Naproxen does not alter indices of muscle damage in resistance-exercise trained men

Purpose: Unaccustomed exercise is associated with an elevated plasma creati ne kinase (CK), myofibrillar inflammation, and delayed onset muscle sorenes s (DOMS). Nonsteroidal antiinflammatory drugs (NSAID) may attenuate DOMS an d indirect indices of inflammation in humans. Methods: We studied the effec ts of an NSAID (naproxen sodium (500 mg, 2 times a day for 38 h)) taken bef ore and after resistance exercise in eight healthy, moderately trained men in a randomized, double-blind trial. The exercise consisted of unilateral k nee concentric/eccentric weight lifting with 6 sets x 10 repetitions at 80- 85% of the 1 repetition maximal contraction. Muscle biopsies of each vastus lateralis (EX = exercised/REST = control) were taken 24 h after exercise f or immunohistochemical staining of inflammatory cells (leukocyte common ant igen). At 24 and 48 h postexercise, we also determined DOMS, plasma CK acti vity, and knee extensor muscle torque. Results: Exercise resulted in an inc reased CK activity at +24 and +48 h (vs preexercise: P < 0.01), with no tre atment effect. There were no treatment effects for any of the measured vari ables except for a return of voluntary knee extension torque to baseline by +48 h postexercise for NSAID treatment (P < 0.05). Conclusions: NSAID admi nistration did not alter CK rise, muscle force deficit at 24 h postexercise , nor perceived muscle pain. In addition, the increased CK at 24 h postexer cise was not associated with an acute myofibrillar inflammatory cell infilt rate in moderately trained men after resistance exercise.