G-Force Exposure and Functional Recovery in High School Ice Hockey Players
Susan Y. Kwiecien, Luigi Olinto, Andrew H. Kim, Stephen J. Nicholas, Malachy P. McHugh, FACSM. Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, NY. (Sponsor: Malachy P. McHugh, FACSM)
PURPOSE: To measure G-force exposure in games and practices of high school hockey players over the course of 1 season and record weekly functional recovery.
METHODS: 6 players from a high school hockey team (age 15±1.2 yr, height 1.8±0.1 m, mass 68±12.0 kg) were instrumented with accelerometers during 12 games and 17 practices over 11 weeks. Players expected to have the most on-ice time were selected for the study. A small triaxial accelerometer (mass 5 g) with a flash memory chip data logger (Axivity, Newcastle, UK) was fitted to the players' garter belts. Data were acquired at 100 Hz. Resultant G-force was calculated from the raw accelerometer data collected in all 3 planes (scale ±16G). G-force data were analyzed by quantifying the time spent above 1G, 2G, etc. up to >8G. Players completed weekly functional recovery questionnaires on weeks 2-11 (0-30 scale;; <20 = impaired recovery). ANOVA with Bonferroni corrections was used to compare G-force exposure in games vs. practices.
RESULTS: Resultant G-force was ≤ 2G 98% of the time in games and practices. Despite longer duration for games versus practices (104±15 min vs. 85±24 min P<0.01), differences in G-force exposure were only apparent at high G-force thresholds (P<0.01). Weekly functional recovery score was consistent across the season (22.6±3). Impaired recovery (<20) was evident in 8 of 60 (13%) recovery questionnaires. G-force exposure was not related to indices of recovery.
CONCLUSIONS: Differences in G-force exposure between games and practices at high (>4G) but not low (>2G) G-force thresholds likely reflects greater physical contact in games versus practices. Functional recovery data indicated that players mostly had adequate recovery time. This technology and method of quantifying G-force exposure may prove useful in monitoring the physical stresses imposed on ice hockey players. (email email@example.com)