| Rest Periods |
| Energy Utilization - For bouts of high-intensity exercise of less than 30 s in duration, the primary energy sources are adenosine triphosphate (ATP) and creatine phosphate, which are stored in the muscles - Intense training can deplete these phosphagen stores in 15 s - It takes about 2.5 to 3 min to replenish the phosphagen stores needed for the next set of high-intensity effort |
| Training for Absolute Strength - Accomplish maximal or near-maximal repetitions with a heavy load usually need to take 3 to 5 min between heavy sets of exercise (for absolute strength <1RM>) |
| Training for Hypertrophy and Local Endurance - 30-60 s = 8-12RM - Work-rest ratio = 1:1 or more - 1-3 min = long-sprint running (400-1,000m) or swimming (100-200m) - Work-rest ratio = 1:1 or more |
| Circuit Training - Work-rest ratio = 1:1 or more - The increases are 30-50% less than those achieved with traditional strength and endurance training - 15 s of high-intensity work followed by an equal time of rest allows for the most work to be performed in the shortest amount of time |
| Other Factors - Athletes returning to training after prolonged periods of detraining should begin by resting longer than usual between sets of exercise |