Purpose: To determine the impact of local muscle heating and cooling on myogenic and proteolytic gene responses following resistance exercise.
Methods: Recreationally trained males (n = 12), age 25.3 ± 1.5, % body fat 13.6 ± 1.92, completed four sets of 8-12 repetitions of unilateral leg press and leg extension while heating one leg, and cooling the other. Muscle biopsies were taken from the vastus lateralis of each leg pre and 4 h post exercise.
Results: MyoD, FOXO1, and MuRF1 mRNA increased with exercise regardless of temperature (p < 0.05). Myostatin, MYF5, and atrogin-1 mRNA decreased with exercise regardless of temperature (p < 0.05). Myogenin, MRF4, and CASP3 mRNA were higher in the hot condition, compared to the cold (p < 0.05). PAX7 mRNA was lower in the hot compared to cold condition (p = 0.041). FOXO3 mRNA was higher in the cold compared to hot condition (p = 0.037). AKT1 and AKT2 were unaffected by either exercise or temperature. Femoral artery blood flow volume was higher in the hot (375.2 ± 41.2 ml min- 1), compared to the cold condition (263.5 ± 23.9 ml min- 1), p = 0.01. Tissue oxygen saturation was higher in the hot (71.7 ± 4.8%) than cold condition (55.3 ± 5.0%).
Conclusion: These results suggest an impaired muscle growth response with local cold application compared to local heat application.
Keywords: Cold; Hot; Muscle breakdown; Muscle growth; Resistance exercise; Temperature.