Warm-up reduces delayed onset muscle soreness but cool-down does not: a randomised controlled trial.

QUESTION Does warm-up or cool-down (also called warm-down) reduce delayed-onset muscle soreness? DESIGN Randomised controlled trial of factorial design with concealed allocation and intention-to-treat analysis. PARTICIPANTS Fifty-two healthy adults (23 men and 29 women aged 17 to 40 years). INTERVENTION Four equally-sized groups received either warm-up and cool-down, warm-up only, cool-down only, or neither warm-up nor cool-down. All participants performed exercise to induce delayed-onset muscle soreness, which involved walking backwards downhill on an inclined treadmill for 30 minutes. The warm-up and cool-down exercise involved walking forwards uphill on an inclined treadmill for 10 minutes. OUTCOME MEASURE Muscle soreness, measured on a 100-mm visual analogue scale. RESULTS Warm-up reduced perceived muscle soreness 48 hours after exercise on the visual analogue scale (mean effect of 13 mm, 95% CI 2 to 24 mm). However cool-down had no apparent effect (mean effect of 0 mm, 95% CI -11 to 11 mm). CONCLUSION Warm-up performed immediately prior to unaccustomed eccentric exercise produces small reductions in delayed-onset muscle soreness but cool-down performed after exercise does not.