The Ely test detects contracture of the rectus femoris component of the quadriceps muscle. With the patient prone, the examiner gently flexes the knee to 130 degrees. Contracture of the rectus femoris is indicated by simultaneous flexion of the hip, which causes the buttocks to rise off the table.
Adapted from Aronsson, DD. The pediatric orthopedic examination. In: Lovell and Winter's Pediatric Orthopedics, 5th ed, Morrissy, RT, Weinstein, SL (Eds), Lippincott Williams &Wilkins, Philadelphia, 2001. p. 99.