Ever wondered why you've been told you need to stretch your calf muscles when you have pain in your heel? What's the connection and does it really help? This article discusses the link between your calf muscles and plantar fasciitis and whether it's worth your time and effort to do stretching exercises.
Tightness of the calf muscles has long been implicated as a causative factor in plantar fasciitis. The main effect of having tight calf muscles is reduced ankle joint range of motion, which results in abnormal loading stress on the foot. It is proven that a tight tight calf muscles will result in increased tensile stres s on the plantar fascia, (Carlson et al 2000; Stecco 2013) therefore a logical treatment is to reduce this increased stress. This is easily achieved via stretching exercises which have long been prescribed to help treat plantar fasciitis. The positive clinical effect of stretching as a treatment option supports this theory (Davis et al 1994).
Research has demonstrated a considerable association between limited ankle joint range of motion and plantar fasciitis. A recent study found that 211 of 254 (83%) patients with plantar fasciitis had limited ankle dorsiflexion (Patel & DiGiovanni 2011). Dorsiflexion is the movement which points the foot towards shin bone. However focusing stretching on the calf muscles only may provide suboptimal results. DiGiovanni and colleagues (2003) compared protocols of calf muscle stretching versus specific stretching of the plantar fascia. An Improvement was found in the plantar fascia stretch specific group at 8 weeks in 52% of patients, compared with 22% in the calf muscle only stretching group.
Porter et al (2002) conducted a prospective, randomised, blinded (moderate quality research) study. 94 patients (122 affected feet) were diagnosed with "heel pain syndrome". patients were randomised into two stretching groups. One group performed sustained calf muscle stretches (three minutes, three times daily), the other performed intermittent stretches (five sets, 20 seconds each, two times daily). Participants were evaluated once a month for a period of four months. At each monthly visit, participants completed subjective questionnaires about their pain. Also, a physical therapist measured each participant's calf muscle flexibility.
The study determined that both groups had an increase in calf muscle flexibility. This increase in flexibility correlated with a decrease in pain. There was no significant difference in outcome between the sustained and intermittent stretching groups. The data suggest that both sustained and intermittent calf muscle stretching exercises were effective nonsurgical treatments for painful heel syndrome. "Heel pain syndrome" was defined in this study as plantar fasciitis, entrapment of the first branch of the lateral plantar nerve at the level of the abductor hallucis (muscle along the arch of the foot) and, possibly, the presence of a plantar heel spur. Meaning that the authors were not entirely sure what the true nature of the patient's symptoms was.
Don't forget the hamstrings
It has recently been found that patients are 8 times more likely to develop plantar fasciitis with tight hamstrings. The Labovitz et al (2011) study results indicate that an increase in hamstring tightness may induce prolonged forefoot loading and through the windlass mechanism (an important part of normal foot function) be a factor that increases repetitive injury to the plantar fascia.
Another recent study also published in the medical journal - Foot & Ankle International also found a significant relationship between tight hamstrings as well as tight calf muscles in plantar fasciitis sufferers in comparison to a control group of people who did not have plantar fasciitis and who had good hamstring a calf flexibility (Bolivar et al 2013).
Finally, the American Physical Therapy Association (APTA) published clinical practice guidelines for plantar fasciitis. They graded the overall evidence strength of different treatments ranging from A (highest strength) to F (lowest strength). Stretching exercises were graded as an A (APTA 2014).
Soft tissue stretching exercises are generally very safe, low-risk treatment with no common associated risks providing they are done with the correct technique. If you experience any pain whilst performing any of these exercises you should discontinue them immediately and consult a podiatrist or suitable health professional.
Poor flexibility of the calf (muscles at the back of the leg) is one of the main, and perhaps the most significant contributing factor to the development of plantar fasciitis due to the excess consequential mechanical overloading that occurs on the plantar fascia. There is also a good body of evidence to prove this association. Addressing tightness in the plantar fascia, calves and hamstrings (collectively known as the superficial back line) is perhaps the most important factor that must be addressed in the treatment of plantar fasciitis.
For detailed instructional videos on stretching exercises for the plantar fascia, calves, and hamstrings visit my youtube channel here.
Thanks for reading.