Science of rugby league football: A review

Magnetic resonance imaging of the shoulder in symptomatic professional rugby players: a retrospective analysis

OBJECTIVE

Shoulder injuries in rugby players are common due to frequent high-impact collisions and tackles. This study aimed to describe the spectrum and pattern of shoulder MRI findings in professional rugby players.

METHODS

Single-center retrospective study of shoulder MRI was carried out between 2012 and 2016 in symptomatic professional male rugby league and rugby union players. One hundred ten shoulder MRIs were scored for rotator cuff and long head of biceps tendons, labral, bursal, joint, and osseous abnormalities. MRI features were compared using the chi-square or Fisher's exact tests for categorical variables.

RESULTS

There were a total of one hundred ten professional male rugby players (80 rugby league and 30 rugby union), with a mean age of 24.6 (range 17-38) and 23.7 (range 17-33) years old, respectively. Rotator cuff or long head biceps abnormality was found in 36 (33%) players, of which 22 (20%) were either partial or full-thickness tears. Glenoid labral tears were present in 63 (57%) players. There was no significant difference (p > 0.05) in the frequency of tears of the superior (24%), anterior inferior (25%), posterior superior (25%), and posterior inferior (32%) labrum. Forty-seven percent of players presented with two or more abnormalities of the rotator cuff tendons and glenoid labrum. There were significantly more osseous abnormalities in backs compared to forwards (48% vs. 21%; p = 0.01).

CONCLUSIONS

There is a wide spectrum of shoulder abnormalities on MRI in professional rugby players, and many have two or more abnormalities. In common with other contact sports, posterior labral injury was a common finding and may relate to sub-clinical trauma, without an association with instability.

Positional Differences in Decision-Making Situations during Professional Rugby League Match-Play

The aim of this study was to explore the types and frequency of decision-making situations of rugby league players during defensive situations and examine whether they were predictive of key performance indicators (KPI). Fifteen elite rugby league matches were coded using notational analysis methods. Specific defensive situations were analysed, including the number of: one-on-one situations with an opposing attacker (1-on-1), two-on-one situations (2-on-1), and combined 1-on-1 and 2-on-1 situations (i.e., total decisions; TDs). There was no relationship between the game outcome and game KPIs for TDs or 1-on-1 decision-making situations. However, successful tackles and missed tackles were predictive of 2-on-1 decision-making situations. Positional differences revealed that back rowers were exposed to the greatest number of decision-making situations, while wingers had the lowest exposure. The total number of decisions and the number of 1-on-1 decisions made by the centres and wingers were significant predictors of line breaks. Additionally, 2-on-1 decisions were significant predictors of line breaks for backrowers. The findings of this study suggest that the type and frequency of decision-making situations in Rugby League are position specific. Practical applications for coaches are discussed to ensure that practice approaches are representative of the various defensive decision-making demands players experience during a game, based on their position.

Acute beetroot juice supplementation did not enhance intermittent running performance in trained rugby players

ABSTRACTPurpose: Since the effect of dietary nitrate (NO3-) supplementation on rugby performance is unclear, the aim of the present study was to determine the effect of acute NO3- supplementation, on the modified Yo-Yo intermittent recovery level 1 (IR1) performance test in trained male rugby players.Methods: In a randomised, counterbalanced, double-blind, placebo-controlled crossover design, 12 trained rugby union players performed two experimental trials three hours after supplementation of either 140 mL NO3--rich (BRJ; ∼12.8 mmol NO3-) or NO3--depleted (PLA) BRJ. After blood sampling, players performed the modified Yo-Yo IR1 test. Countermovement jumps (CMJ) were also measured before (pre-CMJ) and after (post-CMJ) the prone Yo-Yo IR1 test.Results: Plasma NO3- (BRJ: 570 ± 146 µM vs. PLA: 72 ± 23 µM) and nitrite (NO2-) concentrations (BRJ: 320 ± 123 nM vs. PLA: 103 ± 57 nM) were increased after BRJ compared to PLA supplementation (both P < 0.001). Performance in the modified Yo-Yo IR1 test did not differ between BRJ (542 ± 209 m) and PLA (498 ± 185 m, P = 0.3). The jump height in pre-CMJ and in post-CMJ were similar between trials (both P > 0.05).Conclusions: Acute BRJ supplementation increased plasma NO3- and NO2- concentrations but had no benefit on an intermittent running test that reflects the demands of rugby performance, and CMJ performances. The findings do not support acute high-dose NO3- supplementation as an ergogenic aid to enhance physical performance in trained male rugby players.

Association between Variation in Body Fat Mass Magnitude and Intake of Nutrients, including Carbohydrates, Fat, and B Vitamins, in a Cohort of Highly Trained Female Athletes

The most common sports nutrition strategies were constructed not only for maximizing musculoskeletal adaptations to exercise, but also to minimize health risks in athletes. Given the lack of research highlighting the potential effects of the intake of carbohydrates, fats, and B vitamins on body fat percentage in a population of female athletes, this study aimed to elucidate whether the intake of macronutrients and B vitamins could be associated with the variation in body fat percentage in a cohort of professional female athletes. This cross-sectional study was weighted to represent Lithuanian elite female athletes (n = 89). The dietary assessment of the female athletes was carried out using a 3-day dietary recall method. Their body composition was assessed using the bioelectrical impedance analysis method. For females, the reported average intakes of energy, carbohydrates, protein, and fat were 2475 kcal/day, 5.1 g/kg/day, 1.5 g/kg/day, and 36.7%, respectively. Excess B vitamin intake was revealed, ranging within plus 1-2 standard deviations (SDs) around the mean requirements. As a consequence, excessive body fat percentage was potentially factored as a negative outcome in maintaining optimal body composition in female athletes. Multivariate logistic regression analysis of a sample of female athletes revealed that, despite a slightly positive energy balance (∆ 95 kcal/day), the carbohydrate-deficient diet (adjusted odds ratio (aOR) 0.3, 95% confidence interval (CI) 0.1; 0.7), along with higher intakes of vitamin B1 (aOR 2.9, 95% CI 2.6; 7.8), vitamin B2 (aOR 6.7, 95% CI 1.1; 8.3), and vitamin B3 (aOR 1.8, 95% CI 1.4; 7.8) from food, was associated with a lower percentage of body fat. Therefore, more attention should be given to the intake of B vitamins in professional athletes with a range of body fat mass percentages for the purpose of achieving long-term goals of maintaining body composition and fitness.

Effects of treatment dosage of whole-body cryotherapy upon post-match recovery of endocrine and biochemical markers in elite rugby league players: An experimental study

Background and Aims

The use of whole-body cryotherapy (WBC) for athletic recovery is becoming increasingly popular despite the lack of evidence supporting the dosage parameters in its implementation. The aim of the current study was to investigate the dose-response effects of WBC following match-play in elite rugby league players.

Methods

We observed endocrine (salivary cortisol and testosterone) and biochemical (creatine kinase) responses following three separate post-match recovery periods in elite rugby league players. Comparisons were made between a single exposure (3 min at -120°C to --135°C) of WBC to two consecutive exposures (2 × 3 min), to a control (no exposure) during the recovery trials. Recovery characteristics were measured 36 h prematch, immediately postmatch, and 60 h postmatch.

Results

Cortisol concentrations remained unchanged in its pattern of response during the postmatch recovery periods across all WBC doses. Testosterone concentrations increased significantly (p < 0.0005) at 60 h, in the WBC2 trial. The Testosterone:Cortisol ratio increased significantly (p < 0.0005) at 60 h in the WBC2 trial, while during the WBC0 trial it did not recover to baseline levels. No significant effect on creatine kinase concentration was observed, although a statistical trend was shown in WBC2 for improved reduction of this marker at 60 h.

Conclusions

These findings suggest that two, consecutive exposures to WBC immediately following fatiguing rugby league competition appear to stimulate an increase to the anabolic endocrine profile of participants by 60 h post-match, and may reduce the CK concentration. Coaches and athletes should consider the treatment dosage of WBC when used to optimize the desired response following a high-stress environment.

Body Composition Asymmetry in University Rugby Players: Influence of Sex, Position, and Injury

CONTEXT

Measures of side-to-side asymmetry in body composition may help identify players who are predisposed to lower limb injuries (LLI) or lower back pain (LBP). This study aimed to examine (1) side-to-side asymmetry in college rugby players according to sex and position and (2) whether side-to-side asymmetry is associated with LBP or LLI.

DESIGN

Cross-sectional study.

METHODS

Thirty-six rugby players (61% female) underwent a dual-energy X-ray absorptiometry assessment for total and regional (appendicular, truncal) outcomes of fat mass, lean mass, and bone mass. A subsample (n = 23) of players had a second dual-energy X-ray absorptiometry assessment 2 months postbaseline. Two-way analysis of variance was used to assess the effect of position (forward and backs) and sex on body composition asymmetry. Student paired t tests were used to assess side-to-side difference in body composition and compare baseline and follow-up measures. Logistic regression was used to assess possible associations between LLI, LBP, and the degree of side-to-side asymmetry in body composition.

RESULTS

Male players had greater asymmetry in arm bone mass compared with female players (P = .026), and trunk fat mass asymmetry was greater in forwards as compared with backs (P = .017). Forwards had significantly greater fat mass (P = .004) and percentage of fat (P = .048) on the right leg compared with the left. Backs had significantly greater bone mass in the right arm compared with the left (P = .015). From baseline to postseason, forwards had a significant increase in side-to-side asymmetry in arm lean mass (P = .006) and a significant decrease in side-to-side asymmetry in leg fat mass (P = .032). In backs, side-to-side asymmetry at baseline compared with postseason was significantly different (P = .011) for trunk fat mass. There were no significant associations between body composition asymmetry, LLI, or LBP by sex or position.

CONCLUSION

Our results revealed the presence of side-to-side asymmetries in body composition in university rugby players between sex and position. The amount of asymmetry, however, was not associated with LBP and LLI.

Playing Disability Rugby League with Charcot-Marie-Tooth Disease: A Case Study

Charcot-Marie-Tooth (CMT) disease is a common inherited neurological disorder that causes damage to peripheral nerves. Reports of CMT patients participating in team-based sports such as disability rugby league are scarce. The objective of this case report was to evaluate the benefits of participation in disability rugby league in a 50-year-old male with CMT. Leg muscle mass and strength was worse for the case subject compared to two age-matched CMT participants with an exercise history; however, evidence of greater function in the case subject was observed through better 6-min walk test performance. Performance in a series of sport specific tests was noticeably worse for the case subject compared to a fellow rugby league player (age matched) with cerebral palsy. Inferior in-game performance was observed for the case subject compared to his fellow rugby league player in terms of distance covered, top running speed, and intensity. However, the case subject may have assumed a different role when playing as evident by the different behaviours he displayed during the games (i.e., less player contacts, tackles, or touches, but more passes of the ball). This case study provides information concerning disability rugby league as an adjunctive mode of treatment for CMT populations.

Does fatigue influence joint-specific work and ground force production during the first steps of maximal acceleration?

During initial acceleration, the first steps of a maximal-effort (sprint) run often determine success or failure in the capture and evasion of an opponent, and is therefore a vital factor of success in many modern sports. However, accelerative events are commonly performed after having already run considerable distances, and the associated fatigue should impair muscle force production and thus reduce acceleration. Despite this, the effects of running-induced fatigue on our ability to accelerate as well as the running technique used to achieve it have received little attention. We recorded 3-D kinematics and ground reaction forces during the first three steps of the acceleration phase from a standing start before and after performing a high-speed, multi-directional, fatiguing run-walk protocol in well-trained running athletes who were habituated to accelerative sprinting. We found that the athletes were able to maintain their acceleration despite changing running technique, which was associated with use of a more upright posture, longer ground contact time, increased vertical ground reaction impulse, decreased hip flexion and extension velocities, and a shift in peak joint moments, power, and positive work from the hip to the knee joint; no changes were detected in ankle joint function. Thus, a compensatory increase in knee joint function alleviated the reduction in hip flexor-extensor capacity. These acute adaptations may indicate that the hip extensors (gluteal and hamstring muscle groups) were more susceptible to fatigue than the ankle and knee musculature, and may thus be a primary target for interventions promoting fatigue resistance.

Body Fat Evaluation in Male Athletes from Combat Sports by Comparing Anthropometric, Bioimpedance, and Dual-Energy X-Ray Absorptiometry Measurements

Multiple anthropometric equations have been developed aiming to provide accurate and affordable assessment of body fat composition in male athletes. This study examined correlations of values obtained from seventeen different anthropometric equations to DXA as well as BIA and DXA values. Male athletes (n = 101) from three different combat sports, wrestling (n = 33), judo (n = 35), and kickboxing (n = 33), with an average age of 20.9 ± 4.2 were included. Body fat percentage was estimated using anthropometry, BIA, and DXA. Correlations between anthropometric methods and DXA, as well as BIA and DXA, were determined using Spearman's rank correlation. Sixteen out of seventeen estimates of body fat percentages using existing anthropometric equations showed strong positive correlation with the values derived from DXA measurements (r = 0.569 - 0.909). The highest correlation was observed using the equation derived by Yuhasz, r = 0.909, followed by the equations from Oliver et al., Evans et al., Faulkner, and Thorland et al. (r ≈ 0.9). Statistical analysis of body fat percentages from DXA and BIA measurements also showed high positive correlation (r = 0.710). Correlation of seventeen anthropometric equations with BIA and DXA methods revealed that equations by Yuhasz, Oliver et al., Evans et al., Faulkner, and Thorland et al. are suitable alternative for assessing body fat percentage among male athletes from combat sports, showing even stronger correlation than BIA method.

The Incidence, Cost, and Burden of Concussion in Women's Rugby League and Rugby Union: A Systematic Review and Pooled Analysis

BACKGROUND

The extent of concussion injury in the rugby codes for women is unclear.

OBJECTIVE

Our aim was to review all published studies reporting concussion injuries from match and training participation in rugby codes and report the pooled data estimates for rugby league and union concussion injury epidemiology.

METHODS

We conducted a systematic literature analysis of concussion in rugby league and rugby union for published studies from January 1990 to July 2021. Data from 16 studies meeting the inclusion criteria were extracted for women's concussion injuries and were subsequently pooled. Costs from Accident Compensation Corporation (ACC) data were attributed to the results to provide cost estimates.

RESULTS

The pooled analysis match injury incidence of women's concussion was higher for rugby league (10.3 per 1000 match hours) than rugby 15 s (2.8 per 1000 match hours) or rugby 7 s (8.9 per 1000 match hours). There was a fourfold difference in the pooled incidence of concussion in women's rugby league (risk ratio [RR] 4.53, 95% confidence interval [CI] 1.8-11.3]; p = 0.0001) when compared with rugby 15 s. There was also a ninefold higher risk of a concussion during match participation compared with training participation for women's rugby 15 s (RR 9.3, 95% CI 1.29-66.78; p = 0.0070). The total estimated costs for the concussions reported were NZ$1,235,101. For rugby 7 s, the pooled concussive injury burden was 33.2 days.

CONCLUSIONS

Our pooled analysis clarified the extent of concussion injury and the possible associated costs at several levels of the game for women's rugby codes. The pooled mean days lost because of concussions was 33 days. As this was considerably longer than the 7- to 10-day expected timeframe outlined in the Concussion in Sport Consensus statement, these guidelines need to be updated to include sex-specific differences.

The Distribution of Match Activities Relative to the Maximal Mean Intensities in Professional Rugby League and Australian Football

ABSTRACT

Johnston, RD, Thornton, HR, Wade, JA, Devlin, P, and Duthie, GM. The distribution of match activities relative to the maximal mean intensities in professional rugby league and Australian football. J Strength Cond Res 36(5): 1360-1366, 2022-This study determined the distribution of distance, impulse, and accelerometer load accumulated at intensities relative to the maximal mean 1-minute peak intensity within professional rugby league and Australian football. Within 26 rugby league (n = 24 athletes) and 18 Australian football (n = 38 athletes) games, athletes wore global navigation satellite system devices (n = 608 match files). One-minute maximal mean values were calculated for each athlete per game for speed (m·minP-1P), accelerometer load (AU·minP-1P), and acceleration (m·sP-2P). Volumes for each parameter were calculated by multiplying by time, specifying total distance, accelerometer load, and impulse. The distribution of intensity of which these variables were performed relative to the maximal mean was calculated, with percentages ranging from 0-110%, separated into 10% thresholds. Linear mixed models determined whether the distribution of activities within each threshold varied, and positional differences. Effects were described using standardized effect sizes (ESs), and magnitude-based decisions. Across both sports, the distribution of activity (%) largely reduced the closer to the maximal mean 1-minute peak and was highest at ∼60% of the maximal mean peak. When compared with Australian football, a higher percentage of total distance was accumulated at higher intensities (70-80% and 100-110%) for rugby league (ES range = 0.82-0.87), with similar, yet larger differences for accelerometer load >80% (0.78-1.07) and impulse >60% (1.00-2.26). These findings provide information of the volume of activities performed relative to the mean maximal 1-minute peak period, which may assist in the prescription of training.

Match and training injury incidence in rugby league: A systematic review, pooled analysis, and update on published studies

In studies reporting rugby league injuries, match injuries varied depending upon participation level. To review and update pooled data estimates for rugby league injury epidemiology and add information for participation levels in match and training environments. A systematic review and pooled analysis for published studies reporting rugby league match and training injuries. Searches were performed in the PubMed, CINHAL, ScienceDirect, Scopus, SPORTDiscus, SpringerLink, and Wiley Online databases. Studies were considered if they reported on rugby league match or training injuries between Jan 1990 to June 2021. Two authors (DK, TC) extracted the study characteristics, numerical data and assessed the article quality, by adhering to the protocol for systematic review of observational studies (MOOSE) and the STrengthening and Reporting of OBservational studies in Epidemiology (STROBE) statement. The 46 studies included a combined exposure of 419,037 h and 18,783 injuries incorporating 158,003 match-hr and 15,706 match injuries (99.4 [95%CI: 97.9–101.0] per 1000 match-hr) and 264,033 training-hr and 3077 training injuries (11.8 [95%CI: 11.4–12.2] per 1000 training-hr). Of included studies, 47.9% utilised a medical attention/treatment injury definition. There was a five-fold difference in injuries for the semi-professional participation level (431.6 per 1000 match-hr) compared with professional (RR: 4.92; p < 0.001) and elite (RR: 3.77; p < 0.001) participation levels. The hooker recorded the highest pooled injury incidence (93.1 per 1000 match-hr). Compared to the 2014 analysis there was a 10-fold increase for head-neck region (RR: 10.7; p < 0.001) injury incidence, and more injuries for the ball carrier (RR: 1.1; p = 0.008) and tackler (RR: 1.2; p = 0.001). There was a three-fold decrease in injury incidence in the first half (RR: 2.9; p < 0.001) and a two-fold decrease in the second half (RR: 2.3; p < 0.001) of matches. While rugby league match and training injury incidence had decreased since 2014, the increase in head injuries, and greater injury rate at the semi-professional level, mean further injury prevention interventions are needed.

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Based on 46 studies, updated estimates of injury incidence for rugby league-related activities ranged from 14.6 per 1000 match-hr (Junior) to 431.6 per 1000 match-hr (Semi-Professional) participation levels for match activities and 5.3 per 1000 training-hr (Professional) to 97.1 per 1000 training-hr (Elite) participation levels for training activities.

Compared with the pooled analysis in 2014, the current analysis showed:•

The hooker playing position continues to have the highest match injury risk (93.1 per 1000 match-hr).

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The lower limb (64.5 per 1000 match-hr) continues to be the body region with the highest injury risk.

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The quadriceps was the most reported injury site (28.5 per 1000 match-hr).

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The incidence of concussion in studies reporting on rugby league match injuries increased (7.7 vs. 11.6 per 1000 match-hr); and

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Most concussions took 28 days to recover, which conflicts with the Concussion in Sport Consensus Statement that reported 80%–90% of all concussions recover in seven to ten days.

The influence of warm-up duration on simulated rugby league interchange match performance

OBJECTIVE

The study was conducted to understand the effects of a short (10 min) and a long (30 min) duration warm-up on subsequent readiness to exercise and movement during simulated rugby league match play. Methods: Using a randomised cross-over design, 13 male rugby players (age: 23.6 ± 4.1 y) completed 10- or 30-min warm-up immediately before 2 × 23 min rugby league movement simulation protocol. Results: Total distance, high- and low speed running and tympanic temperature (ES = 0.56 to 20.8) were all higher in the 30 min warm-up, with differences in relative distance and heart rate unclear (ES = -0.36 to 0.06). Differences in participants' readiness to exercise after the warm-ups were unclear (ES = 0.25). Differences between trials for movement characteristics (ES = -0.13 to -0.32), RPE (ES = -0.13 to 0.04) and B[La] after the simulation were mostly unclear, with only trivial changes in high-speed running (ES = 0.08) and a lower heart rate (ES = -0.26) between the two playing bouts after the 30 min warm-up trial. Conclusion: Practitioners can use warm-ups between 10 or 30 minutes for rugby league interchange players without any implications for subsequent match running performance.

Epidemiology of injuries in elite male and female futsal: a systematic review and meta-analysis

The main purpose of this study was to conduct a systematic review and meta-analysis quantifying the incidence of injuries in futsal players. A systematic search was conducted using MEDLINE, PubMed, Web of Science and Scopus databases and subsequently, six studies (14 cohorts) were selected. Separate meta-analyses for male and female players were conducted using a Poisson random-effect regression model approach. The overall and match incidence rates in elite male futsal players were 6.8 (95% CI = 0.0-15.2) and 44.9 (95% CI = 17.2-72.6) injuries/1000 hours of exposure. Pooled training injury rate in male players was not calculated due to the lack of studies reporting training injuries in this cohort. For females, an overall, training and match incidence rates of 5.3 (95% CI = 3.5-7), 5.1 (95% CI = 2.7-7.6) and 10.3 (95% CI = 0.6-20.1) injuries/1000 hours of exposure were reported. In males, match incidence rate in International tournaments was 8.5 times higher than in national leagues (77.2 [95% CI = 60.0-94.5] vs 9.1 [95% CI = 0.0-19.3] for international tournaments and national leagues, respectively). Elite male and female futsal players are exposed to a substantial risk of sustaining injuries, especially during matches.

Conceptualising Rugby League Performance Within an Ecological Dynamics Framework: Providing Direction for Player Preparation and Development

Across team sports, it is critically important to appropriately define, evaluate and then aptly describe individual and team performance. This is of particular significance when we consider that performance models govern the direction of player preparation (short term) and development (long term) frameworks. Within the context of rugby league, this has traditionally been undertaken through hierarchical and linear processes. Such approaches have resulted in research and performance analysis techniques which aim to support these operational outcomes. Yet, these methods may deliver limited application on how or why match-play unfolds and therefore might be sub-optimal in providing insights to truly support coaches. In this paper, we propose the conceptualisation of rugby league performance through the lens of ecological dynamics, which may offer a different view to this traditional approach. We propose that this approach eliminates the silos of disciplinary information (e.g. technical, physical and medical) that may currently exist, allowing for a holistic approach to performance, preparation and development. Specifically, we consider that through the implementation of this ecological approach, all performance coaches (technical, physical and medical) may (co-)design learning environments that more collaboratively develop players for rugby league match-play. As a result, we put forward a new rugby league performance model from which preparation and development programs can be anchored toward. We conclude the paper by offering practical examples where these concepts are contextualised within the landscape familiar to practitioners working within rugby league.

A GNSS-based method to define athlete manoeuvrability in field-based team sports

This study presented a method of quantifying the manoeuvrability of two field-based team sport athletes and investigated its relationship with running velocity during competition. Across a season, 10 Hz Global navigation satellite system (GNSS) devices were worn during matches by 62 athletes (Australian Football League [AFL]; n = 36, 17 matches, National Rugby League [NRL]; n = 26, 21 matches). To quantify manoeuvrability, tortuosity was calculated from the X and Y coordinates from match GNSS files (converted from latitude and longitude). Tortuosity was calculated as 100 x natural logarithm of the chord distance (distance travelled between X and Y coordinates), divided by the straight-line distance. The maximal tortuosity was then quantified for each 0.5 m∙s-1 speed increment, ranging from 0 to the highest value for each game file. A quadratic model was fitted for each match file, controlling for the curvilinear relationship between tortuosity and velocity. A comparison of the quadratic coefficients between sports, and within sport between positions was investigated using linear mixed models. Resulting standard deviations (SDs) and mean differences were then assessed to establish standardized effect sizes (ES) and 90% confidence intervals (CI). A curvilinear relationship exists between maximal tortuosity and running speed, reflecting that as speed increases, athletes' ability to deviate from a linear path is compromised (i.e., run in a more linear path). Compared to AFL, NRL had a greater negative quadratic coefficient (a) (ES = 0.70; 0.47 to 0.93) for the 5 second analysis, meaning that as speed increased, NRL athletes' manoeuvrability reduced at a faster rate than when compared to AFL. There were no positional differences within each sport. GNSS derived information can be used to provide a measure of manoeuvrability tortuosity during NRL and AFL matches. The curvilinear relationship between tortuosity and speed demonstrated that as speed increased, manoeuvrability was compromised.

A Case-Control Study of Tackle-Based Head Injury Assessment (HIA) Risk Factors in the National Rugby League

Background

The tackle is the in-game activity carrying the greatest risk for concussion in rugby. A recent evaluation of tackle characteristics in rugby union precipitated a rule modification to reduce head impact risk during tackles. This study aims to replicate the work conducted in rugby union by examining the association between tackle characteristics and head injury events in professional rugby league.

Methods

There were 446 tackles resulting in a head injury assessment (HIA) and 5,694 tackles that did not result in a head injury from two National Rugby League (NRL) seasons that were reviewed and coded. Tackle height, body position of players, and contact area on an opponent’s body were evaluated, with the propensity of each situation to cause an HIA calculated as HIAs per 1000 events.

Results

The propensity for tacklers to sustain a head injury was 0.99 HIAs per 1000 tackles, 1.74-fold greater than for the ball carrier (0.57 HIAs per 1000 tackles). There was a 3.2-fold higher risk for an HIA when the tackler was upright compared to bent-at-the-waist. The greatest risk of a tackler HIA occurred when head contact was very low (knee, boot) or high (head and elbow). HIAs were most common following head-to-head impacts. The lowest propensity for tackler HIA was found when the tackler’s head was in proximity with the ball carrier’s torso.

Conclusions

The result of this study replicated the findings in professional rugby union. This has implications for the injury prevention initiatives implemented to reduce HIA risk because the majority of injuries are sustained by the tackler.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-021-00377-9.

Predictors and Correlates of Perceived Cognitive Decline in Retired Professional Rugby League Players

Objective: Rugby league is an international full-contact sport, with frequent concussive injuries. Participation in other full-contact sports such as American football has been considered to be a risk factor for neuropsychiatric sequelae later-in-life, but little research has addressed the mental and cognitive health of retired professional rugby league players. We examined predictors and correlates of perceived (self-reported) cognitive decline in retired National Rugby League (NRL) players. Methods: Participants were 133 retired male elite level rugby league players in Australia. Participants completed clinical interviews, neuropsychological testing, and self-report measures. The Informant Questionnaire on Cognitive Decline in the Elderly, self-report (IQCODE-Self), measured perceived cognitive decline. Results: The median age of the sample was 55.0 (M = 53.1, SD = 13.9, range = 30-89) and the median years of education completed was 12.0 (M = 11.9, SD = 2.6, range = 7-18). The retired players reported a median of 15.0 total lifetime concussions (M = 28.0, SD = 36.6, range = 0-200). The mean IQCODE-Self score was 3.2 (SD = 0.5; Range = 1.3-5.0); 10/133 (7.5%) and 38/133 (28.6%) scored above conservative and liberal cutoffs for cognitive decline on the IQCODE-Self, respectively. Perceived cognitive decline was positively correlated with current depressive symptoms, negatively correlated with years of professional sport exposure and resilience, and unrelated to objective cognition and number of self-reported concussions. A multiple regression model with perceived cognitive decline regressed on age, concussion history, professional rugby league exposure, depression, resilience, objective cognitive functioning, daytime sleepiness, and pain severity showed depression as the only significant predictor. Conclusion: This is the first large study examining subjectively experienced cognitive decline in retired professional rugby league players. Similar to studies from the general population and specialty clinics, no relationship was found between objective cognitive test performance and perceived cognitive decline. Depressive symptoms emerged as the strongest predictor of perceived cognitive decline, suggesting that subjective reports of worsening cognition in retired elite rugby league players might reflect psychological distress rather than current cognitive impairment.

Monitoring Prescribed and Actual Resistance Training Loads in Professional Rugby League

ABSTRACT

Redman, KJ, Connick, MJ, Beckman, EM, and Kelly, VG. Monitoring prescribed and actual resistance training loads in professional rugby league. J Strength Cond Res 35(6): 1604-1610, 2021-Coaches devote a considerable amount of time and effort prescribing and selecting exercises to elicit training adaptations. Adherence to the prescribed resistance training load may vary for a number of reasons. The aim of this study was to quantify the difference between prescribed and actual resistance training loads in a team of professional rugby league players. Training loads were quantified using volume load and training intensity throughout a season. The competition was categorized into preseason, early competition, mid-competition, and late competition. Twenty-seven players participated in this study. Four exercises were monitored: back squat, bench press, bench pull, and clean pull. A Friedman's test was used to assess differences between prescribed and actual training loads throughout different phases of the season, for different exercises, and during different weeks in a training block. There were significantly greater differences in prescribed and actual volume loads during the mid-competition in comparison to all other phases of the season (p < 0.01). Although players adherence to prescribed training intensity was significantly greater during the preseason compared with the remainder of the season (p < 0.05), they completed significantly less prescribed training load during week 1 in comparison to week 4 within a training block (p < 0.05). The results of this study demonstrate that regular monitoring of completed resistance training loads may be of greater importance to strength and conditioning coaches to assist in examining potential progress and fatigue or allow for more accurate prescription of load to enhance adaptation throughout a season.

Sport Concussion Assessment Tool-5th Edition (SCAT5): Normative Reference Values for the National Rugby League Women's Premiership

Objective: To establish normative reference values for the Sport Concussion Assessment Tool-5th Edition (SCAT5) for the new National Rugby League Women's Premiership. Methods: Preseason SCAT5 baseline testing was administered individually to all National Rugby League Women's Premiership players (N = 117). Testing was completed by the medical staff. Normative reference values were calculated for the components of the SCAT5, including the Standardized Assessment of Concussion, modified Balance Error Scoring System, and the Symptom Scale. A small case series of players who sustained concussions were included to illustrate the use of the new normative data. Results: The median Standardized Assessment of Concussion total score was 27.0 (M = 26.9, SD = 2.1). The median modified Balance Error Scoring System score was 2.0 (M = 2.4, SD = 2.2). The median number of symptoms score was 1.0 (M = 3.2, SD = 4.7) and the median symptom severity score was 2.0 (M = 5.4, SD = 8.2). The most common baseline symptom was fatigue or low energy (33%), followed by trouble sleeping (24%), headache (23%), neck pain (22%), and difficulty remembering (21%). In the total sample, 41% reported no symptoms. The clinical interpretation of these new normative data to a case series of women with concussions is provided. Conclusions: Normative reference values are provided for the SCAT5 for women who are professional rugby league players. Using these normative data will improve clinical interpretation of SCAT5 scores following a concussion.

Body Mass and Body Composition Changes over 7 Years in a Male Professional Rugby Union Team

The purpose of this study was to investigate longitudinal body mass and body composition changes in one professional rugby union team (n=123), (i) according to position [forwards (n=58) versus backs (n=65)], analysis of players with 6 consecutive seasons of DXA scans (n=21) and, (iii) to examine differences by playing status [academy and international], over 7 years. Players [mean age: 26.8 y, body mass index: 28.9+kg.m²] received DXA scans at fourtime points within each year. A modest (but non-significant) increase in mean total mass (0.8 kg) for professional players was reflected by increased lean mass and reduced body fat mass. At all-time points, forwards had a significantly greater total mass, lean mass and body fat percentage compared to backs (p<0.05). Academy players demonstrated increased total and lean mass and decreased body fat percentage over the first 3 years of senior rugby, although this was not significant. Senior and academy international players had greater lean mass and lower body fat percentage (p<0.05) than non-international counterparts. Despite modest increases in total mass; reflected by increased lean mass and reduced fat mass, no significant changes in body mass or body composition, irrespective of playing position were apparent over 7 years.

Concurrent Validity of a Rugby-Specific Yo-Yo Intermittent Recovery Test (Level 1) for Assessing Match-Related Running Performance

ABSTRACT

Dobbin, N, Highton, J, Moss, SL, Hunwicks, R, and Twist, C. Concurrent validity of a rugby-specific Yo-Yo intermittent recovery test (level 1) for assessing match-related running performance. J Strength Cond Res 35(1): 176-182, 2021-This study investigated the concurrent validity of a rugby-specific high-intensity intermittent running test against the internal, external, and perceptual responses to simulated match play. Thirty-six rugby league players (age 18.5 ± 1.8 years; stature 181.4 ± 7.6 cm; body mass 83.5 ± 9.8 kg) completed the prone Yo-Yo Intermittent Recovery Test (Yo-Yo IR1), of which 16 also completed the Yo-Yo IR1, and 2 × ∼20 minute bouts of a simulated match play (rugby league match simulation protocol for interchange players [RLMSP-i]). Most likely reductions in relative total, low-speed and high-speed distance, mean speed, and time above 20 W·kg-1 (high metabolic power [HMP]) were observed between bouts of the RLMSP-i. Likewise, rating of perceived exertion (RPE) and percentage of peak heart rate (%HRpeak) were very likely and likely higher during the second bout. Pearson's correlations revealed a large relationship for the change in relative distance (r = 0.57-0.61) between bouts with both Yo-Yo IR1 tests. The prone Yo-Yo IR1 was more strongly related to the RLMSP-i for change in repeated sprint speed (r = 0.78 cf. 0.56), mean speed (r = 0.64 cf. 0.36), HMP (r = 0.48 cf. 0.25), fatigue index (r = 0.71 cf. 0.63), %HRpeak (r = -0.56 cf. -0.35), RPEbout1 (r = -0.44 cf. -0.14), and RPEbout2 (r = -0.68 cf. -0.41) than the Yo-Yo IR1, but not for blood lactate concentration (r = -0.20 to -0.28 cf. -0.35 to -0.49). The relationships between prone Yo-Yo IR1 distance and measures of load during the RLMSP-i suggest that it possesses concurrent validity and is more strongly associated with measures of training or match load than the Yo-Yo IR1 using rugby league players.

Match and Training Injuries in Women's Rugby Union: A Systematic Review of Published Studies

BACKGROUND

There is a paucity of studies reporting on women's injuries in rugby union.

OBJECTIVE

The aim of this systematic review was to describe the injury epidemiology for women's rugby-15s and rugby-7s match and training environments.

METHODS

Systematic searches of PubMed, SPORTDiscus, Web of Science Core Collection, Scopus, CINAHL(EBSCO) and ScienceDirect databases using keywords.

RESULTS

Ten articles addressing the incidence of injury in women's rugby union players were retrieved and included. The pooled incidence of injuries in women's rugby-15s was 19.6 (95% CI 17.7-21.7) per 1000 match-hours (h). Injuries in women's rugby-15s varied from 3.6 (95% CI 2.5-5.3) per 1000 playing-h (including training and games) to 37.5 (95% CI 26.5-48.5) per 1000 match-h. Women's rugby-7s had a pooled injury incidence of 62.5 (95% CI 54.7-70.4) per 1000 player-h and the injury incidence varied from 46.3 (95% CI 38.7-55.4) per 1000 match-h to 95.4 (95% CI 79.9-113.9) per 1000 match-h. The tackle was the most commonly reported injury cause with the ball carrier recording more injuries at the collegiate [5.5 (95% CI 4.5-6.8) vs. 3.5 (95% CI 2.7-4.6) per 1000 player-game-h; χ²₍₁₎ = 6.7; p = 0.0095], and Women's Rugby World Cup (WRWC) [2006: 14.5 (95% CI 8.9-23.7) vs. 10.9 (95% CI 6.2-19.2) per 1000 match-h; χ²₍₁₎ = 0.6; p = 0.4497; 2010: 11.8 (95% CI 6.9-20.4) vs. 1.8 (95% CI 0.5-7.3) per 1000 match-h; χ²₍₁₎ = 8.1; p = 0.0045] levels of participation. Concussions and sprains/strains were the most commonly reported injuries at the collegiate level of participation.

DISCUSSION

Women's rugby-7s had a higher un-pooled injury incidence than women's rugby-15s players based on rugby-specific surveys and hospitalisation data. The incidence of injury in women's rugby-15s and rugby-7s was lower than men's professional rugby-15s and rugby-7s competitions but similar to male youth rugby-15s players. Differences in reporting methodologies limited comparison of results.

CONCLUSION

Women's rugby-7s resulted in a higher injury incidence than women's rugby-15s. The head/face was the most commonly reported injury site. The tackle was the most common cause of injury in both rugby-7s and rugby-15s at all levels. Future studies are warranted on injuries in women's rugby-15s and rugby-7s.

PROSPERO REGISTRATION NUMBER

CRD42018109054 (last updated on 17 January 2019).

Time Course of Recovery for Performance Attributes and Circulating Markers of Muscle Damage Following a Rugby Union Match in Amateur Athletes

BACKGROUND

We sought to determine the time course of changes in neuromuscular performance and muscle damage following a single rugby union match.

METHODS

Fourteen male amateur rugby players (28.9 ± 3.5 yrs; 1.7 ± 5.1 m; 86.1 ± 11.1 kg) participated. Plasma activity of creatine kinase ([CK]) and lactate dehydrogenase (LDH), L-run test (change of direction) and 30-m sprint (T30; speed) with 10-m lap time (T10; acceleration) were assessed on six occasions: one week before the match (PRE) and immediately, 24, 48, 72, and 96 h post-match.

RESULTS

Relative to PRE, LDH was elevated immediately post-match (+33.6% ± 13.6%; p < 0.001) and [CK] was elevated immediately (+64.1% ± 38.8%, p = 0.001) and 24 h post-match (+352% ± 317%; p = 0.024). L-run test time increased 16.0 ± 8.7% relative to PRE at 24 h post (p < 0.001) and remained elevated through 96 h post-match (p < 0.05). T10 and T30 times increased relative to PRE immediately post-match (+12.0% ± 10.4%, p = 0.008; and +6.1% ± 4.9%; p = 0.006, respectively), though T30 times were similar to baseline by 48 h post-match whereas T10 times remained elevated through 72 h post-match.

CONCLUSIONS

A single, competitive rugby union match induces significant muscle damage and performance decrements with distinct time courses of recovery in amateur athletes. Notably, change of direction attributes (i.e., L-run) appear to have the longest time course to full recovery.

“Someone to Talk to”: Influence of Player Welfare Provision on Mental Health in Professional Rugby League Players

Player welfare is an important development in supporting elite athletes during their professional careers. Little is known about how player engagement with player welfare provision impact on mental health. Over two consecutive years, professional rugby football league (RFL) players were invited to complete an anonymous online survey assessing psychological stress, athletic identity, and attitudes to player welfare provision. Findings indicate that nearly half of respondents experienced symptoms of anxiety and depression. Multivariate analyses suggest that higher psychological stress and athletic identity and less knowledge and less positive attitudes to RFL mental health support is associated with worse mental health, whereas older age is associated with better mental health. The study has identified some key variables to focus on in developing player care and support management, and also suggest directions for future research guiding player welfare support, especially regarding increasing positive attitudes to mental health supports.

The Demands of Professional Rugby League Match-Play: a Meta-analysis

Background

Rugby league is a collision sport, where players are expected to be physically competent in a range of areas, including aerobic fitness, strength, speed and power. Several studies have attempted to characterise the physical demands of rugby league match-play, but these studies often have relatively small sample sizes based on one or two clubs, which makes generalisation of the findings difficult. Therefore, the aim of this review was to synthesise studies that investigated the physical demands of professional rugby league match-play.

Methods

SPORTDiscus, CINAHL, MEDLINE (EBSCO) and Embase (EBSCO) databases were systematically searched from inception until October 2018. Articles were included if they (1) recruited professional rugby league athletes aged ≥ 18 years and (2) provided at least one match-play relevant variable (including playing time, total and relative distance, repeat high-intensity efforts (RHIE), efforts per RHIE, accelerations and decelerations, total and relative collisions). Meta-analyses were used to provide pooled estimates ± 95% confidence intervals.

Results

A total of 30 studies were included. Pooled estimates indicated that, compared to adjustables and backs, forwards have less playing time (− 17.2 ± 5.6 and − 25.6 ± 5.8 min, respectively), cover less ‘slow-speed’ (− 2230 ± 735 and − 1348 ± 655 m, respectively) and ‘high-speed’ distance (− 139 ± 108 and − 229 ± 101 m, respectively), but complete more relative RHIEs (+ 0.05 ± 0.05 and + 0.08 ± 0.04 per minute, respectively), and total (+ 12.0 ± 8.1 and + 12.8 ± 7.2 collisions, respectively) and relative collisions (+ 0.32 ± 0.22 and + 0.41 ± 0.22 collisions per minute, respectively). Notably, when the distance was expressed relative to playing time, forwards were not different from adjustables and backs in slow-speed (P ≥ 0.295) and high-speed (P ≥ 0.889) relative distance. The adjustables and backs subgroups were similar in most variables, except playing time (shorter for adjustables, − 8.5 ± 6.2 min), slow-speed distance (greater for adjustables, + 882 ± 763 m) and total relative distance (greater for adjustables, + 11.3 ± 5.2 m·min⁻¹). There were no significant differences between positional groups for efforts per RHIE, accelerations and decelerations (P ≥ 0.745).

Conclusions

These results indicate the unique physical demands of each playing position and should be considered by strength and conditioning and tactical coaches when planning for professional rugby league performance.

Protocol Registration

https://osf.io/83tq2/

Electronic supplementary material

The online version of this article (10.1186/s40798-019-0197-9) contains supplementary material, which is available to authorized users.

Effects of Strength Training on Body Composition in Young Male Professional Soccer Players

The present prospective cohort study investigated changes in body composition (BC) in young male football players (n = 18, 16.1 ± 0.8 years; 181.0 ± 0.1 cm; 71.3 ± 4.9 kg) after combined football and strength training (ST) during a whole in-season period (26 weeks). BC was measured at whole-body absolute and regional levels by dual-energy X-ray absorptiometry in eighteen players at the beginning and at the end of the competitive period. The ST was organized into three different session types: ST in the gym, specific ST on the field, and individual ST (weak points). The results of the present study indicated that fat-free mass (FFM) was substantially higher following the competitive period (5.1% ± 1.2%), while percentage of fat showed no changes during the competitive period. At the regional level, arms’ and legs’ FFM increased at the end of the season, and bone mineral content (BMC) and density (BMD) increased in arms, legs, pelvis, thoracic spine, and lumbar spine. In conclusion, within the limitation of the potential positive impact of growth and/or maturation, present results seem to indicate that an ST program that supplements football-related training sessions could be an effective option to increase FFM, BMC, and BMD at both whole-body and regional level across the competitive season in young male professional football players.

A Reliable Testing Battery for Assessing Physical Qualities of Elite Academy Rugby League Players

Dobbin, N, Hunwicks, R, Highton, J, and Twist, C. A reliable testing battery for assessing physical qualities of elite academy rugby league players. J Strength Cond Res 32(11): 3232-3238, 2018-This study assessed the interday reliability of a testing battery for the assessment of physical qualities of rugby league players. Fifty players (age 17.1 ± 1.1 years; stature 181.3 ± 6.3 cm; and body mass 89.0 ± 11.6 kg) from 3 Super League academies participated in this study. Tests of countermovement jump performance, 10- and 20-m sprint performance, change of direction, medicine ball throw, and a modified Yo-Yo Intermittent Recovery Test Level 1 (prone Yo-Yo IR1) were completed on 3 separate occasions. Between-day intraclass correlation coefficient, typical error (TE), coefficient of variation, and the smallest worthwhile change (SWC) were calculated to determine the reliability and sensitivity of each measure. Individual tests (except medicine ball throw) were not systematically different between trials (p > 0.05), with an interday variability that was <10%. In all instances, the TE was larger than the calculated SWC change, although variability was less than that typically observed after a training intervention or specific training period (i.e. preseason). Using a magnitude-based inference approach, we present the required change for all performance tests to be 75% confident and the change is beneficial. This simple and time efficient testing battery is sufficiently reliable to detect previously observed changes in a range of physical qualities of rugby league players.

In-season eccentric-overload training in elite soccer players: Effects on body composition, strength and sprint performance

The aim of this study was to describe the changes in body composition, strength and sprint performance in response to an entire competitive season of football training supplemented with 2 inertial eccentric-overload training sessions a week in young male professional soccer players. Whole body and regional composition (assessed using dual-energy X-ray absorptiometry), power output in half-squat and 40-m sprinting performance were evaluated in fourteen players. The eccentric-overload training consisted of training sessions a week of 1–2 sets of 10 exercises of upper-body and core (Day 1) and lower-body (Day 2), during the entire competitive season (27 weeks). Whole body fat mass decreased (-6.3 ± 3.6%, ES = -0.99 ± 0.54) substantially while lean mass increased (2.5 ± 0.8%, ES = 0.25 ± 0.09), with some regional differences. There was a substantial increase in half-squat power output (from 3% to 14%, ES from 0.45 to 1.73) and sprint performance (from 1.1% to 1.8%, ES from -0.33 to -0.44), however performance changes were not correlated with changes in body composition. A combined soccer and eccentric-overload training program was able to promote positive changes in body composition and physical factors relevant to both on-field performance and injury prevention in elite soccer players.

An examination of a modified Yo-Yo test to measure intermittent running performance in rugby players

This study examined how starting each shuttle in the prone position altered the internal, external and perceptual responses to the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1). Using a randomized crossover design, 17 male rugby players completed the Yo-Yo IR1 and prone Yo-Yo IR1 on two separate occasions. External loads (via microtechnology), [Formula: see text], heart rate (HR) and rating of perceived exertion (RPE) were measured at 160, 280 and 440 m (sub-maximal) and when the test was terminated (peak). The pre-to-post change in blood lactate concentration (Δ[La]_b) was determined for both tests. All data were analysed using effect sizes (ES) and magnitude-based inferences. Between-trial differences (ES ± 90% CL) indicated that total distance was most likely lower (-1.87 ± 0.19), whereas other measures of peak external load were likely to very likely higher during the prone Yo-Yo IR1 (0.62-1.80). Sub-maximal RPE was likely to most likely higher (0.40-0.96) and peak RPE very likely higher (0.63 ± 0.41) in the prone Yo-Yo IR1. The change in [La]_b was likely higher after the prone Yo-Yo IR1. Mean HR was possibly lower at 440 m (-0.25 ± 0.29) as was peak HR (-0.26 ± 0.25) in the prone Yo-Yo IR1. [Formula: see text], [Formula: see text] and [Formula: see text] were likely to very likely higher at 280 and 440 m (ES = 0.36-1.22), while peak values were possibly to likely higher (ES = 0.23-0.37) in the prone Yo-Yo IR1. Adopting a prone position during the Yo-Yo IR1 increases the internal, external and perceptual responses, placing greater emphasis on metabolically demanding actions typical of rugby.

Differences in Glenohumeral Joint Rotation and Peak Power Output Between Super League and Championship Rugby League Players

Haines, MR. Differences in glenohumeral joint rotation and peak power output between Super League and Championship Rugby League players. J Strength Cond Res 32(6): 1685-1691, 2018-Rugby league is a high-intensity sport with large impact forces sustained during play, resulting in high prevalence of shoulder injury. Consequently, shoulder strength and player power are important considerations for injury prevention and performance. Additionally, professional teams regularly compete against semiprofessional teams, where differences in physical conditioning could be marked. The aim of this study was to test for differences in glenohumeral joint rotation and peak power between a professional Super League (SL) and semiprofessional Rugby League Championship (RLC) teams. A cross-sectional analysis was used to test 25 SL and 24 RLC players during preseason training. Isokinetic dynamometry, at 240°·s for concentric and eccentric actions was used to assess glenohumeral rotation. Peak power was determined using a maximal 30-second cycle ergometer test. Selective muscular development of the internal rotators without concomitant external rotator strength was evident in the SL team but not the RLC team. Internal rotation peak torque was higher for the SL club for concentric (∼24%) and eccentric (∼16%) muscle actions (p ≤ 0.05), and this contributed to a lower ipsilateral reciprocal muscle group ratio (external to internal concentric) for the SL team compared with the RLC team (∼47% and ∼60% respectively; p ≤ 0.05). Peak power output was also higher for the SL team (1,409 ± 153 vs. 1,273 ± 159 W; p ≤ 0.05). The results highlight a mismatch in the physical conditioning of SL and RLC players with implications for practitioners to design strength and conditioning programs that minimize the risk of injury while optimizing performance.

Psychometric evaluation of commonly used game-specific skills tests in rugby: A systematic review

Objectives

To (1) give an overview of commonly used game-specific skills tests in rugby and (2) evaluate available psychometric information of these tests.

Methods

The databases PubMed, MEDLINE CINAHL and Africa Wide information were systematically searched for articles published between January 1995 and March 2017. First, commonly used game-specific skills tests were identified. Second, the available psychometrics of these tests were evaluated and the methodological quality of the studies assessed using the Consensus-based Standards for the selection of health Measurement Instruments checklist. Studies included in the first step had to report detailed information on the construct and testing procedure of at least one game-specific skill, and studies included in the second step had additionally to report at least one psychometric property evaluating reliability, validity or responsiveness.

Results

287 articles were identified in the first step, of which 30 articles met the inclusion criteria and 64 articles were identified in the second step of which 10 articles were included. Reactive agility, tackling and simulated rugby games were the most commonly used tests. All 10 studies reporting psychometrics reported reliability outcomes, revealing mainly strong evidence. However, all studies scored poor or fair on methodological quality. Four studies reported validity outcomes in which mainly moderate evidence was indicated, but all articles had fair methodological quality.

Conclusion

Game-specific skills tests indicated mainly high reliability and validity evidence, but the studies lacked methodological quality. Reactive agility seems to be a promising domain, but the specific tests need further development. Future high methodological quality studies are required in order to develop valid and reliable test batteries for rugby talent identification.

Trial registration number

PROSPERO CRD42015029747.

The effect of generalised joint hypermobility on rate, risk and frequency of injury in male university-level rugby league players: a prospective cohort study

Background

Rugby league is a collision sport where musculoskeletal injuries are common. There has been little research on generalised joint hypermobility (GJH) as a risk factor for injury in rugby league. The aim of this study was to investigate the role of GJH on the incidence of injuries in first and second team rugby league players from one British university.

Methods

We conducted a prospective cohort study of 45 student players from one British university first and second team rugby league squads (mean age 20.93±1.57 years). At the beginning of the season, GJH was determined using a 9-point Beighton scale, and injury and exposure data were collected on a weekly basis throughout the 2013–2014 season.

Results

The prevalence of GJH was 20%. There was no statistically significant difference in the frequency of injuries between GJH and non-GJH participants (p=0.938, Mann-Whitney U test).Participants categorised as having GJH did not experience a higher fequency of injury (p=0.722, Fisher's exact test) and there was no tendency to demonstrate a higher risk of injury for participants categorised as GJH (OR=0.64, 95% CI 0.15 to 2.78; relative risk (RR)=1.188, 95% CI 0.537 to 2.625). The most common site of injury was the ankle, but this was not statistically significant (OR=0.152, 95% CI 0.008 to 2.876; RR=0.195, CI 0.012 to 3.066).

Conclusion

British university rugby league players with GJH did not demonstrate a greater risk of injury than those without GJH.

Performance and antrhropometric characteristics of Elite Rugby Players

Background and aim of the study:

Physical performance is the result of a complex combination of several factors such as genetic and anthropometric aspects, nutrition and hormonal status. In the past few years many studies have considered the impact of vitamin D on muscular strength and athletic performance. The aim of the present study was to assess the anthropometric measures impacting on physical performance in a group of professional rugby athletes. As a secondary aim we investigated a possible relationship between baseline vitamin D status and athletic performance status in these subjects.

Methods:

All rugby players completed a test–retest reliability study on performance measures, as 70kg jump squat and body weight (BW) jump squat to assess musculoskeletal performance. Additionally at the time point we collected a blood sample of every athletes for the assessment of serum vitamin D.

Results:

We found that lean mass was an important independent predictor of performance score in 70kg jump squat (p=0.007, R2=0.74) and BW jump squat (p=0.010, R2=0.66) in these well trained athletes. No statistically significant association was present between performance score and serum vitamin D in this specific setting.

Conclusions:

We demonstrate a positive interaction between lower limb lean mass and performance score, but we have not been able to identify any statistically significant association between worsening in performance measures and decrease of serum 25 OH Vitamin D. (www.actabiomedica.it)

Influence of Cleats-Surface Interaction on the Performance and Risk of Injury in Soccer: A Systematic Review

OBJECTIVE

To review the influence of cleats-surface interaction on the performance and risk of injury in soccer athletes.

DESIGN

Systematic review.

DATA SOURCES

Scopus, Web of science, PubMed, and B-on.

ELIGIBILITY CRITERIA

Full experimental and original papers, written in English that studied the influence of soccer cleats on sports performance and injury risk in artificial or natural grass.

RESULTS

Twenty-three articles were included in this review: nine related to performance and fourteen to injury risk. On artificial grass, the soft ground model on dry and wet conditions and the turf model in wet conditions are related to worse performance. Compared to rounded studs, bladed ones improve performance during changes of directions in both natural and synthetic grass. Cleat models presenting better traction on the stance leg improve ball velocity while those presenting a homogeneous pressure across the foot promote better kicking accuracy. Bladed studs can be considered less secure by increasing plantar pressure on lateral border. The turf model decrease peak plantar pressure compared to other studded models.

CONCLUSION

The soft ground model provides lower performance especially on artificial grass, while the turf model provides a high protective effect in both fields.

Nutrition and Supplementation in Soccer

Contemporary elite soccer features increased physical demands during match-play, as well as a larger number of matches per season. Now more than ever, aspects related to performance optimization are highly regarded by both players and soccer coaches. Here, nutrition takes a special role as most elite teams try to provide an adequate diet to guarantee maximum performance while ensuring a faster recovery from matches and training exertions. It is currently known that manipulation and periodization of macronutrients, as well as sound hydration practices, have the potential to interfere with training adaptation and recovery. A careful monitoring of micronutrient status is also relevant to prevent undue fatigue and immune impairment secondary to a deficiency status. Furthermore, the sensible use of evidence-based dietary supplements may also play a role in soccer performance optimization. In this sense, several nutritional recommendations have been issued. This detailed and comprehensive review addresses the most relevant and up-to-date nutritional recommendations for elite soccer players, covering from macro and micronutrients to hydration and selected supplements in different contexts (daily requirements, pre, peri and post training/match and competition).

Collective effectiveness in the XV de France: selections and time matter

The aim of this study was to quantify the impact of selections and shared selections in the rugby union. Players' names, positions, and number of selections were collected for all XV de France's games (1906-2014). Every team's percentage of renewal of workforce was calculated for backs and forwards. During the 1987-2014 period, all second row forwards (locks), halfbacks, and centres' shared selections (number of times when two players have competed together) were recreated. The Best vs. Rest method was applied to these remodelled dyads. They were analysed and compared with surrounding teammates as well as opponents. Head coaches similarly change their workforce for upcoming matches after winning or losing (around 30%), but losing teams renew significantly more positions in their line-ups. The recreated halfbacks, locks, and centres reveal a common pattern. Whether victorious or not, the 'renewed couples' victory percentage will congregate towards the XV de France's victory percentage. For all the best recreated couples, the cumulated number of selections for forwards' is always higher than the ones part of less efficient teams: 231.3 ± 80 vs. 212.9 ± 91 selections for locks' teammates (Effect sizes (ES) small, possibly positive, 54.8%). In best recreated couples, number 8's are significantly more experienced than their counterparts in less efficient pairs (ES small, likely positive, 76.3%). The XV de France's collective effectiveness relies on a balance between stability and workforce renewal, which allows the building of specific position interactions and builds on experimented forwards packs. Selections and shared selections are serious collective performance parameters associated with performance.

Influence of Fatigue on Tackling Ability in Rugby League Players: Role of Muscular Strength, Endurance, and Aerobic Qualities

This study investigated the influence of repeated high-intensity effort exercise on tackling ability in rugby league players, and determined the relationship between physical qualities and tackling ability under fatigued conditions in these athletes. Eleven semi-professional rugby league players underwent measurements of speed (10 m and 40 m sprint), upper-body strength (4 repetition maximum [RM] bench press and weighted chin-up), upper-body muscular endurance (body mass maximum repetition chin-up, body mass maximum repetition dips), lower-body strength (4RM squat), and estimated maximal aerobic power (multi-stage fitness test). Tackling ability was assessed using a standardized one-on-one tackling test, before, during, and following four bouts of repeated high-intensity effort (RHIE) exercise. The relationship between physical qualities and fatigue-induced decrements in tackling ability were determined using Pearson product moment correlation coefficients. Each cycle of the RHIE protocol induced progressive reductions in tackling ability. A moderate reduction (Effect Size = ~-1.17 ± 0.60, -34.1 ± 24.3%) in tackling ability occurred after the fourth cycle of the RHIE protocol. Players with greater relative lower-body strength (i.e. 4RM squat/kg) had the best tackling ability under fatigued conditions (r = 0.72, p = 0.013). There were no significant relationships between tackling ability under fatigued conditions and any other physical quality. These findings suggest that lower-body strength protects against fatigue-induced decrements in tackling ability. The development of lower-body strength should be a priority to facilitate the development of robust tackling skills that are maintained under fatigue.

Shoulder injuries in adolescent rugby players

BACKGROUND

Rugby is a high-intensity contact sport, frequently causing shoulder injuries. Between the ages of 12 years to 18 years, academy and county level players are being selected for professional contracts, making this is a critical stage of their career. The present study aimed to describe the patterns of injury in adolescent rugby players with shoulder injuries.

METHODS

Academy and county level rugby players in the target age group, over a 7-year period, were included in the present study. Data collected included the mechanism of injury, position and level of play, radiology and surgical findings, and recurrence rate at a minimum of 2 years post-surgery.

RESULTS

One hundred and sixty-nine cases adhered to the inclusion criteria, with most cases involving two or more pathologies in the shoulder (54%). Forwards sustained more shoulder injuries than backs, incurring more labral injuries. By contrast, backs had a higher incidence of bony pathology. The mechanism of injury frequently correlated with player positions. There was a 21% injury recurrence rate, with forwards (7%) and higher level academy players (11%) most likely to suffer a recurrence.

CONCLUSIONS

Shoulder injury patterns in this important group of adolescent contact athletes are complex, with recurrence rates being higher than those in older rugby players.