Plantar Fasciitis

Review: Loading The Plantar Fasciia

High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12-month follow-up

Plantar Fasciitis is a condition that affects both active and non active populations. It is characterised by medial heel pain were the plantar fascia attaches to the calcaneus (heel). It is particularly painful with the first few steps in the morning and after long periods of inactivity, (Jariwala et al, 2011).

Plantar fasciitis was thought to be an inflammation of the plantar fasciia, however current thinking considers it a degeneration of the collegen matrix, with similar markers to a tendinopathy, (Burchbinder,  2004, Lemont, 2003). Recent research into tendinopathies have shown that load management specific to the phase of the tendinopathy can have better patient outcomes with regard to pain and function (Cook & Purdam, 2009).

In this paper, Rathleff et al, (2014) have extended this strategy to the treatment of plantar fasciitis. Common modalities in the treatment of plantar fasciitis include night splints, heel inserts, orthotics, stretching.

The aim of this study was to compare the effectiveness of shoe inserts and plantar-specific stretching versus shoe inserts and high load strength training. The effects of both groups were documented using the foot function index (FFI). The foot function index is a validated self reported questionnaire based on pain, disability and activity imitations.

Forty-eight patients with ultrasonography-verified plantar fasciitis were block randomized to shoe inserts and daily plantar-specific stretching (the stretch group) or shoe inserts and high-load strength training  every second day (the strength group) using a computer-generated sequence created by the main investigator in blocks of 6. Randomisation complied with the CONSORT statement.

Inclusion criteria was defined as:

1. Inferior heel pain for the last 3 months before enrolment.
2. Pain on palpation of the medial calcaneal tubercle or the proximal plantar fascia.
3. Thickness of the plantar fascia of 4.0 mm or greater.

Exclusion criteria was defined as:

1. Under 18 years of age.
2. History of systemic disease.
3. Prior heel surgery.
4. Pregnant.
5. Steroid injection within the previous 6 months.

Both groups were equal at baseline. Each group were given an information leaflet and gel heel inserts prior to treatment.

The High Load Strength Group

The high load strength group were required to perform heel raises from a step with a towel placed under their toes so as to increase dorsi flexion, every second day. The time under tension (TUT) consisted of 3 sec eccentric, 3 sec concentric and 2 sec isometric. Initially subjects were required to perform 3 sets of 12 rep max. After 2 weeks the load was increased sufficiently to allow for  a 10 rep max. Simultaneously the sets were increased from 3 to 4. After 4 weeks subjects progressed to 5 sets of an 8 rep max. Progression was maintained through the trial.

Plantar Specific Stretching Group

Using the hand on the affected side, they were instructed to place the fingers across the base of the toes on the bottom of the foot and pull the toes back toward the shin until they felt a stretch in the arch of the foot. They were instructed to palpate the plantar fascia during stretching to ensure tension in the plantar fascia. Each stretch was performed 10 times for 10 seconds three times a day.

Outcomes Measured

After 3 months the strength group had a significantly better FFI score (CI 95%, P=0.016). However after 12 months there was no significant difference between groups. The authors have noted that exercise compliance may have impacted upon this. As exercises were home based, there was a lack of supervision. They contend that subjects probably stopped their exercises once their pain reduced to an acceptable level. In light of this the high load strength group still showed a quicker reduction in pain, disability and activity limitation after 3 months. This implies there is a place for high load strength training in the management of plantar fasciitis.

Some limitations of the study surrounds randomisation, as consecutively selected subjects were not definitive. This may raise an issue of selection bias. As highlighted by the authors, exercise adherence and correct technique could not be controlled as the subjects performed home exercises. A possible gender bias may have occurred as 66% of subjects were female. However this couldn’t have been avoided given subjects were supposedly selected consecutively.

The strengths of this study lie in its comparability to other studies in relation to loading, plantar fasciia thickness and BMI. Also all subjects were equal at baseline. All subjects were given the same heel inserts, patient education and instructions on the intervention according to each group. Outcomes were measured using the foot function index which has been well validated for foot and ankle pathologies, (SooHoo et al, 2006).

In conclusion, I found this to be a very thorough RCT. It has highlighted the need for further studies into loading, frequency and compliance. Given that the primary outcome was better in the high load strength group, I would advocate its use in the rehabilitation of plantar fasciitis.

References

Buchbinder R. (2004) Plantar Fasciitis. The New England Journal of Medicine, 350:21.

Cook JL, Purdam CR. (2009) Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. Br J Sports Med: 43: 409–416.

Drew BT, Smith TO, Littlewood C. (2014) Do structural changes (eg, collegen/matrix) explain the response to therapeutaic exercises in tebdinopathy: a systematic review. British Journal of Sports Medicine 48:966-972.

Jariwala A, Bruce D, Jain A. (2011) A Guide to the Recognition and Treatment of Plantar Fasciitis. Primary Healthcare, 21:7: 22-24.

Lemont H, Ammirati KM, Usen N. (2003) Plantar fasciitis: a degenerative process (fasciosis) without inflammation. Journal Am Podiatr Med Assoc, 93:234-237

SooHoo NF, Samimi DB, Vyas R, Botzler T. (2006) Evaluation of the validity of the foot function index in measuring outcomes in patients with foot and ankle disorders. Foot and ankle journal, 27:1:38-42.

Rathleff MS, Molgaard CM, Fredberg U. (2014) High-load strength training improves outcome in patients with plantar fasciitis: a randomized controlled trial with 12-month follow-up. Scan Jour Med Sci Sport.