How Foot Placement During Squats Changes Which Muscles Do The Work

Something as minor as the angle of the toes during a squat can reshape the way the nervous system coordinates muscle teamwork across the entire lower body, according to a new study.

Published in the journal Gait & Posture, research finds that widening your stance and turning your toes outward during a squat appears to cause the nervous system to ease off its reliance on stabilizing muscles and increase activation of the body’s primary power-producing muscles instead. That shift could matter for everyone from athletes tweaking their training to engineers building wearable robotic devices that help people stand and move.

The finding goes beyond just measuring which individual muscles fire harder or softer. By analyzing how groups of muscles coordinate with one another, a concept scientists call muscle synergy, researchers identified a deeper pattern. The brain appears to have a default coordination blueprint for squatting that stays constant no matter how the feet are positioned, but it layers additional adjustments on top of that blueprint depending on foot angle and stance width.

How the Squat Study Worked

Nineteen healthy young men performed squats under six different conditions in a university lab. The conditions combined three stance widths (narrow, medium, and wide) with two foot angles: toes pointing straight ahead and toes turned outward at 30 degrees. Participants held a lightweight wooden stick across their shoulders to mimic the position of a barbell, but no heavy load was used. This was a bodyweight-only experiment.

Researchers attached sensors to seven muscles on each participant’s right leg, including the large thigh muscles responsible for straightening the knee, the calf muscles, a hip muscle, a hamstring muscle, and a muscle running along the outside of the lower leg that keeps the ankle stable from side to side. Each participant completed three repetitions of each squat variation, 18 total, while cameras tracked a marker on the hip to identify when the lowering and rising phases began and ended.

Rather than just looking at how hard each muscle worked on its own, the research team used a statistical method that identifies patterns of muscles working together in coordinated groups. It’s a bit like listening to an orchestra: instead of measuring how loud each instrument plays individually, this approach identifies which instruments tend to play together and how their combined volume changes from one piece to the next.

How Foot Placement Changes Muscle Coordination During Squats

The most dominant coordination pattern, accounting for roughly half of the variation in muscle signals during both the lowering and rising phases, was driven primarily by the large muscle on the outside of the thigh, a major power generator during squats. This dominant pattern did not change across any of the six foot positions, confirming the researchers’ prediction that the body’s core squatting strategy remains stable regardless of how the feet are set up.

The secondary patterns told a different story. During the lowering phase, a coordination pattern linking the outer ankle stabilizer and the outer thigh muscle showed meaningful changes. When participants kept their toes pointed straight ahead, this stabilizer-heavy pattern was more active than when toes were turned out to 30 degrees. A narrow stance also produced higher scores in this pattern than a wide stance. In plain terms, the body recruited more side-to-side ankle stabilization effort when the feet were narrow and straight, and that effort dropped when the stance widened or the toes pointed outward.

During the rising phase, a different coordination pattern emerged involving the outer thigh muscle, a front thigh muscle, and the deeper calf muscle. This group of primary movers was linked to greater activation when toes were turned outward at 30 degrees compared to straight ahead.

One of the study’s more notable findings is that the traditional approach to analyzing muscle activity, simply looking at peak activation of each muscle one at a time, missed details that the coordination analysis caught. Changes in the outer thigh and calf muscles during the rising phase showed up clearly in the coordination patterns but were invisible when researchers looked at each muscle’s peak effort separately.

Meanwhile, two muscles that did show individual differences, the hamstring and the large hip muscle, were working at barely perceptible levels, so their contributions didn’t register in the dominant coordination patterns. The researchers attributed the low hip muscle activation to the absence of heavy external loading. Without a barbell on the shoulders, that muscle simply didn’t need to work very hard.

From the Gym to Wearable Robotics

The practical takeaway for fitness and rehabilitation is direct but comes with an important caveat: the study tested only young, healthy men performing bodyweight squats, so the results may not apply to women, older adults, or loaded barbell squats. Within that group, turning the toes out to 30 degrees and widening the stance shifted the muscular burden toward the primary movers and away from the stabilizers. Squatting with feet straight and narrow demanded more from the stabilizing muscles, something that could be deliberately useful in rehab settings where ankle stability training is the goal. Even casual exercisers adjusting their squat form might notice a difference in which muscles feel most engaged depending on foot angle.

The researchers also pointed to an unexpected application: wearable robotic leg braces, often called exoskeletons, which are increasingly used in rehabilitation and industrial settings to help people squat and stand. Most existing designs assist movement only in a forward-and-backward direction. But this study’s findings suggest that approach may be incomplete. When someone squats with toes straight and a narrow stance, there is a real demand for side-to-side stability, something a purely forward-backward device would ignore. The authors suggest exoskeleton designers consider building in lateral support, especially when the user’s foot position creates that demand, much the way a well-designed knee brace adapts to different types of motion rather than restricting movement to a single plane.

The researchers also noted that keeping the toes pointed straight ahead resulted in lower activation of the primary power-producing muscles during the rising phase. That could actually be an advantage when wearing a knee exoskeleton, because the device would be doing more of the work, and lower natural muscle activation would complement that mechanical assistance more efficiently.

At its core, this research demonstrates that the brain maintains a stable master plan for squatting, a core coordination strategy that doesn’t budge, while simultaneously making precise, condition-dependent tweaks to how supporting muscles participate. Even without any weight on the bar, just shifting foot position by 30 degrees was enough to trigger a measurable reorganization of muscle teamwork. For anyone who has ever debated foot placement at the squat rack, the answer appears to be less about finding a universally “correct” position and more about knowing which muscles the squatter is actually trying to work.

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Disclaimer: This article is for general informational purposes only and is based on findings from a controlled research study. It is not intended as medical, fitness, or rehabilitation advice. Individual needs and responses to exercise can vary, so consult a qualified professional before making changes to your training routine.

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