AUTHOR=Girard Olivier , Millet Grégoire P. , Micallef Jean-Paul 

TITLE=Constant low-to-moderate mechanical asymmetries during 800-m track running

JOURNAL=Frontiers in Sports and Active Living

VOLUME=Volume 6 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2024.1278454

DOI=10.3389/fspor.2024.1278454

ISSN=2624-9367

ABSTRACT=Modifications in asymmetry in response to self-paced efforts have not been thoroughly documented, particularly regarding horizontally-derived ground reaction force variables. We determined the magnitude and range of gait asymmetries during 800-m track running. Eighteen physical education students completed an 800-m self-paced run on a 200-m indoor track. During the run, vertical and horizontal ground reaction forces were measured at a sampling frequency of 500 Hz using a 5-m-long force platform system, with data collected once per lap. The following mechanical variables were determined for two consecutive steps: contact time and duration of braking/push-off phases along with vertical/braking/push-off peak forces and impulses. The group mean asymmetry scores were evaluated using the 'symmetry angle' (SA) formula, where scores of 0% and 100% correspond to perfect symmetry and perfect asymmetry, respectively. There was no influence of distance interval on SA scores for any of the nine biomechanical variables (P≥0.095). The SA scores were ~1-2% for contact time (1.3±0.5%), peak vertical forces (1.8±0.9%), and vertical impulse (1.7±1.0%). The SA scores were ~3-8% for duration of braking (3.6±1.1%) and push-off (3.2±1.4%) phases, peak braking (5.0±2.1%) and push-off (6.9±3.1%) forces as well as braking (7.6±2.3%) and push-off (7.7±3.3%) impulses. The running velocity progressively decreased at 300 m and 500 m compared to that at 100 m but levelled off at 700 m (P<0.001). There were no modifications in gait asymmetries, as measured at 200-m distance intervals during 800-m track running in physical education students. The 800-m self-paced run did not impose greater mechanical constraints on one side of the body. Experimental procedures for characterizing the gait pattern during 800-m track running could be simplified by collecting leg mechanical data from only one side.