Sensorimotor deficits in distance runners with medial plantar pain

ContextMedial plantar pain is a complex and multifactorial condition experienced by some distance runners, which makes etiological differentiation and diagnosis challenging. ObjectiveTo assess plantar sensation, pain perception and sensitivity, intrinsic foot strength, and foot morphology before and after a 9.7 km run in long-distance runners with and without medial plantar pain. DesignDescriptive laboratory study SettingLaboratory. PatientsSeven distance runners with medial plantar pain (four males, three females; aged 22.3{+/-}3.7 years; BMI 22.3{+/-}3.5 kg/m2) and seven matched healthy controls (four males, three females; aged 20.3{+/-}1.0 years; BMI 22.0{+/-}1.7 kg/m2) were recruited from a public university. Intervention(s)Participants ran a six-mile course in their own footwear at a self-selected pace. Main Outcome MeasuresPain visual analogue scale (VAS), pressure pain thresholds (PPT), plantar sensation, foot morphology, weight-bearing dorsiflexion (WBDF), forefoot joint mobility, toe flexion, intrinsic foot muscle strength, and a seated neural provocation test were analyzed pre-and post-run utilizing mixed model group by time ANOVAs, post hoc effect size point estimates, and 95% confidence intervals. ResultsA significant group by time interaction was observed for PPT at the mid-arch (Control: pre: 83.0{+/-}27.4N, post: 79.5{+/-}22.6N; Symptomatic: pre: 90.5{+/-}31.9N, post: 70.1{+/-}32.7 N; p=.03) and posterior tibialis (PT) (Control: pre: 75.7{+/-}19.5 N, post: 65.7{+/-}14.2N; Symptomatic: pre: 75.8{+/-}20.4 N, post: 51.1{+/-}11.9 N; p=.05) sites. PPT in the posterior tibialis significantly decreased in the symptomatic group following the run (ES=1.5, 95% CI: 0.3, 2.7). Both groups demonstrated significantly decreased plantar sensation thresholds at the base of the 5th metatarsal (p=.04), PPT at the calcaneal tuberosity (p=.001), and increased TMT extension (p=.01) and WBDF (p=.01) following the run. ConclusionsThe etiology of medial plantar pain observed in our sample was likely attributed to central sensitization and running-induced sensory changes. Clinicians should include sensorimotor testing when managing patients with medial plantar pain. Key PointsMedial plantar pain is a unique pathologic entity that has not been previously well described and likely caused by central sensitization. Clinicians should include sensorimotor testing and interventions when managing patients with medial plantar pain.