Normative Running Kinematics in Healthy Adolescent Runners: A 2-Dimensional Video Analysis

Background: The literature on the running kinematics of youth distance runners is limited.Purpose: We sought to describe 2-dimensional (2D) video analysis of running kinematics in healthy adolescent distance runners, which has not been previously described.Methods: We conducted an observational study of healthy, competitive runners between the ages of 14 and 18 years, prospectively recruited through local running clubs and our hospital's outreach between August 2019 and July 2023. Participants ran on a treadmill at a self-selected speed with markers attached to the thorax, pelvis, and lower extremities. A high-definition video camera recorded the runners in the sagittal and frontal planes. Kinematic measurements were completed using Dartfish software and reported as means and standard deviations.Results: Of the 53 participants (51% boys, mean age: 16.0 +/- 1.4 years) included in the 2D running analysis, 91% ran with a rearfoot strike pattern, with a mean foot inclination angle of 10.2 degrees +/- 6.2 degrees. Knee flexion angle at initial contact was 13.2 degrees +/- 3.8 degrees, tibia inclination angle was 8.5 degrees +/- 3.2 degrees, and peak knee flexion was 44.5 degrees +/- 3.6 degrees. Cadence was 168.7 degrees +/- 8.6 degrees. Contralateral pelvic drop was 6.0 degrees +/- 2.2 degrees and peak rearfoot eversion was 11.8 degrees +/- 3.6 degrees.Conclusions: This study is the first to describe running kinematics as captured by 2D video in healthy adolescent runners and to identify kinematic variables that may differ from those of adult runners. Further research is required to determine if adult recommendations are applicable to adolescent populations.