The effects of weight loss (dehydration) techniques (which mimicked techniques used prior to actual competition) used by intercollegiate wrestlers on selected physiological parameters (strength, anaerobic power, anaerobic capacity, the lactate threshold (LT), and peak aerobic power) were examined in seven intercollegiate wrestlers. During the 36 h weight loss period, subjects lost 3.3 kg (4.9% body weight), all of which occurred during the 12 h prior to weigh-in, using exercise in a rubberized sweat suit. Weight loss resulted in a reduction in upper body but not lower body strength measures (peak torque and average work per repetition). Anaerobic power and anaerobic capacity were significantly reduced in a dehydrated state (81.4 kgm.s-1, normal weight; 63.9 kgm.s-1, weight loss; 1984.3 kgm.40 s-1, normal weight; 1791.4 kgm.40 s-1, weight loss). Analyses of treadmill data revealed the following: 1) velocity was decreased at LT (4.4%) and peak (6.5%) during weight loss (P less than 0.05); 2) VO2 peak was significantly reduced with weight loss (6.7%, P less than 0.05); 3) treadmill time to exhaustion was significantly reduced in the weight loss state (12.4%) (35.7 min, normal weight; 31.3 min, weight loss). It was concluded that typical wrestling weight loss techniques result in deleterious effects on strength, anaerobic power, anaerobic capacity, the lactate threshold, and aerobic power.