Movement description and prediction on 14-km Ruck in Marine Corps Officer Training

Ruck marches are a common military training activity important for traveling in units together safely and can be assessed with portable technology to measure their demand on the Marines are a field-based test with lab-based measurements to measure demand on the Marines. PURPOSE: to measure biomechanical gait factors during a 14-km ruck march as descriptive changes in movement. An additional study aim is to investigate if output from the isometric mid-thigh pull (IMTP) and counter movement jump (CMJ) will provide additional insight into biomechanical changes onset during ruck marches and performance predictors. METHODS: 46 Officer candidates (34 male, 12 female) participated in a ruck march as part of their training with attached inertial measurement units (IMU) . The 14-km ruck march was assessed IMUs strapped over subjects’ boots. Subjects completed pretesting counter movement jumps and isometric mid-thigh pull on dual plated force plates. The first two kilometers (km) were compared to the last 2 km for analysis. The T-test analyzed changes from the first 2 km and last 2 km step count, impact load, and average intensity. 2-way ANOVA compared measurements between men and women Marine Corp Officer Candidates. IMTP, CMJ, and symmetry angle (SA) for correlations performance measures on effects of biomechanical performance in the 14 km ruck march. RESULTS: There was significant increase in the impact load of the left leg, right leg and total at first 2 km (6613.99 ± 1824.27; 6731.48±1780.18; 13345.48±3544.09) and last 2 km of the ruck march (7130.92 ± 1856.15; 7190.92±1791.72; p <0.001) . There was significant increase in the impact load of the average intensity on left leg at first 2-km (8.85 ± 1.47 g; 8.97±1.48 g; 8.90±1.40 g) and last 2-km of the ruck march (9.58 ± 1.76 g; 9.59±1.67 g; 9.58±1.61 g; p