A pooled data analysis of injury incidence in rugby league football

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.

New Zealand cricket injury analysis based on 12 years of Accident Compensation Corporation data

Objectives

To provide epidemiological data for cricket injuries in New Zealand.

Methods

A retrospective analytical review using epidemiological cricket data obtained from the national Accident Compensation Corporation (ACC) for 2005–2016. Injury incidence was calculated per 1000 participants.

Results

There were 86 562 injuries (77 212 males and 9350 females) during the 12 years with higher injury incidence for males (64.1) than females (36.1). While cricket-related injury claims increased by 42.6%, the injury incidence decreased from 59.0 in 2006 to 42.8 in 2016. The pooled injury rate per 1000 participants was highest for hand/fingers (9.2) and lumbar (8.1) body regions, and for contact (44.7) activities. Players aged 10–20 years were more likely to experience injury.

Conclusions

Analysis of 12 years of ACC cricket-related injury claims showed only minimal reductions in injury incidence over the years. Therefore, cricket-related contact injuries to the hand/fingers and head need to be the focus of injury prevention programmes (eg, via promoting use of protective gear and correct technique), particularly in players aged 10–20 years.

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.

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).

Investigation of the Influence of Reduced Graphene Oxide Flakes in the Dielectric on Surface Characteristics and Material Removal Rate in EDM

Background: Touch (rugby/football) is a minimal contact sport for which the type and incidence of injuries remains unknown in Europe. Objectives: To establish the incidence, severity and nature of injuries sustained during a four-day European Touch Championship competition. Methods: A prospective cohort design was adopted to record match-related injuries during the European Touch Championships 2016. Injuries were collected from five countries and classified using the Orchard Sports Injury Classification (OSICS-10). Data were combined from all participating countries and injury incidence was recorded as number of injuries/1000 player hours. Results: A total of 135 injuries were recorded during the tournament with injury incidence calculated as 103.5 injuries per 1000 player match hours. Injuries were mainly recorded as transient (76%) occurring most frequently in the lower limb (69%). Injuries occurred more frequently on successive days, with exception to the final day of the tournament. The number of injuries was not different between the first and second half of matches and there was no relationship between the day of the tournament and the half of the match that injury occurred. Conclusion: Match injury incidence was 103.5 injuries per 100 player match hours. The most injured site was that of the lower limb, with the most common injury type reported as muscle/tendon injury. It is postulated that fatigue plays a role in injury incidence during a multiday tournament.

The Incidence of Injury in Amateur Male Rugby Union: A Systematic Review and Meta-Analysis

Background

Rugby union is a physically demanding, full-contact team sport that has gained worldwide popularity. The incidence of injury in rugby union has been widely reported in the literature. While comprehensive injury surveillance and prevention programmes have been implemented within the professional game, there is a need for similar strategies in the amateur game. Despite recent increases in the volume of research in rugby, there is little consensus regarding the true incidence rate of match and training injuries in senior amateur male rugby union players.

Objective

The aim of the current review was to systematically review the available evidence on the epidemiology of time-loss injuries in senior amateur male rugby union players and to subsequently conduct a meta-analysis of the findings.

Methods

A comprehensive search of the PubMed, Scopus, SportDiscus and Google Scholar electronic databases was performed using the following keywords; (‘rugby’ OR ‘rugby union’) AND (‘amateur’ OR ‘community’) AND (‘injur*’ OR ‘pain*’). Six articles regarding the incidence of injury in senior amateur male rugby union players, in both matches and training, were retrieved and included in the meta-analysis to determine the overall incidence rate of match injury, with descriptive analyses also provided for other reported variables.

Results

The overall incidence rate of match injuries within senior amateur rugby union players was 46.8/1000 player hours [95% confidence interval (CI) 34.4–59.2]. Contact events accounted for the majority of injuries, with the tackler more at risk than the player being tackled, and with respective incidence rates of 15.9/1000 player hours (95% CI 12.4–19.5) and 12.2/1000 player hours (95% CI 9.3–15.1).

Conclusion

This meta-analysis found that the incidence rate of injury in amateur rugby union players was lower than that in professional players, but higher than the incidences reported in adolescent and youth rugby players. By understanding the true incidence and nature of injuries in rugby, injury prevention strategies can best be implemented. Future prevention strategies may best be aimed towards the tackle area, specifically to the tackler, in order to minimize injury risk.

Incidence and characteristics of injury in under-19 academy level rugby league match play: A single season prospective cohort study

Academy rugby league competition is an important step along the pathway to professional status, but little is known about injury at this level of the game. The aim of this research was to establish the nature, incidence and burden of injury in English academy rugby league. Using an observational prospective cohort study design, and a time-loss injury definition, the injury outcomes of three professional rugby league academies were recorded during the 2017 season. A total of 87 injuries occurred in 59 matches for an overall injury incidence of 85 (95%CI 67-103) injuries per 1000 hours played. The mean severity of injury was 22 ± 19 days resulting in an overall injury burden of 1898 (95%CI 1813-1983) days lost per 1000 hours. The tackle event was the most common cause of injury (77% of all injuries). Forwards sustained a greater proportion of injuries than backs (forwards 67% vs. backs 33% of injuries). Concussion (13 (6-20) per 1000 hours) and ankle sprains (11 (4-17) per 1000 hours) were the most commonly diagnosed injuries. The shoulder joint was the most commonly injured site (17 (9-25) per 1000 hours). The incidence of injury for academy rugby league is similar to senior professional rugby league.

Semi-Professional Rugby League Players have Higher Concussion Risk than Professional or Amateur Participants: A Pooled Analysis

A combined estimate of injuries within a specific sport through pooled analysis provides more precise evidence and meaningful information about the sport, whilst controlling for between-study variation due to individual sub-cohort characteristics. The objective of this analysis was to review all published rugby league studies reporting injuries from match and training participation and report the pooled data estimates for rugby league concussion injury epidemiology. A systematic literature analysis of concussion in rugby league was performed on published studies from January 1990 to October 2015. Data were extracted and pooled from 25 studies that reported the number and incidence of concussions in rugby league match and training activities. Amateur rugby league players had the highest incidence of concussive injuries in match activities (19.1 per 1000 match hours) while semi-professional players had the highest incidence of concussive injuries in training activities (3.1 per 1000 training hours). This pooled analysis showed that, during match participation activities, amateur rugby league participants had a higher reported concussion injury rate than professional and semi-professional participants. Semi-professional participants had nearly a threefold greater concussion injury risk than amateur rugby league participants during match participation. They also had nearly a 600-fold greater concussion injury risk than professional rugby league participants during training participation.

Descriptive Epidemiology of Musculoskeletal Injuries and Concussions in the National Football League, 2012-2014

Background:

The risk of all-cause injury and concussion associated with football is significant. The National Football League (NFL) has implemented changes to increase player safety warranting investigation into the incidence and patterns of injury.

Purpose:

To document the incidence and patterns of all-cause injury and concussions in the NFL.

Study Design:

Descriptive epidemiology study.

Methods:

Injury data were collected prospectively from official NFL injury reports over 2 regular seasons from 2012 to 2014, with identification of injury incidence rates and patterns. Concussion rate ratios were calculated using previously reported NFL rates.

Results:

A total of 4284 injuries were identified, including 301 concussions. The all-cause injury rate was 395.8 per 1000 athletes at risk (AAR) and concussion incidence was 27.8 per 1000 AAR. Only 2.3% of team games were injury free. Wide receivers, tight ends, and defensive backs had the highest incidence of injury and concussion. Concussion incidence was 1.61-fold higher in 2012 to 2014 compared with 2002 to 2007. The knee was injured most frequently, followed by the ankle, hamstring, shoulder, and head.

Conclusion:

The incidence of all-cause injury and concussion in the NFL is significant. Concussion injury rates are higher than previous reports, potentially reflecting an improvement in recognition and awareness. Injury prevention efforts should continue to reduce the prevalence of injury associated with football.

Metastatic involvement of the pituitary gland: a systematic review with pooled individual patient data analysis

PURPOSE

To report a rare case of pituitary metastasis (PM) from hepatocellular carcinoma (HCC) and help better understand the incidence of PM and its most common presenting symptoms through a pooled individual patient data analysis.

METHODS

Literature regarding PM was systematically reviewed with a pooled individual patient data analysis conducted. Pooled individual data analysis result is also compared with the result in a most recent systematic review.

RESULTS

Our results demonstrate that the incidence of PM among all intracranial metastases is 0.87% (95% CI 0.56, 1.18); it is 1.9% (95% CI 1.46, 2.34) among all autopsied cancer cases; it is 11.56% (95% CI 7.08, 16.04) among all breast cancer patients who had hypophysectomies and 12.83% (95% CI 10.5, 15.16) among all autopsied breast cancer patients. The fixed effect model showed that the incidence of PM in breast cancer patients group is significantly higher (p < 0.001) with an odds ratio of 6.71 (95% CI 4.24, 10.61). Breast and lung cancer are the most common primary cancer of PM with a percentage of 37.2 and 24.2 respectively. The next most common primary sites are prostate and kidney respectively, although the percentages for each are only about 5. Diabetes insipidus (DI) remains the most common symptom among all reported PM cases with a pooled incidence of 42.34% (95% CI 36.15, 48.53). Although not significant (χ(2) = 2.846, df = 1, p = 0.061), it is less common in the most recent reported cases which has a pooled incidence of 32.76% (95% CI 20.31, 45.21). DI is extremely rare in the reported PM cases from HCC (none of the eight cases presented with DI). The symptoms of anterior hypopituitarism (23.68 vs 39.66%, p = 0.015), visual deterioration (27.89 vs 41.38%, p = 0.039), cranial nerve palsies (21.58 vs 41.38%, p = 0.003) and headaches (15.79 vs 32.76%, p = 0.005) were reported significantly higher than previously described in the literature.

CONCLUSIONS

Pituitary metastasis is rare in patients with cancer, and the pituitary gland is an uncommonly involved location in patients with intracranial metastases. With advanced diagnostic imaging techniques and increased awareness about the manifestation of sellar lesions, the incidence of cranial nerve palsies and anterior pituitarism are higher than reported. This information may allow earlier diagnosis of PM.

Tackle and impact detection in elite Australian football using wearable microsensor technology

The effectiveness of a wearable microsensor device (MinimaxX(TM) S4, Catapult Innovations, Melbourne, VIC, Australia) to automatically detect tackles and impact events in elite Australian football (AF) was assessed during four matches. Video observation was used as the criterion measure. A total of 352 tackles were observed, with 78% correctly detected as tackles by the manufacturer's software. Tackles against (i.e. tackled by an opponent) were more accurately detected than tackles made (90% v 66%). Of the 77 tackles that were not detected at all, the majority (74%) were categorised as low-intensity. In contrast, a total of 1510 "tackle" events were detected, with only 18% of these verified as tackles. A further 57% were from contested ball situations involving player contact. The remaining 25% were in general play where no contact was evident; these were significantly lower in peak Player Load™ than those involving player contact (P < 0.01). The tackle detection algorithm, developed primarily for rugby, was not suitable for tackle detection in AF. The underlying sensor data may have the potential to detect a range of events within contact sports such as AF, yet to do so is a complex task and requires sophisticated sport and event-specific algorithms.

Injury and biomechanical perspectives on the rugby scrum: a review of the literature

As a collision sport, rugby union has a relatively high overall injury incidence, with most injuries being associated with contact events. Historically, the set scrum has been a focus of the sports medicine community due to the perceived risk of catastrophic spinal injury during scrummaging. The contemporary rugby union scrum is a highly dynamic activity but to this point has not been well characterised mechanically. In this review, we synthesise the available research literature relating to the medical and biomechanical aspects of the rugby union scrum, in order to (1) review the injury epidemiology of rugby scrummaging; (2) consider the evidence for specific injury mechanisms existing to cause serious scrum injuries and (3) synthesise the information available on the biomechanics of scrummaging, primarily with respect to force production. The review highlights that the incidence of acute injury associated with scrummaging is moderate but the risk per event is high. The review also suggests an emerging acknowledgement of the potential for scrummaging to lead to premature chronic degeneration injuries of the cervical spine and summarises the mechanisms by which these chronic injuries are thought to occur. More recent biomechanical studies of rugby scrummaging confirm that scrum engagement forces are high and multiplanar, but can be altered through modifications to the scrum engagement process which control the engagement velocity. As the set scrum is a relatively 'controlled' contact situation within rugby union, it remains an important area for intervention with a long-term goal of injury reduction.

Match injuries in English youth academy and schools rugby union: an epidemiological study

BACKGROUND

Numerous injury epidemiology studies have reported injury patterns in senior rugby union, but investigations in youth rugby are limited.

PURPOSE

To describe the nature of injuries resulting from match play within the English youth rugby union, including a comparison between 2 levels of play within the same age group: professional academy versus school rugby.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A 2-season (2006-2007 and 2007-2008) study obtained information on injuries sustained in male youth rugby union players (age, 16-18 years) from 12 English Premiership academies (n = 250) and 7 schools (n = 222). Match exposure (player-hours) and injury details were recorded.

RESULTS

Match injury incidence was 47 per 1000 player-hours for the academy and 35 per 1000 player-hours for the school groups; these rates were statistically different (P = .026). The most common injury site was the lower limb and the most common injury type was a ligament sprain, with injuries to the knee and shoulder region resulting in the greatest burden of injury for both groups. The tackle event was the most common cause of match injury for both academy (51% of injuries) and school (57% of injuries) groups.

CONCLUSION

Overall, the incidence of injury for youth rugby was lower than for previous studies in senior rugby, but injury patterns (location, type) and causes were similar. The study confirmed that match injury incidence was significantly greater in elite academy youth rugby union than schools rugby. The results suggest that the specific focus for injury risk management in youth rugby should be on players' tackle technique and prevention strategies for knee and shoulder injuries.

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

OBJECTIVES

To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass.

DESIGN

A repeated measure, prospective, observational, cohort study.

SETTING

Griffith University, Gold Coast, Australia.

PARTICIPANTS

37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season.

RESULTS

Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm(2); mid=1.296(0.093) g/cm(2); p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury.

CONCLUSIONS

Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.

Effects of footwear on comfort and injury in professional rugby league

The aim of this study was to determine the effectiveness of a tailored footwear programme on lower-limb comfort in professional rugby league players. The study was conducted over 30 weeks and involved two professional teams (n = 59 players) from the Australian National Rugby League competition. One team was assigned to a footwear programme (intervention), while players from the control group continued usual practices of self-selected footwear. The tailored footwear programme consisting of player education, prescription of footwear, and frequent rotation of footwear resulted in a lower incidence of injury and higher comfort ratings. The intervention group had fewer lower-limb injuries (P = 0.005; Cohen d = 0.72) and higher comfort ratings (P < 0.001, Cohen d = 1.24) than the control group. Specifically, the intervention group reported a lower incidence of poor comfort events (mean = 3.8, s = 2.7) than the control group (mean = 7.9, s = 3.7). Observations also included fewer time loss events in the intervention (mean = 6.3, s = 4.8) than the control group (mean = 11.0, s = 6.3) and reduced injuries per 1000 h in the intervention (24.79/1000) than the control group (30.76/1000). These findings should help medical advisers improve footwear comfort in sportspeople and so reduce the incidence of related injuries.

Training loads and incidence of injury during the preseason in professional rugby league players

Research into rugby league has found a significant, positive relationship between training load and injury rates. However, there has been limited research investigating this relationship in the preseason period, and the relationship between training load, and injury among professional rugby league players is yet to be examined. The primary aim of this study was to examine the relationships between training load, various psychological data, and the incidence of injury during preseason training at a professional rugby league club. Thirty-six male professional rugby league players undertook a 14-week training program. Each player's training time, intensity rating, and injury status were recorded after each training session. In addition, players rated their sleep, food, energy, mood, and stress on a scale of 1-10 (with 1 being extremely poor and 10 being excellent) biweekly. Over the entire preseason period, a total of 2,877.9 training hours were recorded for the players, with an overall incidence of injury of 6.9 per 1,000 training hours. Higher training loads during the first half of the preseason corresponded to a higher injury rate in comparison to the second half of the preseason. No significant relationship was found between the preseason weekly injury rate and the weekly load, nor was there a relationship between injury and psychological data. These findings suggest no relationship between training load, psychological data, and injury incidence during the preseason training period in professional rugby league players. However, results suggest that players may have an increased risk of injury during the early preseason period. The findings of this study may be particularly useful in professional rugby league teams to determine when a player is at increased risk of injury, using their training loads and psychological data.

Reliability of an instrument to determine lower limb comfort in professional football

AIMS AND OBJECTIVES

This study extends previous work in the field of injury awareness using a novel lower limb comfort index (LLCI), which was developed to assess comfort in professional football. Participants rated comfort for designated anatomical segments of the lower limb utilizing a seven point Likert scale. The aims of the study were (i) to assess the reliability of the LLCI in a competitive football environment (Australian Rules and Rugby League), and (ii) to assess whether LLCI measurements were responsive to changes in lower limb comfort over time.

METHODS AND RESULTS

THE RELIABILITY OF THE LLCI WAS OBSERVED IN TWO PROFESSIONAL FOOTBALL ENVIRONMENTS: Training Week (mean difference 0.1 point, intra-class correlation coefficient, ICC 0.99) for n = 41 participants; and Match Day (mean difference 0.2 points, ICC 0.97) for n = 22 players. Measurements of lower limb comfort were responsive to changes in comfort over time. Within-player differences were not significant for periods 0-8 hrs (P > 0.05) but, generally, significant for time periods 0-24 hrs (P < 0.05), and significant between 24-96 hrs (P < 0.01). The results indicate that the LLCI was reliable when tested for repeated measures and indicated how the index measures lower limb comfort changes over time.

CONCLUSION

This study shows that the use of a lower limb comfort index, when used in a competitive football environment, is both reliable and responsive to change during both a training week and under match day conditions.

Match and training injuries in rugby league: a review of published studies

Rugby league is an international collision sport played by junior, amateur, semiprofessional and professional players. The game requires participants to be involved in physically demanding activities such as running, tackling, passing and sprinting, and musculoskeletal injuries are common. A review of injuries in junior and senior rugby league players published in Sports Medicine in 2004 reported that injuries to the head and neck and muscular injuries were common in senior rugby league players, while fractures and injuries to the knee were common in junior players. This current review updates the descriptive data on rugby league epidemiology and adds information for semiprofessional, amateur and junior levels of participation in both match and training environments using studies identified through searches of PubMed, CINHAL, Ovid, MEDLINE, SCOPUS and SportDiscus databases. This review also discusses the issues surrounding the definitions of injury exposure, injury rate, injury severity and classification of injury site and type for rugby league injuries. Studies on the incidence of injuries in rugby league have suffered from inconsistencies in the injury definitions utilized. Some studies on rugby league injuries have utilized a criterion of a missed matchas an injury definition, total injury incidences or a combination of both time-loss and non-time-loss injuries, while other studies have incorporated a medical treatment injury definition. Efforts to establish a standard definition for rugby league injuries have been difficult, especially as some researchers were not in favour of a definition that was all-encompassing and enabled non-time-loss injuries to be recorded. A definition of rugby league injury has been suggested based on agreement by a group of international researchers. The majority of injuries occur in the match environment, with rates typically increasing as the playing level increases. However, professional level injury rates were reportedly less than semiprofessional participation. Only a few studies have reported training injuries in rugby league, where injury rates were reported to be less than match injuries. Approximately 16-30% of all rugby league injuries have been reported as severe, which places demands upon other team members and, if the player returns to playing too early, places them at an increased risk of further injuries. Early research in rugby league identified that ligament and joint injuries were the common injuries, occurring primarily to the knee. More recently, studies have shown a change in anatomical injury sites at all levels of participation. Although the lower limb was the frequent injury region reported previously, the shoulder has now been reported to be the most common injury site. Changes in injury site and type could be used to prompt further research and development of injury reduction programmes to readdress the issue of injuries that occur as a result of participation in rugby league activities. Further research is warranted at all participation levels of rugby league in both the match and training environments to confirm the strongest risk factors for injury.

Applied physiology of rugby league

Rugby league football is played in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs), with matches played over two 40-minute halves separated by a 10-minute rest interval. Several studies have documented the physiological capacities of rugby league players and the physiological demands of competition, with the physiological capacities of players and the physiological demands of competition increasing as the playing level is increased. However, there is also evidence to suggest that the physiological capacities of players may deteriorate as the season progresses, with reductions in muscular power and maximal aerobic power and increases in skinfold thickness occurring towards the end of the rugby league season, when training loads are lowest and match loads and injury rates are at their highest. Player fatigue and playing intensity have been suggested to contribute to injuries in rugby league, with a recent study reporting a significant correlation (r=0.74) between match injury rates and playing intensity in semi-professional rugby league players. Studies have also reported a higher risk of injury in players with low 10-m and 40-m speed, while players with a low maximal aerobic power had a greater risk of sustaining a contact injury. Furthermore, players who completed <18 weeks of training prior to sustaining their initial injury were at greater risk of sustaining a subsequent injury. These findings provide some explanation for the high incidence of fatigue-related injuries in rugby league players and highlight the importance of speed and endurance training to reduce the incidence of injury in rugby league players. To date, most, but not all, studies have investigated the movement patterns and physiological demands of rugby league competition, with little emphasis on how training activities simulate the competition environment. An understanding of the movement patterns and physiological demands of specific individual positions during training and competition would allow the development of strength and conditioning programmes to meet the specific requirements of these positions. In addition, further research is required to provide information on the repeated effort demands of rugby league. A test that assesses repeated effort performance and employs distances, tackles and intensities specific to rugby league, while also simulating work-to-rest ratios similar to rugby league competition, is warranted.

Incidência de lesões na prática do rúgbi amador no Brasil

Este estudo visou verificar a incidência de lesões traumáticas na prática esportiva do rúgbi amador no Brasil. A amostra constituiu-se de 42 praticantes amadores de duas equipes de rúgbi de São Paulo, do sexo masculino, com idade entre 18 e 30 anos. Foi aplicado a cada jogador um questionário em forma de entrevista para verificar a ocorrência de lesões após cada jogo de rúgbi disputado pela respectiva equipe durante cinco meses de 2006. Lesão foi definida como alguma dor ou dano físico sofrido por um jogador durante o treino e durante ou imediatamente após uma partida de rúgbi. Os dados das respostas dos jogadores foram analisados estatisticamente, com nível de significância estabelecido em p£0,05. A incidência total de lesões foi de 574,16 por 1.000 horas de jogo. Houve predomínio de lesões nos membros inferiores em ambas as equipes. A manobra conhecida como tackle foi a maior causa de lesões. O segundo tempo foi o período do jogo em que a maioria das lesões ocorreu. Atacantes foram mais freqüentemente lesionados quando comparados aos defensores. A incidência de lesões traumáticas no rúgbi amador no Brasil mostrou-se extremamente alta, caracterizando uma importante diferença quando comparada à incidência de lesões em outros estudos feitos em países onde o rúgbi é um esporte mais popular.

For debate: consensus injury definitions in team sports should focus on missed playing time

OBJECTIVE

To compare the most commonly used and proposed injury definitions for surveillance systems in team sports and attempt to assess their suitability for consensus definitions in terms of reliability and functionality.

DATA SOURCES

The PubMed and SportDiscus databases were searched for papers on team sports that discussed consensus definitions or compared various definitions of injury.

DATA SYNTHESIS

A continuum between the most broad "tissue damage" definition and the most narrow "match time loss only" definition was developed.

RESULTS

A "match time loss only" injury definition can be reliably and accurately applied but only captures a small percentage of the total pool of all "tissue damage" injuries. There are some inherent biases in using a match time loss only definition (late season matches, matches with unequal breaks between games), but these are clearly visible. All other definitions improve the volume of data captured but suffer serious theoretical and/or practical flaws with respect to accuracy and reliability. No study using a broad definition has demonstrated good reliability to date (eg, using 2 independent recorders at the same team).

CONCLUSION

A "match time loss only" injury definition is the most accurate and reliable of those commonly used in team sports. Other injury definitions are broader and may be more appropriate for individual team and specific injury studies. However, a match time loss definition is the most accurate and reliable tool for comparing injury rates at different teams and between different seasons within teams. Hence, we recommend this as the basis for the injury definition in a consensus statement.

An analysis of injury rates after the seasonal change in rugby league

OBJECTIVES

To determine whether the increase in the incidence of injury found for the first summer season in which rugby league (RL) was played in the UK was repeated in subsequent summer seasons.

DESIGN

A retrospective and prospective cohort study design.

SETTING AND PARTICIPANTS

Injuries were recorded from all players who took part in 141 games over 3 summer seasons (1997 to 1999) for 1 professional team. These were compared against rates from previously collected data for 3 earlier winter and 1 summer season.

ASSESSMENT OF RISK FACTORS

For each injury it was recorded in which season it occurred; how many games or training sessions, if any, were subsequently missed; the type, site and severity of injury.

MAIN OUTCOME MEASURES

Injuries were reported as rate per 1000 hours, also broken down into severity according to the number of games missed and whether subsequent training sessions were missed.

RESULTS

A sustained increase in injury incidence has been found comparing summer RL over RL played in the winter. There was an increase in injury rates for all sites and types, but not all reached significance.

CONCLUSIONS

Data collected over 6 seasons indicate a higher risk of sustaining an injury playing summer RL, but the cause may be related to a combination of factors. These may include the ground or weather conditions associated with summer rugby, player characteristics or changes in the game itself and future research needs to investigate these further.

Incidence of injuries in the New Zealand national rugby league sevens tournament

This study investigated the incidence, site, nature and causes of injuries sustained in the New Zealand national rugby league sevens tournament. A total of 218 players competing in 47 matches were studied. All injuries sustained within the tournament were prospectively recorded. Injuries were categorised according to the severity assessment at the time of the injury. Information obtained included the time, site, nature and cause of the injury. The incidence of injury was 497.6 per 1000 playing hours. More than 40% (216.1 per 1000) of injuries sustained occurred within the lower limbs. The shoulder was the single most commonly injured site (78.6 per 1000). Sprains were the most common injury type (189.9 per 1000). The ball-carrier sustained significantly more (p<0.05) injuries than the tackling player (216.1 per 1000 [43.4%] versus 117.8 per 1000 [23.7%]). There were significantly more injuries on the first day of competition than on the second day of competition (600.4 per 1000 [76.3%] versus 320.9 per 1000 [23.7%]). The findings of higher injury rates on the first day of competition and during the second period of matches suggest that playing intensity and player fatigue may contribute to injuries in rugby league sevens.

Injury in rugby league

It was the purpose of this review to document the range, incidence, location and mechanism of injury occurring in the sport of rugby league. Rugby league is a collision sport played in Europe and the Pacific regions including Australia. The sport is well established and has competitions ranging from junior to elite professional. Due to the contact nature of the game, injury is relatively common. The most common injuries are musculotendinous in nature and afflict the lower limb more frequently than elsewhere. Despite the high incidence of minor (sprains/strains) to moderate musculoskeletal injury (fracture, ligament and joint injury) and minor head injuries such as lacerations, nasal fractures and concussions, rare more serious spinal cord and other injuries causing death have also been recorded. The literature on rugby league injury is small but growing and suffers from a lack of consistent definition of what an injury is, thereby causing variability in the nature and incidence/prevalence of injury. Information is lacking on the injury profiles of different age groups. Importantly, there has been little attempt to establish a coordinated injury surveillance program in rugby league in the junior or professional levels. The implementation of such programs would require a universal definition of injury and a focus on important events and competitions. The implementation could provide important information in the identification and prevention of risk factors for injury.

Science of rugby league football: A review

The purpose of this paper is to provide a comprehensive review of the science of rugby league football at all levels of competition (i.e. junior, amateur, semi-professional, professional), with special reference to all discipline-specific scientific research performed in rugby league (i.e. physiological, psychological, injury epidemiology, strength and conditioning, performance analysis). Rugby league football is played at junior and senior levels in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs). The game is played over two 30 - 40 min halves (depending on the standard of competition) separated by a 10 min rest interval. Several studies have documented the physiological capacities and injury rates of rugby league players. More recently, studies have investigated the physiological demands of competition. Interestingly, the physiological capacities of players, the incidence of injury and the physiological demands of competition all increase as the playing standard is increased. Mean blood lactate concentrations of 5.2, 7.2 and 9.1 mmol . l(-1) have been reported during competition for amateur, semi-professional and professional rugby league players respectively. Mean heart rates of 152 beats . min(-1) (78% of maximal heart rate), 166 beats . min(-1) (84% of maximal heart rate) and 172 beats . min(-1) (93% of maximal heart rate) have been recorded for amateur, semi-professional and junior elite rugby league players respectively. Skill-based conditioning games have been used to develop the skill and fitness of rugby league players, with mean heart rate and blood lactate responses during these activities almost identical to those obtained during competition. In addition, recent studies have shown that most training injuries are sustained in traditional conditioning activities that involve no skill component (i.e. running without the ball), whereas the incidence of injuries while participating in skill-based conditioning games is low. Collaborative research among the various sport science disciplines is required to identify strategies to reduce the incidence of injury and enhance the performance of rugby league players. An understanding of the movement patterns and physiological demands of different positions at all standards of competition would allow the development of strength and conditioning programmes to meet the precise requirements of these positions. Finally, studies investigating the impact of improvements in physiological capacities (including the effect of different strength and conditioning programmes) on rugby league playing performance are warranted.

Effect of incorporating low intensity exercise into the recovery period after a rugby match

BACKGROUND

The psychological and physiological condition of athletes affect both their performance in competitions and their health. Rugby is an intense sport which appears to impose psychological and physiological stress on players. However, there have been few studies of the most appropriate resting techniques to deliver effective recovery from a match.

OBJECTIVES

To compare the difference in recovery after a match using resting techniques with or without exercise.

METHODS

Fifteen Japanese college rugby football players were studied. Seven performed only normal daily activities and eight performed additional low intensity exercise during the post-match rest period. Players were examined just before and immediately after the match and one and two days after the match. Blood biochemistry and two neutrophil functions, phagocytic activity and oxidative burst, were measured to assess physiological condition, and the profile of mood states (POMS) scores were examined to evaluate psychological condition.

RESULTS

Immediately after the match, muscle damage, decreases in neutrophil functions, and mental fatigue were observed in both groups. Muscle damage and neutrophil functions recovered with time almost equally in the two groups, but the POMS scores were significantly decreased only in subjects in the low intensity exercise group.

CONCLUSIONS

Rugby matches impose both physiological and psychological stress on players. The addition of low intensity exercise to the rest period did not adversely affect physiological recovery and had a significantly beneficial effect on psychological recovery by enhancing relaxation.

Does generalised ligamentous laxity increase seasonal incidence of injuries in male first division club rugby players?

OBJECTIVES

To investigate if ligamentous laxity increases seasonal incidence of injury in male first division club rugby players, and to determine if strength protects against injury in hypermobile and tight players.

METHODS

Fifty one male first division club rugby players were examined for ligamentous laxity using the Beighton-Horan assessment and graded with an overall laxity score ranging from 0 (tight) to 9 (hyperlax). Each participant was classified into a group determined by their laxity score: tight (0-3), hypermobile (4-6), or excessively hypermobile (7-9). The incidence of joint injuries was recorded prospectively throughout the rugby season and correlated with laxity score. Differences between the groups were analysed.

RESULTS

The overall prevalence of generalised joint hypermobility was 24% (12/51). The incidence of injuries was significantly higher in hypermobile (116.7 per 1000 hours) than tight (43.6 per 1000 hours) players (p = 0.034). There were no significant differences in peak strength between the hypermobile and tight groups.

CONCLUSIONS

The laxity of the players may explain the differences in injury rates between these groups. Peak strength does not protect the hypermobile joint against injury. It appears that hypermobility may cause an increase in the injury rate of male first division club rugby players.

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.

Reductions in pre-season training loads reduce training injury rates in rugby league players

OBJECTIVES

To investigate if reductions in pre-season training loads reduced the incidence of training injuries in rugby league players, and to determine if the reductions in training loads compromised the improvements in physical fitness obtained during the pre-season preparation period.

METHODS

A total of 220 sub-elite rugby league players participated in this 3 year prospective study. Players underwent measurements of speed, muscular power, and maximal aerobic power before and after three 4 month (December to March) pre-season preparation periods (2001-2003). A periodised skills and conditioning program was implemented, with training loads progressively increased in the general preparatory phase of the season (December to February) and reduced slightly in March in preparation for the competitive phase of the season. Training loads were calculated by multiplying the training session intensity by the duration of the training session. Following the initial season (2001), training loads were reduced through reductions in training duration (2002) and training intensity (2003). The incidence of injury was prospectively recorded over the three pre-season periods.

RESULTS

The training loads for the 2002 and 2003 pre-season periods were significantly lower (p<0.001) than those in 2001. The incidence of injury was significantly higher in the 2001 pre-season than the 2002 and 2003 pre-season periods. The increases in maximal aerobic power progressively improved across the three seasons with a 62-88% probability that the 2002 and 2003 pre-season improvements in maximal aerobic power were of greater physiological significance than the 2001 pre-season improvements in maximal aerobic power.

CONCLUSIONS

These findings demonstrate that reductions in pre-season training loads reduce training injury rates in rugby league players and result in greater improvements in maximal aerobic power.

Influence of injuries on team playing performance in Rugby League

All injuries have the potential to impact on individual sporting performance and as a result may influence team playing performance. However, the influence of injuries on team playing performance is unclear. The purpose of this study was to investigate the influence of injuries on team playing performance in Rugby League. All injuries sustained by one semi-professional first grade Rugby League team were prospectively studied during the 2001 competitive season. An injury was defined as any pain or disability suffered by a player during a match. Team playing performance for each match was estimated from the metres gained while in possession of the football, points scored, points conceded, the final points differential and the completion rates of attacking sets of tackles. A total of 294 injuries were recorded. The average metres gained for all matches was 1471 (95% confidence interval, CI: 1383 to 1559) m. The team averaged 42 (95% CI: 32 to 51) points in attack each match and conceded an average of 15 (95% CI: 9 to 21) points in defence. The average completion rate for the season was 65.3 (95% CI: 60.6 to 70.0)%. There was no significant association (p>0.05) between the number of injuries sustained and team-playing performance. These findings suggest that injuries have minimal impact on team-playing performance in Rugby League. Further research on a larger sample (including winning and losing teams), is required to provide a detailed analysis of the influence of injuries on team playing performance in Rugby League.

Risk factors for sports injuries--a methodological approach

The methodology for studies designed to investigate potential risk factors for sports injury is reviewed, using the case of hamstring strains as an example. Injuries result from a complex interaction of multiple risk factors and events. Therefore, a multivariate statistical approach should be used. In addition, the sample size of the study needs to be considered carefully. Sample size mainly depends on the expected effect of the risk factor on injury risk, and to detect moderate to strong associations 20-50 injury cases are needed, whereas small to moderate associations would need about 200 injured subjects. Studies published to date on the risk factors for hamstring strains have methodological limitations, and are too small to detect small to moderate associations.

The use of ice in the treatment of acute soft-tissue injury: a systematic review of randomized controlled trials

BACKGROUND

There are wide variations in the clinical use of cryotherapy, and guidelines continue to be made on an empirical basis.

STUDY DESIGN

Systematic review assessing the evidence base for cryotherapy in the treatment of acute soft-tissue injuries.

METHODS

A computerized literature search, citation tracking, and hand searching were carried out up to April 2002. Eligible studies were randomized-controlled trials describing human subjects recovering from acute soft-tissue injuries and employing a cryotherapy treatment in isolation or in combination with other therapies. Two reviewers independently assessed the validity of included trials using the Physiotherapy Evidence Database (PEDro) scale.

RESULTS

Twenty-two trials met the inclusion criteria. There was a mean PEDro score of 3.4 out of of 10. There was marginal evidence that ice plus exercise is most effective, after ankle sprain and postsurgery. There was little evidence to suggest that the addition of ice to compression had any significant effect, but this was restricted to treatment of hospital inpatients. Few studies assessed the effectiveness of ice on closed soft-tissue injury, and there was no evidence of an optimal mode or duration of treatment.

CONCLUSION

Many more high-quality trials are needed to provide evidence-based guidelines in the treatment of acute soft-tissue injuries.

Is there a relationship between ground and climatic conditions and injuries in football?

Most soccer, rugby union, rugby league, American football, Australian football and Gaelic football competitions over the world are played on natural grass over seasons that commence in the early autumn (fall) and extend through winter. Injury surveillance in these competitions has usually reported high rates of injury to the lower limb and an increased incidence of injuries early in the season. This 'early-season' bias has not usually been reported in summer football competitions, or in sports played indoors, such as basketball. Although easily compared rates have not often been published there has also been a reported trend towards a greater injury incidence in football played in warmer and/or drier conditions. Injury incidence in American football played on artificial turf has often been reported to be higher than in games played on natural grass. This review concludes that the most plausible explanation for all of these reported findings involves variations in playing surface characteristics. Shoe-surface traction for the average player is the specific relevant variable that is most likely to correlate with injury incidence in a given game of football. Shoe-surface traction will usually have a positive correlation with ground hardness, dryness, grass cover and root density, length of cleats on player boots and relative speed of the game. It is possible that measures to reduce shoe-surface traction, such as, ground watering and softening, play during the winter months, use of natural grasses such as perennial ryegrass (Lolium perenne L.) and player use of boots with shorter cleats, would all reduce the risk of football injuries. The most pronounced protective effect is likely to be on injuries to the lower limb of a noncontact nature, including anterior cruciate ligament injuries. Intervention studies should be performed, both using randomised and historical controls.