Effect of Naproxen on delayed onset muscle soreness

The purpose was to determine the effect of Naproxen in attenuating the symptoms (muscle soreness level) and signs (plasma CK activity and muscular strength decrement) of delayed onset muscle soreness (DOMS). Twenty subjects were randomly assigned Naproxen (500 mg BID) or placebo in a double-blind, crossover design. Two testing phases, each 8 days in duration, were separated by a washout period of 7 days. Eccentric single-leg exercises were performed on Days 1, 3 and 4 to induce DOMS in the quadriceps muscles. Perception of muscle soreness, plasma CK, and knee extensor torque were evaluated throughout each phase. Following the eccentric exercise, plasma CK levels were similarly elevated in both Naproxen and placebo conditions. After DOMS had developed, Naproxen reduced the perception of soreness on Day 3 when muscle soreness was highest. Following treatments with Naproxen, peak quadriceps torque during leg extension at 60$ sp circ$/s was higher compared to placebo, however at higher velocity (180 and 300$ sp circ$/s) peak muscle torques were similar. The data indicate that therapeutic doses of Naproxen do not prevent CK release into the plasma but decreases the perception of muscle soreness and positively influences quadriceps peak torque