The Effects of Plantar Fasciitis on Multi-segment Foot Running Gait Kinematics

Abstract

Plantar fasciitis is a common lower extremity injury caused by mechanical overload that affects 10% of all runners. Despite its commonality, research results investigating the etiology of the condition and the most efficacious treatment have been equivocal. A potential limitation of previous research assessing the mechanical changes associated with plantar fasciitis may be the modeling of the foot as a single segment. To date no study has investigated running kinematics in individuals with plantar fasciitis using a multi-segment foot model. Sonography has also reported plantar fascia thickening and degeneration associated with plantar fasciitis in non-athletic populations; however it has not been used to investigate the plantar fascia in runners with plantar fasciitis. Therefore, the primary purpose of this study was to compare running kinematics between runners with plantar fasciitis and uninjured runners using a six foot segment model. The secondary purpose was to investigate differences in plantar fascia thickness between the two groups. Fifteen runners with plantar fasciitis (age: 30 ± 8.74 yrs, mass: 67.98 ± 8.20 kg) and 15 age, gender and mileage matched uninjured runners (age: 29.33 ± 6.53 yrs, height: 170.52 ± 7.78 cm, mass: 68.07 ± 9.99 kg) were recruited. Data collection included foot structure assessment, ultrasound imaging, and running gait analysis. Stance phase was separated into 4 subphases, and MANOVAs (&alpha &le 0.05) were performed to assess between-subject ROM differences for the functional articulations (rearfoot complex, calcaneocuboid, and calcaneonavicular complex, medial and lateral forefoot, and 1st metatarsophalangeal complex). Independent t-tests (&alpha &le 0.05) were conducted to investigate differences in plantar fascia thickness. Results revealed calcaneocuboid eversion ROM during phase 1 (p = 0.003) and plantar fascia thickness (p = 0.004) were significantly greater in the plantar fasciitis group. The increased eversion excursion of the calcaneocuboid in the plantar fasciitis group may suggest decreased lateral midfoot stability. Although the results of this study advance the understanding of the effect of plantar fasciitis on running gait, additional study of the influence of extrinsic and intrinsic foot musculature and foot strike pattern are warranted before conclusions regarding the effect of plantar fasciitis on running gait can be drawn.