Heat pack treatment does not attenuate repeated muscle damage in collegiate females

OBJECTIVE: Unaccustomed exercise causes transient Delayed Onset Muscle Soreness (DOMS); creatine-kinase and DOMS are indirect markers of muscle damage. Heat pack treatment increases blood flow and relieves pain. We determined the effects of heat pack treatment on DOMS, Creatine-Kinase, pain and jumping following maximum calf-raise exercises. METHODS: Exercise (3 days): calf-raise, 1 movement every 3 seconds until subjects could not maintain movement speed, Recovery: monitored for 7 days. Subjects: 14 female collegiate students (age: 20-22) with previous regular moderate exercise history, divided into heat pack treatment (n = 7; 40oC, 20-min on both calf muscles immediately after exercise) vs. no treatment (n = 7). Measured parameters: number of daily movements, Creatine-Kinase, one-leg long jumping (JUMP) and perceived pain (PAIN). Maximum dorsiflexion, calf maximum circumference and isometric muscle strength were also measured, but showed no significant variation. RESULTS: There were no differences between groups regarding the number of the calf-raise repetitions; Creatine-Kinase increased significantly from day 3 of the Exercise-period to day 5 of the recovery period and peaked on Recovery day 2 in both groups; it was higher in the treated-group vs. controls; PAIN significantly decreased immediately after the heat pack treatment; DOMS peaked in both groups on day 3 of the Exercise-period, and recovered by day 4 of the recovery period. JUMP values decreased significantly after the initial exercise and recovered to initial values by Day 4 of the recovery period. CONCLUSION: Heat pack treatment for 20 minutes did not minimize DOMS following the maximum calf-raise exercise, but reduced immediate muscle soreness.