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Training to Failure or Stopping Short: What Three Meta-Analyses Say About Strength and Muscle Size

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Whether each set should be pushed until no further repetition can be completed is one of the most argued questions in home training. Three published systematic reviews with meta-analysis have compared training to failure with training that stops short. This article summarises what each reports and where the evidence stops. It covers general findings about resistance training in healthy adults and is not advice for anyone with an injury or health condition.

Why the definition matters

The reviews do not use one definition. The 2023 review by Refalo and colleagues separates momentary muscular failure from “set failure”, which it defines as anything other than momentary muscular failure, because the included studies used different definitions of failure. It also compares training to different velocity loss thresholds. A finding about one definition cannot be assumed to hold for another.

Strength: the 2016 meta-analysis

Davies, Orr, Halaki and Hackett pooled eight studies comparing failure with non-failure training for strength. Four controlled training volume and four did not. The main results were:

  • non-failure training produced a 0.6 to 1.3% greater strength increase, with a small pooled effect favouring non-failure training (effect size 0.34, p = 0.02);
  • small effects favouring non-failure training were also found for compound exercises (0.37 to 0.38) and for trained participants (0.37);
  • in the four volume-controlled studies there was no significant effect, although the trend favoured non-failure training;
  • the methodological quality of the included studies was rated as moderate.

The authors conclude that the small percentage improvement is unlikely to be meaningful, so similar strength gains appear achievable with or without failure. They add that it seems unnecessary to train to failure to maximise strength and suggest that, if it is used, it should be used sparingly to limit the risks of injury and overtraining.

Strength and size: the 2022 meta-analysis

Grgic, Schoenfeld, Orazem and Sabol included 15 studies, all in young adults. The results were:

  • no significant difference between training conditions for strength (effect size -0.09, 95% confidence interval -0.22 to 0.05) or for hypertrophy (0.22, 95% confidence interval -0.11 to 0.55);
  • in studies that did not equate training volume, a significant effect favouring non-failure training on strength (-0.32, confidence interval -0.57 to -0.07);
  • in resistance-trained participants, a significant effect favouring training to failure for hypertrophy (0.15, confidence interval 0.03 to 0.26).

The authors conclude that training to muscle failure does not seem to be required for gains in strength and muscle size, but does not seem to have detrimental effects on these adaptations either. They call for more studies among older adults and highly trained individuals.

Muscle size: the 2023 meta-analysis

Refalo, Helms, Trexler, Hamilton and Fyfe pooled 15 studies that measured hypertrophy in healthy adults of any age or training experience. They report:

  • a trivial advantage for training to set failure over non-failure (effect size 0.19, 95% confidence interval 0.00 to 0.37, p = 0.045), with no moderating effect of volume load or relative load;
  • no advantage for momentary muscular failure over non-failure (0.12, confidence interval -0.13 to 0.37, p = 0.343);
  • no advantage for higher over moderate velocity loss thresholds (0.08, confidence interval -0.16 to 0.32, p = 0.529).

The authors conclude there is no evidence that momentary muscular failure is superior to non-failure training for hypertrophy, and that closer proximity to failure does not always produce more growth. They suggest a possible non-linear relationship between proximity to failure and hypertrophy.

Reading the three reviews together

The reviews point the same way. For strength, neither of the two analyses that measured it finds a benefit for failure, and the 2016 analysis leans slightly towards stopping short. For muscle size, the effects near zero are small: the 2022 review reports a benefit for training to failure only in the resistance-trained subgroup, and the 2023 review reports a trivial advantage under a broad definition of set failure that disappears for momentary failure. The confidence intervals in several results touch or cross zero, so these findings describe averages across studies and not a rule for any individual.

Limits apply to all three. The studies in the 2022 review were all in young adults, and that review calls for more work in older adults and highly trained people. The numbers of trials are modest, at 8 to 15 per review, and protocols differ. None of them can say how stopping short, by a fixed number of repetitions or by an effort rating, should be prescribed. That question is covered on this site in RPE and RIR: Using Perceived Effort to Set Your Training Load.

Where equipment enters

These reviews do not evaluate products. Equipment matters in a practical sense: going close to failure with a loaded barbell is easier to do safely where the setup includes pins, straps or spotter arms, which are compared in Safety Systems on Racks. Stopping short of failure reduces how often that hardware is needed, and the reviews suggest little is lost in doing so on average.

Frequently asked questions

Does training to failure build more muscle?

Across the 2022 and 2023 meta-analyses, the average difference in muscle size is small and often not statistically significant. The 2022 review found an advantage for failure among resistance-trained participants.

Is it harmful to train to failure?

The 2022 authors report that training to failure does not seem to have detrimental effects on strength and size adaptations. The 2016 authors suggest using it sparingly to limit injury and overtraining risk, which is a suggestion and not a finding of the pooled data.

The bottom line

Three meta-analyses find that stopping short of failure produces, on average, similar strength gains (two analyses) and similar or slightly lower muscle growth (two analyses) than training to failure, with a possible small edge for failure among trained lifters in one review. None supports treating failure as a requirement. The trials pooled are modest in number, one review covers only young adults, and none can dictate an exact number of repetitions to leave in reserve.

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