Where should resistance be applied when testing latissimus dorsi in shoulder adduction?

Where should resistance be applied when testing latissimus dorsi in shoulder adduction?

• A. At the distal humerus near the elbow as the arm moves toward the midline; stabilize the scapula
• B. At the wrist
• C. At the shoulder joint
• D. At the upper arm near the biceps

Answer: (A)

When testing latissimus dorsi during shoulder adduction, the resistance should oppose the muscle’s action along the limb and be applied on a distal segment so the movement occurs at the shoulder joint and is not aided or overridden by other joints. Pressing on the distal humerus near the elbow as the arm moves toward the midline directly challenges the latissimus dorsi’s pull on the humerus, matching the muscle’s line of action and keeping the effort focused at the glenohumeral joint. Stabilizing the scapula is important to prevent compensatory movements from the scapulothoracic system, which can mask true strength of the latissimus dorsi and blur the test’s isolation. Testing with resistance at the wrist, or at the shoulder joint itself, or on the proximal upper arm near the biceps would either fail to counter the latissimus dorsi effectively, recruit other muscles, or allow scapular motion to contribute, reducing the accuracy of the strength assessment.

When testing latissimus dorsi during shoulder adduction, the resistance should oppose the muscle’s action along the limb and be applied on a distal segment so the movement occurs at the shoulder joint and is not aided or overridden by other joints. Pressing on the distal humerus near the elbow as the arm moves toward the midline directly challenges the latissimus dorsi’s pull on the humerus, matching the muscle’s line of action and keeping the effort focused at the glenohumeral joint.

Stabilizing the scapula is important to prevent compensatory movements from the scapulothoracic system, which can mask true strength of the latissimus dorsi and blur the test’s isolation. Testing with resistance at the wrist, or at the shoulder joint itself, or on the proximal upper arm near the biceps would either fail to counter the latissimus dorsi effectively, recruit other muscles, or allow scapular motion to contribute, reducing the accuracy of the strength assessment.