Exploring the Affective Responses to Resistance Training: A Comparison of the Predetermined and the Estimated Repetitions to Failure Approaches

In resistance training, the number of repetitions is traditionally prescribed using a predetermined approach (e.g., three sets of 10 repetitions). An alternative is the estimated repetitions to failure (ERF) approach (e.g., terminate sets two repetitions from failure). The latter may be a more enjoyable way to train as it allows trainees to better regulate their efforts. Accordingly, here we compared the affective responses and repetition numbers performed under both conditions among women (range: 23-45 years) inexperienced in resistance-training. Initially, one Repetition Maximum (1RM) prediction tests were conducted in four exercises. In the next two counterbalanced sessions, participants completed three sets of either ten repetitions (predetermined), or terminated sets two repetitions before reaching task-failure (ERF) using 70%1RM across exercises. Affective responses and approach-preference were collected during and after the sessions. We observed trivial differences in the affective responses and an approximately even approach-preferences split. Repetition numbers were mostly similar under both conditions in the chest-press, knee-extension and lat-pulldown (difference of ~1 repetition). However, under the ERF condition participants completed more repetitions in the leg-press (17 vs. 10, p<0.01). While the ERF approach may allow trainees to better regulate their efforts, the comparable affective responses in both approaches, suggests that trainees preferences should be considered prior to implementing either one.