Strength asymmetries are fairly common in people, especially if they have suffered a prior injury or participate in repetitive activities and sports. Training lower the lower leg in a unilateral fashion can pose a challenge in the face of painful range of motion, limited eccentric control and balance. In this column, I will discuss an effective exercise to improve lower extremity strength using an exercise ball.
Position a stability ball in the small of the back and the wall. Next, ensure the stance leg’s foot is in a position that is far enough away from the wall so the knee will remain in good alignment throughout the squatting motion. Flex the non-stance knee to 90 degrees. 

With the arms resting at the sides, slowly squat down on the stance leg in a slow controlled motion in a stable, pain-free range of motion. The uninvolved leg will simply stay flexed with the foot moving posteriorly toward the wall during the descent. Ideally, the unsupported foot should not touch the wall or floor. Pause at the bottom for 1-2 seconds and then return to the start position. Repeat for 10 repetitions and then switch legs. Perform 2-3 sets..

This exercise will allow for hip and knee strengthening while allowing the client to incrementally adjust the depth of the squat based on strength, stability and any discomfort that occurs. The ball allows for a predictable and consistent center of gravity, in addition to providing kinesthetic feedback to the user. The client can load the leg with more confidence in this manner if they would otherwise struggle with balance and body control in a free standing manner. The single leg ball squat offers a systematic way to focus on strength and stay in a safe range of motion. Additionally, longer isometric holds can be employed to challenge the client and strengthen with more time under tension in certain points in the motion. 


1. Increase time under tension and/or range of motion.

2. Decrease stability by folding the arms across the chest, then moving them to the top of the head and finally holding them extended overhead. 

3. Add more load via weights, kettlebells, etc.

1. Decrease time under tension and/or limit range of motion
2. Perform isometric holds (single leg wall sit)
3. Use the uninvolved foot for additional support via light toe/heel touch on the wall during descent phase.

Brian Schiff, PT, OCS, CSCS, is a licensed physical therapist, respected author and fitness professional. Currently, he serves as the supervisor for EXOS API at Raleigh Orthopaedic. Brian conducts live continuing education webinars and presents nationally at professional conferences and seminars on injury prevention, rehab and sport-specific training. For more information on his products and services,

Topic: Functionally Fit

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