Single leg squat examination

(A) In a correctly performed single leg squat examination maneuver, the patient's toe, knee, and hip should be aligned in a straight line or slightly varus position (solid line); the elbows and hips should be level (dashed lines); and the knees should remain slightly apart (arrow).
(B) Dipping of the pelvis toward the unsupported leg (Trendelenberg position) indicates weakness of the gluteus medius and minimus in the planted leg.
(C) Common signs of weakness include collapse of the knee of the supported leg inward (valgus collapse), which indicates gluteal and/or quadriceps weakness (solid line). Another common sign of weakness (and valgus collapse) is a squeezing together of the planted and unsupported legs (X). Normal strength enables the patient to maintain distance between the knees.
(D) Another sign of gluteal weakness is the compensated, or reverse Trendelenberg, position. The patient lifts the pelvis on the free side and/or leans their trunk towards the planted leg to compensate for gluteal weakness.