Epidemiology of injuries in Australian junior rugby league players

ObjectivesConduct a large-scale epidemiological study of injury characteristics (location, type, mechanism, severity, burden) and incidence in community junior rugby league.DesignProspective cohort epidemiology study.MethodsInjury surveillance was conducted in three district leagues (Penrith, Canberra, Melbourne) in under 6 (U6) to under 18 years (U18) age groups across the 2016 season. Club sports trainers recorded all match/training medical-attention injuries using a commercial electronic application which recorded injury circumstances and characteristics.ResultsA total of 13,169 players from 897 teams participated and 408 (89% male) players sustained 485 injuries, 94% of which were match related. The overall injury incidence was 5.9 injuries/1000 player hours and highest in U13–U18 female players (22.2 injuries/1000 player hours). The mean injury severity of 16 ± 31 days missed training/match-play caused an overall injury burden of 94.2 days missed/1000 player hours). Tackles accounted for 84% of injuries. Joint and contusion injuries were the most prevalent injury type and the head (35% total injuries, primarily bruising and bleeding) was the most injured body site.ConclusionsThis is the first study to report injuries across a large cohort of all-age Australian community junior rugby league players over one season. Injury prevalence was lower than previously reported in junior rugby league suggesting the sport has not become more dangerous for junior players. These findings provide an evidence-base to inform or revise policy, training and injury prevention programs and athlete development pathways in relation to game-wide safety and develop best-practice protocols in injury management for rugby league athlete support personnel.     

Physiological characteristics of junior and senior rugby league players

OBJECTIVES: To investigate the physiological characteristics of subelite junior and senior rugby league players and establish performance standards for these athletes. METHODS: A total of 159 junior (under 16, 15, 14, and 13, n = 88) and senior (first grade, second grade, and under 19, n = 71) rugby league players (forwards, n = 80, backs, n = 79), competing at a subelite level, underwent measurements of body mass, muscular power (vertical jump), speed (10 m, 20 m, and 40 m sprint), agility (Illinois agility run), and estimated maximal aerobic power (multistage fitness test). Data were also collected on match and training frequency and playing experience. RESULTS: There was a significant effect (p<0.05) of age and playing level on playing experience, body mass, muscular power, speed, agility, and estimated maximal aerobic power, with the physiological capacities of players increasing as the playing level increased. Forwards were heavier than backs for all junior and senior teams. Forwards and backs had similar estimated maximal aerobic power, except for under 16 players, for whom significant (p<0.05) differences were detected (mean (95% confidence intervals) 42.9 (40.1 to 45.7) v 49.5 (46.4 to 52.6) ml/kg/min for forwards and backs respectively). Scores for speed, muscular power, and agility were not significantly different between forwards and backs for any of the junior or senior teams. CONCLUSIONS: The results show that there is a progressive improvement in the physiological capacities of rugby league players as the playing level increases. These findings provide normative data and performance standards for subelite junior and senior rugby league players. Further studies on the sociological, physical, psychological, and personal predictors of talent in rugby league are warranted.     

Incidence of injury in junior and senior rugby league players

Rugby league is an international collision sport played at junior, amateur, semi-professional and professional levels. Due to the high numbers of physical collisions and tackles, musculoskeletal injuries are common. A large percentage of injuries result in long-term employment and study limitations, medical costs and loss of income. Review articles addressing the applied physiology of rugby league and common rugby league injuries have been published. However, both of these review articles have focused on the professional rugby league player. This review addresses the extent of the injury problem in rugby league in all levels of competition (i.e. junior, amateur, semi-professional and professional). The incidence of rugby league injuries typically increases as the playing level is increased. The majority of studies have shown that the head and neck is the most common site of match injuries in senior rugby league players, while knee injuries are the most common site of injury in junior rugby league players. Muscular injuries are the most common type of injury sustained by senior rugby league players, while junior rugby league players more commonly sustain fractures. Injuries are most commonly sustained in tackles, by the tackled player. Thigh and calf strains are the most common injuries sustained during rugby league training, while overexertion is the most common cause of training injuries. Player fatigue may influence the incidence of injury, with most sub-elite (amateur and semi-professional) rugby league injuries occurring in the second half of matches or the latter stages of training sessions. The majority of training injuries occur in the early stages of the season, while match injuries occur in the latter stages of the season, suggesting that changes in training and playing intensity may influence the incidence of injury in rugby league. Injury prevention studies are required to reduce the incidence, severity and cost of rugby league injuries. These injury prevention strategies could include coaching on defensive skills, correct tackling technique, correct falling technique and methods to minimise the absorption of impact forces in tackles. Game-specific attacking and defensive drills practised before and during fatigue may also encourage players to make appropriate decisions under fatigued conditions and apply learnt skills during the pressure of competitive matches. Further studies investigating risk factors for injury in junior and senior rugby league players, injuries sustained by specific playing positions and the influence of injuries on playing performance are warranted.     

Incidence of injury in junior rugby league players over four competitive seasons

While several studies have documented the incidence of injury in senior rugby league players, information on the injury rates of junior rugby league players is limited. In addition, all of the injury surveillance studies performed on junior rugby league players have been performed over a limited time frame (typically one season). The purpose of this study was to document the incidence of injury in junior rugby league players over four competitive seasons. Injury data were collected from 84 matches. An injury was defined as one that occurred in a match and resulted in the player missing a subsequent match. The overall incidence of injury was 56.8 (95% CI, 42.6–70.9) per 1000 playing hours. The majority of injuries were sustained to the shoulder (15.6 [95% CI, 8.2–23.0] per 1000 playing hours). Sprains were the most common type of injury (24.7 [95% CI, 15.4–34.1] per 1000 playing hours). Injuries were most commonly sustained while being tackled (19.2 [95% CI, 11.0–27.5] per 1000 playing hours) and while tackling (10.1 [95% CI, 4.1–16.0] per 1000 playing hours). While there was a tendency towards differing injury rates over the four competitive seasons (χ² = 6.3, d.f. = 3), the differences were not statistically significant (p = 0.10). These findings demonstrate that the incidence of junior rugby league injuries is similar to previously reported for senior competitors. A long-term collaborative effort to reduce the incidence of injury in junior rugby league players is warranted.     

A comparison of physiological and anthropometric characteristics among playing positions in junior rugby league players

Objectives: To compare the physiological and anthropometric characteristics of specific playing positions and positional playing groups in junior rugby league players. Methods: Two hundred and forty junior rugby league players underwent measurements of standard anthropometry (body mass, height, sum of four skinfolds), muscular power (vertical jump), speed (10, 20, and 40 m sprint), agility (L run), and estimated maximal aerobic power (multi-stage fitness test) during the competitive phase of the season, after players had obtained a degree of match fitness. Results: Props were significantly (p<0.05) taller, heavier, and had greater skinfold thickness than all other positions. The halfback and centre positions were faster than props over 40 m. Halfbacks had significantly (p<0.05) greater estimated maximal aerobic power than props. When data were analysed according to positional similarities, it was found that the props positional group had lower 20 and 40 m speed, agility, and estimated maximal aerobic power than the hookers and halves and outside backs positional groups. Differences in the physiological and anthropometric characteristics of other individual playing positions and positional playing groups were uncommon. Conclusions: The results of this study demonstrate that few physiological and anthropometric differences exist among individual playing positions in junior rugby league players, although props are taller, heavier, have greater skinfold thickness, lower 20 and 40 m speed, agility, and estimated maximal aerobic power than other positional playing groups. These findings provide normative data and realistic performance standards for junior rugby league players competing in specific individual positions and positional playing groups.     

Considering maturation status and relative age in the longitudinal evaluation of junior rugby league players

This study longitudinally evaluated whether maturation and relative age interact with time during adolescence to differentially affect the development of anthropometric and fitness characteristics in junior rugby league players. Anthropometric and fitness characteristics of 81 junior players selected into the UK Rugby Football League's talent identification and development process were assessed over three consecutive occasions (i.e., under‐13s, ‐14s, ‐15s). Players were grouped and compared in relation to maturational status (i.e., early, average, late) and relative age quartile (i.e., quartile 1). Repeated measures multivariate analysis of variance identified significant (P < 0.001) overall main effects for maturation group, relative age quartile and importantly a maturation group by time interaction. Findings showed that the early‐maturing group had the greatest anthropometric characteristics and medicine ball throw across the three occasions. However, the late‐maturing group increased their height (early = 5.0 cm, late = 10.3 cm), medicine ball throw and 60‐m sprint (early = ?0.46 s, late = ?0.85 s) the most throughout the 2‐year period. Early (de)selection policies currently applied in talent identification and development programs are questionable when performance‐related variables are tracked longitudinally. During adolescence, maturation status alongside relative age should be considered and controlled for when assessing athlete potential for future progression.     

Back squat velocity to assess neuromuscular status of rugby league players following a match

ObjectivesBack squat mean concentric velocity (MV) and countermovement jump (CMJ) performance were examined in sub-elite rugby league players post-match to monitor changes in neuromuscular status (NMS) from baseline. Relationships between changes in back squat MV and CMJ performance variables were used to compare back squat MV to an established method to monitor NMS.DesignLongitudinal observational design.Methods18 male sub-elite rugby league players (mean ± SD, 20.5 ± 2.4 yr; 180.0 ± 6.7 cm; 93.3 ± 11.2 kg) performed 3 repetitions of CMJ and back squat with an individualised, pre-determined load at ?2 h (baseline), +30 min, +24 h, and +48 h in relation to a match. Back squat MV, CMJ height, CMJ peak power, and CMJ peak velocity were measured with a linear position transducer.ResultsSignificant (p < 0.05), small to large decreases (ES = 0.52–1.24) were observed in back squat MV up to +48 h post-match. Significant (p < 0.05), small to moderate decreases (ES = 0.52–0.70) in CMJ height were also observed up to +24 h post-match, returning to baseline at +48 h. CMJ peak power and peak velocity post-match changes were not significant compared to baseline (p > 0.05). Significant positive correlations were found between changes in back squat MV and CMJ height at +30 min (r = 0.59; p = 0.009) and +48 h (r = 0.51; p = 0.03).ConclusionsThese findings suggest back squat MV may be a suitable alternative or addition to CMJ testing for monitoring NMS in rugby league players.     

Incidence of injury in semi-professional rugby league players

OBJECTIVES: To investigate the site, nature, cause, and severity of injuries in semi-professional rugby league players. METHODS: The incidence of injury was prospectively studied in one hundred and fifty six semi-professional rugby league players over two competitive seasons. All injuries sustained during matches and training sessions were recorded. Injury data were collected from a total of 137 matches and 148 training sessions. Information recorded included the date and time of injury, site, nature, cause, and severity of injury. RESULTS: During the two seasons, 1,694 playing injuries and 559 training injuries were sustained. The match injury incidence was 824.7 per 1,000 player-position game hours and training injury incidence was 45.3 per 1,000 training hours. Over 20% of the total training (17.4 per 1,000) and playing (168.0 per 1,000) injuries sustained were to the thigh and calf. Muscular injuries (haematomas and strains) were the most common type of injury sustained during training (22.0 per 1,000, 48.7%) and matches (271.7 per 1,000, 32.9%). Playing injuries were most commonly sustained in tackles (382.2 per 1,000, 46.3%), while overexertion was the most common cause of training injuries (15.5 per 1,000, 34.4%). The majority of playing injuries were sustained in the first half of matches (1,013.6 per 1,000, 61.5% v 635.8 per 1,000, 38.5%), whereas training injuries occurred more frequently in the latter stages of the training session (50.0 per 1,000, 55.3% v 40.5 per 1,000, 44.7%). Significantly more training injuries were sustained in the early half of the season, however, playing injuries occurred more frequently in the latter stages of the season. CONCLUSIONS: These results suggest that changes in training and playing intensity impact significantly upon injury rates in semi-professional rugby league players. Further studies investigating the influence of training and playing intensity on injuries in rugby league are warranted.     

Physiological and anthropometric characteristics of amateur rugby league players

OBJECTIVES: To investigate the physiological and anthropometric characteristics of amateur rugby league players. METHODS: Thirty five amateur rugby league players (19 forwards and 16 backs) were measured for height, body mass, percentage body fat (sum of four skinfolds), muscular power (vertical jump), speed (10 m and 40 m sprint), and maximal aerobic power (multistage fitness test). Data were also collected on match frequency, training status, playing experience, and employment related physical activity levels. RESULTS: The 10 m and 40 m sprint, vertical jump, percentage body fat, and multistage fitness test results were 20-42% poorer than previously reported for professional rugby league players. Compared with forwards, backs had significantly (p<0.01) lower body mass (79.7 (74.7-84.7) kg v 90.8 (86.2-95.4) kg) and significantly (p<0.01) greater speed during the 40 m sprint (6.45 (6.35-6.55) v 6.79 (6.69-6.89) seconds). Values for percentage body fat, vertical jump, 10 m sprint, and maximal aerobic power were not significantly different (p>0.05) between forwards and backs. When compared with professional rugby league players, the training status of amateur rugby league players was 30-53% lower, with players devoting less than three hours a week to team training sessions and about 30 minutes a week to individual training sessions. The training time devoted to the development of muscular power (about 13 minutes a week), speed (about eight minutes a week), and aerobic fitness (about 34 minutes a week) did not differ significantly (p>0.05) between forwards and backs. At the time of the field testing, players had participated, on average, in one 60 minute match every eight days. CONCLUSIONS: The physiological and anthropometric characteristics of amateur rugby league players are poorly developed. These findings suggest that position specific training does not occur in amateur rugby league. The poor fitness of non-elite players may be due to a low playing intensity, infrequent matches of short duration, and/or an inappropriate training stimulus.     

Risk factors for injury in subelite rugby league players

BACKGROUND: Although player fatigue and playing intensity have been suggested to contribute to injuries in rugby league players, no study has confirmed if the level of physical fitness is a risk factor for injury in rugby league players. The aim of this study was to identify risk factors for injury in subelite rugby league players. HYPOTHESIS: Low physical fitness levels are risk factors for injury in subelite rugby league players. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: One hundred fifty-three players from a subelite rugby league club underwent preseason measurements of muscular power (vertical jump), speed (10- and 40-m sprint), and maximal aerobic power (multistage fitness test) over 4 competitive seasons. All injuries sustained by players were prospectively recorded over the 4 competitive seasons. RESULTS: The risk of injury was greater in players with low 10- and 40-m speed. Players with a low maximal aerobic power had a greater risk of sustaining a contact injury. In addition, players who completed less than 18 weeks of training before sustaining their initial injuries were at greater risk of sustaining a subsequent injury. CONCLUSIONS: Subelite rugby league players with low speed and maximal aerobic power are at an increased risk of injury. In addition, players who complete less than 18 weeks of training before sustaining an initial injury are at greater risk of sustaining a subsequent injury. These findings highlight the importance of speed and endurance training to reduce the incidence of injury in subelite rugby league players.     

Training injuries in New Zealand amateur rugby league players

This study investigated the incidence, site, nature and severity of training injuries in a New Zealand amateur rugby league team. The incidence of injuries was prospectively studied in a senior amateur rugby league club over one domestic season. All injuries sustained during training sessions were recorded. Injury data was collected from a total of 77 training sessions. Information recorded included the date, time, site, nature, cause and severity of injury. A total of 66 training injuries were recorded. The total injury incidence was 22.4 per 1000 training hours. Injuries resulting in missed training sessions were 16.9 per 1000 h. The most common injury site was the thigh for both overall injuries and injuries resulting in missed training weeks. The incidence of overexertion injuries peaked immediately prior to the commencement of the competitive season. The high rates of overexertion injuries suggest that an increase in intensity may contribute to training injuries in amateur rugby league players. An understanding of the demands of training, and the effects that injuries have on players is essential for the identification of injury prevention strategies.     

Acute injuries in Finnish junior floorball league players

Objectives

To investigate the incidence and characteristics of acute time-loss injuries in Finnish junior floorball league players.

Incidence,prevalence and consequences of illness in academy rugby league players

ObjectivesTo assess the incidence, prevalence and consequences of illness in one professional academy rugby league club during an in-season period.DesignObservational prospective cohort study.MethodSeventeen male rugby league players (age 17.7 ± 0.7 years, stature 178.8 ± 5.1 cm, body mass 87.2 ± 9.6 kg) completed a weekly self-report illness questionnaire using an amended version of the Oslo Sports Trauma Research Centre (OSTRC) questionnaire on health problems.ResultsA total of 24 new illnesses were reported over the 25-week study period. 65% of players experienced at least one illness during the study. The incidence of illness in this cohort was 14.3 per 1000-player days, with the respiratory system being most commonly affected (n = 15; 62.5%). The average weekly illness prevalence was 10.3%. Time-loss illness incidence was 1.4 per 1000-player days. Loss of body mass and sleep disruptions were the most commonly reported consequences of illness episodes. Mean body mass loss during a period of illness was 2.2 ± 0.6 kg.ConclusionsAcademy rugby league players are most commonly affected by respiratory illness with a total of nineteen training and competition days lost to illness. Associated consequences of illness, such as loss of body mass and sleep disruptions may present a challenge and negatively impact a rugby league player’s development. Appropriate medical provisions should be provided for Academy rugby league players to support them during periods of illness to limit the impact of these consequences.