Name the primary hip extensor targeted in single-leg exercises.

The primary hip extensor targeted in single-leg exercises is the gluteus maximus. This muscle is crucial for extending the hip joint, especially during activities that involve lifting the leg backward or performing movements like lunges or single-leg deadlifts. The gluteus maximus is the largest muscle in the buttock region and plays a key role in maintaining stability and proper alignment of the pelvis during single-leg work.

In single-leg exercises, the engagement of the gluteus maximus not only helps in generating power for the movement but also assists in stabilizing the hip joint, which is essential for preventing injuries and maintaining balance. This makes it an integral muscle for anyone practicing Pilates, particularly in exercises that challenge balance and strength on one leg.

While the hamstrings do play a role in hip extension, particularly in knee-flexed positions, the gluteus maximus is the more dominant muscle activated during typical single-leg hip extension actions. The quadriceps are primarily involved in knee extension rather than hip extension, and the adductor magnus primarily functions in adduction of the thigh and can assist in hip extension to some extent, but it is not the main target in single-leg exercises.