One-repetition maximum

The 1RM is defined as the maximal weight that can be lifted once while keeping correct lifting technique [1]. In the 1RM test, the lowering and lifting phases of a movement (eccentric and concentric actions) are usually combined [1].

How consistent the test is from one session to the next is called test-retest reliability. One systematic review included studies that reported it as an intraclass correlation coefficient (ICC), a coefficient of variation (CV) or both [1]; a higher ICC and a lower CV mean more consistent results. Across its 32 studies (1,595 participants pooled), the review found ICCs from 0.64 to 0.99, with a median of 0.97, and CVs from 0.5% to 12.1%, with a median of 4.2% [1].

The review concluded that the test generally has good to excellent reliability regardless of training experience, number of familiarization sessions, the exercise chosen, upper or lower body, sex or age, and most included studies found no systematic change between test sessions [1]. Its results suggest familiarization sessions are not necessary for a reliable 1RM [1].

Because the test is reliable, researchers can use the 1RM as a measure of muscular strength [1]. In a supplement trial, the result that counts is the difference in 1RM change between the supplement group and the placebo group.

The CV describes the typical variation between test sessions; in the review it ranged up to 12.1% [1]. That variation is the background against which a supplement-versus-placebo difference in strength is judged, and a 1RM gain in one exercise is not the same outcome as a gain in another.

NootropicsWork reports 1RM findings with the exercise tested, the training program, the population and the comparison.

Systematic review, placebo, lean mass.