Elite Rugby League Players Research Articles

The use of match-based exact movement activities to classify elite rugby league players into positional groups

AbstractThe cluster analysis of elite rugby league players identified groups of distinct playing positions that can be referred to as broad positional groups. However, the identified positional groups were based on traditional indicators (physical and technical–tactical) that provided no information about the exact match-based movement activities that led to such similarity grouping and the classification of elite rugby league players into these broad positional groups remains unexplored. Hence, this study finds the best model to classify elite rugby league players into positional groups, using data characterised by movement patterns to uncover the similar movement activities of distinct playing positions within a positional group. Key movement patterns for the positional group classification and differences between the groups were also investigated. A total of 18,173 unique movement patterns were derived from 422 players’ GPS data across the 2019 and 2020 seasons, where only 36 were identified as key patterns. The highest classification accuracy of 77.58% using all unique patterns and 74.5% accuracy using the key patterns was achieved, outperforming studies that used traditional indicators. Further analyses based on key patterns revealed differences between forwards and backs. These findings establish movement patterns as viable indicators to classify rugby league players into positional groups, enabling coaches and trainers to develop position-specific training programmes that cater to the unique physical demands of each position, leading to better player development and team performance. Movement patterns are therefore recommended as an alternative approach to quantifying players’ external loads and obtaining granular information.

The effects of wide vs. self-selected squat stance width on performance indices in elite rugby league players; an 8-week pre-season randomized controlled intervention

This study examined the efficacy of wide compared to self-selected stance width squats in terms of mediating performance improvements during an 8-week period of pre-season training in elite rugby league players. Participants (N = 26) were randomly separated into either wide (N = 13) (i.e. self-selected squat stance width increased by 20%) or self-selected (N = 13) squat stance width training groups, and they completed an 8-week pre-season training block. Measures of 505-agility test time (primary outcome), 3 repetition maximum (3RM) squat strength in participants self-selected stance position and counter movement jump height were measured at baseline and 8-weeks. There were no significant differences between training groups in terms of the improvements made during the intervention period for 505-agility test (wide: pre = 2.47 ± 0.08 & post = 2.34 ± 0.11’s and self-selected: pre = 2.46 ± 0.05 & post = 2.35 ± 0.08’s), counter movement jump (wide: pre = 42.68 ± 9.57 & post = 44.65 ± 9.04 cm, and self-selected: pre = 49.33 ± 6.70 & post = 50.33 ± 4.67 cm) or 3RM squat strength (wide: pre = 159.00 ± 15.24 & post = 178.00 ± 19.32 kg and self-selected: pre = 168.33 ± 11.73 & post = 185.56 ± 16.48kg). As such the findings from the current randomized controlled trial suggest that there is not sufficient evidence to suggest that wide stance width squats represent a more efficacious method of resistance training prescription in elite rugby league.

Hamstring and knee injuries are associated with isometric hip and trunk muscle strength in elite Australian Rules and Rugby League players

ObjectivesThis study investigated relationships between isometric trunk and hip extensor strength, lumbar muscle morphology, and the risk of hamstring and knee ligament injuries in Australian Football League and National Rugby League players. DesignProspective cohort study. MethodsTrunk and hip extensor strength, multifidus and quadratus lumborum cross-sectional area were measured during the 2020 pre-season. Logistic regressions and decision trees were employed to explore associations between maximum strength, strength endurance, multifidus and quadratus lumborum cross-sectional area, age, previous injuries, and hamstring and knee ligament injury risk. ResultsGreater strength endurance [odds ratio = 0.42 (0.23–0.74), p = 0.004] and maximum strength [odds ratio = 0.55 (0.31–0.94), p = 0.039] reduced hamstring injury risk. Increased risk of knee ligament injuries was associated with larger multifidus [odds ratio = 1.66 (1.14–2.45), p = 0.008] and higher multifidus to quadratus lumborum ratio (odds ratio = 1.57 (1.13–2.23), p = 0.008]. Decision tree models indicated that low strength endurance (< 99 Nm) characterised hamstring strains, while high (≥ 1.33) multifidus to quadratus lumborum ratio mitigated risk. Knee ligament injuries were associated with larger (≥ 8.49 cm2) multifidus, greater (≥ 1.25) multifidus to quadratus lumborum ratio, and lower maximum strength (< 9.24 N/kg). ConclusionsPlayers with lower trunk and hip extensor maximum strength and strength endurance had increased risk of hamstring injuries, while knee ligament injury risk was elevated with larger multifidus cross-sectional area, higher multifidus to quadratus lumborum ratio, and lower maximum trunk and hip extensor strength.

Understanding elite rugby league players’ experience of collision, effective contact coaching techniques, and player contact psychology: A focus group study

ABSTRACT The current study performed a series of online focus groups to understand elite rugby league players’ experiences of collision. Eighteen rugby league players comprising different playing positions from four teams were recruited to participate in a series of online focus groups, via the Microsoft Team’s platform, facilitated by a moderator. Players were competing in Europe’s elite rugby league competition, the European Super League (ESL), during the 2021 season. All focus group data were transcribed, coded and analysed using reflexive thematic analysis guide to ensure robust exploring, interpreting and reporting through pattern-based analysis. The findings are split into five key themes: 1) the three-man tackle – the perceived optimal defensive strategy with simultaneous contact, 2) not all collisions are the same; matchplay events change the collision intensity, 3) bracing and blindsiding – two factors that influence experiences of collision and concussion, 4) coaching philosophies and orientations, 5) psychological readiness for collision. Collision sports have an inherent risk of injury; however, in some players’ subjective experiences, there are collision types that have a greater association with risk or intensity (blind-sided collisions or long closing distances). It is essential that future research comprehends the effects of these collision types and the further themes.

The Perceptions of Elite Professional Rugby League Players and Staff on the National Rugby League Annual Calendar: A Mixed-Methods Study

BackgroundIn recent years, the length of elite sporting competitions has raised concerns regarding player well-being, highlighting a need to review current match calendars. Therefore, this study aimed to explore the perceptions of elite National Rugby League (NRL) players and staff on the annual training and competition calendar from a player workload and well-being perspective.MethodsThis study adopted a mixed-methods approach, using a sequential explanatory design. Phase one implemented a cross-sectional survey, and phase two utilised semi-structured interviews. Four hundred and thirty-nine elite rugby league players and 46 staff completed the survey. Eighteen elite professional NRL players and six football staff were interviewed, and verbal data were analysed into pre-defined topic summaries using qualitative coding reliability methods. Topics included in-season, off-season, pre-season and well-being.ResultsData analysis suggests that elite NRL players and staff believe players appear particularly comfortable with the current number of games; however, they are at their maximum capacity. Importantly, this study identified several minority groups that may require support to enhance player well-being. Players believe reducing the pre-season would negate fatigue experienced later in the subsequent season. Players and staff believe this timeframe still provides sufficient time to prepare for the upcoming season. Further, players were open to extending the off-season to 8–10 weeks and believed that extra time would allow for greater recovery from the previous season. Mid-season congested scheduling affects players following the intensified period and requires attention to alleviate fatigue.ConclusionThe results of this study convey important implications for the NRL, emphasising a need to review their annual training and competitive calendar, or to implement specific strategies to enhance the well-being of minority groups. The findings from this study should be considered when discussing the ideal length and structure of the match calendar to support players’ physical and mental welfare.

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.

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. 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. 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. 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.

Mental fatigue and technical performance in elite rugby league

ABSTRACT The aims of this study were to determine the impact of elite rugby league competition on mental fatigue; and to investigate how mental fatigue influenced in-match technical performance. Twenty elite male rugby league players recorded their pre- and post-game subjective mental fatigue and had their technical performance analysed during matches across one competition season. Metrics were created to assess in-match technical performance and described the percentage of positive, neutral, and negative involvements for each player, while accounting for the context and difficulty of each involvement. Self-reported mental fatigue increased from pre-game to post-game (maximum a posteriori estimation [MAP] = 33.1, 95% high-density interval [HDI] = 26.9–39.8), with backs reporting higher changes in mental fatigue than forwards (MAP = 18.0, 95% HDI = 9.7–26.9). Larger increases in mental fatigue from pre-game to post-game were negatively associated with the adjusted percentage of positive involvements metric (MAP = −2.1, 95% HDI = −5.6 to 1.1). Elite rugby league players reported increased mental fatigue following competitive games, with backs reporting a greater increase than forwards. Mental fatigue impacted technical performance, whereby participants had a lower percentage of positive involvements when they reported being more mentally fatigued.

A novel application of entropy analysis for assessing changes in movement variability during cumulative tackles in young elite rugby league players.

The aim of this study was to identify between-position (forwards vs. backs) differences in movement variability in cumulative tackle events training during both attacking and defensive roles. Eleven elite adolescent male rugby league players volunteered to participate in this study (mean ± SD, age; 18.5 ± 0.5 years, height; 179.5 ± 5.0 cm, body mass; 88.3 ± 13.0 kg). Participants performed a drill encompassing four blocks of six tackling (i.e. tackling an opponent) and six tackled (i.e. being tackled by an opponent while carrying a ball) events (i.e. 48 total tackles) while wearing a micro-technological inertial measurement unit (WIMU, Realtrack Systems, Spain). The acceleration data were used to calculate sample entropy (SampEn) to analyse the movement variability during tackles performance. In tackling actions SampEn showed significant between-position differences in block 1 (p = 0.0001) and block 2 (p = 0.0003). Significant between-block differences were observed in backs (block 1 vs 3, p = 0,0021; and block 1 vs 4, p = 0,0001) but not in forwards. When being tackled, SampEn showed significant between-position differences in block 1 (p = 0.0007) and block 3 (p = 0.0118). Significant between-block differences were only observed for backs in block 1 vs 4 (p = 0,0025). Movement variability shows a progressive reduction with cumulative tackle events, especially in backs and when in the defensive role (tackling). Forwards present lower movement variability values in all blocks, particularly in the first block, both in the attacking and defensive role. Entropy measures can be used by practitioners as an alternative tool to analyse the temporal structure of variability of tackle actions and quantify the load of these actions according to playing position.

Examining for Cavum Septum Pellucidum and Ventricular Enlargement in Retired Elite-Level Rugby League Players.

ObjectiveA cavum septum pellucidum (CSP) has been reported as a visible brain anomaly in normal individuals as well in some former combat and collision sport athletes. The appearance of CSP with fenestrations and ventricular enlargement are considered associated features of the neuropathological diagnosis of chronic traumatic encephalopathy. The current study examined CSP anatomic features and lateral ventricle size in retired elite rugby league players and controls.MethodsForty-one retired rugby league players and 41 healthy community controls, similar in age and education, underwent structural MRI scans. CSP grade, CSP length, corpus callosum septal length, and Evans' ratio (for lateral ventricle size) were rated by two of the current study authors. All participants also self-reported concussion exposure histories, depressive symptoms, daytime sleepiness, and impulsivity. They completed a neuropsychological test battery assessing premorbid intellectual functioning, attention, processing speed, language, visuospatial skills, memory, and aspects of executive functioning.ResultsThe two raters had high agreement for CSP grade (Cohen's κ = 0.80), CSP length [intraclass correlation (ICC) = 0.99], corpus callosum septal length (ICC = 0.73), the CSP/septal ratio (ICC = 0.99), and the Evans' ratio (ICC = 0.75). Twenty-five retired players (61.0%) had an abnormal CSP compared to 17 controls [41.5%; = 3.12, p = 0.08, odds ratio = 2.21]. The CSP/septal ratio was larger for retired players than for the controls. The Evans' ratio did not differ between the two groups. In the retired rugby league players (n = 41), those with normal (n = 16) and abnormal (n = 25) CSP grades did not differ across age, age of first exposure to collision sport, years of sport exposure, concussion history, or 23 clinical and cognitive variables.ConclusionThis study revealed a difference in the size of the CSP between retired professional rugby league players and controls. There was no significant difference in the size of the ventricles between the two groups. There were no significant differences between those with vs. without an abnormal CSP on age of first exposure to rugby league, years of exposure to repetitive neurotrauma, number of lifetime concussions, depression, impulsivity, perceived cognitive decline, or on any neuropsychological test.

Partial-Body Cryotherapy Exposure 2Hours Prior to a Shuttle Run Does Not Enhance Running Performance.

To determine whether a single acute preexercise bout of partial-body cryotherapy (PBC) enhanced maximal-effort shuttle run performance, salivary enzyme concentration, and self-reported performance readiness. A total of 18 male rugby league players (age = 20.1 [0.5]y; mass = 91.4 [12.4]kg) were exposed to either PBC for 3minutes at -136°C (1°C) or a control condition prior to a continuous, high-intensity 6 × 40-m shuttle run test. Passive saliva samples were collected to determine salivary alpha amylase (sAA) concentration. Perceived performance readiness and well-being questionnaires were completed using a 1-to-7 Likert scale. The PBC exposure did not elicit a greater improvement in 6 × 40-m shuttle run performance in comparison with the control condition (standardized difference; +0.4 [5.9%]; P = .881; mean ± 90% confidence limits). The increase in sAA concentration was moderately greater 15minutes after PBC compared with the control group (+67 [32%], P = .012) and remained moderately higher up to 2hours post-PBC exposure compared with the control condition (+41 [40%], P = .045). There were greater improvements in self-reported perceptions of muscle soreness (+0.6 [0.4%], P = .043; units ±90% confidence limits) and mood (+0.6 [0.7%], P = .038) after PBC compared with control. It appears that a single 3-minute bout of PBC does not augment maximal effort shuttle run performance in elite rugby league players. Beneficial increases in sAA concentration, coupled with improved perceptions of muscle soreness and mood, should be explored further for alternative training or precompetition practices.

The anthropometric and physical qualities of women's rugby league Super League and international players; identifying differences in playing position and level.

Participation in women's rugby league has been growing since the foundation of the English women's rugby league Super League in 2017. However, the evidence base to inform women's rugby league remains sparse. This study provides the largest quantification of anthropometric and physical qualities of women's rugby league players to date, identifying differences between positions (forwards & backs) and playing level (Women's Super League [WSL] vs. International). The height, weight, body composition, lower body strength, jump height, speed and aerobic capacity of 207 players were quantified during the pre-season period. Linear mixed models and effects sizes were used to determine differences between positions and levels. Forwards were significantly (p < 0.05) heavier (forwards: 82.5 ± 14.8kg; backs: 67.7 ± 9.2kg) and have a greater body fat % (forwards: 37.7 ± 6.9%; backs: 30.4 ± 6.3%) than backs. Backs had significantly greater lower body power measured via jump height (forwards: 23.5 ± 4.4cm; backs: 27.6 ± 4.9cm), speed over 10m (forwards: 2.12 ± 0.14s; backs: 1.98 ± 0.11s), 20m (forwards: 3.71 ± 0.27s; backs: 3.46 ± 0.20s), 30m (forwards: 5.29 ± 0.41s; backs: 4.90 ± 0.33s), 40m (forwards: 6.91 ± 0.61s; backs: 6.33 ± 0.46s) and aerobic capacity (forwards: 453.4 ± 258.8m; backs: 665.0 ± 298.2m) than forwards. Additionally, international players were found to have greater anthropometric and physical qualities in comparison to their WSL counterparts. This study adds to the limited evidence base surrounding the anthropometric and physical qualities of elite women's rugby league players. Comparative values for anthropometric and physical qualities are provided which practitioners may use to evaluate the strengths and weaknesses of players, informing training programs to prepare players for the demands of women's rugby league.

The reliability, validity and sensitivity of an individualised sub-maximal fitness test in elite rugby league athletes

ABSTRACT We aimed to examine the reliability, validity and sensitivity of an individualised sub-maximal fitness test (SMFTIFT60). Nineteen elite rugby league players performed a one-week test-retest of SMFTIFT60. Typical Errors and ICCs were: small (<3.5%) and extremely high (>0.90) for accelerometer-derived variables; moderate (<2.5% points) and moderate to very high (0.71–0.89) for exercise and recovery heart rate (HRex and HRR, respectively). Convergent validity correlations with the 10-week pre-season change in 30–15 Intermittent Fitness Test performance were large for changes in SMFTIFT60 HRex (r = −0.57) and HRR (0.60), and very large for changes in accelerometer measures (range: −0.71 to −0.79). For sensitivity, within-player dose–response relationships between SMFTIFT60 HRex and prior 3-day training loads were negative and ranged from moderate (session ratings of perceived exertion [sRPE-TL], r = −0.34), to large (high-speed running distance, −0.51; acceleration load, −0.73) and very large (heart rate Training Impulse [TRIMP], −0.83). All other relationships were unclear or trivial to small. Physiological and accelerometer-derived measures from the SMFTIFT60 are reliable and valid for the assessment of fitness in rugby league players. Only HRex appears sensitive to acute changes in training load. The SMFTIFT60 could be a useful monitoring tool in team sports

Impact of prior ACL, hamstring or groin injury on lower limb strength and jump kinetics in elite female footballers

Introduction: Prior injury is a risk factor for lower limb injury in female footballers. An improved understanding of the impact of the most common and severe injuries on lower limb strength and biomechanics may help to optimise rehabilitation strategies and decrease subsequent injury rates. The aim of this cross-sectional study was to compare lower limb strength and countermovement jump (CMJ) kinetics between elite female footballers with and without a history of anterior cruciate ligament reconstruction (ACLR), hamstring strain, or hip/groin injury. Methods: 369 elite female Australian football, soccer and rugby league players aged 15–35 years underwent assessments of isometric hip adductor and abductor strength, eccentric knee flexor strength, and CMJ vertical ground reaction forces. Players reported their lifetime history of ACLR, and whether they had sustained a hamstring strain, or hip/groin injury in the previous 12-months. Strength and jump/landing kinetics, including between-leg asymmetry, were compared between players with and without prior injury. Logistic regression was used to determine the variables that best distinguished between players with and without prior injury. Results: Players with a unilateral history of ACLR (n=24) displayed asymmetry (injured<uninjured leg) in eccentric knee flexor strength (mean difference=-6.9%, 95%CI=-9.1 to -4.8%), isometric hip abductor strength (mean difference=-2.4%, 95%CI=-4.4 to -0.4%), and peak landing force (mean difference=-5.9%, 95%CI=-11.0 to -0.9%). Together, between-leg asymmetry in eccentric knee flexor strength, isometric hip abductor strength, and CMJ peak landing force distinguished between players with and without prior ACLR with 93% accuracy. No differences in strength or CMJ kinetics were observed between players with and without a history of hamstring or hip/groin injury. Discussion: Elite female footballers with a history of ACLR, but not hamstring or hip/groin injury, exhibit persistent between-leg asymmetries in lower limb strength and jump kinetics following a return to sport. To address the effects of prior injury, ACLR rehabilitation programs for elite female footballers should consider targeting between-leg asymmetries in eccentric knee flexor strength, isometric hip abductor strength, and CMJ kinetics. Conflict of interest statement: Funding for travel costs associated with data collection was provided by Vald Performance (Brisbane, Australia) and SMA Research Grant. My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

Relationships between trunk morphology and strength with non-contact lower limb injuries in elite rugby league and Australian football players

Background: Non-contact lower limb injuries (NCLLI) are common within the National Rugby League (NRL) and Australian Football League (AFL). Smaller lumbar multifidus at L5 (LM L5) cross-sectional area (CSA) and lower levels of trunk and hip extension and knee flexion strength have been associated with increased NCLLI risk in AFL players. However, such associations have not been reported in the NRL. This study aims to explore relationships between NCLLI, trunk morphology and isometric trunk and hip extension strength in NRL and AFL players. Methods: NRL and AFL players had their LM L2-L5 and quadratus lumborum (QL) CSA (n=238), and isometric trunk and hip extension strength (n=153) measured using ultrasonography and a novel field-based test in preseason. Isometric trunk and hip extensor strength were measured using a 65s maximal voluntary isometric contraction (MVIC) protocol (5s MVIC, 5s off, 45s MVIC, 5s off, 5s MVIC). Team medical staff reported all NCLLIs sustained in the subsequent competitive season. The associations between LM and QL CSA, 5s and 45s MVIC, age, and previous injury, and prospectively occurring NCLLI were analysed using univariable and then multivariable logistic regression. Logistic regression analysis was also performed for the most sustained NCLLI (hamstring and knee). Results: Seventy-two players sustained a NCLLI in the 2020 competitive seasons (51 NRL, 21 AFL). From univariable logistic regression previous injury increased the risk of any NCLLI in NRL (OR=2.43, 95%CI=1.16-5.09, p=0.019). Reduced 5s MVIC (OR=1.00, 95%CI=1.00-1.01, p=0.012), increased QL CSA (OR=1.55, 95%CI=1.05-2.38, p=0.033) and lower ratio between LM and QL CSA (OR=0.03, 95%CI=0.01-0.60, p=0.02) increased NCLLI risk in AFL. Pooled hamstring injuries (n=28) were most common and were associated with lower 5s MVIC (OR=0.99, 95%CI=0.99-1.00, p=0.02) and 45s MVIC (OR=0.99, 95%CI=0.99-1.00, p=0.001). Pooled knee injuries (n=21) were associated with both reduced LM CSA (OR=1.35, 95%CI=1.08-1.70, p=0.018) and LM to QL ratio (OR=3.62, 95%CI=1.41- 9.66, p=0.043). Conclusions: Larger QL CSA and reduced levels of trunk and hip extension strength are observed in AFL players in preseason who sustain a NCLLI in the subsequent playing season. Only previous NCLLI was associated with future risk of NCLLI for NRL players. These results suggest that risk factors for NCLLI are football code specific, and prevention strategies should be tailored accordingly. Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest relevant to the submission of this abstract.

Risk factors for ACL, hamstring strain, and hip/groin injuries in elite Australian female footballers: A prospective study.

Introduction: Female footballers are at high risk of sustaining lower limb injuries, with some of the most prevalent and severe injuries being hamstring strains, hip/groin pain, and knee ligament sprains. However, there is currently limited evidence to guide injury prevention strategies and injury risk assessment testing in female footballers. The aim of this study was to assess risk factors for ACL, hamstring, and hip/groin injuries in elite female footballers. Methods: Data were collected from 321 elite female Australian Football, soccer, and Rugby League players during pre-season. Players underwent field-based assessments of isometric hip adductor and abductor strength (ForceFrame), eccentric knee flexor strength during the Nordic hamstring exercise (NordBord), countermovement jump (CMJ) on dual forceplates (ForceDecks), and a single-leg triple vertical hop (TVH) using a makerless motion capture system (HumanTrak). Players were subsequently followed for injuries for 18 months. Risk factors were identified prospectively using simple and multiple logistic regression and decision tree learning. Results: A total of 12 anterior cruciate ligament (ACL) ruptures, 17 hamstring strains, and 12 hip/groin injuries were recorded. Risk factors for ACL injury included prior ACL injury (standardised odds ratio [OR]=12.3, P<.001), lower body weight normalised adductor torque (OR=2.1, P=.028), greater body weight normalised CMJ peak force (OR=1.9, P=.013), lower CMJ impulse (OR=2.0, P=.037), greater triple vertical hop knee frontal plane projection angle (OR=2.3, P=.014), and greater triple vertical hop lateral trunk flexion (OR=1.7, P=.038). Multiple logistic regression and decision tree models classified ACL injured players with high accuracy (sensitivity=67% and 75% respectively, and specificity=88% and 100% respectively). Risk factors for time-loss hamstring injury included smaller stature (OR=1.8, P=.030), greater between-leg asymmetry in CMJ peak force (OR=2.0, P=.011) and eccentric impulse (OR=1.9, P=.016). There were no statistically significant risk factors for hip/groin injury. Discussion: This is the first study to explore risk factors for lower limb injury in elite female Australian football codes. These results provide insight into the potential modifiable factors associated with subsequent injury in elite female footballers, which may inform player testing batteries and the design of targeted injury risk reduction strategies. Conflict of interest statement: Funding for travel was provided by Vald Performance (Brisbane, Australia) and SMA Research Foundation. My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

External workload patterns of injured elite Rugby League players before and after return to play

Introduction: Return to play protocols (RTP) are imperative to ensuring injured athletes are adequately prepared to return to competition without re-injury. This study aimed to characterise the acute and chronic external workloads achieved by injured National Rugby League (NRL) athletes before and after RTP. Methods: Global positioning system (GPS) workload variables were investigated for 10 injured NRL athletes (n= 10, mean age 23.6 years, backs n=5, forwards n=5) two weeks before and after RTP. All athletes had sustained injuries of ≥14-day severity. GPS variables included total (TD) and high to very-high speed running (V-VHSR) distance (≥18km/h), accumulated absolute acceleration (acceleration load), and number of repeat high-intensity efforts (RHIE). Both acute (current week) and chronic (4-week mean) workload was determined for each observation week and analysed using linear mixed models that included time as a fixed effect, mean-centred injury severity as a covariate, and participant as a random effect. Effect magnitude was determined by percentage difference and 95% confidence interval. Results: Mean injury severity was 24 days (range: 14-49 days) and did not significantly moderate any acute (p≥0.614) or chronic (p≥0.272) workload variable. Time significantly affected acute TD, acceleration load, and RHIE (p≤0.038), but not VVHSR distance (p=0.070). Acute workload was highest during the week of RTP for all variables, with an 86 ±51% (TD), 41 ±37% (V-VHSR), 95 ±50% (acceleration load), and 116 ±72% (RHIE) increase compared to the previous rehabilitation week. Time significantly affected chronic RHIE (p=0.038), but not TD (p=0.315), V-VHSR (p=0.931), or acceleration load (p=0.213). Chronic workload was highest during the second week after RTP, with the three previous weeks being decreased by -13 to 17 ±18% (TD), -7 to -8 ±24% (V-VHSR), -14 to -18 ±17% (acceleration load), and -22 to -28 ±19% (RHIE). Discussion: The acute external workloads of injured NRL athletes demonstrated large increases during the RTP week which may increase the likelihood of re-injury. In contrast, chronic workload was relatively stable before and after RTP for all external workload variables except RHIE which was low until 2 weeks after RTP. Greater focus on RHIE workload in the lead up to RTP may be needed to ensure adequate exposure to that aspect of rugby league. Conflict of interest statement: my co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.

Impact of prior anterior cruciate ligament, hamstring or groin injury on lower limb strength and jump kinetics in elite female footballers

ObjectiveTo compare lower limb strength and countermovement jump (CMJ) kinetics between elite female footballers with and without a history of anterior cruciate ligament reconstruction (ACLR), hamstring strain, or hip/groin injury. DesignCross-sectional. SettingField-based. Participants369 elite female Australian football, soccer and rugby league players aged 15–35. Main outcome measuresIsometric hip adductor and abductor strength, eccentric knee flexor strength, and CMJ vertical ground reaction forces, including between-leg asymmetry. Players reported their lifetime history of ACLR, and whether they had sustained a hamstring strain, or hip/groin injury in the previous 12-months. ResultsPlayers with a unilateral history of ACLR (n = 24) had significant between-leg asymmetry in eccentric knee flexor strength (mean = −6.3%, 95%CI = −8.7 to −3.9%, P < .001), isometric hip abductor strength (mean = −2.5%, 95%CI = −4.3 to −0.7%, P = .008), and CMJ peak landing force (mean = −5.5%, 95%CI = −10.9 to −0.1%, P = .046). Together, between-leg asymmetry in eccentric knee flexor strength, isometric hip abductor strength, and CMJ peak landing force distinguished between players with and without prior ACLR with 93% accuracy. ConclusionElite female footballers with a history of ACLR, but not hamstring or hip/groin injury, exhibit persistent between-leg asymmetries in lower limb strength and jump kinetics following a return to sport.

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.

The efficacy of repetitions-in-reserve vs. traditional percentage-based resistance training: a 4-week pre-season randomized intervention in elite rugby league players

PurposeThis two-experiment study aimed to examine (1) the accuracy and reliability of repetitions-in-reserve and (2) using a randomized trial, the efficacy of repetition-in-reserve compared to traditional percentage-based training during a 4-week pre-season strength training block in elite rugby league players.MethodsIn experiment 1, participants performed deadlift, bench press and weighted pull up exercises for 3, 6, and 9 repetitions to failure using self-selected loads. This was undertaken on two occasions, separated by 8-weeks. In experiment 2, participants were randomly separated into either repetitions-in-reserve or percentage-based training groups. They completed a 4-week pre-season training block with training prescribed based on the group to which they were assigned. Measures of body mass and 3 repetition max strength in the aforementioned exercises were measured pre and post intervention.ResultsExperiment 1 showed that repetitions-in-reserve exhibited generally acceptable levels of accuracy and moderate-good levels of reliability. However, the deadlift when the required number of repetitions was 6 and 9 and the bench press when number of repetitions was 9 were not associated with acceptable levels of accuracy and reliability, respectively. Experiment 2 showed that there were no differences between repetitions-in-reserve or percentage-based training group for the strength outcomes, although there were significant increases in body mass in the percentage-based group (pre = 85.6 ± 10.6 kg, post = 86.4 ± 10.8 kg).ConclusionRepetitions-in-reserve is generally associated with acceptable levels of accuracy and moderate-good levels of reliability, although there were some exceptions for the deadlift in relation to accuracy and bench press for reliability. Experiment 2 shows that although there were no differences between groups for the strength-based outcomes, significant increases in body mass in the percentage-based group may make this approach a more effective approach to prepare players for the rigors of the rugby league season.

The Effects of Sprint vs. Resisted Sled-Based Training; an 8-Week in-Season Randomized Control Intervention in Elite Rugby League Players.

The aim of the current study was to examine the efficacy of resisted sled-based training compared to traditional unresisted sprint training in terms of mediating improvements in speed, agility, and power during an eight-week period of in-season training in elite rugby league players. Participants were randomly separated into either resisted sled or traditional sprint-based training groups and they completed an eight-week in-season training block with training prescribed based on the group to which they were assigned. Measures of 5 m, 10 m, and 20 m sprint times in addition to countermovement jump height and 505-agility test time were measured at baseline, four-weeks and eight-weeks. For sprint-based outcomes, although both groups improved significantly, there were no statistical differences between the two training methods. However, at the eight-week time point there were significant improvements in 505-agility test (sprint group: baseline = 2.45 and eight-weeks = 2.42 s/sled group: baseline = 2.43 and eight-weeks = 2.37 s) and countermovement jump (sprint group: baseline = 39.18 and eight-weeks = 39.49 cm/sled group: baseline = 40.43 and eight-weeks = 43.07 cm) performance in the sled training group. Therefore, the findings from this investigation may be important to strength and conditioning coaches working in an elite rugby league in that resisted sled training may represent a more effective method of sprint training prescription.