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Corey P. Ochs, Melissa C. Kay and Johna K. Register-Mihalik

professional athletes in collision sports? Summary of Search, “Best Evidence” Appraised, and Key Findings • The literature search was limited to articles that were level 3 evidence or higher, investigated the effect of concussions on individual performance of professional-level collision-sport athletes

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Nick Dobbin, Jamie Highton, Samantha Louise Moss and Craig Twist

Purpose: To investigate the factors affecting the anthropometric and physical characteristics of elite academy rugby league players. Methods: One hundred ninety-seven elite academy rugby league players (age = 17.3 [1.0] y) from 5 Super League clubs completed measures of anthropometric and physical characteristics during a competitive season. The interaction between and influence of contextual factors on characteristics was assessed using linear mixed modeling. Results: All physical characteristics improved during preseason and continued to improve until midseason, whereafter 10-m sprint (η 2 = .20 cf .25), countermovement jump (CMJ) (η 2 = .28 cf .30), and prone Yo-Yo Intermittent Recovery (Yo-Yo IR) test (η 2 = .22 cf .54) performance declined. Second (η 2 = .17) and third (η 2 = .16) -year players were heavier than first-years, whereas third-years had slower 10-m sprint times (η 2 = .22). Large positional variability was observed for body mass, 20-m sprint time, medicine-ball throw, CMJ, and prone Yo-Yo IR1. Compared with bottom-ranked teams, top-ranked teams demonstrated superior 20-m (η 2 = −.22) and prone Yo-Yo IR1 (η 2 = .26) performance, whereas middle-ranked teams reported higher CMJ height (η 2 = .26) and prone Yo-Yo IR1 distance (η 2 = .20) but slower 20-m sprint times (η 2 = .20). Conclusion: These findings offer practitioners who design training programs for academy rugby league players insight into the relationships between anthropometric and physical characteristics and how they are influenced by playing year, league ranking, position, and season phase.

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Craig Twist and Jamie Highton

Rugby league is a contact team sport performed at an average intensity similar to that of other team sports (~70–80% VO2max), made up of unsystematic movements of varying type, duration, and frequency. The high number of collisions, repeated eccentric muscle contractions associated with accelerating and decelerating, and prolonged aerobic nature of rugby league matches result in the development of fatigue in the days after exercise. Monitoring the presence and magnitude of this fatigue to maximize performance and training adaptation is an important consideration for applied sports scientists. Several methods have been proposed to measure the magnitude of fatigue in athletes. Perceptual measures (eg, questionnaires) are easy to employ and are sensitive to changes in performance. However, the subjective nature of such measures should be considered. Blood biochemical markers of fatigue may provide a more objective measure of homeostatic disturbances associated with fatigue; however, the cost, level of expertise required, and high degree of variability of many of these measures often preclude them from being used in the applied setting. Accordingly, simple measure of muscle function (eg, jump height) and simulated performance offer the most practical and appropriate method of determining the extent of fatigue experienced by rugby league players. A meaningful change in each measure of fatigue for the monitoring of players can be easily determined, provided that the reliability of the measure is known. Multiplying the coefficient of variation by 0.3, 0.9, and 1.6 can be used to determine a small, moderate, and large change, respectively.

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Georgia M. Black and Tim J. Gabbett

Purpose:

No study has investigated the frequency and nature of repeated high-intensity-effort (RHIE) bouts across elite and semielite rugby league competitions. This study examined RHIE activity in rugby league match play across playing standards.

Participants:

36 elite and 64 semielite rugby league players.

Methods:

Global positioning system analysis was completed during 17 elite and 14 semielite matches.

Results:

The most commonly occurring RHIE bouts involved 2 efforts (2-RHIE) for both elite and semielite players. Only small differences were found in 2-RHIE activity between elite and semielite match play (effect size [ES] ≥0.31 ± 0.15, ≥88%, likely). RHIE bouts were more likely to involve contact as the number of efforts in a bout increased (ES ≥0.40 ± 0.15, 100%, almost certainly). Semielite players performed a greater proportion of 2-contact-effort RHIE bouts than their elite counterparts (68.2% vs 60.6%, ES 0.33 ± 0.15, 92%, likely), while elite players performed a greater proportion of 3-effort bouts (26.9% vs 21.1%, ES 0.31 ± 0.15, 88%, likely). Elite players also had a shorter recovery (1.00−3.99 vs ≥4.00 min) between RHIE bouts (ES ≥1.60 ± 0.71, ≥94%, likely).

Conclusion:

These findings highlight the RHIE demands of elite and semielite rugby league match play. Elite players are more likely to perform RHIE bouts consisting of 3 efforts and to have a shorter recovery time between bouts. Exposing players to these RHIE demands in training is likely to improve their ability to tolerate the most demanding passages of match play.

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Takeaki Ando, Shannon Gehr, Melanie L. McGrath and Adam B. Rosen

The purpose of this report is to present the case of a National Junior Collegiate Athletic Association football player diagnosed with Chiari malformation postconcussion. A Chiari malformation is characterized by the cerebellum presenting below the level of the foramen. The uniqueness of this case stems from the patient’s health history, length of symptoms, and diagnosis. The effectiveness of treatment options, and the primary means to reduce the risk of catastrophic head injury in those with Chiari malformations are debatable. Clinicians should be familiar with the potential for the presence of a Chiari malformation with persistent symptoms postconcussion.

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Nick Dobbin, Richard Hunwicks, Ben Jones, Kevin Till, Jamie Highton and Craig Twist

Purpose: To examine the criterion and construct validity of an isometric midthigh-pull dynamometer to assess whole-body strength in professional rugby league players. Methods: Fifty-six male rugby league players (33 senior and 23 youth players) performed 4 isometric midthigh-pull efforts (ie, 2 on the dynamometer and 2 on the force platform) in a randomized and counterbalanced order. Results: Isometric peak force was underestimated (P < .05) using the dynamometer compared with the force platform (95% LoA: −213.5 ± 342.6 N). Linear regression showed that peak force derived from the dynamometer explained 85% (adjusted R2 = .85, SEE = 173 N) of the variance in the dependent variable, with the following prediction equation derived: predicted peak force = [1.046 × dynamometer peak force] + 117.594. Cross-validation revealed a nonsignificant bias (P > .05) between the predicted and peak force from the force platform and an adjusted R2 (79.6%) that represented shrinkage of 0.4% relative to the cross-validation model (80%). Peak force was greater for the senior than the youth professionals using the dynamometer (2261.2 ± 222 cf 1725.1 ± 298.0 N, respectively; P < .05). Conclusion: The isometric midthigh pull assessed using a dynamometer underestimates criterion peak force but is capable of distinguishing muscle-function characteristics between professional rugby league players of different standards.

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Shane Ball, Mark Halaki, Tristan Sharp and Rhonda Orr

Rugby union is a highly physically demanding collision sport where match play comprises intermittent periods of high-intensity sprinting, low-speed walking and jogging, and contact events such as tackling, rucking and mauling, and scrummaging. 1 As contact events are a major component of the game

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Leilani Madrigal, Jamie Robbins, Diane L. Gill and Katherine Wurst

Collegiate rugby is a competitive, collision sport, yet insufficient empirical evidence exists regarding participants’ perspectives on pain and injury. This study addressed male and female rugby players’ experiences with injury, and their views about playing through pain and injury. Eleven rugby players (five male; six female) competing in USA Rugby’s National College 7’s tournament participated in semistructured interviews, which were recorded, transcribed, and content-analyzed. Two major themes emerged: passion for sport and sport ethic. Passion for sport was composed of (a) love of the sport, (b) meaning of the sport, and (c) desire to be on the field. Sport ethic included: (a) helping the team, (b) game time sacrifice, (c) personality, (d) minimize, and (e) accepted behavior. The researchers explain these findings and propose strategies for increasing future athletes’ understanding of the dangers associated with playing through pain, and confronting the currently accepted culture of risk.

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James Cameron Morehen, Warren Jeremy Bradley, Jon Clarke, Craig Twist, Catherine Hambly, John Roger Speakman, James Peter Morton and Graeme Leonard Close

Rugby League is a high-intensity collision sport competed over 80 min. Training loads are monitored to maximize recovery and assist in the design of nutritional strategies although no data are available on the total energy expenditure (TEE) of players. We therefore assessed resting metabolic rate (RMR) and TEE in six Super League players over 2 consecutive weeks in-season including one game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium 2H) and oxygen (18O) stable isotopes in the form of water (2H2 18O). Every 24 hr thereafter, players provided urine for analysis of TEE via DLW method. Individual training load was quantified using session rating of perceived exertion (sRPE) and data were analyzed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than predictive equations (7.9 ± 0.4 cf. 9.2 ± 0.4 MJ, respectively). A most likely increase in TEE from Week 1 to 2 was observed (17.9 ± 2.1 cf. 24.2 ± 3.4 MJ) explained by a most likelyincrease in weekly sRPE (432 ± 19 cf. 555 ± 22 AU), respectively. The difference in TEE between forward and backs was unclear (21.6 ± 4.2 cf. 20.5 ± 4.9 MJ, respectively). We report greater TEE than previously reported in rugby that could be explained by the ability of DLW to account for all match and training-related activities that contributes to TEE.

Open access

Brittany M. Ingram, Melissa C. Kay, Christina B. Vander Vegt and Johna K. Register-Mihalik

Clinical Scenario Youth ice hockey participation has exponentially increased over the last decade with over 600,000 young athletes currently participating each year. 1 Ice hockey, a collision sport, characterized by high speed, strength, and endurance, predisposes players to a high risk of