Using the interaction of speed and acceleration to detect repeated-sprint activity in team sports.

PURPOSE: To compare the occurrence and characteristics of repeated-sprint (RS) activity in elite team sport competition when classified according to speed and/or acceleration, and their interaction via metabolic power (Pmet). Methods: Elite male hockey players (N = 16) wore player-tracking devices in six international matches. Sprint efforts were defined using four separate classifications: speed >5.5 m∙s-1, acceleration >1.5 m∙s-2, speed-or-acceleration, and Pmet >25.5 W∙kg-1. RS bouts were defined as ≥3 efforts with mean recovery ≤21 s. For Pmet, RS bouts were also classified using a maximal recovery period ≤21 s. The number of sprint efforts and RS bouts, and the number of efforts, effort durations and recovery periods within RS bouts, were compared across each classification method, and between mean and maximal recovery criteria. Results: More RS bouts were identified via Pmet (8.5 ± 2.8) than either speed and/or acceleration, and comprised more efforts (4.0 ± 0.4) with shorter recovery periods (11.5 ± 1.8 s). Fewer RS bouts (7.3 ± 2.8 vs. 8.5 ± 2.8) were identified with a maximum rather than mean recovery criterion. Conclusions: Definitions of sprint efforts and recovery periods which reflect ATP depletion and replenishment via Pmet suggest that RS activity occurs frequently in team sport competition, and is more demanding than when speed and/or acceleration are used to define RS activity in variable-speed locomotion.

Division I Hockey Players Generate More Power Than Division III Players During on- and Off-Ice Performance Tests.

Current research has found anthropometric and physiological characteristics of hockey players that are correlated to performance. These characteristics, however, have never been examined to see whether significant differences exist between on- and off-ice performance markers at different levels of play; Division I, Elite Junior, and Division III. The purpose of this study was to examine the differences that may exist between these characteristics in Division I (24), Elite Junior (10), and Division III hockey (11) players. Forty-five (age: 18-24 years) hockey players completed anthropometric, on-ice, and off-ice tests to ascertain average measures for each division of play. On-ice testing was conducted in full hockey gear and consisted of acceleration, top-speed, and on-ice repeated shift test (RST). Off-ice tests included vertical jump, Wingate, grip strength, and a graded exercise test performed on a skating treadmill to ascertain their (Equation is included in full-text article.). Division I players had significantly lower body fat than their Division III peers (p = 0.004). Division I players also scored significantly better on measures of anaerobic power; vertical jump (p = 0.001), Wingate peak power (p = 0.05), grip strength (p = 0.008), top speed (p = 0.001), and fastest RST course time (p = 0.001) than their Division III counterparts. There was no significant difference between Division I and Elite Junior players for any on- or off-ice performance variable. The results of this study indicate that performance differences between Division I and Division III hockey players seem to be primarily because of the rate of force production.

Examining the relationship between relative age, competition level, and dropout rates in male youth ice-hockey players.

The relative age effect suggests that athletes born in the first two quartiles of a given selection year experience a selection advantage and therefore a greater opportunity for success. We describe two studies examining the relationship between relative age, competition level, and dropout rates of Ontario Minor Hockey Association male ice-hockey players from ages 10 to 15 years (n = 14 325). In Study 1, dropout was highest among players born in quartiles three and four [χ(2) (3) = 16.32, P < 0.05; w = 0.06], while Study 2 found dropped out players to have less movement between competition levels compared to retained players. This study confirms a relationship between relative age and dropout from ice-hockey and adds further depth to our understanding of this persistent phenomenon.

Professional roller hockey injuries.

OBJECTIVE: To study the incidence and types of injuries sustained by professional roller hockey players in practices and games, and to compare these statistics with those from ice hockey. DESIGN: This injury survey used a strict definition of injury, standardized reporting strategies, and diagnosis by a team physician as standards by which to analyze the characteristics of roller hockey injuries. SETTING: The injuries were recorded after the players had been examined by a team physician at the game or practice site or in the physician's office. PARTICIPANTS: During three seasons for one roller hockey team and one season for another team, an average of 22 players per team participated in the study. Due to personnel changes, the team rosters were modified between seasons. Each player injury was included in the study. An injury was defined as any physical impairment caused during a practice or game that eliminated the player from that practice or game or the next day's practice session or contest, or any physical ailment that necessitated a physical examination by the team physicians. MAIN OUTCOME MEASURE: Injury data were categorized and injury rates were calculated. RESULTS: 122 injuries were recorded during four professional roller hockey seasons, resulting in an overall participation injury rate of 14.4 per 1,000 player hours. The game injury rate was 304.9 per 1,000 player hours. The players were 105.1 times more likely to be injured during a game than during practice. Preseason practices produced 4.5 times more injuries than regular season practices. In comparison, sample data from the only other published study of roller hockey injuries and from several studies of ice hockey have indicated game injury rates of 139.0 (roller hockey), 119.0, 96.1, 78.4, 78.8, and 66.0 per 1,000 player hours, respectively. CONCLUSION: Results of this study demonstrate that roller hockey produces a higher rate of both contact and noncontact injuries than ice hockey; this contradicts the findings of the only other published research study on injuries in roller versus ice hockey. This increased incidence of injury may be due in part to the differences in surfaces, and can prove hazardous to even the recreational roller hockey player or in-line skater.

Injuries in youth ice hockey: a pilot surveillance strategy.

OBJECTIVE: To determine the incidence and type of injuries in youth hockey players during practice and games as well as to test the applicability of the current methods to a national surveillance study of youth hockey injuries. DESIGN: During the 1993 to 1994 season, we undertook a prospective observational analysis of youth hockey players on four competitive teams at three levels of participation: Squirt, Peewee, and Bantam. MATERIAL AND METHODS: In a study group of 66 youth hockey players, types and anatomic sites of injury, mechanisms of injury, player position affected, and occurrence of injuries during practice or games were determined and analyzed statistically. An injury was strictly defined, standardized reporting strategies were used, and a single physician examined all injured athletes and made the diagnoses. RESULTS: A total of 14 injuries occurred during the season. The on-ice injury rate (per 1,000 player-hours) was 1.0 at the Squirt level (ages 9 and 10 years), 1.8 at the Peewee level (ages 11 and 12 years), and 4.3 at the Bantam level (ages 13 and 14 years). No game injuries and only one mild practice injury occurred in Squirt players (N = 16), and only two mild injuries occurred during practice sessions for Peewees (N = 17). No differences were noted between practice injury rates at the various levels; all recorded game injuries occurred only in Bantam players (N = 33). The most common types of injuries were contusions, fractures, strains, and sprains. The arm and shoulder were most frequently injured. CONCLUSION: Further research is necessary to determine whether injuries in youth ice hockey can be reduced by changes in playing rules, enforcement of existing rules, improvements in protective equipment, alteration in coaching techniques, and institution of educational programs.