Susan Y. Kwiecien1, Malachy P. McHugh, FACSM1, Julianna Villella1, Dominic McHugh2, Stephen J. Nicholas1.
1Nicholas Institute of Sports Medicine and Athletic Trauma, New York, NY. 2Digital Forensics Ireland Ltd, Belfast, United Kingdom. (Sponsor: MALACHY P MCHUGH, FACSM)
PURPOSE: Wearable technologies are increasingly used to monitor athletes across a range of sports. Ice hockey is uniquely suited to the use of accelerometers due to the physical nature of the sport and the rapid directional changes required to perform in a confined space. The purpose of this study was to develop accelerometer-based metrics representing high physiological and physical intensity in male ice hockey players.
METHODS: Skaters on a junior hockey team playing in the United States Hockey League wore triaxial accelerometers during 36 regular season games and 10 playoff games. Accelerations in 3 planes of motion were recorded at 100 Hz with the resultant calculated for each time interval and reported as gravitational force equivalent (G-force). For each game the time spent above 1.1G, 1.2G, etc. was calculated for 0.1G increments up to time above 6.0G. These times were expressed as a percentage of the player’s time on ice (TOI) for each game. The G-force threshold above which no player had a time that exceeded 50% of their TOI was defined as activity representing high physiological intensity. High physical intensity was defined as the G-force threshold at which no player had a time that exceeded 1% of their TOI. Mixed model analysis of variance was used to compare physiological and physical intensity between forwards and defensemen and between regular season and playoff games.
RESULTS: Time above 1.4G averaged 31±6% of TOI with a range of 15-48% (high physiological intensity). Time above 4.0G averaged 0.23±0.12% of TOI with a range of 0-1% (high physical intensity). Forwards spent a greater proportion of their TOI at a high physiological intensity than defensemen (33±6% vs. 27±4%, P<0.001). Forwards also spent a greater proportion of their TOI at a high physical intensity versus defensemen (0.27±0.12% vs. 0.16±0.06%, P<0.001). The proportion of TOI spent at high physiological intensity was slightly decreased (4%) in the playoffs (30±6% vs. 31±6%, P=0.008). However, the proportion of TOI spent at a high physical intensity was increased (15%) in the playoffs (0.26±0.12% vs. 0.23±0.11%, P<0.001).
CONCLUSIONS: Physiological and physical intensity in ice hockey can be quantified using an inexpensive triaxial accelerometer. Forwards had 24% higher physiological intensity and 68% higher physical intensity than defensemen.