Changing how you perform resistance exercises, such as squats or bench presses, changes the amount of mechanical stress applied to the muscles being worked.
Mechanism
Synthesis from 4 studies
Changing how you move during a workout—like bending your elbow more or moving slower—shifts where the resistance pulls on your muscles. This makes some muscles work harder because they’re in a better position to fight the force, while others get a break because they’re not pulled as effectively....
Most probable mechanism
When you change how you move during a workout—like bending your elbow more, moving slower, or keeping your shoulders lower—the way your joints rotate and how far your limbs extend changes. This shifts where the resistance pulls on your muscles, making some muscles work harder and others work less. Muscles that are stretched more or pulled at a better angle produce more force, while those pulled at a worse angle or not stretched enough don’t have to work as hard.
Changes in joint angle during movement alter the moment arm between the line of resistance and the joint axis, increasing or decreasing the torque required to move the limb.
Altered torque demand directly determines the level of muscle activation needed to generate sufficient force to overcome resistance.
Muscle activation is modulated based on the mechanical advantage of the muscle’s line of pull relative to the joint, with muscles positioned for optimal leverage experiencing greater force production.
Movement velocity influences inertial forces and dynamic load, with slower movements reducing impulsive forces and increasing sustained tension on muscles involved in stabilization and control.
Body posture and limb alignment (e.g., scapular position, hand orientation) reorient the direction of resistance relative to muscle origins and insertions, changing which muscles bear the greatest load.
Increased joint range of motion and faster movement velocities increase the total mechanical work and torque production across multiple joints, redistributing stress from smaller stabilizers to larger prime movers.
Evidence from Studies
Supporting (4)
Community contributions welcome
Numerical Modeling of Load-Driven Changes in Squat Technique Using a Moment-Limited Joint Framework
Contradicting (0)
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Gold Standard Evidence Needed
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