Heel drop exercises are a common movement regimen prescribed in physical therapy to address pain and pathology in the Achilles tendon. These movements provide a highly controlled, specific type of stress to the tendon, which stimulates the healing process. Understanding the recommended daily frequency and technique is essential for effective application. This article will provide the specific, evidence-based steps and recommended frequency for incorporating heel drops into a rehabilitation program.
Understanding the Purpose of Heel Drops
The therapeutic value of the heel drop exercise centers on eccentric loading. This describes the muscle contracting while it is lengthening, which is the opposite of concentric contraction where the muscle shortens. For the Achilles tendon, the concentric phase is when the calf muscle raises the heel, and the eccentric phase is the controlled lowering of the heel back down.
This controlled lengthening under tension provides mechanical stress to the tendon structure, encouraging the remodeling of collagen fibers. The mechanical stimulus from this loading helps to strengthen the tendon and improve its capacity to handle future forces. Eccentric exercises are widely accepted as a standard method for managing Achilles tendinopathy, which is chronic pain and injury in the tendon.
The Standard Daily Protocol and Dosage
The most widely researched protocol for daily heel drop dosage is based on a regimen developed by Alfredson and colleagues. This suggests performing three sets of 15 repetitions, completed twice daily, seven days a week, for 12 weeks. This totals 90 repetitions in the morning and 90 in the evening, resulting in 180 eccentric heel drops per day.
This high volume maximizes the loading stimulus for tendon adaptation. The protocol requires performing the repetitions in two positions: once with the knee straight and once with the knee slightly bent. This dual-position approach ensures that both major calf muscles—the gastrocnemius (straight knee) and the soleus (bent knee)—are fully targeted, as they both connect into the Achilles tendon.
Progression involves moving from unweighted to weighted drops once the initial volume can be completed without significant pain. Once a patient can perform three sets of 15 repetitions in both positions without pain, the protocol suggests adding external resistance, often weights carried in a backpack. The weight should be increased gradually, in increments of five kilograms, until a mild or moderate level of discomfort is again felt during the exercise.
Essential Technique for Maximizing Results
Proper execution is crucial because the therapeutic benefit comes specifically from the eccentric phase of the movement. The exercise is performed standing on the edge of a step or curb, with the balls of the feet on the edge and the heels hanging over. The concentric (lifting) phase is performed using both legs to rise up onto the toes.
Once raised, the non-injured leg is lifted off the step, and the injured leg performs the eccentric lowering phase alone. This lowering must be slow and controlled, ideally taking three to five seconds to reach the lowest point, where the heel is below the step’s edge. The injured leg should not perform the lifting action; the non-injured leg must be used to return to the starting position.
The straight-knee variation primarily targets the gastrocnemius muscle. Performing the same lowering movement with the knee slightly bent focuses the load onto the soleus muscle. Both variations should be included in the daily routine to ensure comprehensive strengthening of the calf muscle-tendon unit.
Knowing When to Adjust or Stop the Exercise
A key principle in tendon rehabilitation is “acceptable pain” during the exercise. It is common to feel mild to moderate discomfort, sometimes rated up to a 3 or 4 out of 10 on a pain scale, as this indicates the tendon is being adequately stimulated. However, the pain should never be sharp, disabling, or unbearable.
A critical monitoring step is checking the tendon’s reaction in the hours following the exercise and the following morning. If the pain is significantly worse or stiffness has dramatically increased the next day, the exercise volume or added weight should be reduced. The goal is for any exercise-induced pain to settle down within a few hours.
If pain remains disabling, sharp, or increases consistently despite reducing the load or repetitions, the exercise should be paused and a medical professional consulted. Persistent, high-level pain or a failure to improve after several weeks of consistent effort may signal the need for a reassessment of the diagnosis or the training program. Progression is achieved by maintaining the exercise even as the pain lessens, only adding more resistance when the drops become pain-free.