Effects of prior exercise on muscle metabolism during sprint exercise in horses

2 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210; and 1 Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada N1G 2W1 The effect of warm-up exercise on energy metabolism and muscle glycogenolysis during sprint exercise (Spr) was examined in six fit Standardbred horses exercised at 115% of maximal O 2 consumption ( O 2 max ) until fatigued, 5 min after each of three protocols: 1 ) no warm-up (NWU); 2 ) 10 min at 50% of O 2 max [low-intensity warm-up (LWU)]; and 3 ) 7 min at 50% O 2 max followed by 45-s intervals at 80, 90, and 100% O 2 max [high-intensity warm-up (HWU)]. Warm-up increased ( P