(7) LOCATION OF LINEAR POSITIONAL TRANSDUCER AFFECTS RELIABILITY OF INJURY RISK VARIABLES DURING A JUMP-LANDING TASK

Background: Linear positional transducers (LPT) are a common tool to evaluate kinetic and kinematic performance variables, but their use as a tool to evaluate injury risk remains understudied. A jump-landing task is a common injury risk model, but LPT placement during this task for optimal reliability is unknown.

Purpose: To evaluate the test-retest reliability and differences in kinetic and kinematic LPT variables at three locations during a jump-landing task.

Methods: 20 males completed three standardized jump-landings at three different LPT locations (n = 60 for each location). The LPT locations were Takeoff (next to a 30 cm tall box from which the subjects jump), Halfway (mid-way between the Takeoff and Landing), and Landing (located 0.5 * height (cm) in front of the box). A popular commercially available LPT was used to record eccentric mean velocity, eccentric peak power and force, dip or eccentric depth, and contact time. Separate one-way repeated measures ANOVAs analyzed differences in device variables among locations. Coefficient of variation and intraclass correlation coefficients (ICC) characterized reliability. ICC’s were calculated across all three positions.

Results: Eccentric peak power, eccentric peak force, and dip were lowest at Takeoff and progressively increased from Halfway to Landing (all, p < 0.01). This trend was reversed for average eccentric mean velocity and contact time (all, p < 0.01). ICCs were high for eccentric peak force (0.95), contact time (0.93), dip (0.92), and eccentric peak power (0.90) but low for eccentric mean velocity (0.67). The coefficients of variation were not consistent across variables nor LPT location (Takeoff, Halfway, Landing): eccentric mean velocity (7.4%, 6.1%, 6.5%), eccentric peak power (8%, 10.6%, 11.3%), eccentric peak force (5.8%, 7.6%, 7.3%), dip (7.2%, 6.4%, 6.9%), and contact time (6.9%, 6.7%, 5.5%).

Conclusions: LPT reliability across variables and location was not uniform but generally acceptable (CV < 11%) with good to excellent ICC. LPT location should be consistent and based upon the variable of interest. PRACTICAL APPLICATION: The use of a LPT during a jump-landing task could provide valuable information for practitioners and researchers if used in a consistent location. More research is required to establish which location offers the best construct validity.

Acknowledgements:

Acknowledgements: The views expressed in this abstract are those of the authors and do not reflect the official policy of the U.S. Government, Department of Energy, Department of the Army, or Department of Defense. Funding provided through the Medical Technology Enterprise Consortium (#W81XWH-22-9-0014).