preexhaustion

Preexhaustion, also called pre-exhaust training, is a resistance-training technique in which a target muscle group is fatigued with an isolation exercise before performing a subsequent compound exercise that also uses that muscle group. The goal is to increase the involvement of the target muscle during the compound movement and to emphasize its development when coordination or strength elsewhere might limit activation.

In practice, a trainee selects an isolation exercise (for example leg extensions for the quadriceps) and performs a set to near failure, then immediately performs a multi-joint movement (such as squats) with minimal rest and a load that may be lower than typical; the emphasis remains on the target muscle during the compound lift.

Rationale: The technique tries to pre-fatigue the targeted muscle so that the subsequent compound movement recruits more motor units within that muscle due to fatigue-induced changes in force production, potentially enhancing time-under-tension and hypertrophy of the target muscle. Some evidence shows altered muscle activation patterns, but results are inconsistent and performance on the compound lift may be reduced.

Practical considerations: It can be used to address lagging muscles or to add variety, but it often reduces strength output on the main lift and may increase soreness. It is not ideal for beginners, and proper form and load management are essential to minimize injury risk.

Variations and related concepts: Preexhaust can be combined with different isolation and compound pairings, and is related to other techniques such as post-exhaustion, supersets, and blood-flow restriction training.