A short to long change in the supine to sit test suggests which of the following?

A short to long change in the supine to sit test is indicative of posterior pelvic rotation. When a patient is supine and their legs are measured, what is typically assessed is the alignment of the tibial lengths relative to each other. If one leg appears shorter when the patient is supine, but lengthens relative to the other leg when moving to a sitting position, this suggests that the involved side has undergone posterior rotation.

In the context of pelvic mechanics, a posterior rotation typically involves the ilium of the pelvis rotating backward, which would bring the innominate bone of that side closer to the ground, creating an appearance of a shorter leg while supine. When transitioning to a sitting position, this rotation is “corrected,” and the leg may appear longer, leading to the observed change from short to long.

Understanding this test is critical because it can be used in clinical assessment to identify specific pelvic dysfunctions contributing to lower extremity discrepancies or issues with the kinetic chain. Interventions in physical therapy often focus on addressing these pelvic alignment issues to improve functional mobility and reduce discomfort.