Collegiate Ice Hockey Players Research Articles

Inter-Segment Coordination of Male and Female Collegiate Ice Hockey Players During Forward Skating Starts

ABSTRACT Purpose: Coordination in ice hockey skating has been minimally investigated, particularly in females. The objective was to compare lower-extremity inter-segment coordination of collegiate male and female ice hockey players during forward skating starts. Methods: 3D kinematic data were collected on collegiate male (n = 9) and female (n = 10) participants during accelerative steps. Continuous relative phase (CRP) was calculated for shank-sagittal/thigh-sagittal, shank-sagittal/thigh-frontal, and foot-sagittal/shank-sagittal segment pairs across 2.5 strides on each side. Principal component analysis (PCA) extracted features of greatest variability of the CRP and relationships between principal components and sex were investigated using hierarchical linear model. Results: Males demonstrated more out-of-phase coordination (higher CRP) for side one (p = .01) and side two (p < .01) shank-sagittal/thigh-sagittal as well as side one shank-sagittal/thigh-frontal (p < .01) segment pairs throughout each step. Females demonstrated a greater change in CRP from late stance/early swing to late swing/early stance on side two for shank-sagittal/thigh-frontal segments (p < .01). For side two shank-sagittal/thigh-frontal segments, faster males utilized more out-of-phase coordination throughout each step whereas faster females utilized more in-phase coordination (p < .01). Conclusion: Males and females may employ different coordinative strategies to achieve faster skating speeds. Males tend to utilize more out-of-phase coordination of the shank and thigh throughout strides, although coordinative differences of the shank and foot were not found between sexes. Further investigation is needed to examine the relationship between lower limb strength and coordination as well as the effect of targeted training protocols on lower extremity coordinative patterns.

Comparing the Effects of an Off-Ice Sprint-Change of Direction Task on Trunk Kinematics and Gait Laterality in Collegiate Ice Hockey Players

Laterality preferences are intrinsic in most physical activities, and ice hockey is one domain wherein these preferences might influence performance. Biomechanical laterality between dominant and nondominant (or preferred and nonpreferred) limbs is believed to be an advantageous attribute that is linked with skilled performance. Yet little is known about the implications of motor asymmetries for skilled performers in dynamic, time-constrained, team-based activities in an off-ice environment. This can be extended to when player position is considered, notably for those playing in a defensive or an offensive position. In this study, fourteen semi-professional collegiate male ice hockey players (age: 21.87 ± 2.98 years; BMI: 25.26 ± 3.21 kg/m) performed a randomized repeated 15 m sprint-change of direction task. Assessments of lower limb laterality were carried out as participants commenced the 15 m sprint change of direction task in both a right and left foot rear setback position. Biomechanical laterality between right and left rear foot setback positions was inferred by an ActiGraph GTx3 triaxial accelerometer that was located on the participants’ spinous process, representing the trunk centre of mass (CoM). Overall, ANOVA results indicated significant differences across all sprint split times between the right and left foot rear setback positions, with times significantly quicker when players commenced in a right rear foot setback position (p &lt; 0.001). ANOVA revealed significant differences in trunk CoM acceleration between in a right and left rear setback position, specifically during the initial 0–10 m sprint split, with offensive players observed to have lesser trunk anteroposterior and vertical CoM acceleration (p = 0.05) and during the final 5 m sprint split (p = 0.002, d = 0.7), despite overall smaller effect sizes seen in the left foot rear setback position. It appears that starting with the foot in a right rear setback position results in quicker 15 m performance times and concurrent lower magnitudes of trunk CoM acceleration. Although we demonstrated that offensive players were quicker and displayed less trunk CoM acceleration, we recommend that future studies use a greater number of participants for inter-limb symmetry in these movement tests.

Assessing Brain Processing Deficits Using Neuropsychological and Vision-Specific Tests for Concussion.

Since verbal memory and visual processing transpire within analogous cerebral regions, this study assessed (i) if a visual function can predict verbal memory performance. It also hypothesized whether neurocognitive (e.g., ImPACT) tests focusing on the Visual Memory and Cognitive Efficacy Index will predict Verbal Memory scores and (ii) if vision metrics and age can identify individuals with a history of concussion. Finally, it also hypothesized that King-Devick and near point of convergence scores alongside age considerations will identify candidates with a prior reported history of concussion. This observational cohort assessed 25 collegiate ice hockey players prior to the competitive season considering age (19.76 ± 1.42 years) and BMI (25.9 ± 3.0 kg/cm2). Hypothesis 1 was assessed using a hierarchical (sequential) multiple regression analysis, assessing the predictive capacity of Visual Memory and Cognitive Efficacy Index scores in relation to Verbal Memory scores. Hypothesis 2 utilized a binomial logistic regression to determine if King-Devick and near point of convergence scores predict those with a prior history of concussion. Hypothesis 1 developed two models, where Model 1 included Visual Memory as the predictor, while Model 2 added the Cognitive Efficacy Index as a predictor for verbal memory scores. Model 1 significantly explained 41% of the variance. Results from Model 2 suggest that the Cognitive Efficacy Index explained an additional 24.4%. Thus, Model 2 was interpreted where only the Cognitive Efficacy Index was a significant predictor (p = 0.001). For every 1 unit increase in the Cognitive Efficacy Index, Verbal Memory increased by 41.16. Hypothesis 2's model was significant, accounting for 37.9% of the variance in those with a history of concussion. However, there were no significant unique predictors within the model as age (Wald = 1.26, p = 0.261), King-Devick (Wald = 2.31, p = 0.128), and near point of convergence (Wald = 2.43, p = 0.119) were not significant predictors individually. The conflicting findings of this study indicate that baseline data for those with a history of concussion greater than one year may not be comparable to the same metrics during acute concussion episodes. Young athletes who sustain a concussion may be able to overcompensate via the visual system. Future prospective studies with larger sample sizes are required using the proposed model's objective metrics.

Effect Of Ice Hockey Repetitive Head Impacts On Dual Task Tandem Gait Performance

Repetitive head impacts (RHI) may adversely affect neurophysiological health, but their effect of functional tasks remain to be further elucidated. PURPOSE: To determine the effect of RHI on single task (ST) and dual task (DT) tandem gait performance in collegiate ice hockey players. METHODS: 36 male collegiate ice hockey players (age: 19.7 + 1.2 y.o., ht: 1.80 + 0.06 m, wt: 80.9 + 6.8 kg, concussion history: 48.6% (17/36), 0.8 + 0.9 concussions) were assessed over the course of a club collegiate ice hockey season between 2016 and 2019. Head impact monitoring occurred during each practice and home game using the Smart Impact Monitor (SIM-G) through visual and/or video review. Participants performed five trials each of ST and DT Tandem Gait (TG) at pre-season, mid-season, and post-season. The DT challenges were working memory tasks which included subtraction, spelling, and reciting the months of the year backwards as the participant walked heel-to-toe down a 3-meter line, turned around, and returned. To assess changes over the course of the season, a repeated measures mixed model ANOVA was performed for ST and DT tandem gait total time with pairwise post-hoc on significant findings. RESULTS: There was a significant main effect for time for both ST tandem gait (p = 0.001, partial eta = 0.217) and DT tandem gait (p < 0.001, partial eta = 0.305). There was a significant improvement in ST tandem gait from Pre-season to Post-season (pre; 10.3 + 1.8 sec, post; 9.2 + 1.8 sec, p < 0.001, d = 0.61), but not Mid-Season (mid; 9.7 + 1.8 sec, p = 0.067). There was a significant main effect for time in DT tandem gait from pre-season to both mid-season (pre; 13.8 + 4.7 sec, mid; 12.2 + 3.3 sec, p = 0.001, d = 0.39) and Post-Season (post; 11.9 + 3.9 sec, p < 0.001, d = 0.43). CONCLUSION: Contrary to our hypothesis that repetitive head impacts experienced over the course of an ice hockey season would result in reduced/worsened tandem gait performance, the participants herein showed significant improvements over time with medium to large effects sizes. While prior studies have shown modest improvements in tandem gait performance with repeat administration, these results suggest that participation in collegiate club ice hockey season are not associated with postural control impairments as measured by either ST or DT tandem gait.

Hip Adduction and Abduction Strength Profiles Among Bantam, High School, Juniors, and Collegiate American Ice Hockey Players.

BackgroundAdductor strains are the most common non-contact musculoskeletal injury sustained in ice hockey. Systematic reviews have determined higher level of play and lower hip adduction to abduction strength ratios to be associated with an increased risk of adductor strain across multiple sports. Limited research exists regarding hip adduction and abduction strength profiles across various levels of ice hockey players.PurposeTo compare isometric hip adduction and abduction strength profiles among bantam, high school, tier one juniors, and NCAA Division I collegiate ice hockey players. A secondary purpose was to identify whether differences in strength profiles between dominant and non-dominant limbs exist.Study DesignCross-sectional cohort study.MethodsA questionnaire of demographic data, hockey, and injury specific information was completed by all subjects. The mean of three reps of maximal hip isometric adduction and abduction strengths were quantified using a handheld dynamometer with external belt-fixation. Ratios of hip adduction-to-abduction strength were calculated and normalized for body weight.ResultsA total of 87 uninjured skaters were included in this study with a mean age of 17 years. Mean hip adductor-to-abductor ratios for Bantam hockey players were 121% followed by collegiate (115%), Juniors (111%), and high school (109%) hockey players. No statistically significant differences were found between peak hip adduction and abduction isometric strength and playing level. In addition, there was no difference between unilateral hip strength ratios and shooting hand or leg dominance. While 34.5% of subjects reported a history of adductor injury, no significant differences existed regarding strength ratios during bilateral comparison or when compared to their team norms. Three subjects were found to have unilateral ratios of less than 80%, while two subjects demonstrated bilateral ratios of less than 80%.ConclusionsSymmetry is illustrated between dominant and non-dominant legs in ice hockey players with and without a history of adductor injury. Results align well with previously established cross-sectional data from Australian football, with ratios of 103% in high school players, 107% in semi-professional players, and 113% in collegiate players.Level of EvidenceLevel 3

Effects of training load and non‐training stress on injury risk in collegiate ice hockey players

This prospective cohort study investigated the relationships between cumulative training loads measured in arbitrary units (AU), non-training stress levels, and athletic injury risk in one team of male collegiate ice hockey players. Measures of athlete training load and non-training stress were recorded each on-ice session over one season. Daily load and stress sums were calculated for the two-day and two-week periods preceding each on-ice session. Athletic injuries were also recorded, and odds ratio analyses were used to determine relationships between training load and injury risk, as well as non-training stress and injury risk. Athletes who exerted training loads of 360 AU-540 AU and of 540 AU-1380 AU over 2 days experienced significantly greater odds of injury compared to athletes who exerted training loads <360 AU and <540 AU, respectively. This study concluded that as two-day training load increases, so do the odds of injury in this sample. In an effort to reduce the odds of athletic injury, the monitoring of individual two-day cumulative training load should be incorporated into the training programs of elite ice hockey players.

Physical Performance Testing Measures Are Poor Predictors Of Ice Hockey Game Performance

Physical performance testing is used to evaluate ice hockey players’ physical preparedness for competition. Identifying relationships between performance tests and game performance outcomes (GPO) could be valuable for predicting which players will be most successful. PURPOSE: To evaluate relationships between measures obtained during off- and on-ice physical performance tests and GPO during a collegiate ice hockey season. METHODS: Nineteen male, collegiate ice hockey players (age = 18-24 yr; ht = 1.8 ± 0.1 m, wt = 85.3 ± 5.1 kg) completed physical performance tests including vertical jump (VJ), 30-sec Wingate, incremental treadmill (TM), and a repeated shift ability (RSA) test during preseason. Players received 3-5 attempts to perform their maximum vertical jump (nearest 0.5 inch). The 30-sec Wingate was performed with 0.075 kg per kg of body weight and provided peak power (WPW) and percent fatigue decrement (WFD). Time to volitional exhaustion was measured on the TM which entailed 3-min run stages separated by 90-sec rest. The RSA was performed on-ice in full gear. The RSA involved eight, ~22-sec maximal skating shifts with 90-sec rest between each shift. The fastest shift (FS) and fatigue decrement index (FDI) were measured and calculated. Throughout the 2019-2020 season, Corsi For (CF) and Ice Time (IT) were recorded each game. Spearman correlations were used to assess relationships between each performance test and GPO. RESULTS: VJ heights averaged 30.4 ± 2.5 in, WPW and WFD averaged 11.6 ± 1.4 W/kg and 14.8 ± 4.8% respectively, TM time to exhaustion averaged 20.1 ± 1.5 min, and FS and FDI averaged 22.0 ± 0.4 sec and 7.7 ± 2.5% respectively. Correlations revealed TM times were inversely associated with FDI (r = -0.52, p < 0.05), CF (r = -0.60, p < 0.05), and IT (r = -0.65, p < 0.01). No relationships were identified between other physical performance and GPO measures. CONCLUSION: Inverse relationships between TM times and CF and IT were surprising as we expected greater aerobic fitness to contribute to faster recovery and consequently, more ice time and higher CF during competition. We also anticipated measures from the VJ, Wingate, and RSA to relate to GPO. Further investigation into how off- and on-ice performance test measures relate to aspects of competition could improve the rationale for using these preseason tests.

Prevalence of shoulder labral abnormalities on MRI in a non-athletic asymptomatic young adult population.

To determine the prevalence of shoulder (specifically labral) abnormalities on MRI in a young non-athletic asymptomatic cohort. We hypothesize that this population will have fewer labral abnormalities than an athletic population. In this cross-sectional study, non-athletic young adults age 18-29 with no history of shoulder pain received bilateral shoulder MRIs. A total of 58 total shoulder MRIs were completed on a 3-T MRI scanner (PRISMA-Fit Siemens Medical). MRIs were read by two board-certified fellowship-trained musculoskeletal radiologists at two time points 3 months apart to determine prevalence of labral and other shoulder anatomy abnormalities. Kappa statistics and the associated 95% confidence intervals were computed for inter/intra-reader reliability. Fisher's exact test was used to compare rates of abnormalities in our study with a similarly designed study involving ice hockey athletes. Prevalence of labral abnormalities was 9% (5/58). Kappa coefficient was 1.0 for both readers for intra-reader reliability and 0.57 for inter-reader reliability of labral abnormalities. We further compared our results in asymptomatic athletes with previously published work using the same protocol at our institution. The prevalence of labral abnormalities on MRI in asymptomatic professional and collegiate ice hockey players (49 imaged shoulders) was 24%, which demonstrated a statistically significant (p value < 0.05) difference compared with our data with a p value of 0.03. Non-athletic young adults with no history of shoulder pain/injury had an overall prevalence of shoulder MRI abnormalities less than asymptomatic professional and collegiate ice hockey players in a similarly designed study.

Comparison Of Off-ice And On-ice Performance Tests In Collegiate Ice Hockey Players

Ice hockey is a high-intensity sport that requires optimally performing energy systems to compete at an elite level. Typically, off-ice performance tests are used to evaluate player fitness, but little is known about their relationships to on-ice tests. PURPOSE: To compare performance, blood lactate (LAC), and heart rate (HR) obtained during off- and on-ice fitness tests in collegiate ice hockey players. METHODS: Nineteen male, collegiate ice hockey players, (age=18-24 yr; ht=1.81±0.05m, wt=84.9±4.74 kg) were assessed off-ice using a discontinuous, incremental treadmill (TM) test. 3-min run stages were separated by 90-sec rest, until players reached volitional exhaustion. The on-ice test, in full gear, was a repeated shift ability (RSA) test consisting of eight, ~22-sec stages of maximal effort skating with 90-sec rest between stages. Fatigue decrement index (FDI) was calculated by subtracting fastest from slowest RSA stage times. During both tests, fingerstick LAC was obtained during rest intervals and HR was measured continuously. Spearman correlations were used to assess the relationship between TM completion time and FDI, as well as the relationships in Stage4 LAC and HRrecovery between off- and on-ice tests. RESULTS: TM times to exhaustion averaged 19.8±1.1 min, and RSA times averaged 22.0±0.4 sec. Corrrelations revealed no relationship between TM time and FDI (r=0.301, ns). Average HRmax during the TM tests was 192±6 b.min-1 versus highest achieved HR of 175±9 b.min-1 (91% of TM HRmax) during the RSA tests. For the TM tests, Stage4 LAC and HRrecovery averaged 10.2±2.8mmol and reduction to 76±8% HRmax, respectively. For the RSA tests, Stage4 LAC and HRrecovery averaged 13.3±1.9mmol and reduction to 74±4%HRmax. Stage4 TM and RSA LAC values were significantly related (r=0.52, p<0.05); however no significant relationship existed between Stage4 TM and RSA values for HRrecovery (r=0.34, ns). CONCLUSION: The lack of relationship between TM time and FDI was expected given the two tests’ emphases on different energy systems and the homogeneity of the athletes’ overall fitness. Moderate to high correlation found between LAC measures, regardless of test modality, supports previous research from our lab indicating the predictive value of LAC measures on ice hockey player performance.

Validation Of Player Tracking Sensors For Measuring Sprint Speed With Collegiate Ice Hockey Players

Validation Of Player Tracking Sensors For Measuring Sprint Speed With Collegiate Ice Hockey Players

Prevalence of MRI Shoulder Abnormalities in Asymptomatic Professional and Collegiate Ice Hockey Athletes.

Background:The literature demonstrates a high prevalence of asymptomatic knee and hip findings on magnetic resonance imaging (MRI) in athletes. Baseball pitchers are shown to have a high prevalence of asymptomatic shoulder MRI findings, but the incidence of asymptomatic shoulder MRI findings has not been systematically evaluated in nonthrowing contact athletes.Purpose/Hypothesis:The purpose of this study was to determine the prevalence of shoulder abnormalities in asymptomatic professional and collegiate hockey players. We hypothesized that, similar to overhead throwing athletes, ice hockey players will have a high prevalence of asymptomatic MRI findings, including labral, acromioclavicular (AC), and rotator cuff pathology on MRI.Study Design:Cross-sectional study; Level of evidence, 4.Methods:A total of 25 asymptomatic collegiate and professional hockey players (50 shoulders) with no history of missed games or practice because of shoulder injury, pain, or dysfunction underwent bilateral shoulder noncontrast 3.0-T MRI. MRIs were read blinded by 2 board-certified radiologists at 2 separate time points, 3 months apart, to determine the prevalence of abnormalities of the joint fluid, bone marrow, rotator cuff tendon, biceps tendon, labrum, AC joint, and glenohumeral joint. Interrater and intrareader reliability was determined, and regression analysis was performed to identify the prevalence and relationship to stick-hand dominance.Results:Labral abnormalities were seen in 25% of the shoulders. AC joint abnormalities and rotator cuff findings were noted in 8% and 6% of shoulders, respectively. One shoulder was noted to have a biceps tendon abnormality, and 1 shoulder demonstrated glenohumeral joint chondral findings. Interrater reliability coefficients were 0.619 for labral abnormalities. Intrareader reliability kappa coefficients were 0.493 and 0.718 for both readers, respectively, for labral abnormalities. Regression analysis was performed and revealed that the overall shoulder pathology was more common in the nondominant stick hand (top stick hand) (coefficient –0.731; P = .021).Conclusion:Professional and collegiate ice hockey players had an overall prevalence of labral abnormalities in 25% of their shoulders, with findings more often found in the nondominant stick hand. Rotator cuff abnormalities were uncommon in ice hockey players. These findings differ significantly from published reports examining professional baseball players and other overhead sports athletes.

Epidemiology of Foot and Ankle Injuries in National Collegiate Athletic Association Men's and Women's Ice Hockey.

Background:Ice hockey is a high-speed contact sport in which athletes are prone to many different injuries. While past studies have examined overall injury rates in ice hockey, foot and ankle injuries among collegiate ice hockey players have yet to be analyzed.Purpose/Hypothesis:The purpose of this study was to elucidate the epidemiology of foot and ankle injuries among collegiate ice hockey players utilizing data from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program. We hypothesized that male ice hockey players would sustain more injuries compared with female ice hockey players and that the injuries sustained would be more severe.Study Design:Descriptive epidemiology study.Methods:Data on all foot and ankle injuries sustained during the academic years 2004 through 2014 were obtained from the NCAA Injury Surveillance Program. Injury rates, rate ratios (RRs), and injury proportion ratios were reported with 95% CIs.Results:Over the study period, the overall rate of foot and ankle injuries for men was higher than that for women (413 vs 103 injuries, respectively; RR, 4.01 [95% CI, 3.23-4.97]). Injury rates were highest during the regular season for both men (358 injuries; RR, 64.78 [95% CI, 58.07-71.49]) and women (89 injuries; RR, 38.37 [95% CI, 30.40-46.35]) compared with the preseason or postseason. The most common injury in men was a foot and/or toe contusion (22.5%), while women most commonly sustained a low ankle sprain (31.1%). For men, foot and/or toe contusions accounted for the most non–time loss (≤24 hours ) and moderate time-loss (2-13 days) injuries, while high ankle sprains accounted for the most severe time-loss (≥14 days) injuries. For women, foot and/or toe contusions accounted for the most non–time loss injuries, low ankle sprains accounted for the most moderate time-loss injuries, and high ankle sprains accounted for the most severe time-loss injuries.Conclusion:Foot and ankle injuries were frequent among collegiate ice hockey players during the period studied. For men, contusions were the most commonly diagnosed injury, although high ankle sprains resulted in the most significant time lost. For women, low ankle sprains were the most common and resulted in the most moderate time lost. These findings may direct future injury prevention and guide improvements in ice skate design.

Seasonal Changes in Physiological Responses and Body Composition During a Competitive Season in Male and Female Elite Collegiate Ice Hockey Players.

Delisle-Houde, P, Reid, RER, Insogna, JA, Chiarlitti, NA, and Andersen, RE. Seasonal changes in physiological responses and body composition during a competitive season in male and female elite collegiate ice hockey players. J Strength Cond Res 33(8): 2162-2169, 2019-Ice hockey continually overloads athletes with limited time for recovery, which may affect several physiological responses and alter body composition. The purpose of this study was to identify changes in physiological parameters and body composition profiles over the competitive season in elite collegiate ice hockey players. Forty-four players, 24 males (age = 22.7 ± 1.3 years, height = 1.82 ± 0.6 m, and body mass = 86.87 ± 6.44 kg) and 20 females (age = 19.9 ± 1.8 years, height = 1.66 ± 0.7 m, and body mass = 68.76 ± 5.91 kg) participated in 4-minute submaximal exercise tests and body composition assessments at pre-season, mid-season, and end-season. Changes in physiological parameters and body composition were analyzed using repeated-measures analysis of covariance controlling for age. Males' postexercise blood lactate concentration decreased (p ≤ 0.05) from pre- to mid-season (9.3 vs. 6.2 mmol·L) and increased (p ≤ 0.05) from mid- to end-season (6.2 vs. 8.0 mmol·L). Heart rate increased (p ≤ 0.05) after the third and fourth minute of the submaximal test in both sexes from pre- to end-season and from mid- to end-season. Males' body fat percentage decreased (p ≤ 0.05) from mid-season (17.4 vs. 16.1%), whereas increases were observed (p ≤ 0.05) in both sexes from mid- to end-season. This study produced evidence that male and female collegiate hockey athletes' physiological responses and body composition profiles change over the season. Sport scientists working with collegiate hockey teams, may need to revise annual training programs to attenuate reductions in fitness and hopefully prevent injuries.

Relationships between Head Impacts, Competitive Aggression, and Risk-taking Behavior in Collegiate Ice Hockey Players

Abstract Purpose To examine relationships between head impact kinematics sustained over a season and competitive aggression and self-reported risk-taking behavior in collegiate club ice-hockey athletes. Methods Twenty male ice-hockey players (19.9±1.2 y.o, 1.8±0.06 m, 78.5±5.7 kg) completed the Competitive Anger and Aggression Scale (CAAS, Range:0-84) and the Brief Sensation Seeking Scale (BSSS, Range:8-40) during the preseason as measures of competitive aggression and risk-taking behavior with higher/lower reflecting higher/lower aggression and risk taking. Penalty minutes (PM) and games played (GP) were taken from official game records. Head impact kinematics (number of impacts, linear mean, peak, cumulative acceleration) were recorded by tri-axial accelerometers worn during games/practices. Spearman correlation was performed to examine relationships between variables. Results The mean number of impacts was 76.6±54.9 (range: 6–171); mean and cumulative acceleration were 36.3±4.2g (range:27.8–42.2g) and 2829.4±2024.9g (range:198.4–6527.2g), respectively. Neither CAAS (mean: 48.7±10.9, range: 24–64) nor BSSS scores (mean: 25.3±4.4, range:15–32) were significantly related to impact kinematics. GP was significantly correlated with number of impacts (r=.63, p=.003) and cumulative linear acceleration (r=.61, p=.004). PM was significantly correlated with number of impacts (r=.52, p=.20) and cumulative linear acceleration (r=.55, p=.13). Conclusion There were no relationships between the head impact kinematics and self-reported aggressiveness or risk taking behavior, but more PM was strongly related to higher head impact loads. Considering PM may be useful in aiding to identify athletes who may sustain higher head impact loads, however, self-reports of behavior may not be.

Effects of Optimizing the Respiratory Pump on Performance During a Simulated Ice Hockey Period

Ice hockey requires high-intensity activity during shifts with inactive recovery between shifts. During recovery periods, blood may pool in the legs, reducing central blood volume and the ability to clear lactic acid. Impedance threshold devices (ITD) were developed to treat conditions of central hypovolemia, such as hemorrhage. By creating a negative intrathoracic pressure, venous return is enhanced, increasing stroke volume and cardiac output. PURPOSE: To determine the effects of breathing with an ITD during recovery periods between simulated ice hockey shifts. METHODS: Five male collegiate ice hockey players skated a course, the Peterson On-Ice Repeated Sprint Test, eight times (shifts) with 90 s recovery between each shift. Each athlete completed two test sessions separated by 48 hr, one while breathing freely during the recovery periods (control condition) and one while breathing with the ITD during the recovery periods. RESULTS: Performance, measured as time to skate the course, was similar between conditions (p > .05). Average time to complete each shift was 22.10 ± 0.74 s (SEM) and increased with successive shifts. After shift 4, lactate was 12.0 ± 0.8 mM (control) and 11.0 ± 2.0 mM (ITD). After skating eight shifts, lactate continued to increase during the control condition (14.0 ± 0.4 mM) and was 28% higher than the ITD condition (10.9 ± 1.5 mM). Ratings of perceived exertion increased from shift 1 to shift 8 with the average slope of increase greater for the control condition (0.87, 95% CI 0.80-0.94) than the ITD condition (0.65, 95% CI 0.60-0.70, Z = -7.54, p < .001). CONCLUSIONS: Breathing with the ITD during recovery periods did not affect skating performance measured as time to complete each shift, but lactate was lower after shift 8 and athletes rated their exertion lower during the ITD condition. Thus, use of an ITD has potential to enhance recovery during repeated bouts of high-intensity, intermittent exercise.

Test-retest reliability of TRIMP in collegiate ice hockey players.

The utility of the heart rate derived variable TRaining IMPulse (TRIMP) for assessing internal training load in ice hockey players is not clear. Having a reliable measure of internal training load during on-ice training sessions would help coaches program exercise training. This study determined the reliability of TRIMP during on-ice training sessions in ice hockey players. Twelve Division I collegiate male ice hockey players (aged 18–23 years) had their heart rate (HR) data recorded during two on-ice practice sessions separated by two weeks. TRIMP and other descriptive HR variables were compared between sessions. TRIMP demonstrated moderate reliability during on-ice sessions. Systematic error, quantified as standardized change in means was negligible (–0.19); random error quantified as the percent typical error (%TE) was moderate (12.2%); and, test-retest correlation was very strong (0.75). TRIMP is suitable for quantifying training load during intermittent work in hockey athletes. The results from our study can be used to determine the threshold for meaningful change in TRIMP, which may aid in informing decisions by coaches and strength training staff regarding on-ice training session difficulty and composition.

Pediatric Sports Specialization in Elite Ice Hockey Players.

Background:Pediatric sports specialization, defined as intense year-round training in a single sport as a result of excluding other sports for more than 8 months per year, is common in the United States. There are demonstrated physical and social risks to early pediatric sports specialization (defined as before age 12 years). While thought to be needed to acquire appropriate experience and excel in a given sport, there remains little information on when athletes at the highest levels of their sport specialized. This study aimed to define when professional and collegiate ice hockey players specialized.Hypothesis:Early sports specialization before age 12 years will not be common among elite-level (professional and collegiate) ice hockey players.Study Design:Retrospective cross-sectional survey study.Level of Evidence:Level 3.Methods:Male professional and collegiate ice hockey players within 1 National Hockey League organization and 2 National Collegiate Athletic Association (NCAA) organizations who were 18 years of age or older completed a survey at training camp detailing their history of sports participation and specialization.Results:A total of 91 athletes participated in the study (mean age, 22.8 years; range, 18-39 years). The mean age at the start of any sports participation was 4.5 years, and the mean age of sports specialization was 14.3 years. The mean age of specialization in the professional group, the NCAA Division I group, and the NCAA Division III group was 14.1, 14.5, and 14.6 years, respectively.Conclusion:Early pediatric sports specialization is not common in elite-level (professional and collegiate) ice hockey players.Clinical Relevance:Early pediatric sports specialization before age 12 years is not necessary for athletic success in professional and collegiate ice hockey. This study provides further evidence supporting the recommendations of the American Medical Society for Sports Medicine, American Academy of Pediatrics, and American Orthopaedic Society for Sports Medicine against early sports specialization.

Training history constrains postural sway dynamics: A study of balance in collegiate ice hockey players

BackgroundBalance and postural control are integral to training and sport performance. Demands on posture are contextual and vary in different ways depending on the specific physical activity. Research questionThe purpose of this study was to examine the possibility that sustained exposure to environmental constraints, through specific sport participation, might lead to a persistent modification of postural control. MethodsDouble and single-leg postural sway were compared between ice hockey players, American football players and physically active college students. Data from 30 s trials were analyzed using traditional postural sway measures of range and pathlength of the center of pressure, as well as with Sample Entropy (SEn), in both mediolateral (ML) and anteroposterior (AP) directions. ResultsEach group displayed unique postural sway characteristics. During single-leg stance, ice hockey players show significantly different ML pathlength and ML and AP SEn from the physically active college students (all p < 0.05), and significantly different ML and AP pathlength and AP SEn from the American football players (all p < 0.05). The American football players and the physically active college students differed for all single-legged conditions (all p < 0.05). SignificanceThis suggests that the organization and development of postural sway is not only context dependent but also influenced by training history; supporting the idea that balance training for sport should be designed with regards to sport specific conditions.

Neuro-Metabolite Changes in a Single Season of University Ice Hockey Using Magnetic Resonance Spectroscopy

Background: Previous research has shown evidence for transient neuronal loss after repetitive head impacts (RHI) as demonstrated by a decrease in N-acetylaspartate (NAA). However, few studies have investigated other neuro-metabolites that may be altered in the presence of RHI; furthermore, the relationship of neuro-metabolite changes to neurocognitive outcome and potential sex differences remain largely unknown.Objective: The aim of this study was to identify alterations in brain metabolites and their potential association with neurocognitive performance over time as well as to characterize sex-specific differences in response to RHI.Methods: 33 collegiate ice hockey players (17 males and 16 females) underwent 3T magnetic resonance spectroscopy (MRS) and neurocognitive evaluation before and after the Canadian Interuniversity Sports (CIS) ice hockey season 2011–2012. The MRS voxel was placed in the corpus callosum. Pre- and postseason neurocognitive performances were assessed using the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT). Absolute neuro-metabolite concentrations were then compared between pre- and postseason MRS were (level of statistical significance after correction for multiple comparisons: p < 0.007) and correlated to ImPACT scores for both sexes.Results: A significant decrease in NAA was observed from preseason to postseason (p = 0.001). Furthermore, a trend toward a decrease in total choline (Cho) was observed (p = 0.044). Although no overall effect was observed for glutamate (Glu) over the season, a difference was observed with females showing a decrease in Glu and males showing an increase in Glu, though this was not statistically significant (p = 0.039). In both males and females, a negative correlation was observed between changes in Glu and changes in verbal memory (p = 0.008).Conclusion: The results of this study demonstrate changes in absolute concentrations of neuro-metabolites following exposure to RHI. Results suggest that changes in Glu are correlated with changes in verbal memory. Future studies need to investigate further the association between brain metabolites and clinical outcome as well as sex-specific differences in the brain's response to RHI.

Epidemiology of Upper Extremity Injuries in NCAA Men’s and Women’s Ice Hockey

Background: Ice hockey is a physically demanding sport where athletes are susceptible to a variety of injuries. Several studies reported the overall injury rates in ice hockey; however, there is a paucity of information on upper extremity (UE) injuries among collegiate ice hockey players. Purpose: To describe the epidemiology of UE injuries among collegiate male and female ice hockey players with NCAA (National Collegiate Athletic Association) injury surveillance data from 2004-2005 to 2013-2014. Study Design: Descriptive epidemiology study. Methods: Data were obtained from the NCAA Injury Surveillance Program for all UE injuries sustained during the academic years 2004-2005 to 2013-2014. Injury rates, rate ratios (RRs), and injury proportion ratios were reported with 95% CIs. Results: During the 10 years studied, the overall rate of UE injuries for men was higher than that for women (236 vs 125 injuries per 100,000 athlete-exposures [AEs]; RR, 1.89; 95% CI, 1.67-2.15). UE injuries sustained during either pre- or postseason were approximately 3 times higher for men than for women (preseason: 149 vs 53 per 100,000 AEs; RR, 2.83; 95% CI, 1.69-4.74; postseason: 143 vs 49 per 100,000 AEs; RR, 2.91; 95% CI, 1.33-6.38). The overall injury rate was highest during the regular season (men: 257 per 100,000 AEs; 95% CI, 242-272; women: 143 per 100,000 AEs; 95% CI, 126-160). Additionally, the injury rate for men and women was higher during competition than practice (men: 733 vs 83 per 100,000 AEs; 95% CI, 687-780 and 75-92; women: 303 vs 64 per 100,000 AEs; 95% CI, 259-348 and 52-76). The most common injury observed was acromioclavicular joint sprain (men, 29.1%; women, 13.8%). For both groups, acromioclavicular joint injuries accounted for most non–time loss, moderate time loss (2-13 days), and severe time loss (≥14 days) injuries. Conclusion: Men and women sustained a significant number of UE injuries playing collegiate ice hockey during the period studied, with acromioclavicular joint sprain being the most common UE injury and the one that most frequently led to significant time loss. These data may provide insight for future injury prevention and guide improvements in training.