The Claim

In resistance-trained adults, performing single-set resistance training to muscular failure for 8 weeks, twice weekly, is associated with modestly greater increases in muscle thickness of the biceps brachii, triceps brachii, and quadriceps femoris compared to training with two repetitions in reserve.

Source: Without Fail: Muscular Adaptations in Single Set Resistance Training Performed to Failure or with Repetitions-in-Reserve.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
61score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

In adults who regularly lift weights, doing one set of exercises until muscle fatigue for 8 weeks twice a week results in slightly larger increases in biceps, triceps, and quadriceps muscle thickness than doing the same exercises while stopping two repetitions before fatigue.

See the scientific wording

In resistance-trained adults, performing single-set resistance training to muscular failure for 8 weeks, twice weekly, is associated with modestly greater increases in muscle thickness of the biceps brachii, triceps brachii, and quadriceps femoris compared to training with two repetitions in reserve, though differences are not statistically decisive and may not be clinically meaningful.

Why this might work

When muscles are pushed to complete fatigue, more muscle fibers are activated and forced to work harder, creating stronger physical stress and buildup of metabolic byproducts. This triggers the muscle to build more protein and grow thicker over time.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Without Fail: Muscular Adaptations in Single Set Resistance Training Performed to Failure or with Repetitions-in-Reserve.

    For people who already lift weights, doing one set of each exercise until you can't do another rep might help your muscles grow just a tiny bit more than stopping two reps early — but the difference is so small that it might not matter in real life.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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