Using momentum to lift weights during resistance training lets people lift heavier weights, but the heavier weights do not necessarily mean the muscles have become stronger.

Pro

Against

Mechanism

Synthesis from 1 study

How it works

When you swing a weight instead of lifting it slowly, the motion does most of the work — your muscles don’t have to push as hard. Because strength grows only when muscles are truly challenged, using momentum means you’re lifting more weight without actually getting stronger.

Most probable mechanism

In Simple Terms

When you use momentum to swing a weight, your muscles don’t have to work as hard to move it because the motion carries the load for you — so even though you’re lifting something heavier, your muscles aren’t getting stronger because they’re not being challenged the same way.

Causal chain

External momentum transfers kinetic energy to the load, reducing the force required by skeletal muscles to initiate and sustain motion

Verified by multiple studies

which leads to

Reduced muscular force demand decreases mechanical tension on muscle fibers, limiting activation of signaling pathways that trigger muscle adaptation

Supported by evidence

which leads to

Lower mechanical tension results in diminished recruitment of high-threshold motor units and reduced metabolic stress, preventing the stimuli necessary for strength gains

Supported by evidence

Evidence from Studies

Supporting (1)

Community contributions welcome

Do Cheaters Prosper? Effect of Externally Supplied Momentum During Resistance Training on Measures of Upper Body Muscle Hypertrophy

Randomized Controlled Trial

Human

2025

Contradicting (0)

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Similar Assertions

Using momentum to lift weights during isolated exercises does not lead to greater muscle growth in people who are new to training, even if they lift more total weight, because shifting the effort to other muscles doesn't help the intended muscle grow.

80%

When lifting weights until complete fatigue, using momentum from body movement does not lessen muscle growth in the targeted muscles.

79%

When lifting weights with a swinging motion instead of strict control, untrained people can lift more total weight, but this does not lead to bigger muscles. This suggests that how much tension is placed on the muscle matters more than the total amount of weight moved.

78%

Using external momentum to lift heavier weights during resistance training may still lead to muscle growth in people new to exercise, even if their form is less strict, because the muscles may still experience sufficient tension.

77%

When you use momentum (like swinging or cheating) to do exercises, you lift about twice as much total weight—but that extra work doesn't seem to make your muscles grow bigger than doing the exercise slowly and strictly.

77%