Motor Behavior in a Single-Leg Squat

The single-leg squat is a challenging movement that requires good stability and motor control at the hip, knee and ankle joints. A strong understanding of the biomechanics and motor control patterns of the movement will be beneficial in performing, coaching or prescribing single-leg squats. In addition, understanding proper motor patterns in the movement can help trainers, coaches, spotters and practitioners identify potential injuries and asymmetries.

  1. Low Back Motor Pattern

    • The lower back motor pattern in a single-leg squat is flexion and extension in the sagittal plane. From an upright position, as the squat is performed the lower back flexes and the hips are shifted backward as the knee bends into the squat position. The low back and hips hinge backwards, creating a balanced center of gravity over the foot. Upon return to standing position the hips and low back extend forward.

    Motor Behavior in the Knee

    • The motor pattern of the knee in a single-leg squat is also flexion-extension in the sagittal plane. But due to its position between two long levers it has a greater stability demand. To perform the squat, the knee will bend or flex backward until the thigh is parallel to the ground. To return to starting position, the knee joint will extend or straighten. Throughout the movement the surrounding muscles of the quadriceps, hamstrings, adductors and abductors work to keep the knee joint in place as a fulcrum between the upper and lower leg.

    Role of the Ankle

    • The ankle has to provide a mobile base for the foundation of the leg in the single-leg squat motion. The foot should remain flat on the ground, and the ankle works in flexion/extension in the sagittal plane. The ankle primarily functions in dorsiflexion in the single leg squat motion; as the body sinks into the squat position the ankle flexes to absorb the motion, then holds strong as the leg straightens.

    Mobility and Stability Concerns

    • All three joints are connected, and incorrect motor function in one can cause poor motor behavior in the others. It is important before practicing single leg squats to assess hip mobility, knee stability, and ankle mobility to prevent overcompensation, asymmetry, and potential injuries. Understanding the correct motor patterns of the single leg squat can help practitioners, coaches, and trainers identify these limiting factors to improve performance.