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- 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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| 2. |
- 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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| 3. |
- 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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| 7. |
- 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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| 9. |
- 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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| 10. |
- Cunningham, Gregory, et al.
(författare)
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Neural Correlates of Clinical Scores in Patients with Anterior Shoulder Apprehension
- 2015
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 47:12, s. 2612-2620
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Anterior shoulder apprehension is a commonly reported complaint in anterior shoulder instability, which may lead to patient morbidity and impede shoulder function. It is the result of a cognitively complex mechanism, which includes anxiety, salience, fear, and anticipation. Purpose The aim of this prospective case-control study was to correlate five clinically established scores using functional magnetic resonance imaging to assess brain activation patterns in patients with apprehension related to anterior shoulder instability. Methods This study includes 28 consecutive male right-handed patients ( mean +/- SEM, 26.8 +/- 1.2 yr) with positive shoulder apprehension test and 10 healthy matched control participants without apprehension or a history of instability. Task- related and functional connectivity functional magnetic resonance imaging activation patterns occurring during apprehension video cue stimulation were correlated with five clinical tests and scores: Visual Analog Scale ( VAS), Rowe score for instability, Simple Shoulder Test, Subjective Shoulder Value ( SSV), and Western Ontario Shoulder Instability ( WOSI). Results Rowe, pain VAS, and WOSI scores correlated with prefrontal cortex, dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, somatosensory area, and parieto-occipital and temporal areas (default mode network). Rowe score additionally correlated with frontal pole, anterior midcingulate cortex, and visual areas. Moreover, SSV correlated with task-related brain activity in the bilateral precentral gyrus, bilateral postcentral gyrus, and bilateral superior parietal lobe. Conclusions Overall, Rowe score provides the strongest link between shoulder apprehension and brain level alterations as it correlates with the highest number of independent components involving areas responsible for both motor and cognitive functions, whereas pain VAS and WOSI occupy an intermediately strong link recruiting less brain networks. Finally, Simple Shoulder Test and SSV have the weakest link at the brain level.
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