Most bodybuilders switch from training large muscle groups with free weights to isolation machines, Hammer equipment, and cardio as they reduce calories and prepare for a show. However new research shows that sticking to basic core exercises burns more calories. There is evidence indicating that exercise volume is a major determinant of the total oxygen uptake and energy expenditure during resistance training. Several studies have shown that total oxygen consumption would be more elevated in protocols with high exercise volume compared with low exercise volume, so remember to increase the amounts of sets while preparing for a contest. Most bodybuilders use short rest periods to increase calories burned leading into a contest; however rest periods may not be as important as the exercise selection for larger muscle groups. Researchers from Brazil had resistance-trained men either perform four randomized protocols (5 sets of 10 repetitions with 15-rep maximum workloads with large leg press) and small-muscle (chest flye) group exercises, but varied the rest time with short (one-minute) or prolonged (three-minute) rest periods. The oxygen consumption increased in all protocols, being higher within the leg-press exercise than in the chest flye regardless of the rest interval. The one-minute rest-interval induced higher accumulated oxygen consumption during the leg press but not during the chest flye. Total energy expenditure was mainly influenced by muscle mass. They found that the leg press generated more metabolic activity than the chest flye, regardless of the rest-period duration.