Accuracy in Estimating Repetitions to Failure During Resistance Exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Accurate monitoring of resistance training intensity is crucial for optimizing performance and preventing overtraining.
• Estimating repetitions to failure (ERF) is a common practice, but its reliability requires further investigation.

Purpose of the Study:

• To assess the accuracy of estimating repetitions to failure (ERF) during resistance exercise.
• To determine if training status, sex, or exercise type influences ERF accuracy.

Main Methods:

• Eighty-one adults performed sets at 70% and 80% of 1 repetition maximum (1RM) for chest press and leg press.
• Subjects reported ERF after each set, followed by repetitions to actual failure (ARF).
• Error in ERF was analyzed across different ARF ranges (0-10).

Main Results:

• ERF accuracy decreased as ARF increased, with errors around 1 repetition at ARF 0-5 and over 2 repetitions at ARF 7-10.
• Chest press showed greater ERF accuracy than leg press.
• Men demonstrated higher ERF accuracy than women for the leg press, but not the chest press.

Conclusions:

• Resistance exercise participants can accurately estimate repetitions to failure when close to failure (ARF 0-5).
• ERF can be a practical tool for prescribing and monitoring resistance exercise.
• Exercise type and sex can influence ERF accuracy, highlighting the need for individualized approaches.