The effects of short-term overwork on performance measures, blood lactate, and plasma ammonia concentrations were examined in 28 elite junior weightlifters who participated in a 2 wk high volume resistance training camp. Performance testing (maximum effort vertical jump test and snatch lift) and blood chemistry analyses (ammonia and lactate) were conducted before (T1) and after (T2) 7 d of high volume training (2-3 workouts/d). Blood samples were collected from an antecubital vein at rest, preexercise, 5 min postexercise, and 15 min postexercise at T1 and T2. Results indicated a significant decrease from T1 to T2 in the maximum effort vertical jump test while the snatch lift test yielded no difference across time. Blood lactate and ammonia concentrations were significantly lower at 5 min postexercise at T2 while resting ammonia concentrations were significantly elevated at T2 compared to corresponding measures at T1. These data suggest possible early symptoms of overwork at T2 (decrease in performance of the maximum effort vertical jump test and the elevated resting ammonia concentrations); however, lower 5 min postexercise concentrations of lactate and ammonia at T2 indicated a positive adaptation to the 1 wk high volume resistance training period.