When learning a new movement, it is preferable to avoid muscular and technical failure by keeping at least 3 repetitions in reserve (RIR).

noli's read

This advice is based on the principles of motor learning, where the precise repetition of a gesture is crucial for consolidating neural connections. When fatigue sets in, technique inevitably degrades, which risks integrating errors into the motor pattern being acquired. Studies on motor learning suggest that precision and the quality of the gesture take precedence over intensity for skill development. Greg Nuckols relies here on a sports science approach that prioritizes long-term technical consistency rather than immediate extreme fatigue. Although training close to failure is useful for hypertrophy once a movement is mastered, it is considered counterproductive for automating a complex gesture. This recommendation is consistent with recommended practices in strength and conditioning (such as literature reviews on motor learning), where the emphasis is placed on 'deliberate practice' without the alteration of form.

the sources

1. 1strongerbyscience.com