Momentum as an Injury Risk

Momentum-assisted lifting gives the appearance of greater muscle strength, but it actually decreases demands on the target muscle groups and increases stress on the joint structure. Common momentum techniques include using assisting muscle groups to begin a lift (e.g., using back muscles and trunk movement to initiate barbell curls) and bouncing the bar off the chest during the bench press — which, in addition to the high injury potential, reduces the training effect on the target muscles (chest, shoulders, triceps).

In the cheat system, care must be exercised: using heavier resistance and a cheating movement to start the resistance moving increases the chance of injury (for example, swinging the hips and lower back during arm curls places additional stress on the lower back) (Fleck & Kraemer, 1997). While momentum has its place in sporting events, it should play a minor role in weight-training programs.

• Momentum increases stress on joint structures and injury potential.
• Bouncing the bar off the chest in the bench press has high injury potential.
• Cheat-system swinging of the hips/lower back stresses the lower back.
• Momentum reduces the training stimulus to the target muscles.

• momentum — the momentum principle.
• movement-speed-safety — slow lifting minimizes momentum.
• cheat-system — cheating increases injury chance.
• proper-form — proper form limits unwanted momentum.