Plantar load characteristics among runners with different strike patterns during preferred speed

Objectives: This study aimed to compare the plantar loads between habitual rearfoot strike (RFS) and non-RFS (NRFS) during running under the participant's preferred speed. Methods: A total of 66 (36 RFS, 30 NRFS) healthy amateur male runners were included in our study. In- shoe pressure sensors were utilised to the test plantar loads when participants were running using their preferred foot strike pattern and running speed (RFS: 3.2 +/- 0.3 m/s; NRFS: 3.4 +/- 0.4 m/s). Results: Results indicated that running speed has a signi ficant effect on the total contact area [F (1, 64) = 7.061, P = 0.01, eta(2) = 0.101], which also affects midfoot and forefoot regions. No signi ficant dif- ference was found on the total maximum force, force-time-integral, peak pressure (PP) and pressure- time-integral (PTI), but the total contact area of RFS was higher than that of NRFS runners [F (1, 64) = 77.406, P < 0.001, eta(2) = 0.551]. Plantar loads were mainly focused on the heel and midfoot for RFS runners in all variables, and NRFS runners experienced increased PP and PTI in medial forefoot regions. Conclusion: Habitual runners tend to adjust their contact area according to the running speed through midfoot and forefoot regions. RFS runners remain susceptible to high impact force on the heel and midfoot, and NRFS runners experience high impact force in the first metatarsal regions. Therefore, runners should note this situation to avoid running-related injuries. (C) 2020 The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).