To determine the effect of naproxen in attenuating the symptoms (muscle soreness level) and signs (plasma creatine kinase [CK] activity and muscular strength decrement) of delayed onset muscle soreness (DOMS) induced by repeated bouts of eccentric exercise.Design
The design was a randomized, double-blind, placebo-controlled, crossover trial with two testing phases of 8 days' duration that were separated by a “washout” period of 7 days.Setting
University-based sports science center.Participants
Twenty healthy male volunteers who responded to a notice in the university's athletic complex.Interventions
Eccentric single-leg exercises were performed on days 1, 3, and 4 to induce DOMS in the quadriceps muscles. Naproxen or placebo tablets (500 mg) were taken orally twice per day beginning on day 2 and continuing until the end of the testing phase.Main Outcome Measures
Perception of muscle soreness and knee extensor torque were evaluated daily throughout each phase. Plasma CK levels were evaluated on days 1, 3, 6, and 8 of each phase.Results
After the eccentric exercise, plasma CK levels were similarly elevated in both naproxen and placebo conditions (F = 1.42; p = 0.25). After DOMS developed, naproxen reduced the perception of soreness on day 3, when muscle soreness was highest (F = 2.20; p = 0.04). After treatments with naproxen, peak quadriceps torque during leg extension at 60°/s was higher than that after treatment with the placebo (F = 4.77; p = 0.04). There were no significant differences between the naproxen and placebo conditions for leg extension at 180°/s (F = 1.66; p = 0.21) and 300°/s (F = 0.71; p = 0.41).Conclusion
The data indicate that therapeutic doses of naproxen do not prevent CK release into the plasma but decrease the perception of muscle soreness and positively influence quadriceps peak torque.