Effects of Running Intensity on Forefoot Plantar Pressure Elevation

Running had been known producing a posterior muscle tightness in lower extremity, particularly calf muscles, resulting in a relative equinus deformity. Numerous study reported the association between equinus deformity and foot pain, partially due to the increased plantar pressure of forefoot. This study was directed to find a relation between running intensity and increased forefoot plantar pressure. Subjects were divided into two groups according to running intensity as classified as runner or non-runner. Forefoot plantar pressures data were obtained using a foot imprinter and analyzed into numerical values. Ankle maximum dorsiflexion was also examined in an extended knee to detect the calf tightness. Mean forefoot plantar pressure value was Grau 2.89 (range 2-4) in runner group, and Grau 2.15 (range 1-4) in non-runner group (p=0.004). Ankle maximum dorsiflexion was also limited in runner group (16.05±1.98⁰) compared with 19.30±1.38⁰ in non-runner group (p<0.001). There was an association found between running intensity and plantar pressure elevation. Considering the potential damaging effects to the foot, it is recommended for runners or treating physician to look into this problem as well as to make sure that regular calf stretching is advocated.