Effect of Penalty Minute Rule Change on Injuries and Game Disqualification Penalties in High School Ice Hockey.

BACKGROUND: Recent efforts have focused on eliminating dangerous hits in ice hockey. Fair play rule changes have successfully reduced injury risk but have not been widely implemented. PURPOSE: To determine the effect of a penalty infraction minutes (PIM) rule change in high school boys' ice hockey on injuries and game disqualification penalties. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Injury data were collected from 2 Rhode Island hospital systems and game/penalty data through the Rhode Island Hockey Coaches Association website. Participants included high school boys' hockey varsity players aged 13 to 19 years presenting to 5 emergency departments for hockey injuries during 6 seasons (December 2012-April 2018). Rule change for the 2015-2016 season implemented varying suspensions for players accumulating ≥50 PIM and ≥70 PIM during regular season and playoffs. Injuries were classified as body checking or non-body checking related, and injury rates pre- versus post-rule change were compared via the Cochran-Mantel-Haenszel chi-square test with the odds ratio (OR) to measure risk reduction. RESULTS: During the study period, 1762 boys' high school varsity hockey games were played. Of 134 game-related injuries, 82 (61.2%) were attributable to body checking. The PIM rule change was associated with a significant reduction in all injuries (OR, 0.55; 95% CI, 0.35-0.86; P = .008), concussion/closed head injury (OR, 0.44; 95% CI, 0.23-0.85; P = .012), and combined subgroups of concussion/closed head injury and upper body injury (OR, 0.50; 95% CI, 0.31-0.80; P = .003). Game disqualification penalties per season were not significantly reduced following the rule change, occurring in 5.2% of games before the rule change and 4.4% of games after (OR, 0.84; 95% CI, 0.54-1.31; P = .440). CONCLUSION: Implementation of a statewide PIM restriction rule change effectively reduced the mean number of game-related injuries per season among high school boys' hockey varsity players.

Gluteal muscle activity during weightbearing and non-weightbearing exercise.

BACKGROUND: Researchers suggest that decreased strength of the gluteus medius (GMed) and the gluteus maximus (GMax) muscles contributes to the etiology of various orthopedic pathologies of the knee. Currently, equivocal evidence exists regarding Electromyography (EMG) activity of gluteal musculature during weightbearing (WB) and non-weightbearing (NWB) exercise. The purpose of this study was to compare GMed and GMax muscle activation during WB functional exercise and NWB 10 repetition maximum (RM) exercises. METHODS: Surface EMG electrodes recorded the muscle activity of the GMax and GMed as subjects performed three sets of 10 repetitions of the following exercises: (1) forward step-up, (2) lateral step-up, (3) 10 repetition maximum (10 RM) side-lying hip abduction and (4) 10 RM prone hip extension. The 10 RM resistances were determined one week prior to data collection. RESULTS: The GMed was recruited significantly more during side-lying 10 RM than the remaining exercises (side-lying, 99.9±17% vs. lateral step-up, 61±20%; Forward step-up, 62.7±18.2%; prone, 38±22.2%)(p<0.001). The GMax was recruited to the greatest extent during prone 10 RM hip extension (prone, 100.7±14.5% vs. forward step-up, 28.7±18.7%; lateral step-up, 31±19.9%; side-lying, 38±23.3%)(p<0.001). DISCUSSION: These results suggest that performing a 10 RM NWB exercise results in greater muscle activation than two functional WB exercise without load in young, healthy individuals. In addition, forward and lateral step-ups failed to effectively recruit the GMax at a high enough level to achieve a strengthening stimulus. The GMed was recruited to a higher extent than the GMax during the stepping tasks which might be further augmented if the activity is performed with an additional external load. LEVEL OF EVIDENCE: III.