How Hard and How Much: Proximity to Failure and Set Volume

Overview

Two dials control the hypertrophy dose of a program: how close each set gets to failure, and how many hard sets a muscle gets. This lecture covers a meta-analysis and a trained-lifter trial on proximity to failure, plus a 12-week trial that doubled the sets on the main lifts.

Does every set need to hit failure?

A meta-analysis of 15 studies compared training to set failure with stopping short of it.^[1]

• Any definition of failure vs non-failure: a trivial advantage for failure (effect size 0.19, 95% CI 0.00 to 0.37).
• Momentary muscular failure vs non-failure: no significant difference (effect size 0.12).
• High (over 25%) vs moderate (20-25%) velocity-loss thresholds: no difference (effect size 0.08).

The authors concluded that the relationship is likely non-linear. Sets must be taken close to failure to be effective, but going all the way to failure does not reliably add growth.

A 2026 study tested this in 19 resistance-trained men and women.^[2] For 8 weeks, each person trained one arm on the preacher curl to momentary failure and the other arm to 1-3 reps in reserve, at 70-80% of 1RM, twice a week.