Squats are not inherently bad for Achilles tendonitis, but the stress they place on an already injured tendon can worsen the condition. Achilles tendonitis, or tendinopathy, is a common overuse injury characterized by pain, thickening, or degeneration of the Achilles tendon, the strong band of tissue connecting the calf muscles to the heel bone. This condition often results from repetitive strain that exceeds the tendon’s current tolerance level, commonly happening with a sudden increase in activity intensity or volume. The concern for someone managing this injury is whether a staple exercise like the squat will exacerbate the problem and delay healing.
Understanding Squat Stress on the Tendon
A standard barbell squat requires significant ankle dorsiflexion, the movement where the shin moves forward over the foot. This forward movement stretches the Achilles tendon, creating tensile stress. The deeper the squat, the more the ankle is forced into dorsiflexion, increasing the load on the tendon.
The mechanical strain is further complicated by the type of Achilles tendonitis present. If the injury is located near the heel bone, known as insertional Achilles tendinopathy, deep dorsiflexion also creates compressive stress. During a deep squat, the tendon is compressed and “pinched” against the back of the heel bone (calcaneus), which can be highly irritating to the compromised tissue. This compressive force is a major factor in flaring up pain, especially when the ankle angle is acute.
The total force on the tendon during a squat is a combination of body weight, external load, and the degree of ankle mobility required. Pushing the knee far forward over the toes demands the greatest ankle mobility and therefore places the highest strain on the Achilles complex. Attempting to perform a full-depth squat with a heavy load often produces a sharp, immediate pain response in an irritated tendon.
Adjusting Squat Mechanics for Pain Relief
If continuing to squat is a priority, mechanical adjustments can significantly reduce the stress on the Achilles tendon. The primary goal of these modifications is to minimize the amount of required ankle dorsiflexion. A simple strategy is to introduce a heel elevation, either by wearing weightlifting shoes with a raised heel or by placing small wedges or plates under the heels.
Elevating the heels places the ankle into a slightly plantar-flexed position, which effectively pre-tensions the calf muscles and reduces the degree of stretch and compression on the Achilles during the descent. Decreasing the overall depth of the squat is another immediate way to manage symptoms. Performing partial squats, where the hips descend only until the first sensation of pain is felt, keeps the tendon within a comfortable range of motion.
A wider stance naturally reduces the amount of forward knee travel, which decreases the demand for ankle dorsiflexion. Focusing on pushing the hips back to initiate the movement, rather than driving the knees forward, helps maintain a more vertical shin angle. These combined adjustments allow the user to continue training the quadriceps and glutes while respecting the current pain tolerance of the injured tendon.
Alternative Lower Body Strengthening Exercises
For individuals experiencing persistent pain, substituting the squat pattern with exercises that isolate the lower body muscles is a prudent temporary measure. The objective is to effectively train the glutes and quadriceps without forcing the ankle into excessive dorsiflexion. Exercises that allow for a controlled range of motion or position the ankle in a neutral or slightly plantar-flexed position are preferable.
The leg press machine is an excellent alternative, as the footplate allows the user to carefully control the depth and prevent the ankle from reaching an aggressively stretched position. Box squats are another useful variation, where squatting to an elevated box ensures the hips stop at a predetermined, pain-free depth, preventing excessive ankle movement. Hip thrusts and glute bridges are highly effective for strengthening the posterior chain with virtually no direct load or movement required from the Achilles tendon.
Progressive Loading and Full Recovery
Full recovery from Achilles tendonitis requires a structured approach centered on progressive tendon loading, rather than complete rest. Tendons adapt to stress, and the goal is to gradually rebuild the tissue’s capacity to tolerate mechanical load. The rehabilitation process often begins with isometric exercises, such as a double-leg heel raise held for 45 seconds, which can provide immediate pain relief and stimulate the tendon.
This is followed by heavy slow resistance (HSR) training, typically involving exercises like eccentric calf raises, where the focus is on slow, controlled lowering of the heel. These exercises should be performed with a load that causes minimal pain, generally rated no higher than a two out of ten on a pain scale. As the tendon’s load tolerance improves, the weight and complexity of the movements are gradually increased.
A safe return to full-depth, un-modified squats is achieved by slowly reintroducing the range of motion and weight over several weeks or months. This should only occur once the tendon is consistently pain-free during all modified activity. It is advisable to seek guidance from a physical therapist or sports medicine professional to ensure the loading program is appropriate for the specific injury and to prevent a painful relapse.