International Sports Sciences Association (ISSA) Trainer Practice Exam

To achieve hypertrophy in strength training, what percentage of the one-repetition max is optimal for performing reps?

1. 60-65%

2. 70-75%

3. 75-80%

4. 80-85%

The correct answer is: 75-80%

Achieving hypertrophy, or muscle growth, generally involves training at a moderate to high intensity that effectively stimulates muscle fibers. The optimal range for promoting hypertrophy is often considered to be around 70-85% of one-repetition maximum (1RM). When you train within this range, you are able to perform enough repetitions (typically around 6-12) to create the muscular stress necessary for growth while also reaching a sufficient volume of training. This percentage allows for an effective balance between intensity and volume, striking the right chord to promote muscle adaptation. It ensures that the muscles are under tension for an adequate duration, leading to microtears in the muscle fibers, which subsequently heal and result in increased muscle size and strength. The other percentage ranges provided, while they may have their own benefits—like enhancing muscular endurance (in the lower ranges) or targeting maximal strength (in the higher ranges)—are less optimal for hypertrophy compared to the selected range. Thus, the choice of 75-80% aligns best with the goals of muscle growth in strength training.