• The influence of sprint spike bending stiffness on sprinting performance and metatarsophalangeal joint function

      Smith, Grace; Lake, Mark; Sterzing, Thorsten; Milani, Thomas; University of Chester; Liverpool John Moores University; Chemnitz University of Technology. (Taylor and Francis, 2016-06-07)
      There is evidence that increasing the longitudinal bending stiffness of sprinting footwear can lead to improved sprinting performance although this has not yet been established. This study examined the effect of four known shoe stiffness conditions on both sprinting performance and metatarsophalangeal joint (MTPJ) motion. Twelve trained sprinters performed 40 m maximal sprints along an indoor running track, two sprints in each stiffness condition, and high speed video (600 Hz) recorded two dimensional MTPJ motion during ground contact. To explore individual responses to the footwear manipulations, three dimensional (1000 Hz) kinematic and kinetic data was collected during maximal sprinting for two sprinters. At the group-level, increasing shoe bending stiffness elicited no significant differences in sprinting performance or MTPJ motion, with any changes between conditions being subject-specific. In-depth individual analyses revealed that increased shoe stiffness could restrict motion about the MTPJ and there appeared to be a preferred stiffness for best performance. This notion of individual optimal sprint shoe stiffness and what factors might contribute to the optimum requires further investigation.