Ankle-Knee Initial Contact Angle and Latency to Maximum Angle are Affected by Prolonged Run.

The initial contact and midstance angles may influence injury risk. Previous literature has not assessed these angles under the influence of new footwear for a non-exhaustive prolonged run or the relationship between the angles. To assess lower extremity kinematic changes and the relationship between kinematic parameters at initial contact and midstance with prolonged running under the influence of different types of footwear. Twelve experienced, recreational runners (6 male; 6 female; 24.8 ± 8.4 years; 70.5 ± 9.3 kg; 174.1 ± 9.7 cm) ran for 31 minutes at a self-selected pace for three testing sessions wearing maximalist, habitual, and minimalist shoes. Sixteen anatomical retroreflective markers and seven tracking clusters were placed on the participants' lower extremities. Kinematic data were collected every five minutes beginning at minute one. Initial contact angle (IC), maximum angle (MAX) during midstance, and latency (Tmax) between IC and MAX were calculated for the ankle and knee joints in the frontal and sagittal planes. No significant differences were observed between footwear. Rearfoot inversion (F3,33 = 9.72, p < .001) and knee flexion (F6,66 = 5.34, p < .001) at IC increased over time. No significant differences were detected for MAX over time. Tmax for dorsiflexion (F6,66 = 10.26, p < .001), rearfoot eversion, (F6,66 = 7.84, p < .001) and knee flexion (F6,66 = 11.76, p < .001) increased over time. Maximum eversion during midstance is related to the angle at initial contact, and regardless of footwear type, IC and Tmax increased over the duration of the run. No differences in the ankle and knee sagittal or frontal plane kinematics between minimalist, habitual, and maximalist footwear were observed During a self-paced run.