Dissociation of Increases in PGC-1 alpha and Its Regulators from Exercise Intensity and Muscle Activation Following Acute Exercise. e71623

Muscle activation as well as changes in peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1 alpha ) following high-intensity interval exercise (HIIE) were examined in young healthy men (n = 8; age, 21.9 plus or minus 2.2 yrs; VO2peak, 53.1 plus or minus 6.4 ml/min/kg; peak work rate, 317 plus or minus 23.5 watts). On each of 3 visits HIIE was performed on a cycle ergometer at a target intensity of 73, 100, or 133% of peak work rate. Muscle biopsies were taken at rest and three hours after each exercise condition. Total work was not different between conditions (~730 kJ) while average power output (73%, 237 plus or minus 21; 100%, 323 plus or minus 26; 133%, 384 plus or minus 35 watts) and EMG derived muscle activation (73%, 1262 plus or minus 605; 100%, 2089 plus or minus 737; 133%, 3029 plus or minus 1206 total integrated EMG per interval) increased in an intensity dependent fashion. PGC-1 alpha mRNA was elevated after all three conditions (p