Should you always train to failure? What a review of 15 studies found

Grinding out the last rep until the bar stops moving feels like proof you worked hard — and "should I always lift to failure?" is one of the most recurring questions lifters ask. A 2022 systematic review and meta-analysis in the Journal of Sport and Health Science pooled 15 studies to settle the question with data instead of gym folklore.

What the review found

Jozo Grgic and colleagues found no significant difference between training to muscular failure and stopping short of it for either strength (effect size − 0.09) or hypertrophy (effect size 0.22) across the pooled studies. That headline result alone answers the most literal version of the question: failure is not a requirement for getting bigger or stronger.

The details that matter more than the headline

Two subgroup findings add nuance worth knowing. First, when total training volume was not equated between groups, non-failure training actually came out ahead for strength gains — makes sense, since stopping a couple of reps short lets you do more total quality work across a session rather than grinding to exhaustion on every set. Second, in resistance-trained (as opposed to untrained) individuals specifically, training to failure showed a small but real edge for hypertrophy. So the more experienced you are, the more occasional failure sets may earn their keep for muscle growth — they just aren’t mandatory on every set of every session.

Training to muscle failure does not seem to be required for gains in strength and muscle size. However, training in this manner does not seem to have detrimental effects on these adaptations, either.

Reps in reserve: the practical middle ground

The framework most coaches now use instead of an all-or-nothing failure rule is reps in reserve (RIR) — how many more reps you could have done before the set ended. Most working sets in a well-built programme land around 1–3 RIR: hard enough to drive adaptation, controlled enough to repeat that quality set after set, week after week, without the fatigue cost of grinding every set to zero. Occasional true failure sets, especially on isolation work late in a session, are a legitimate tool — just not the default setting for every set of a squat or deadlift.

The practical takeaway

You do not need to chase failure to get results, and chasing it every set can actually cost you total volume and recovery. A sensible default is training close to failure — 1–3 reps in reserve on most sets — with occasional harder sets reserved for when fatigue management allows it.

This is the exact logic behind how Misi infers proximity to failure from the weight, reps and RPE you already log — weighting your weekly volume by how close each set actually was to failure, rather than crediting every set equally regardless of effort.

Misi is a coaching and wellness platform, not a medical service, and this article is educational and not a substitute for personalised training or medical advice.