Troubleshooting Knee Pain in Standing Side Splits: A Pilates Instructor’s Guide

How Small Adjustments in Spring Tension, Foot Placement and Muscle Recruitment Can Make a Big Difference in Client Comfort

Have you ever had a client wince in discomfort during a standing side split series, feeling an unexpected pull in their knee? Knee discomfort in both abduction and adduction is something many instructors may encounter, especially with clients who may struggle with stability, alignment, or previous injuries.

For those who might not be familiar with it, the standing side split series on the reformer is a dynamic exercise that involves standing with one leg on the platform and the other on the carriage, then pushing the carriage out and in, creating a controlled side split position.

This movement challenges balance, core stability, and strength, particularly in the hips, legs, and inner thighs, making it a powerful exercise for building lower body strength and flexibility. By adjusting the spring tension, you can modify the exercise to focus more on either the adductors or abductors.

In abduction, where the legs move apart, the knee might experience discomfort due to instability or improper alignment, especially if the abductor muscles (like the gluteus medius) aren’t fully engaged to support the movement. This can place extra strain on the medial side of the knee, potentially causing pain.

In adduction, where the legs come together, the inner thigh muscles (adductors) do more work, and if these muscles are weak or if there’s poor alignment, the knee might again bear extra strain, particularly on the lateral side. Additionally, if there’s any imbalance in the muscle activation or improper tracking of the knee, discomfort can arise.

It’s a common challenge to manage on the fly in a group class setting, but one that can be effectively addressed with a few mindful adjustments.

1. Alignment: If your client feels it more around where the ligaments lie, it might be due to the knee being slightly misaligned or not tracking properly. When the knee isn’t in the best alignment, ligaments such as the medial collateral ligament (MCL) can take on extra strain, especially in a position where there’s a lot of lateral movement or a tendency to rotate.

   
   

   Check the tracking of the knees, and observe if they tend to hyperextend, or if there is a tendency towards valgum (knock-kneed) or varus (bow-leggedness). Ask the client to notice the spiral of the thighbone in the hip-socket, mindful to keep the knees tracking in line with toes in movement, noting whether the feet are in parallel or turnout.

   
   

2. Muscle Recruitment: If the abductors/adductors or quads aren’t engaging as they should, the knee might start compensating by relying more on the ligaments for stability. This can definitely cause that pulling sensation, as the knee’s ligaments try to stabilize the movement without the full support of the muscles.

   
   

   Look for any locking in the joints, jerky motions or a lack of muscle engagement in movement. Ask the client to focus on activating the quads to draw the kneecap into position, cueing the adductor/abductor recruitment to support the action.

   
   

3. Foot Position: Sometimes, the way the foot is placed on the carriage can also affect how the knee tracks. If there’s any pronation (rolling in) of the foot or if the arch isn’t supported, it can cause the knee to collapse inward a bit, putting pressure on the medial side.

   
   

   Check for any pronation or supination of the feet, as well as the distribution of weight between front and back foot, or gripping toes. Guide your client to find even weight between the ball of the big toe, the little toe, and the center of the heel, emphasizing sealing down through the outer blade of the foot when pressing out. Even the smallest adjustments in how the foot connects with the carriage can ripple all the way up to the knee and hip.

   
   

4. Spring Tension: Light springs might cause clients to rely more on stability from their joints rather than their muscles, especially if they’re not fully engaging their core or other stabilizers. This can also contribute to that pulling sensation as the knee tries to take on the brunt of the stabilization.

   
   

   If your client is working on adduction, consider adding an extra quarter spring for support—sometimes just a bit of extra resistance can make all the difference in helping clients find their stability and control, providing that extra bit of support to activate the right muscles and take pressure off the joints.

   
   

A good approach for cueing the class to prevent this occurring could be to encourage them to focus on engaging their adductors and abductors (depending on the exercise focus), finding a clear grounding through the pads of the foot (particularly sealing down through the outer blade of the foot to maintain the arch of the foot in movement), and making sure the knee is tracking in line with the foot. By encouraging clients to listen to their body’s cues and becoming mindful of the little details, the payoffs for your clients will be huge.

If a pulling sensation or pain persists, it might be worth exploring slight modifications to the exercise by adjusting the spring tension to a more appropriate load (adding in adduction and subtracting in abduction), reducing the lever (trying a kneeling rather than standing version), or revisiting foundational Pilates exercises (like footwork) where clients can focus on controlled concentric/eccentric muscle recruitment and closed-chain movement with greater surface support, including tactile feedback for pelvic and foot alignment.

If a client has previous hip issues this can also affect their range of motion in both adduction and abduction. When there’s a history of hip problems, the knee can definitely end up compensating, especially in a movement with a significant range like standing side splits. By making adjustments for them on the spot such as reducing the range of motion or adjusting the load, you can help them to better understand their own body mechanics and learn to self-adjust to suit their body’s needs.

Ultimately, thoughtful adjustments and cues can make a huge difference in a class and for the client in front of you. By understanding individual client needs, checking in on their alignment during the movement, and knowing how to troubleshoot on the fly during a session, your client’s knees will thank you for being so attentive!