A randomized controlled trial of the effect of naproxen on delayed onset muscle soreness and muscle strength

Objective: 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) induc ed by repeated bouts of eccentric exercise. Design: The design was a randomized, double-blind, placebo-controlled. cros sover 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 t he university's athletic complex. Interventions: Eccentric single-leg exerc ises were performed on days 1, 3, and 3 to induce DOMS in the quadriceps mu scles. 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 torq ue were evaluated daily throughout each phase. Plasma CK levels were evalua ted on days 1, 3, 6, and 8 of each phase. Results: After the eccentric exercise, plasma CK levels were similarly elev ated in both naproxen and placebo conditions (F = 1.42; p = 0.25). After DO MS developed, naproxen reduced the perception of soreness on day 3, when mu scle soreness was highest (F = 2.20; p = 0.04). After treatments with napro xen, peak quadriceps torque during leg extension at 60% was higher than tha t after treatment with the placebo (F = 4.77; p = 0.04). There were no sign ificant differences between the naproxen and placebo conditions for leg ext ension at 180 degrees/s (F = 1.66; p = 0.21) and 300 degrees/s (F = 0.71; p = 0.41). Conclusion: The data indicate that therapeutic doses of naproxen do not pre vent CK release into the plasma but decrease the perception of muscle soren ess and positively influence quadriceps peak torque.