Joint and pull phase specific relative effort in weightlifting and simulated training effects.

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Understanding muscle recruitment patterns in weightlifting is crucial for optimizing training.
• Quantifying relative effort (RE) helps assess the demands placed on specific muscle groups.
• The clean lift involves complex coordination of multiple joints and muscle groups.

Purpose of the Study:

• To quantify the relative effort (RE) of extensor and plantarflexor muscles during the clean.
• To simulate the effects of strength and speed-strength training on joint and pull phase-specific RE.

Main Methods:

• Five weightlifters performed the clean at 85% of their one-repetition maximum.
• Motion capture and ground reaction forces were used to calculate lower body net joint moments (NJM_ID) via inverse dynamics.
• A musculoskeletal model estimated maximum theoretical net joint moments (NJM_max) to calculate RE (NJM_ID / NJM_max).

Main Results:

• Simulated strength training decreased RE in all muscle groups during both the first and second pull phases.
• Speed-strength training decreased hip extensor RE during the first pull and knee extensor RE during the second pull.
• Strength training demonstrated broad effects, while speed-strength training showed joint- and phase-specific effects on RE.

Conclusions:

• Strength training interventions can lead to widespread reductions in muscle effort during the clean.
• Speed-strength training may provide more targeted benefits, reducing effort at specific joints and phases of the lift.
• These findings can inform the design of more effective, individualized training programs for weightlifters.