When healthy young men perform a specific Tai Chi exercise with an elastic band, it activates the infraspinatus and coracobrachialis muscles more than another elastic band exercise called the reverse...
Mechanism
Synthesis from 1 study
When you move slowly with bent elbows and lowered shoulders, your front upper arm and back shoulder muscles work harder because they’re in a better position to pull against the band. When you move quickly with straight elbows and raised shoulders, your front and inner shoulder muscles work harder...
Most probable mechanism
When you move your arms slowly with your elbows bent and shoulders low, your front upper arm and back shoulder muscles work harder because the position makes it easier for them to pull against the band. When you move your arms quickly with your elbows straight and shoulders raised, your front shoulder and inner shoulder muscles work harder because the motion stretches them more and requires more force to control the movement.
Sustained elbow flexion increases the mechanical leverage on elbow flexor muscles, enhancing their force production and neuromuscular activation.
Restricted shoulder horizontal abduction and slow movement velocity reduce torque demand on shoulder abductors and external rotators, decreasing their activation.
Low shoulder elevation and neutral hand position optimize the mechanical advantage of the infraspinatus for stabilizing the humeral head against resistive forces.
Scapular protraction and internal rotation position the humerus for horizontal adduction, increasing mechanical demand on the coracobrachialis to generate sustained force.
Extended elbow position and rapid shoulder abduction increase torque and inertial load on anterior deltoid and subscapularis, driving greater recruitment of these muscles.
Evidence from Studies
Supporting (1)
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Contradicting (0)
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