Plantar loading changes with alterations in foot strike patterns during a single session in habitual rear foot strike female runners

Objectives: Characterize plantar loading parameters when habitually rear foot strike (RFS) runners change their pattern to a non-rear foot strike (NRFS). Design: Experimental. Setting: University biomechanics laboratory. Participants: Twenty three healthy female runners (Age: 22.17 +/- 1.64 yrs; Height: 168.91 +/- 5.46 cm; Mass: 64.29 +/- 7.11 kg). Main outcome measures: Plantar loading was measured using an in-sole pressure sensor while running down a 20-m runway restricted to a range of 3.52-3.89 m/s under two conditions, using the runner's typical RFS, and an adapted NRFS pattern. Repeated measures multivariate analysis of variance was performed to detect differences in loading between these two conditions. Results: Force and pressure variables were greater in the forefoot and phalanx in NRFS and greater in the heel and mid foot in RFS pattern, but the total force imposed upon the whole foot and contact time remained similar between conditions. Total peak pressure was higher and contact area was lower during NRFS running. Conclusions: The primary finding of this investigation is that there are distinctly different plantar loads when changing from a RFS to NRFS during running. So, during a transition from RFS to a NRFS pattern; a period of acclimation should be considered to allow for adaptations to these novel loads incurred on plantar regions of the foot. (C) 2015 Elsevier Ltd. All rights reserved.