Using momentum to lift weights during upper-body 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...

Pro

Against

Mechanism

Synthesis from 1 study

How it works

Swinging weights makes it look like you're lifting more, but your arm muscles aren't actually working harder — the motion comes from your body swinging, not your muscles contracting. Since muscle growth needs your arm muscles to be under real tension, the extra weight doesn't help if your arms...

Most probable mechanism

In Simple Terms

When you swing weights during arm exercises, your body uses other muscles and motion to move the weight, so your arm muscles don't have to work as hard. This means the actual force on your arm muscles stays low, even if you're lifting heavier weights. Since muscle growth needs sustained tension in the target muscle, the reduced effort from the arm muscles doesn't trigger the signals needed to make them bigger.

Causal chain

External momentum transfers a portion of the load to non-target muscles and inertial motion, reducing the mechanical tension experienced by the target upper-body muscles during contraction

Supported by evidence

which leads to

Reduced mechanical tension in the target muscles decreases activation of mechanosensitive pathways that regulate protein synthesis and muscle fiber remodeling

Indirect evidence only

which leads to

Without sufficient tension-induced signaling, the cellular processes that drive muscle fiber growth remain below the threshold required for hypertrophy

Indirect evidence only

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.

Source Study

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

Score: 79

DOI: 10.70252/GDBL2230

Similar Assertions

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.

86%

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 untrained people lift weights using a swinging motion instead of a controlled one, their upper arms do not grow larger as a result, based on measurements comparing the two techniques.

80%

In young adults doing arm exercises for eight weeks, using momentum to lift weights does not result in more muscle growth than lifting with strict form, even though more total weight is moved with momentum, suggesting that how tension is distributed across the muscle may offset the reduced focus on individual muscles.

78%

When you do single-joint arm exercises like bicep curls, swinging the weight gives you the same muscle growth as using perfect form. But this doesn't work for leg exercises or movements that use multiple joints at once.

75%