Hypertrophy is defined as an increase in muscle-fiber number. a decrease in muscle-fiber number. a decrease in muscle-fiber size. an increase in muscle-fiber size. Muscular force exerted as a muscle shortens is best classified as. A type of isotonic exercise used by athletes during training to simulate movement during sprinting or throwing is called variable resistance. plyometrics. A good resistance-training technique for developing explosive strength is eccentrics. speed loading. plyometrics. isokinetics. isometrics. eccentric loading. A type of body-weight exercise that emphasizes control of movement is called. Pilates. plyometrics. isometrics. isotonics. two. six. three. five. The minimum number of training days per week for gaining strength is. A recommended amount of resistance and number of repetitions for improving muscular endurance is. 40 60 percent of 1 rm and fifteen to twenty repetitions. 70 80 percent of 1 rm and one to five repetitions. 40 60 percent of 1 rm and one to five repetitions.