Document Detail

Neuromuscular function following prolonged load carriage on level and downhill gradients.
MedLine Citation:
PMID:  20681234     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Decrements in muscle function may reduce physical and skilled performance and have been shown to be greater following walking unloaded on negative gradients. We examined the effects of prolonged walking with load carriage at level and negative gradients on muscle function. METHODS: There were 10 male participants who completed two bouts of load carriage carrying a 25-kg backpack for 2 h at 6.5 km x h(-1) during level walking (LW) and downhill (-8% gradient) walking (DW). Force produced during voluntary and electrically stimulated contractions was measured before, 0, 24, 48, and 72 h post-exercise. RESULTS: Isometric knee extension force decreased immediately after LW (15 +/- 11%) and DW (16 +/- 17%) and recovered to baseline at 72 h. Voluntary activation decreased immediately after LW (95 +/- 5 to 91 +/- 10%) and DW (97 +/- 4 to 94 +/- 12%) and returned to baseline at 24 h. Electrically stimulated 20:50 Hz tetani decreased after LW and DW, with complete recovery by 24 h after DW only. LW and DW caused decreases immediately after exercise in isokinetic peak torque of knee extensors and flexors at 60 degrees x s(-1) and 180 degrees x s(-1), trunk extensors and flexors at 15 degrees x s(-1), and shoulder flexors at 60 degrees x s(-1), with complete recovery at different time points, but all by 72 h. CONCLUSIONS: Level and downhill treadmill walking with load carriage resulted in similar changes in muscle function of the lower and upper body muscles immediately after exercise and during recovery. The decrements in muscle function may increase the risk of musculoskeletal injury and is likely to impair performance during physical and skilled tasks following load carriage.
Sam D Blacker; Joanne L Fallowfield; James L J Bilzon; Mark E T Willems
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  81     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-08-04     Completed Date:  2010-09-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  745-53     Citation Subset:  IM; S    
University of Chichester, Faculty of Sport, Education & Social Sciences, Chichester, West Sussex, UK.
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MeSH Terms
Biomechanics / physiology
Cross-Over Studies
Isometric Contraction / physiology*
Knee / physiology
Muscle Fatigue / physiology*
Shoulder / physiology
Walking / physiology*
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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