Reliability And Validity Of A Local Positioning System For Measuring External Load In Ice Hockey

Abstract

Purpose: The purposes of this study were to i) determine the reliability of the Kinexon local positioning system (LPS) by collecting on-ice measures with two identical LPS sensors on each individual during an on-ice session, and ii) determine the validity of the LPS measures by comparing on-ice speed and acceleration between the LPS and a previously validated robotic sprint device during on-ice 40 m linear sprints. Methods: Fourteen ice hockey players (25.1 y, 78.6 kg, 176.9 cm) wore two LPS sensors on the back of their shoulder pads to examine the reliability of the LPS during five on-ice drills. Reliability LPS measures included time-on-ice, skating distance, peak skating speed, peak acceleration, peak deceleration, number of accelerations and decelerations, accumulative acceleration load, turns, changes of direction, and skating transitions. Peak speed, speed at 5 m, and 0-5 m acceleration derived from LPS were measured during three 40 m linear on-ice sprints and compared to a previously validated robotic sprint device (1080 Sprint) to examine LPS validity. The coefficient of variation (CV), standard error of measurement (SEM), and intra-class correlation coefficient (ICC) were calculated for each LPS measure. Pearson’s correlations, simple linear regressions, and Bland-Altman plots were used to test the agreement and relationship between the two systems. Statistical significance was accepted at p < 0.05. Results: The majority of LPS measures were reliable (CV < 10% and ICC > 0.9) when comparing the two sensors worn by each player. Peak speed, speed at 5 m, and 0-5 m acceleration were all comparable to those reported by the robotic sprint device, with nearly perfect (peak speed and 0-5 m acceleration; r > 0.967; p < 0.001) and very large (speed at 5 m; r = 0.892, p < 0.001) magnitudes of correlation and mean biases <0.5 km/hr for speed measures and < 0.01 m/s2 for acceleration. However, the number of accelerations and decelerations may need to be used with caution at this time. Conclusion: The present results demonstrate that the Kinexon LPS is reliable and valid for investigating on-ice external load in ice hockey players when sensors are consistently secured on the back of the players’ shoulder pads. Supported by Mitacs and PepsiCo.