The squat is a foundational human movement, and achieving a depth where the hip crease descends below the top of the knee is often considered the full expression of this movement. The inability to squat low is rarely due to a single issue, instead resulting from a complex interplay between soft tissue mobility, non-modifiable skeletal structure, and execution mechanics. Identifying the primary cause is the first step toward achieving greater, safer depth in the squat pattern.
Ankle and Hip Mobility Limitations
Mobility restrictions in the ankle and hip are the most common and often the most correctable reasons for limited squat depth. The squat requires synchronized movement across multiple joints, with the ankle and hip joints needing significant ranges of motion to allow the body to descend fully. When the ankle cannot move adequately, the body is forced to compensate elsewhere, typically resulting in a forward lean of the torso or the heels lifting off the floor.
Ankle dorsiflexion, the movement that allows the shin to travel forward over the foot, is necessary for an upright squat posture. Studies suggest that achieving a deep squat requires an ankle dorsiflexion angle of approximately 35 to 38 degrees. This can be measured by the ability to touch the knee to a wall from about 12 centimeters away while keeping the heel down. If this range is restricted, the body shifts its center of mass backward to maintain balance, which immediately limits depth and forces the torso to pitch forward. This compensation increases the load on the lower back and shifts the focus away from the leg muscles.
The hip joint also requires a large range of motion, specifically demanding significant hip flexion to allow the femur to travel close to the torso. Tightness in the soft tissues surrounding the hip, such as the hip flexors and adductors, can physically impede this deep position. Limited mobility in the adductors or hip rotators can cause the knees to cave inward or the hips to feel jammed, restricting the final stage of the descent. Exercises focusing on increasing hip flexion and internal/external rotation can often unlock substantial depth improvements.
Structural Anatomy: When Your Bones Get in the Way
Sometimes, the limitation to squat depth is not a matter of flexibility or training but a result of an individual’s unique skeletal geometry. Unlike muscle tightness, these anatomical differences are non-modifiable and dictate the optimal squat stance an individual must use. The relative length of the femur (thigh bone) compared to the torso profoundly affects the mechanics of the squat.
Individuals with a relatively long femur and a short torso must lean their trunk much further forward to keep their center of mass balanced over the middle of the foot. This necessary forward lean increases the difficulty of maintaining an upright position and can make deep squatting feel awkward or impossible without falling backward. A longer femur naturally requires more hip flexion and less knee flexion to reach depth, which influences the muscles primarily used in the movement.
Differences in the structure of the hip socket, known as the acetabulum, also limit the available range of motion. Some individuals have deep hip sockets, which means the ball of the femur meets the rim of the socket (bony impingement) sooner when the hip is flexed. Similarly, the orientation of the socket and the femoral neck can vary, with some hips facing more forward (anteversion) or more outward (retroversion). These variations pre-determine whether a narrow, toes-forward stance or a wide, toes-out stance will allow the greatest pain-free depth. If a hard, pinching sensation is felt in the hip, it is often the body signaling that the bone structure has run out of room.
Technical Flaws and Setup Mistakes
Beyond the physical limitations of mobility and anatomy, errors in technique and setup can artificially restrict squat depth. The choice of stance width and foot angle is entirely dependent on an individual’s hip anatomy, and an incorrect setup can instantly block the movement. Forcing a narrow stance with straight feet when the hip structure dictates a wider, more flared position will cause the movement to stop prematurely. Experimenting with a slightly wider stance and turning the toes out can often immediately unlock several inches of depth by creating necessary space in the hip joint.
Another common technical error involves a failure to create and maintain sufficient core rigidity, often resulting in “butt wink.” Butt wink is the posterior tilting of the pelvis and rounding of the lower back (lumbar flexion) that occurs at the bottom of the squat. This pelvic tucking can signal that the body has reached its anatomical or mobility limit, but it is often caused by a lack of motor control or core bracing, which causes the spine to lose its neutral position under load.
A proper core brace is achieved by taking a deep breath and expanding the abdomen circumferentially, creating intra-abdominal pressure that stabilizes the spine and pelvis. Without this rigidity, the torso seeks the path of least resistance, leading to the pelvic tuck and a premature stop. Learning to maintain a neutral spine throughout the movement is a critical skill, as spinal flexion under heavy load can increase the risk of injury.
Practical Strategies to Improve Depth
Addressing mobility restrictions is the most productive path for many people seeking to improve squat depth.
Ankle Mobility
For ankle dorsiflexion, the knee-to-wall stretch is a simple and effective drill. Position the foot a few inches from a wall and drive the knee forward without lifting the heel, holding the end range to improve calf and Achilles tendon flexibility. The distance from the wall where the knee can touch provides a measurable way to track progress.
Hip Mobility
To improve hip mobility, the 90/90 stretch targets the internal and external rotation capabilities of the hip capsule, which are necessary for deep squatting. This position involves setting both the front and back legs at 90-degree angles and then leaning the torso over the front shin to stretch the gluteal muscles. The ability to transition between the required rotations translates to greater freedom in the squat.
Temporary Modifications
For those with persistent ankle restrictions or anatomical limitations, temporary modifications allow for immediate depth improvements. Elevating the heels using weightlifting shoes or small plates decreases the required ankle dorsiflexion, allowing the knee to travel forward and the torso to remain more upright, which bypasses the mobility restriction. Additionally, experimenting with a wider stance and flaring the toes outward allows the femur head to sit more optimally in the hip socket, granting greater pain-free depth for those with structural hip limits.