Beyond Body Weight: The Influence of Artificial Load on Lower-Limb Joint-Specific Landing Kinematics and Coordination...

Effective motor coordination is essential for adaptive athletic performance, including musculoskeletal injury prevention, particularly in high impact activities. Understanding how the lower extremities adapt to added constraints, such as increased load, can provide valuable insights into the resilience of movement patterns. This study examined the influence of added load on intralimb coordination during a drop-vertical jump (DVJ). Twenty-six participants (14 female, age = 23.10 +/- 3.97 years, 76.81 +/- 18.73kg) performed 5 body weight DVJs and 5 with an additional 25% body weight using a weighted vest. 3D joint kinematics were recorded using OpenCap markerless motion capture (OpenCap, Menlo Park, CA). Linear measures were calculated for the knee and hip, while nonlinear cross recurrence quantification analysis indexed intralimb coordination between the knee and hip joints. Alpha level was set a priori at α=.05. Paired-sample t-tests revealed smaller peak knee flexion (p=.013) and decreased total range of motion in both the hip and knee (p=.014 and .013, respectively) in the +25% body weight condition. Additionally, recurrence rate (p=.036), determinism (p=.046), adjusted mean line (p=.023), and adjusted trapping time (p=.011) were all lower in the +25% body weight condition. These results indicate that weight-based constraints lead to stiffer landing mechanics and noisier, less tightly coupled intralimb coordination. These findings highlight the need to consider both the landing mechanics and coordination dynamics when considering the implementation of movement assessments for athletic performance and injury prevention under increased load conditions.