I have struggled over the years as to the importance of including toe flexor strengthening as part of a program for plantar fasciitis. Many researches agree that the potential causes of plantar fasciitis are just too numerous and multi-factorial. The evidence in the literature has not been conclusive and I have let many of my patient’s comments that “this is silly” when picking up marbles dictate my decision-making. I have slowly but surely, and I believe wrongly, eliminated this important exercise from my treatment approach. I have recently read several articles that have rekindled my enthusiasm for toe flexor strengthening. So why the change in heart??
I am always looking for ways to get our patients better…faster. I have written a book on plantar fasciitis called the Plantar Fasciitis Treatment Manual and it identifies ankle muscle weakness as a result of plantar fasciitis but not include the presence of toe flexor weakness. That is my oversight and I will correct that in the book. Yes, the literature does identify weakness of the ankle muscles and the toes flexor muscles with the plantar fasciits population, yet the research does NOT confirm any causative factor of this weakness on the development of plantar fasciitis.(1,3,4) It is the chicken or the egg conundrum. Unfortunately, there are theoretical assertions that the “flexor digitorum brevis muscle (the muscle directly underneath the plantar fascia) plays an important role in distributing pressure away from the plantar fascia” that are simply not supported by research. (2) Does this mean that we should not perform strengthening exercises? Let me provide some more evidence.
As we get older, we get weaker. We all lose muscle mass, we lose muscle fibers and, as a consequence, we see decreases in strength between the ages of 30 and 80 within a range of 20-40%.(5) Several articles have also shown that “older people” exhibit 24-40% less strength in the muscles of the foot and ankle(5,6,7,8). As a consequence of foot and ankle weakness, older adults are more susceptible to loss of balance, the development of foot and toe deformities and can be susceptible to overuse syndromes such as plantar fasciitis. (5,6,7,8) The biggest question that has not been answered when it comes to strengthening exercises for older adults is WHICH exercises are the most effective?
As a result, we have to rely on some common sense. If the muscles in our ankles and feet get weaker as we get older (proven!), then we should strengthen them to avoid plantar fasciitis. Right? Not necessarily. There is not a direct correlation between weakness and the development of plantar fasciitis but, then again, many people don’t believe that there is a direct correlation between human activity and climate change. My point is why should we wait to change our approach until it is conclusive – whether it be climate change or your plantar fasciitis?