When the feet turn out during movement, the primary underactive muscles are the medial gastrocnemius (the inner portion of your main calf muscle) and the medial hamstrings (the inner hamstring muscles on the back of your thigh). These two muscle groups share a common job: they help control rotation at the knee and lower leg. When they aren’t firing well, the lower leg rotates outward and pulls the foot with it.
This compensation is most commonly identified during an overhead squat assessment, a standard screening tool used in personal training and corrective exercise. Understanding which muscles are underactive helps you target the right areas with activation and strengthening work.
Why the Medial Gastrocnemius Matters
Your calf is made up of two main heads. The medial (inner) head of the gastrocnemius plays a role in controlling how your lower leg rotates during walking, squatting, and landing. When this muscle has decreased neural drive, meaning your nervous system isn’t sending it strong enough signals, it can’t do its part in keeping your foot and ankle aligned. The lateral (outer) calf muscles and other external rotators essentially win the tug-of-war, pulling the foot outward.
You can think of it this way: muscles on the inner and outer sides of your lower leg work together like reins on a horse. If the inner rein goes slack, the leg drifts outward. The medial gastrocnemius is one of those inner reins.
The Role of the Medial Hamstrings
The hamstrings aren’t just one muscle. The group includes muscles on both the inner and outer sides of the back of your thigh. The medial hamstrings, specifically the semitendinosus and semimembranosus, attach along the inner side of the knee. One of their lesser-known jobs is helping to internally rotate the tibia (your shin bone). This counterbalances the forces that pull the lower leg into external rotation.
When the medial hamstrings are underactive, that internal rotation force weakens. The result is the same pattern: the tibia rotates outward, and the foot follows. This is why feet turning out isn’t purely an ankle or foot problem. It often traces back up the chain to the knee and even the hip.
Other Muscles That May Contribute
While the medial gastrocnemius and medial hamstrings are the textbook answers for this compensation, the picture can be more complex depending on the individual. The popliteus, a small muscle behind the knee, also acts to internally rotate the tibia and inhibit excessive tibial rotation. If the popliteus isn’t functioning well, it removes another check on outward rotation of the lower leg.
Higher up the chain, the gluteal muscles play a stabilizing role worth understanding. The gluteus maximus, medius, and minimus work together to stabilize the hip by controlling adduction and rotation of the thigh. When these muscles aren’t activating properly, the entire leg can lose alignment in multiple planes, which may show up as foot turnout, knee collapse, or both. In many people, foot turnout and knee valgus (knees caving inward) appear together during a squat, pointing to a broader pattern of lower-body dysfunction rather than a single weak muscle.
What’s Happening on the Overactive Side
Underactive muscles don’t exist in isolation. When certain muscles are underactive, their opponents are typically overactive, meaning they’re pulling harder than they should. For feet turning out, the overactive muscles are generally the lateral gastrocnemius (outer calf), the biceps femoris (the outer hamstring), and the external rotators of the hip. These muscles are creating more outward pull than the underactive inner muscles can counteract.
This is a core concept in corrective exercise: you don’t just strengthen the weak muscles. You also need to release or relax the overactive ones. Foam rolling or other soft tissue work on the outer calf, outer hamstring, and hip external rotators helps reduce their dominance. Then you follow up with activation exercises for the underactive muscles to restore balance.
How This Is Identified
The overhead squat assessment is the most common screening tool for spotting this compensation. You stand with feet hip-width apart, toes pointing forward, raise your arms overhead, and squat down. A trained observer watches from the front, side, and back to look for compensations. Feet turning out is one of several things they check for, along with knees caving in, the low back arching, and the torso leaning forward excessively.
It’s important to understand that this assessment isn’t a medical diagnosis. It identifies movement tendencies that suggest certain muscles may not be activating well. The word “underactive” specifically means decreased neural drive: your brain isn’t sending strong enough signals to those muscles during movement. This is different from saying the muscle is structurally weak or damaged. It’s a coordination and activation problem, which is why targeted exercises can often correct it relatively quickly.
Corrective Strategies for Foot Turnout
A typical corrective approach follows a specific sequence. First, you release the overactive muscles using foam rolling or similar techniques. For foot turnout, that means spending time on the outer calf, the outer hamstring (biceps femoris), and the muscles that externally rotate your hip. About 30 seconds of sustained pressure on each tender spot is a common guideline.
Next, you stretch those same overactive muscles to further reduce their pull. Static holds of 20 to 30 seconds work well here.
Then comes the activation piece. Isolated exercises that target the medial gastrocnemius and medial hamstrings help wake those muscles up. For the inner calf, calf raises with your toes pointed slightly inward shift emphasis to the medial head. For the medial hamstrings, ball squeezes between your knees during a bridge exercise can help preferentially recruit the inner hamstrings over the outer ones.
Finally, you integrate the new pattern into a full movement like a squat. Performing squats with a resistance band around your knees or with deliberate attention to keeping your feet straight helps reinforce the corrected movement. Over several weeks, consistent work through this sequence retrains the nervous system to activate those underactive muscles automatically during everyday movement.