How does the "lift off test" differ from the "internal rotation lag sign test"?

The lift-off test and the internal rotation lag sign test are both clinical assessments used to evaluate the integrity of specific shoulder structures, often related to rotator cuff function, but they differ in their approach to patient movement.

The lift-off test requires the patient to actively move their arm. Specifically, the patient is positioned in a way that they can lift their arm off their back by internally rotating and extending the shoulder. The success of this test hinges on the patient's ability to perform the movement, which indicates the strength and function of the subscapularis muscle.

In contrast, the internal rotation lag sign test involves the examiner moving the patient's arm into a position of internal rotation and then asking the patient to maintain that position. This test assesses the strength of the rotator cuff, particularly the subscapularis. The examiner's role is crucial here, as they initiate the movement, and the patient's task is to hold that position against gravity, which relies on passive support initially.

Thus, the distinction lies in the active versus passive nature of the movement required in each test. The lift-off test focuses entirely on the patient's ability to perform an active movement, while the internal rotation lag sign focuses on the patient's ability to sustain a position that was initially set