Strength-training Regimen Effective at Treating Plantar Fasciitis

Study recommends progressive exercise protocol

By Brian Perry, ND

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Reference 

Rathleff MS, Mølgaard CM, Fredberg U, 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.

Design  

A randomized trial comparing 2 treatments for plantar fasciitis (PF)

Participants 

Forty-eight patients with PF verified by ultrasound participated in this study. 

Study Intervention  

This study compared the effectiveness of shoe inserts and daily plantar fascia–specific stretching (“stretch” group=24 participants) vs shoe inserts and high-load progressive strength training (“strength” group=24 participants) performed every second day. This high-load strength training consisted of unilateral heel raises with a towel inserted under the toes.

Outcome Measures 

Primary outcome was the foot function index (FFI) measured at 1, 3, 6, and 12 months. The FFI was developed to measure the impact of foot pathology on function in terms of pain, disability, and activity restriction. This assessment is a self-administered index and consists of 23 items divided into 3 subscales.1

Key Findings 

The simple progressive exercise protocol (strength group) resulted in superior self-reported outcome after 3 months compared with traditional plantar-specific stretching (stretch group). This technique may result in a quicker reduction in pain and improvements in function. At the primary endpoint of 3 months, the strength group had a FFI that was 29 points lower (95% confidence interval: 6-52, P=.016) compared with the stretch group. There was no significant difference at the later follow-up assessments. 

Practice Implications

PF is one of the most common causes of foot pain, resulting in more than a million visits to practitioners per year.2 The typical age of onset is between 40 years and 60 years of age in the general population and younger in runners. Over 10% of the population will at some time have pain attributed to PF,3 and most physicians will encounter the problem in their practices. 
 
The cause of PF is most likely multifactorial. Proposed risk factors include poor footwear, over training, pes planus (flat feet), high arches, shortened Achilles tendons, and tight calf muscles.4,5 Obesity, standing for long periods, or repetitive jumping may also play a role. Heel spurs may coexist with PF, but it is unclear whether they have a causal role or whether they result from PF. There tends to be a high incidence in runners, suggesting that PF could be caused by repetitive microtrauma.6 This accumulation of microtrauma may weaken both the collagen and noncollagen matrix and the vasculature of the tissue, resulting in a chronic tendonopathy or tendonitis.7
Cortisone injections have been a standard therapy in the past, but with these new thoughts on the etiology and structural changes in plantar fasciitis, those injections should be used more judiciously.
PF typically occurs as an isolated problem usually arising at the calcaneal origin of the plantar fascia. Biopsy specimens of this pearly white tissue show a variety of pathological changes. These range from degenerative changes to fibroblastic proliferation, which occur with or without evidence of chronic inflammation.8 Given the frequent lack of inflammatory changes, many now believe PF to be a fasciosis, a degenerative condition, rather than a fasciitis, an inflammatory condition. Our treatment regimens should therefore be reevaluated to reflect this and might include stretching, exercise, and strengthening in lieu of serial cortisone injections.7
 
Treatments generally include a laundry list of modalities, and despite the frequency of PF, there are limited data to suggest that any one treatment is more effective than another. Initial treatments have generally included rest, ice, orthotics, weight loss in the obese, nonsteroidal antiinflammatory drugs (NSAIDs), night splints, and glucocorticoid injections. 
 
Rest and icing may provide some relief, especially when exercise seems to be the aggravating factor. My practice tends to see a large number of runners and triathletes. I generally refer them to a physical therapist for gait analysis to see if any improper biomechanics might be aggravating PF. This usually includes an assessment of shoes and sometimes custom or prefabricated orthotics, especially with symptomatic flat feet. Evidence that orthotics aid in resolution of pain is inconclusive, however.9
 
A 2-to-3 week trial of NSAIDs is reasonable to reduce any acute pain and swelling.10 The use of nighttime foot splints has been shown to be useful and cost effective.11 Exercises, though evidence of benefit is limited, may help. Stretching, especially tissue-specific, is an easy home therapy and may provide long-term benefits of reduction in pain and functional limitations.12
 
The current study comparing plantar-specific strength training to plantar-specific stretching suggests a new modality for treatment of PF. There are numerous studies investigating the use of daily eccentric isokinetic strengthening exercises for the treatment of other chronic tendinopathies, such as Achilles’ tendinopathy and patellar tendinosis. This study extrapolates from those to advocate a similar rehab approach for PF and shows a larger improvement in resolution of symptoms compared to stretching alone at 3 months. This approach addresses the noninflammatory changes that take place in the fascia, strengthens and normalizes fascia and tendon structure, and increases collagen synthesis. Cortisone injections have been a standard therapy in the past, but with these new thoughts on the etiology and structural changes in PF, those injections should be used more judiciously. If noninvasive therapies provide no relief and pain and disability persists, a glucocorticoid injection may be prudent and has been shown to be effective.13
 
Unfortunately, this study doesn’t provide us with a cure for PF, but it does provide a new and noninvasive method for relieving pain. Addressing the noninflammatory, degenerative, structural changes with these exercises and stretches and concurrently addressing the inflammatory changes offers a multifactorial approach that will benefit most patients.

About the Author

Brian Perry, ND, EAMP (LAc), is a graduate of Bastyr University, Kenmore, Washington, in both naturopathic medicine and traditional Chinese medicine. He maintains a private practice in Seattle, Washington, where his focus is in sports medicine and physical rehabilitation. His unique and natural approach to sports injuries, sports nutrition, rehabilitation, and natural performance enhancement has attracted some of the top professional athletes in the world to his practice.

References

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