Effects Of Heating Or Cooling On Muscle Damage Measures Following Eccentric Exercise-induced Muscle Damage

Increased muscle temperatures have been shown to increase muscle force production due to increased rate of ATP synthesis. Following eccentric exercise, a large decrease in force production is caused by a protective mechanism that prevents further muscle damage as the muscle fibers undergo adaptive changes. Increased muscle temperature prior to muscular work and following exercise-induced muscle damage might further exacerbate damage in the muscle fibers. PURPOSE: The purpose of this study was to determine the effects of passive heating and cooling on delayed onset muscle soreness (DOMS), isokinetic strength, and creatine kinase (CK) activity following eccentric exercise-induced muscle damage (EIMD). METHODS: Thirty healthy females (22.0±3.0 y, 165.0±2.8 cm, 61.66±10.3 kg, and 24.1±4.1 % body fat) were randomly assigned to passive heating (H) at 44 °C or passive cooling (C) at 15 °C for 20 minutes, and a no treatment control (NT). On day 1, subjects completed 50 reps of eccentric elbow flexions and extensions at 120 deg·s-1. DOMS was measured pre-exercise (Pre), and at 24h, 48h, 72h, and 96h post-exercise. Isokinetic strength of the elbow extensors and flexors was measured at 60 deg·s-1at Pre, 24h, and 72h. CK activity was measured at Pre, 48h, and 120h after EIMD. RESULTS: No significant group (H, C, and NT) by time (Pre, 24h, 48h, 72h, and 96h) interaction for DOMS, isokinetic strength, or CK activity (p>0.05) was found. However, at all time points, DOMS was significantly increased compared to Pre in each group (p<0.05). In all groups, CK activity (mean ± SE) increased significantly from Pre to 48h and 96h, in H from 48.4±5.2 to 179.5±95.4 and 623±353.0 IU, in C from 99.1±30.7 to 120.7±25.4 and 482.5±246.3 IU, and in NT from 58.5±6.8 to 137.5±33.1 and 451±148.7 IU, respectively. CONCLUSION: Although muscle damage was present as evidenced by increased DOMS and CK across days, passive heating and cooling prior to strength testing but post-EIMD had no effect on ratings of DOMS, isokinetic strength or CK activity when compared to no treatment.