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...
Mechanism
Synthesis from 1 study
Even when you swing the weights to lift more, your arm muscles still get stretched and pulled hard enough to grow — the force just spreads out a bit to other nearby muscles and tissues. As long as the total pull on the muscle fibers is strong and long enough, growth happens just as well as when you...
Most probable mechanism
When people lift weights with momentum, the force gets spread out across more muscles and joints instead of staying focused on just the arm muscles, but the total amount of stretch and pull on the muscle fibers stays high enough to trigger the same growth signals as strict lifting.
External momentum increases total mechanical load and alters force transmission patterns across the elbow joint complex, distributing tension across synergistic muscles and connective tissues.
Despite reduced isolation, the magnitude and duration of muscle fiber strain during the eccentric and concentric phases remain sufficient to activate mechanosensitive signaling pathways in muscle cells.
Mechanotransduction pathways, including mTOR and MAPK signaling, are activated to a similar extent as in strict form, leading to equivalent rates of myofibrillar protein synthesis.
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
Contradicting (0)
Community contributions welcome
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.