Judelson, D. A., Maresh, C. M., Farrell, M. J., Yamamoto, L. M., Armstrong, L. E., Kraemer, W. J., Volek, J. S., Spiering, B. A., Casa, D. J., & Anderson, J. M. (2007). Effect of hydration state on strength, power, and resistance exercise performance. Medicine and Science in Sports and Exercise, 39, 1817-1824.

"Although many studies have attempted to examine the effect of hypohydration on strength, power, and high-intensity endurance, few have successfully isolated changes in total body water from other variables that alter performance (e.g., increased core temperature), and none have documented the influence of hypohydration on an isotonic, multiset, multirepetition exercise bout typical of resistance exercise training. Further, no investigations document the effect of hypohydration on the ability of the central nervous system to stimulate the musculature, despite numerous scientists suggesting this possibility. The purposes of this study were to examine the isolated effect of hydration state on 1) strength, power, and the performance of acute resistance exercise, and 2) central activation ratio".

Healthy resistance-trained males (N = 7) completed three resistance exercise bouts in different hydration states: euhydrated, hypohydrated by approximately 2.5% body mass, and hypohydrated by approximately 5.0% body mass. Hydration status was manipulated via exercise-heat stress and controlled fluid intake one day preceding testing.

Vertical jump height, peak lower-body power, or peak lower-body force did not differ between the two states of hydration. When evaluated as a function of the percentage of total work completed during a six-set back squat protocol, resistance exercise performance decreased significantly during sets 2-3 for 2.5% hypohydration and 2-5 for 5% hypohydration.

Implication. Hypohydration reduces resistance exercise performance.

Return to Table of Contents for this issue.