Each repetition in a set accounts for about what percentage difference in attainable load based on the 1RM?

The correct choice indicates that each repetition in a set accounts for about a 2-3% difference in the attainable load based on the one-repetition maximum (1RM). This percentage is significant for trainers and athletes as it helps in planning training protocols and determining the appropriate resistance during strength training.

Understanding the relationship between repetition ranges and load is crucial for customizing workouts to achieve specific goals, such as strength gains or hypertrophy. A 2-3% variation means that, as the number of repetitions increases, the load that can be lifted decreases by this percentage of the individual's 1RM. For instance, if an athlete's 1RM for a given lift is 100 pounds, a set of 10 repetitions might require the athlete to lift about 70-75 pounds, accounting for the cumulative fatigue and muscular exertion.

This information aids trainers in creating effective workout programs by assisting them in determining how to adjust load according to the number of repetitions planned. The 2-3% rule allows for more precise programming and can help avoid the risks of overtraining while ensuring that athletes train effectively within their capacity.