EXCESSIVE WATER LOSS BEFORE EXERCISE IMPAIRS MUSCULAR PERFORMANCE
Goulet, E. D., Lamontagne-Lacasse, M., Gigou, P-Y., Kenefick, R. W., Ely, B. R., & Cheuvront, S. (June 2, 2010). Pre-exercise hypohydration effects on jumping ability and muscle strength, endurance, and anaerobic capacity: A meta-analysis. Presentation 1681 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.
This investigation determined the magnitude of the effects of pre-exercise hypohydration on leg and arm muscle strength, leg muscle endurance, anaerobic capacity, and jumping ability using a meta-analytic approach. Studies were located via database searches and cross-referencing. Inclusion criteria were: standard measures of muscular performance; hydration level in the euhydrated control group <0.5% >-1% bodyweight; hypohydration level in the experimental group >1% bodyweight and >0.5% than control group bodyweight. Exclusion criteria were: diuretics and caloric restriction-induced bodyweight loss.
Research articles (N = 35) were retrieved, among which 11, 4, 7, and 4 met the inclusion criteria for muscle strength, muscle endurance, anaerobic capacity, and jumping ability, respectively. There were 27, 7, 11, and 11 effect estimates. Mean bodyweight decrease in experimental groups was ~3.0% for muscle strength, ~3.2% for muscle endurance, ~3.2% for anaerobic capacity, and ~2.5% for jumping ability. Mean muscle strength fell by ~4.6% with pre-exercise hypohydration relative to control. Leg (~3.8%) and arm (~4.8%) strength declined when compared to controls. Pre-exercise hypohydration resulted in a mean decrease in muscle endurance of ~11.7% and a decline in anaerobic capacity of ~5.7%. Pre-exercise hypohydration did not alter jumping ability.
Implication. Pre-exercise fluid loss of 1.5 to 5.5% bodyweight does not affect jumping ability, but decreases leg and arm muscle strength, as well as leg muscle endurance and anaerobic capacity.
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