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...
Mechanism
Synthesis from 1 study
Swinging weights makes the lift easier for your whole arm, but that means the muscle you're trying to build doesn't get pulled hard enough to grow. Even if you lift more weight, it's not doing the work — your other muscles and joints are taking the load instead.
Most probable mechanism
When you swing a weight instead of lifting it slowly, the force moves through your joints and other muscles, so the muscle you're trying to work doesn't feel as much pull. Even if you lift more weight overall, that extra weight isn't pulling hard enough on the target muscle to trigger growth.
External momentum transfers a portion of the applied force through joint articulation and synergistic muscle activation, reducing the net tensile load experienced by the target muscle.
The reduced tensile load on the target muscle fails to reach the threshold required to activate mechanotransduction pathways that initiate muscle protein synthesis.
Without sustained mechanical tension above the growth threshold, satellite cell activation and myofibrillar remodeling remain unchanged despite increased total volume load.
Evidence from Studies
Supporting (1)
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Do Cheaters Prosper? Effect of Externally Supplied Momentum During Resistance Training on Measures of Upper Body Muscle Hypertrophy
Contradicting (0)
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Gold Standard Evidence Needed
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