Running Footwear and Impact Peak Differences in Recreational Runners.

Running is a physical activity and the investigation of its biomechanical aspects is crucial both to avoid injuries and enhance performance. Recreational runners may be liable to increased stress over the body, particularly to lower limb joints. This study investigates the different running patterns of recreational runners by analyzing characteristics of the footwear impact peak, spatiotemporal, and kinematic parameters among those that present with a peak impact and those that do not, with a 3D markerless system. Thirty recreational runners were divided into two groups: impact peak group (IP) ( = 16) and no impact peak group ( = 14) (n-IP). Kinematic and spatiotemporal parameters showed a large Cohen's d effect size between the groups. The mean hip flexion was IP 40.40° versus n-IP 32.30° (d = -0.82). Hip extension was IP 30.20° versus n-IP 27.70° (d = -0.58), and ankle dorsiflexion was IP 20.80°, versus n-IP 13.37° (d = -1.17). Stride length was IP 117.90 cm versus n-IP 105.50 cm (d = -0.84). Steps per minute was IP group 170 spm, versus n-IP 163 spm (d = -0.51). The heel-to-toe drop was mainly 10-12 mm for the IP group and 4-6 mm for the n-IP group. Recreational runners whose hip extension is around 40°, ankle dorsiflexion around 20°, and initial foot contact around 14°, may be predisposed to the presence of an impact peak.