Datas_Kinematic Analysis of the Lower Limbs and Trunk of Nonexercisers during Forward Lunges

Objective: In this study, the lower limb and trunk kinematics of exercisers and nonexercisers during forward lunges were compared to determine the movement characteristics of nonexercisers. Methods: Three-dimensional kinematic data were collected from 11 nonexercisers and 13 exercisers using a motion capture system (240 Hz) with 17 inertial measurement units. Joint angles at the hip, knee, and ankle joints; and trunk inclination angles were calculated. Differences throughout the lunge cycle were compared using statistical parametric mapping. Results: Compared with exercisers, nonexercisers had significantly shorter step length (p = 0.033) and lower peak center of mass velocity (forward: p = 0.005, backward: p = 0.016). Additionally, hip extension in the supporting leg was significantly smaller in nonexercisers than in exercisers (p < 0.001), accompanied by significantly smaller peak flexion angles in the leading leg’s hip (p = 0.022), knee (p = 0.036), and ankle (p = 0.001) joints. The trunk of nonexercisers exhibited significantly greater posterior tilt during the initiation phase (0%–16.3%, p = 0.040) and completion phase (92.5%–100%, p = 0.048) of the movement compared with that of exercisers. Conclusion: The lunge movement in nonexercisers is characterized by insufficient propulsive force due to restricted hip extension in the supporting leg and the consequent reduced load on the leading leg. Furthermore, the posterior trunk tilt observed during the initiation and completion phases may reflect a lack of dynamic balance and weakened trunk muscles, warranting attention from an injury risk perspective .