Cervical spine kinematics during machine-based and live scrummaging

The aim of this study was to compare cervical spine kinematics in rugby union front row players during machine-based and “live” scrummaging. Cervical spine kinematics was measured via electromagnetic tracking of sensors attached to the head and thorax. Joint angles were extracted from each trial at two time points (“bind” prior to engagement and instant of impact) for comparison between scrummaging conditions. The effect of scrummaging condition on kinematics was evaluated using a mixed effects model and estimations were based on a Bayesian framework. With differences ranging from 38° to 50°, the results show that the cervical spine is consistently more flexed when scrummaging against opponents than against a scrum machine. In contrast, there are little differences in the excursion of lateral-flexion (range 5–8°) and axial rotation (7°) between the two conditions. The findings from this study provide clear information on motion patterns in different scrum formations, and suggest that the current design of scrum machines may not promote the same pattern of movement that occurs in live scrums. The results highlight that findings from previous studies that have investigated kinematics during machine-based scrummaging may not be generalisable to a competitive scrummaging context.     

Playing surface and UK professional rugby union injury risk

Artificial rugby union playing surface installation is increasing. This prospective cohort study aimed to examine the effect of playing surface on match injury types within 157 players of two UK professional rugby union clubs playing 209 matches (96 on artificial surfaces and 113 on grass) over three seasons. There was no difference in overall injury risk between the two playing surfaces with injury incidence on artificial 80.2 (CI 69.9–91.7) and on grass 81.9 per 1000 match-hours (CI 72.2–92.5), with an incidence rate ratio (RR) of 0.98 (CI 0.82–1.17). There was a higher rate of concussion (RR 0.52, CI 0.34 – 0.78) and chest injuries on grass (RR 0.26 CI 0.07, 0.95), and a higher rate of thigh haematoma (RR 2.25, CI 1.05–4.82) foot injuries (RR 4.12, CI 1.10, 15.40) and injury to players being tackled (RR 1.46, CI 1.00, 2.15) on artificial. Whilst there was no higher injury risk for matches played on artificial versus natural grass surfaces, the higher incidence of concussion and chest injury on grass, and the higher rate of foot injuries on artificial surfaces may be related to tackle and footwear-to-surface interface factors.     

Risk of injury associated with rugby union played on artificial turf

Abstract

The aim of this study was to compare the incidence, nature, and cause of injuries sustained in rugby union played on artificial turf and grass. The study comprised a two-season investigation of match injuries sustained by six teams competing in Hong Kong's Division 1 and training injuries sustained by two teams in the English Premiership. Injury definitions and recording procedures were compliant with the international consensus statement on epidemiological studies of injuries in rugby union. There were no significant differences in the overall incidence (rate ratio = 1.42; P = 0.134) or severity (P = 0.620) of match injuries sustained on the two surfaces. The lower limb and joint (non-bone)/ligament injuries were the most common location and type of match injury on both surfaces; the incidence of anterior cruciate ligament injuries was nearly four times higher on artificial turf than grass but the difference was not statistically significant (rate ratio = 3.82; P = 0.222). There were no significant differences in the overall incidence (rate ratio = 1.36; P = 0.204) or severity (P = 0.302) of training injuries sustained on artificial turf and grass. The lower limb and muscle/tendon injuries were the most common location and type of training injury on both surfaces. The results indicate that the overall risks of injury on artificial turf are not significantly different from those experienced on grass; however, the difference in the incidence of anterior cruciate ligament injuries on the two surfaces is worthy of further study.     

The effects of a rugby playing season on cervical range of motion

Abstract

Rugby players have a reduced active cervical range of motion (ACROM) mid-season compared with age-matched controls. This is most evident in rugby forwards, who have ACROM similar to patients with acute whiplash. This study aims to show if the change in ACROM over an entire rugby season (pre-, mid-, and end of season) shows a pattern of decline. A cross-sectional study of 22 rugby players (11 backs aged 24.9 ± 1.3 years; 11 forwards aged 24.5 ± 1.1 years) from elite English Premiership clubs had their cervical range of motion measured for flexion, extension, left and right side flexion, plus left and right rotation with a cervical range of motion device. The percentage change between start to mid-season, mid- to end of season, and start to end of season were calculated. Group means were compared for absolute ACROM (degrees) and percentage change over the season. The percentage change indicated a decrease in ACROM over the rugby playing season, with most of the decrement occurring in the second half of the season. Most of the relative change was observed in right lateral flexion, while rotation did not change significantly. In conclusion, ACROM declines throughout the playing season, which requires attention in terms of training and rehabilitation.     

The effect of ball-carrying technique and experience on sprinting in rugby union

Abstract

There are several ways of carrying the ball in rugby union, which could influence the speed at which a player can run. We assessed 52 rugby players (34 males, 18 females) during a maximum sprint over 30 m without the ball, with the ball under one arm, and with the ball in both hands. Timing gates were used to measure time over the initial 10 m and the last 20 m. It has previously been reported (Grant et al., 2003 Grant, S. J., Oommen, G., McColl, G., Taylor, J., Watkins, L.Friel, N. 2003. The effects of ball carrying method on sprint speed in rugby union football players. Journal of Sports Sciences, 21: 1009–1015. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) that running with the ball produces a slower sprinting speed than running without the ball. We hypothesized that the decrease in speed caused by carrying the ball would become less marked with the experience of the player. The male and female players were each divided into two groups: a “beginner” group that consisted of players in their first or second season and an “experienced” group that was composed of players who had played for more than two seasons. A 2 × 3 mixed-model analysis of variance was used to identify differences (P < 0.01) between the beginner and experienced groups in the three sprinting conditions. The times for the males for the first 10 m sprints without the ball, with the ball under one arm, and with the ball in both hands were 1.87 ± 0.08 s, 1.87 ± 0.08 s, and 1.91 ± 0.1 s for the beginners, and 1.87 ± 0.1, 1.88 ± 0.1 and 1.88 ± 0.12 for the more experienced players respectively. The times for the females for the first 10 m without the ball, with the ball under one arm, and with the ball in both hands were 2.13 ± 0.16 s, 2.19 ± 0.17 s, and 2.20 ± 0.16 s for the beginners, and 2.03 ± 0.12 s, 2.03 ± 0.09 s, and 2.04 ± 0.1 s for the more experienced players respectively. For the last 20 m of the 30-m sprint, there were differences between the different sprint conditions (P < 0.001) but no differences that were attributable to experience (P = 0.297). The times for the males over the last 20 m without the ball, with the ball under one arm, and with the ball in both hands were 2.58 ± 0.19 s, 2.61 ± 0.12 s, and 2.65 ± 0.12 s for the beginners, and 2.59 ± 0.12, 2.62 ± 0.23, and 2.65 ± 0.18 s for the more experienced players respectively. The times for the females over the last 20 m without the ball, with the ball under one arm, and with the ball in both hands were 3.25 ± 0.38 s, 3.35 ± 0.42 s, and 3.40 ± 0.46 s for the beginners, and 3.04 ± 0.32 s, 3.06 ± 0.22 s, and 3.13 ± 0.27 s for the more experienced players respectively. No gender-specific differences were detected. The results of this study suggest that practising sprints while carrying a ball benefits the early phase of sprinting while carrying the ball.     

Kinetic and kinematic analysis of stamping impacts during simulated rucking in rugby union

Laceration injuries account for up to 23% of injuries in rugby union. They are frequently caused by studded footwear as a result of a player stamping onto another player during the ruck. Little is known about the kinetics and kinematics of rugby stamping impacts; current test methods assessing laceration injury risk of stud designs therefore lack informed test parameters. In this study, twelve participants stamped on an anthropomorphic test device in a one-on-one simulated ruck setting. Velocity and inclination angle of the foot prior to impact was determined from high-speed video footage. Total stamping force and individual stud force were measured using pressure sensors. Mean foot inbound velocity was 4.3 m ? s^?1 (range 2.1–6.3 m ? s^?1). Mean peak total force was 1246 N and mean peak stud force was 214 N. The total mean effective mass during stamping was 6.6 kg (range: 1.6–13.5 kg) and stud effective mass was 1.2 kg (range: 0.5–2.9 kg). These results provide representative test parameters for mechanical test devices designed to assess laceration injury risk of studded footwear for rugby union.     

A 3D kinematic analysis of breathing patterns in competitive swimmers

Abstract

The purpose of this paper was to understand which differences long-term swimming training can cause on trunk mechanics during breathing and how these differences are related to the years of swimming training. The variations and coordination among trunk compartments were considered as target movement patterns. Video-based plethysmography was utilised for data acquisition and pre-processing. A group of swimmers, who followed a long-term intensive swimming training previously to this study, was compared with a non-swimmer control group. The participants of both groups performed quiet breathing and vital capacity tests. From the compartmental volumes associated with each breathing curves, the relative amplitude and cross-correlation among these volumetric time-varying signals were calculated, in order to analyse the relative partial volume variation and the coordination among trunk compartments involved in respiration. The results of a Mixed-ANOVA test (P ≤ 0.05) revealed higher coefficient of variation (P < 0.001) and correlations among trunk compartments in the swimmers group when vital capacity was performed. Significant linear regression was found between the years of swim training and the coefficients of variation and correlation. The results suggest that after long periods of intensive swim training, athletes might develop specific breathing patterns featuring higher volume variations in the abdominal region and more coordination among compartments involved in forced respiratory tasks such as vital capacity.     

Severity and cost of injuries in amateur rugby league: A case study

The aim of this study was to determine the severity and cost of injuries in amateur rugby league. Seventy-two amateur rugby league players aged 28 - 6 years (mean - s) were surveyed at the end of a competitive season. An injury was defined as any pain, disability or injury that occurred as a result of a competition game which caused the player to miss subsequent games. Injuries were classified as minor (one game missed), moderate (two to four games missed) and major (five or more games missed). Of the 72 questionnaires distributed, 34 (47.2%) were returned. Twenty respondents (58.8%) sustained an injury that resulted in one or more missed games. Eight injured players (40.0%) missed five or more training sessions, six of whom (30%) missed five or more games as a result of the injury. The median time lost from employment or study for all injured players was 2 days per playing injury. The respective median direct (e.g. medical expenses) and indirect (e.g. wages lost) costs associated with the injury were 28.29 and 77.04 per playing injury. A considerable proportion of injuries sustained in the present sample of amateur rugby league players were major, resulting in a loss of training, playing and employment or study time, and these injuries were associated with significant direct and indirect economic costs. Further studies, using a larger sample, would complement the present findings in establishing the severity and cost of amateur rugby league injuries. These results suggest that prevention strategies are required to reduce the severity and cost of amateur rugby league injuries.     

Developing rugby in interwar Romania: the case of provincial cities and towns

ABSTRACT

The growth in interest for the historical analysis of sports in Romania has lately been focusing more on general issues or on the major sports (for instance, football). As a result, despite its early apparition in Romania (1913), and its development in comparison with other Central European countries, Rugby has been completely ignored. The aim of this article is to analyze the ways in which the development of the sport was attempted in Interwar Romania. This is a case study focused on the efforts to popularise rugby in the towns outside of Bucharest, the capital of Romania. These efforts were administered in a combination of two ways: the propaganda rugby matches in different cities and the organisation of rugby teams in provincial cities and were based more on individual actions rather than the coordinated action of the Romanian Rugby management of those times. The conclusions emphasise the minor success of this initiative, contextualising it in the rugby and sports’ condition in Interwar Romania.     

对我国部分优秀女子背越式跳高运动员最后4步助跑技术的运动学分析

采用高速摄影法对我国4名优秀女子跳高运动员的最后4步助跑技术进行三维运动学分析。结果表明：我国运动员身体重心水平速度偏低,助跑角度合理,助跑曲线符合跳高技术要求,2名研究对象内倾角在合理范围之内,顾碧威倒数第4、3步内倾角偏大,沈勤莉最后1步内倾角偏大。     

Acute effects of two different tennis sessions on dorsal and lumbar spine of adult players

The aim of the study was to evaluate the dorsal and lumbar spine of expert and recreational tennis players before (pre) and after (post) two different training sessions. The sample consisted of 17 male tennis players, nine expert and eight recreational males (age 21.2 ± 1.6 years). We assessed the back surface by rasterstereography pre and post two different training sessions both lasting 1.5 h: a standard training and a specific over-shoulder shots training session, respectively. Lordotic and kyphotic angle, length, imbalance, inclination for trunk, pelvic torsion, left and right lateral deviation and surface rotation were measured. Tennis expertise (expert versus recreational) significantly affected the surface rotation and right lateral deviation (P < 0.05). Trunk length was affected by intervention (pre versus post) (P < 0.05). Left lateral deviation differed both for type of session (session 1 versus session 2) and intervention (P < 0.001, P < 0.05). Expert tennis players had higher values on surface rotation and right lateral deviation, around or just above physiological values (0–5° and 0–5 mm, respectively). Type of session significantly affected left lateral deviation, indicating that over-shoulder shots lead to a higher stress for the spine; the workload produced by both single sessions led to a shortening effect on trunk length. A single training session can induce acute modifications in some parameters of dorsal and lumbar spine of players.     

Changes in the stature,body mass and age of English professional rugby players: A 10-year review

Abstract

The aim of the study was to evaluate changes in the stature, body mass, age and number of players by playing position in the first team squads of English Premiership rugby union teams from 2002 to 2011. Medical personnel at each club reported the individual data for every first team squad player. The average annual number of players included in the study was 485.2 players per season (standard deviation: 58.0). The mean stature of players in all positions increased in the period 2002 to 2011 but statistically significant trends (P < 0.01) were only observed at fly half and prop. While the mean body mass of players increased in most positions only fly half and back row players showed statistically significant (P < 0.01) upward trends. Apart from second row forwards, the average age of players in all positions decreased but this trend was only significant (P < 0.01) at prop. The numbers of registered players in every position increased but these trends were only significant (P < 0.01) at prop. English Premiership professional rugby players are generally getting taller, heavier and younger but statistically significant changes were limited to fly halves (taller and heavier), props (taller and younger) and back row forwards (heavier).     

基于SWOT分析法下中国橄榄球运动发展现状研究

运用SWOT分析法等对现阶段中国橄榄球运动的发展现状及其内部优势与不足、外部机遇与挑战进行分析研究。结果表明：橄榄球运动在我国大陆地区发展进程较慢,其主要原因包括该项目起步较晚、群众基础较差、硬件设施资源不足、运动文化冲突等因素,但该项目发展上升空间较大。     

A three-dimensional kinematic analysis of the long jump take-off

The long jump has been widely studied in recent years. Two models exist in the literature which define the relationship between selected variables that affect performance. Both models suggest that the critical phase of the long jump event is the touch-down to take-off phase, as it is in this phase that the necessary vertical velocity is generated. Many three dimensional studies of the long jump exist, but the only studies to have reported detailed data on this phase were two-dimensional in nature. In these, the poor relationships obtained between key variables and performance led to the suggestion that there may be some relevant information in data in the third dimension. The aims of this study were to conduct a three-dimensional analysis of the touch-down to take-off phase in the long jump and to explore the interrelationships between key variables. Fourteen male long jumpers were filmed using three-dimensional methods during the finals of the 1994 (n = 8) and 1995 (n = 6) UK National Championships. Various key variables for the long jump were used in a series of correlational and multiple regression analyses. The relationships between key variables when correlated directly one-to-one were generally poor. However, when analysed using a multiple regression approach, a series of variables was identified which supported the general principles outlined in the two models. These variables could be interpreted in terms of speed, technique and strength. We concluded that in the long jump, variables that are important to performance are interdependent and can only be identified by using appropriate statistical techniques. This has implications for a better understanding of the long jump event and it is likely that this finding can be generalized to other technical sports skills.     

对我国部分优秀男子大学生跳远最后2步助跑和起跳技术的运动学研究

通过对我国8名优秀男子大学生跳远运动员最后2步助跑和起跳技术影片的解析,发现我国大学生运动员重心水平速度在助跑倒3步中就开始下降,最后2步中水平速度大幅度下降,不能保持已获得的水平速度进入起跳.起跳过程中最大缓冲膝角小,缓冲阶段相对较长,重心移动扇面角较大,起跳速度慢,通过起跳获得的重心垂直分速度较低和腾起角较小是影响成绩的重要因素.     

The effect of rowing to exhaustion on frontal plane angular changes in the lumbar spine of elite rowers

Abstract

Lumbar spine injury is common in rowers and examination of spinal kinematics may improve the understanding of this injury's prevalence. This study aimed to examine the range of frontal plane angular displacement (AD) in the lumbar spine at L3 during ergometer rowing and to investigate the effect of exhaustion on lumbar kinematics. Twelve elite male rowers completed an incremental test on a Concept 2 ergometer. Lumbar AD at L3 was measured continually throughout the rowing trial using a Spectrotilt Inclinometer and blood lactate was sampled at 3-minute intervals. AD of between 4.7° and 8.8° was recorded at L3. There was a significant increase in AD between the first and last stage of the test (mean increase = 4.1 ± 1.94°, 95% Confidence Interval [CI], 2.9 to 5.3°, t = 7.36, P = 0.000014). Incremental rise in AD was associated with an incremental rise in blood lactate but regression confirmed that only stroke rate was a significant predictor for increasing angle. Thus there is a statistically significant increase in frontal plane AD at L3 over the course of an incremental exercise test although it cannot be confirmed if this is as a result of exhaustion. The values of AD confirm that there is motion in the frontal plane in ergometer rowing.     

近5届乒乓球世界大赛奖牌分布与获奖运动员打法类型分析

采用文献资料法、专家访谈法、数理统计法等,对近5届世界乒乓球大赛各国获奖项目进行统计,并对获奖运动员的打法类型和发展趋势进行分析,结果表明:世界乒坛格局进入"亚洲轴心"的时代;运动员以进攻型打法为主流,弧圈结合快攻型打法占主导地位;女子男性化打法的发展存在较大空间。     

Effects of emphasising opposition and cooperation on collective movement behaviour during football small-sided games

ABSTRACT

Optimizing collective behaviour helps to increase performance in mutual tasks. In team sports settings, the small-sided games (SSG) have been used as key context tools to stress out the players’ awareness about their in-game required behaviours. Research has mostly described these behaviours when confronting teams have the same number of players, disregarding the frequent situations of low and high inequality. This study compared the players’ positioning dynamics when manipulating the number of opponents and teammates during professional and amateur football SSG. The participants played 4v3, 4v5 and 4v7 games, where one team was confronted with low-superiority, low- and high-inferiority situations, and their opponents with low-, medium- and high-cooperation situations. Positional data were used to calculate effective playing space and distances from each player to team centroid, opponent team centroid and nearest opponent. Outcomes suggested that increasing the number of opponents in professional teams resulted in moderate/large decrease in approximate entropy (ApEn) values to both distance to team and opponent team centroid (i.e., the variables present higher regularity/predictability pattern). In low-cooperation game scenarios, the ApEn in amateurs’ tactical variables presented a moderate/large increase. The professional teams presented an increase in the distance to nearest opponent with the increase of the cooperation level. Increasing the number of opponents was effective to overemphasise the need to use local information in the positioning decision-making process from professionals. Conversely, amateur still rely on external informational feedback. Increasing the cooperation promoted more regularity in spatial organisation in amateurs and emphasise their players’ local perceptions.     

男网不同打法类型选手比赛中各阶段得分特征分析

采用文献资料法、录像观察法、数理统计法等,对不同打法类型的世界优秀男子网球选手在比赛中的不同阶段的得分特征进行分析,找出各打法类型运动员在比赛中的得分特点,分析得分的主要战术特征,旨在为我国网球运动员打法类型的培养及训练提供参考。