During manual muscle testing, which position best isolates the gluteus maximus by placing the hamstrings on slack?

• A. Prone with knee flexed 90 and hip extended
• B. Supine with hip extension
• C. Sitting with hip extension
• D. Side-lying with hip extension

Answer: (A)

To isolate the gluteus maximus, you want to remove the hamstrings from contributing to hip extension. The hamstrings cross both the hip and knee, so their involvement can mask the true strength of the gluteus maximus. Positioning the person prone with the knee bent to about 90 degrees places the hamstrings on slack at the knee, reducing their ability to assist in extending the hip. With the hip already extended, the gluteus maximus becomes the primary mover resisting testing, giving a clearer measure of its strength. In other positions, the hamstrings or other muscles may still contribute to hip extension or the test may not effectively isolate the gluteus maximus.