Objective: This study investigated the relationship between Q angle, lower limb posture during dynamic movements (walking and jumping), and potential injury risk using a novel "triangle" metric derived from 3D coordinate data obtained from inertial measurement units and the Perception Neuron motion capture system .
Methods: Twenty-four physically active participants without lower limb injury history participated in this cross-sectional study. Participants performed walking and jumping trials while wearing IMUs and the PN system. Three-dimensional coordinates were obtained from sensors positioned on the lateral aspect of the femur, infragenicular region, and dorsal surface of the foot to calculate Q angle and the triangle metric. Larger triangle areas were hypothesized to indicate higher injury risk .

Results: A weak negative correlation was found between Q angle and triangle area overall (r = -0.24, p = 0.227). During walking, this correlation was negligible (r = -0.11, p = 0.702), while during jumping, a moderate negative correlation was observed (r = -0.54, p = 0.047). Q angle did not differ significantly between walking and jumping (t(13) = 1.20, p = 0.252), with mean Q angles of 91.65° during walking and 90.65° during jumping. The triangle area, representing the proposed injury risk metric, was not significantly different between jumping and walking (t(13) = -0.09, p = 0.928), with mean areas of 0.0219 during walking and 0.0220 during jumping.
Conclusion: The triangle metric, derived from thigh, shank, and foot sensor data, showed a moderate negative correlation with Q angle during jumping, suggesting a potential relationship between lower limb posture and injury risk. However, the lack of significant differences in Q angle and triangle area between walking and jumping indicates that these movements may not present substantially different injury risks in our sample. Further research is needed to validate these findings and explore the clinical significance of the observed correlations.