Strengthen the Feet to Treat Plantar Fasciitis

By Joseph Scherger, MD
Vice President, Primary Care,
Eisenhower Medical Center;
Clinical Professor,
Keck School of Medicine,
University of Southern California, Los Angeles

Dr. Scherger reports no financial relationships relevant to this field of study.

SYNOPSIS: A strength training exercise improved self-reported 3-month outcomes in treating plantar fasciitis compared with inserts and stretching.

SOURCE: Rathleff MS, et al. High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12-month follow-up. Scand J Med Sci Sports 2014;Aug 21 (Epub ahead of print).

A group of Danish researchers studied 48 consecutive patients referred to physical therapy for plantar fasciitis pain of at least 3 months’ duration. The diagnosis was confirmed by ultrasound thickening of the plantar fascia. The patients were randomized to two treatment groups. All were given heel cups for additional support.

The stretching group performed a conventional treatment consisting of crossing the affected heel over the opposite knee and pulling the toes back for 10 seconds. This was repeated in sets of 10 three times a day.

The strengthening group performed heel lifts from a raised platform, such as a step, with a rolled towel placed under the toes to cause maximum dorsiflexion. The heels were raised for more than 3 seconds, held for 2 seconds, and then lowered over 3 seconds. Three sets of 12 repetitions were performed every other day. After 2 weeks, the weight was increased by wearing a backpack filled with books. The heels lifts were increased to 10 repetitions 4 times a day. The weight was increased again after two more weeks, and five sets were performed every other day.

Outcomes were measured between the two groups at 1, 3, 6, and 12 months. The primary outcome was at 3 months. The strengthening group had significantly more improvement at 3 months than the stretching group, with a functional foot index score that was 29 points lower (P = 0.016). The differences between the two groups declined at 6 and 12 months, with the scores of the stretching group no longer statistically different from the strengthening group.

COMMENTARY

Human feet have similar intrinsic muscles as the hand. Human feet are able to grab things and perform functions no longer used in a civilized society that wears shoes and uses feet mainly for walking. As pointed out by Christopher McDougall in his fascinating book, Born to Run,¹ our feet are splinted by supportive shoes and the muscles become weak. A lack of muscle strength in the feet may be a common cause of foot problems such as plantar fasciitis.

Conventional treatment of plantar fasciitis is based on rest, supports, and stretching. If these do not work, steroid injections and even surgery are done. The muscles of the feet have been largely ignored in treatment, and the feet are left in a weakened condition. Runners with plantar fasciitis either give up or keep their goals limited. Some runners now strengthen the feet by going barefoot or wearing shoes with minimal support.

This is a breakthrough study using foot strengthening as a primary treatment for plantar fasciitis. The subjects using foot strengthening recovered faster. It would be interesting to see if the strengthening group was able to perform more activities than the stretching group.

In my clinical practice, I have developed an exercise I call the “foot grip.” This is an isometric contraction of the intrinsic muscles as if to grab something with the bottom of the feet, similar to a hand grip. These can be performed hundreds of times a day, even in shoes, while sitting, standing, or lying down. No equipment is needed. At Eisenhower Medical Center, we are currently doing a pilot study of foot grips as a treatment for plantar fasciitis. My own experience has shown rapid improvement, and if the pilot study is successful, we will proceed with a controlled trial similar to the one reported here.

There is likely to be a paradigm shift toward foot strengthening as the new primary method of treating plantar fasciitis.

REFERENCE

1. McDougall C. Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen. New York: Alfred A. Knopf. 2011.