Background: The aim of this study was to determine whether tightness of the posterior muscles of the lower extremity was associated with plantar fasciitis.
Methods: A total of 100 lower limbs of 100 subjects, 50 with plantar fasciitis and 50 matching controls were recruited. Hamstring and calf muscles were evaluated through the straight leg elevation test, popliteal angle test, and ankle dorsiflexion (knee extended and with the knee flexed). All variables were compared between the 2 groups. In addition, ROC curves, sensitivity, and specificity of the muscle contraction tests were also calculated to determine their potential predictive powers.
Results: Differences between the 2 groups for the tests used to assess muscular shortening were significant (P < .001) in all cases. The straight leg elevation test and ankle dorsiflexion with the knee extended presented respective sensitivities of 94% and 100% and specificities of 82% and 96% as diagnostic tests for the participants in this study.
Conclusion: Tightness of the posterior muscles of the lower limb was present in the plantar fasciitis patients, but not in the unaffected participants.
Clinical relevance: The results of this study suggest that therapists who are going to employ a stretching protocol for treatment of plantar fasciitis should look for both hamstring as well as triceps surae tightness. Stretching exercise programs could be recommended for treatment of plantar fasciitis, focusing on stretching the triceps surae and hamstrings, apart from an adequate tissue-specific plantar fascia-stretching protocol.
Level of evidence: Level III, case control study.