Task demand and load carriage experience affect gait variability among military cadets

Abstract

Load carriage is an inevitable daily task for soldiers. The purposes of this study were to explore the extent to which gait variability (GV) is affected by load carriage and experience among military cadets, and whether experience-related differences in GV are dependent on task demand. Two groups of cadets (30 experienced, 30 less experienced) completed a load carriage task in each of three load conditions (no load, 16 kg, 32 kg). Three categories of GV measures were obtained: spatiotemporal variability, joint kinematic variability, and Lyapunov exponents. Compared to traditional mean gait measures, GV measures were more discriminative of experience: although both groups showed similar mean gait measures, the experienced participants had reduced variability in spatiotemporal measures (p ≤ 0.008) and joint kinematics (p ≤ 0.004), as well as lower levels of long-term local dynamic stability at the ankle (p = 0.040). In both groups, heavier loads were also caused increased GV (p ≤ 0.018) and enhanced short-term local dynamic stability at the knee (p = 0.014). These results emphasize the importance of GV measures, which may provide a more complete description of adaptability, stability, and control; highlight alternate movement strategies during more difficult load carriage; and capture experience-related differences in load carriage strategies.

Effect of Equipment on the Accuracy of Accelerometer-Based Human Activity Recognition in Extreme Environments

“…Previous studies have shown that changes in posture such as trunk angle, gait pattern, and stride length [ 33 , 34 ] are observed when carrying additional loads. This is caused by the larger forces which the body must generate through the muscles to propel and control a larger mass [ 35 ].…”

Army Combat Fitness Test Scores Moderate Cognitive Function Improvements After a Ruck March: A Hierarchical Linear Model Approach

“…However, female subjects are underrepresented in the current load carriage literature because of the male-dominated nature of tactical occupations (1,4,9,10,13). In addition, an individual's experience with load carriage, expressed as years of exposure and training, significantly impacts their oxygen consumption and movement efficiency during a load carriage bout (15,30,42). Thus, an individual with fewer years of load carriage experience may be working at a higher intensity during a ruck march compared with those with more experience.…”