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Thursday, May 5, 2011

Dangerous Achilles Strengthening Exercise

The video above has two basic parts to it. The first part is the stretching part. As long as the heel is on the ground, the stretch is safe and should produce excellent flexibility. The second part however is the strengthening part. This is very risky since a Negative Heel Effect is created when the heel comes off the ground. Negative heel is when the front of the foot is higher than the heel. This is a very unnatural position and definitely the cause of many injuries. Avoid at all costs. The same exercise starting with the heel and front of the foot at the same level is much safer.


  1. Dear Dr. Blake,

    I recently came upon your post about the unsafe nature of the exercise in the above video.

    It has become popular to use eccentric exercise in rehabilitating achillles tendon injuries. The Alfredson heel drop exercises seem to be those most studied. Here is a Google image search page showing various photos of patients performing the heel drop exercises:

    As you can see, this exercise is commonly done through a full range of motion so that the heel ends up well below the toes. The research shows that these exercises are good the achilles. But are they bad for the foot (plantar fascia, plantar ligaments, etc.)? If so, what would be the mechanism of injury? And why would keeping the heel in contact with a wedged surface protect the foot?

    BTW, I am not a therpapist or physician, only an interested athlete.


  2. Dear Dr. Blake,

    Thanks for this post on the dangers of calf stretching. It makes sense that dangling the heel below the forefoot while the foot is loaded puts great stress on the structures of the plantar foot.

    However, there is a protocol used in physical therapy - the drop heel exercises, where the forefeet are on a step and the heels slowly lowered below horizontal - for both calf stretching and eccentric loading of the achilles tendon for rehab. Do you feel that these exercises are inherently unsafe for the foot and should be reassessed?

    How about exercises like the "Downward Dog" pose in yoga, where the heels are off the ground in most folks, is this unsafe also?

    Also, why is the foot more protected during the wall stretch, where the heel is on the ground? By what mechanism are the plantar structures of the foot (PF, plantar ligaments, etc.) protected when the heel is on the ground?

    Ankle dorsiflexion during gait occurs simultaneously with contraction of most of the extrinsic and intrinsic muscles of the foot, which uphold and protect the arch. We know that the achilles tendon is stronger than the passive plantar structures, so it seems that stretching the calf/achilles without also contracting the forefoot plantarflexors might be inherently dangerous for these passive structures. Is there a way to do this?

    For example, when standing on an inclined board to stretch the calves, would it make sense to "pull" the heel toward the forfoot with the plantar intrinsic muscles?


Thank you very much for leaving a comment. Due to my time restraints, some comments may not be answered.I will answer questions that I feel will help the community as a whole.. I can only answer medical questions in a general form. No specific answers can be given. Please consult a podiatrist, therapist, orthopedist, or sports medicine physician in your area for specific questions.