The aim of this study is to examine the differences in frontal plane running mechanics of injured runners, compared to their healthy counterparts. Frontal plane pelvic drop results in the knee moving into a valgus position. The hamstrings are recruiting in valgus moments to stabilize the knee. This extra recruitment of the hamstrings during this initial contact event could be a mechanism of injury.

Thirty-nine subjects performed three 50-meter sprints, with three Opal sensors placed on the pelvis;​ one on each iliac crest and one on the sacrum. Subjects were divided into six groups based on gender, athletic ability and injury history. The vertical acceleration measured by the sensors was used to discern patterns within a subject’s running gait. The data was used to analyze;​ variability, impact magnitude and rate, instability and asymmetry during each single leg stance throughout the run, to investigate between group differences. Differences between injured leg and healthy leg stance were examined for the injured populations as well.

Analysis of the data found significant differences between the groups. Injured athlete displayed greater instability and asymmetry during injured leg stance than healthy leg stance. Differences between athlete and non-athlete populations for variability were present, with athletes exhibiting lower variability than their non-athlete counterparts.

This study demonstrates that within injured athletes there is difference in ground contact dynamics between injured and healthy legs. These athletes might benefit from intervention and rehabilitation strategies targeting postural control and stability during dynamic tasks.