Evidence from various studies indicates that eccentric contractions produce more post-exercise changes in muscular function than do concentric contractions. Delayed muscular soreness, the pain and tenderness present 1 or 2 days after exercise, is negatively correlated with muscular performance and occurs particularly after eccentric work. The action of an analgesic, anti-inflammatory drug (Indocin) on muscular soreness indicates it may be effective in accelerating recovery of muscle function after eccentric work. In the study reported herein the effects of Indocin on muscular performance, as evaluated on the Cybex II isokinetic dynamometer, following prolonged concentric and eccentric work, were evaluated in 48 subjects who were randomly assigned to one of four drug groups. Subjects performed a 30 minute step test during which one limb led the stepping movement throughout (concentric contractions) and the contralateral limb trailed throughout (eccentric contractions). The muscular performance parameters of peak torque (PT), torque acceleration energy (TAE) and average power (AVP), evaluated at slow and high velocities, and the range of motion (ROM) at the knee joint were assessed prior to the step test and at five intervals thereafter. A non-significant decrease in PT and TAE at the contraction speed of 60 deg/sec were present in the eccentric limbs, greater reductions evidenced in the placebo group. Non-significant changes occurred in the concentric limbs, Non-significant changes in ROM and in muscular function parameters evaluated at 250 deg/sec were observed. / Master of Science