The effect of "cool-down" on delayed onset of muscle soreness and muscle strength following eccentric exercise.

Purpose: The purpose was to investigate whether 20 min cool-down exercise performed on an ergometer cycle immediately after eccentric exercise of knee extensors would reduce delayed onset of muscle soreness and maximal isometric force loss. Methods: Twenty-four volunteers, (14 woman and 10 men) were randomly assigned into two groups: a “cool- down” group and a “control” group, i.e., each group consisted of 12 volunteers (7 woman and 5 men). Maximal voluntary isometric contraction force (MVC) in knee extensors, pressure pain threshold (PPT) along the rectus femoris muscle and subjective rating of pain intensity in thigh muscles were obtained before eccentric exercise (baseline), and 24 and 48 hours after eccentric exercise. Subjects in the cool-down group completed 20 min exercise on an ergometer cycle (60-70% of HRmax) immediately after the eccentric exercise. Subjects in the control group did not receive any interventions. Results: A significant group by time interaction from baseline to 48 hours after the eccentric exercise were found for PPT in the distal portion of rectus femoris (P = .047). For both groups, PPT at the distal part of the muscle decreased from day 1 to day 3; however, the reduction was substantially higher for the control group (23.3 %) compared to the cool-down group (9.6 %). A tendency for a group by time interaction from baseline to both 24 and 48 hours after eccentric exercise was found for MVC (P = .06). For both groups the mean force was lower on day 2 and 3 compared to baseline; however, the reduction in force for both comparisons was higher for the control group (22.5 %, 20.4 %) compared to the cool-down group (9.7 %, 8.2 %). The pattern of change in PPT at the central part of the muscle belly over the time period was not different between the groups. No significant difference in pain intensity rating (VAS) was found between the control and cool-down group at 24 and 48 hours after eccentric exercise. Conclusions: The result suggest that 20 min of cycling at moderate intensity performed immediately after eccentric exercise may have a preventive effect on the development of delayed onset of muscle soreness and strength loss after eccentric exercise