In this article I discuss the idea behind strengthening exercises to help with plantar fasciiitis and take a brief look at some recent research into the effectiveness of strengthening exercises, along with me personal views on whether they are important.
Strengthening exercises are often overlooked in the conventional treatment of plantar fasciitis. This may be due to the notion that strengthening exercises may place further strain on the plantar fascia and worsen the condition. This notion, to a degree, may hold some truth and it is therefore not recommended to perform strengthening exercises in the acute phase of treatment or when your symptoms are easily irritated by loading. However, by having weak plantarflexors, fo r example, the calf muscles, may cause an abnormal gait (walking) because weakened muscles have diminished force absorption and production capabilities. Additionally, the plantar fascia is not the only structure responsible for supporting the arch of the foot. There are a number of muscles in the lower leg and the foot which also support the arch of the foot. If these muscles are weak and are not supporting the foot sufficiently, more loading stress is placed on the plantar fascia, which can lead to force overload on the plantar fascia, tissue microtrauma, and pain.
There is evidence to demonstrate an association of weak plantarflexor muscles with plantar fasciitis and other foot disorders (Kibler et al 1991). Although it is not known if the strength deficits are present before injury or whether they are caused secondary to the condition. The authors of this study concluded that a strength deficit of the posterior calf is present in the foot suffering from plantar fasciitis, which creates a functional deficit in the normal foot biomechanics. This deficit either contributes or causes to overt clinical symptoms and should be addressed in the evaluation and treatment of plantar fasciitis.
An exciting recent Scandinavian study (Rathleff et al 2014) compared strengthening exercises vs. plantar fascia stretching exercises in 48 patients with ultrasound scan confirmed plantar fasciitis. Patients were randomised into two groups:
group 1 - strengthening exercises and gel heel cup (24 patients)
group 2 - plantar fascia stretching exercises and gel heel cup (24 patients)
At a 3 month follow-up, the strengthening exercise group demonstrated significantly less foot pain in comparison with the plantar fascia stretch group. However, a 6 month and 12-month review did not demonstrate a difference between to two groups with both improving overall. It is important to highlight that there were no differences seen on ultrasound scan follow-up between the two groups with both demonstrating reduced thickening of the plantar fascia. In conclusion, the strength exercise group made quicker improvements which leveled by 6 and 12 months.
Why was the strength training associated with superior improvement?
What we know is that high-load strength training that causes controlled high tensile loads across a tendon has shown promising results on degenerative tendon disorders such as Achilles and patellar tendinopathy. Although fascia is not the same as tendon they are similar as both are made up of type 1 collagen fibres (Stecco et al 2013). It appears that this type of collagen responds to high-load through increased collagen synthesis (Langberg et al 2007). As patients with plantar fasciitis show degenerative changes at the plantar fascia enthesis (Jarde et al 2003; Lemont et al 2003), increased collagen synthesis may help normalise fascia structure and improve pain.
Soft tissue strengthening exercises are generally a very safe, low-risk treatment with no common associated risks providing they are done with the correct technique. It is possible one may overwork a muscle by doing too much of their strengthening exercises and over exert themselves. It is therefore advised that you introduce the exercise regime with a modest start with very gradual progression. If you experience any pain whilst performing the strengthening exercises you should discontinue them and consult a podiatrist or suitably qualified health professional for further advice.
Strengthening exercises certainly do play a role in the treatment plan for plantar fasciitis. The question is when? At current there is a lack of agreement as to when to introduce these exercises as loading the plantar fascia at the wrong stage may worsen pain, however, this did not appear to be the case in the recent Rathleff et al study (2014). It is recommended to perform calf strengthening exercises whilst symptoms have settled with the aim preventing recurrence of plantar fasciitis as strengthening exercises will improve posterior calf muscle strength and help optimise gait (walking).
Similar to stretching exercises, there are a number of different techniques available to strengthen the posterior calf muscles. I have posted a video here that teaches you how to perform an effective exercise with the correct technique and more importantly how not to perform it, as unfortunately many patients develop bad technique habits after being shown how to perform their strengthening exercises or after following written instructions on a leaflet.
Thanks for reading. Comments welcome.