-related fatigue when compared with placebo despite reduction in timed performance of the 400-m walk. Caffeine seems to enhance exercise tolerance through improved performance with no subsequent increase in fatigue or perception of exertion and may be an appropriate strategy to promote exercise participation in prostate cancer survivors.
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| 48. |
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| 49. |
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| 50. |
- Craig, Cora L, et al.
(författare)
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International physical activity questionnaire : 12-country reliability and validity
- 2003
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 35:8, s. 1381-1395
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Physical inactivity is a global concern, but diverse physical activity measures in use prevent international comparisons. The International Physical Activity Questionnaire (IPAQ) was developed as an instrument for cross-national monitoring of physical activity and inactivity.METHODS: Between 1997 and 1998, an International Consensus Group developed four long and four short forms of the IPAQ instruments (administered by telephone interview or self-administration, with two alternate reference periods, either the "last 7 d" or a "usual week" of recalled physical activity). During 2000, 14 centers from 12 countries collected reliability and/or validity data on at least two of the eight IPAQ instruments. Test-retest repeatability was assessed within the same week. Concurrent (inter-method) validity was assessed at the same administration, and criterion IPAQ validity was assessed against the CSA (now MTI) accelerometer. Spearman's correlation coefficients are reported, based on the total reported physical activity.RESULTS: Overall, the IPAQ questionnaires produced repeatable data (Spearman's rho clustered around 0.8), with comparable data from short and long forms. Criterion validity had a median rho of about 0.30, which was comparable to most other self-report validation studies. The "usual week" and "last 7 d" reference periods performed similarly, and the reliability of telephone administration was similar to the self-administered mode.CONCLUSIONS: The IPAQ instruments have acceptable measurement properties, at least as good as other established self-reports. Considering the diverse samples in this study, IPAQ has reasonable measurement properties for monitoring population levels of physical activity among 18- to 65-yr-old adults in diverse settings. The short IPAQ form "last 7 d recall" is recommended for national monitoring and the long form for research requiring more detailed assessment.
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