The reliability of the scapular posture and scapular dyskinesis tests in rugby union players.

Background: Impact forces during rugby can contribute to scapula dysfunction and shoulder pain. Reliable assessment of static and dynamic scapula position is paramount in managing athletes with, and those at risk of developing, shoulder pain. Objectives: To determine the reliability of static scapular posture (SP), clavicular tilt angle (CTA) and the scapular dyskinesis (SD) assessments by expert and student therapists. Methods: The study design was an inter-rater and intra-rater reliability study in male university level rugby union players. Four sport rehabilitation students and one experienced physiotherapist evaluated the position of the scapular and clavicle of male university-level rugby union players (inter-rater participants: session 1: n=17, session 2: n=12 and session 3: n=16; (intra-rater participants: n = 12). Participants attended 3 testing sessions, each 1 week apart. Scapular orientation and motion were assessed in five planes of movement and using the Scapular Dyskinesis Test (SDT) respectively. The inter-rater analysis included all participants from each session, while in the intra-rater analysis included only the 12 participants who attended all three testing sessions. Results: Kappa coefficient values and percentage agreement ratings for students compared to the experienced therapist were: SP=poor to fair (-0.01 to 0.33), (27% - 94%); SDT=slight (0.16; 41%); CTA=fair (0.21; 59%). Test-retest (intra-rater) agreement was fair to moderate (0.22 - 0.44; 69% - 95%), slight (0.12; 47%), and fair (0.39; 77%) for the SP, SDT, and CTA, respectively. Conclusion: Static and dynamic evaluation of the shoulder by students and an experienced therapist has poor to moderate reliability and should not be used to make clinical decisions based on observation alone.

Association of the Functional Movement Screen™ with match-injury burden in men's community rugby union.

Evidence supporting use of the Functional Movement Screen (FMSTM) to identify athletes' risk of injury is equivocal. Furthermore, few studies account for exposure to risk during analysis. This study investigated the association of FMSTM performance with incidence and burden of match-injuries in adult community rugby players. 277 players performed the FMSTM during pre-season and in-season time-loss injuries and match exposure were recorded. The associations between FMSTM score, pain, and movement-pattern asymmetries with match-injury incidence (≥8-days time-loss/1000hours), severe match-injury incidence (>28-days time-loss/1000hours), and match-injury burden (total time-loss days/1000hours for ≥8-days match-injuries) were analysed using Poisson regression. Multivariate analysis indicated players with pain and movement-pattern asymmetry during pre-season had 2.9 times higher severe match-injury incidence (RR, 90%CI = 2.9, 0.9-9.7) and match-injury burden (RR, 90%CI = 2.9, 1.3-6.6). Players with a typically low FMSTM score (mean - 1SD threshold) were estimated to have a 50% greater match-injury burden compared to players with a typically high FMSTM score (mean + 1SD threshold) as match-injury burden was 10% lower per 1-unit increase in FMSTM score. As the strongest association with injury outcome was found for players with pain and asymmetry, when implementing the FMSTM it is advisable to prioritise these players for further assessment and subsequent treatment.

High acute:chronic workloads are associated with injury in England & Wales Cricket Board Development Programme fast bowlers.

OBJECTIVES: The objectives of this study were to explore the relationship between acute (1 week) and chronic (4-week average) bowling workloads and injury risk in National Development Programme fast bowlers, and to investigate individual differences in the relationship between acute:chronic workloads and injury. DESIGN: Prospective cohort study. METHODS: Bowling workloads and injury data were collected prospectively for 29 male fast bowlers (age range 15-18) on a National Programme over two years. Workload variables were calculated and the likelihood of injury and individual effects were explored using a generalised linear mixed effects model and magnitude-based inferences. RESULTS: Acute:chronic workloads of 109-142% (relative risk [RR]: 1.46, 90% CI: 0.93-2.29; likely harmful), and ≥142% (RR: 1.66, 90% CI: 1.06-2.59, likely harmful) were associated with a substantial increase in injury risk compared with the reference quartile (<87%). A high chronic workload (>83 balls) substantially attenuated the influence of a high (>108%) acute:chronic workload ratio on injury risk (RR: 0.35, 90% CI: 0.17-0.74). Significant individual differences in the acute:chronic workload-injury relationship were evident. CONCLUSIONS: The present study provides further evidence of the association between 'spikes' in workload and injury risk, but also demonstrates that this relationship is individual-specific and dependent on the level of chronic workload. Support teams for fast bowlers should monitor bowling workloads to avoid rapid fluctuations but should also base decisions on individualised data.

The efficacy of a movement control exercise programme to reduce injuries in youth rugby: a cluster randomised controlled trial.

BACKGROUND: Injuries to youth rugby players have become an increasingly prominent health concern, highlighting the importance of developing and implementing appropriate preventive strategies. A growing body of evidence from other youth sports has demonstrated the efficacy of targeted exercise regimens to reduce injury risk. However, studies have yet to investigate the effect of such interventions in youth contact sport populations like rugby union. OBJECTIVE: To determine the efficacy of an evidence-based movement control exercise programme compared with a sham exercise programme to reduce injury risk in youth rugby players. Exercise programme compliance between trial arms and the effect of coach attitudes on compliance will also be evaluated. SETTING: School rugby coaches in England will be the target of the researcher intervention, with the effects of the injury prevention programmes being measured in male youth players aged 14-18 years in school rugby programmes over the 2015-2016 school winter term. METHODS: A cluster-randomised controlled trial with schools randomly allocated to either a movement control exercise programme or a sham exercise programme, both of which are coach-delivered. Injury measures will derive from field-based injury surveillance, with match and training exposure and compliance recorded. A questionnaire will be used to evaluate coach attitudes, knowledge, beliefs and behaviours both prior to and on the conclusion of the study period. OUTCOME MEASURES: Summary injury measures (incidence, severity and burden) will be compared between trial arms, as will the influence of coach attitudes on compliance and injury burden. Additionally, changes in these outcomes through using the exercise programmes will be evaluated. TRIAL REGISTRATION NUMBER: ISRTCNN13422001.

Shoulder Injuries in English Community Rugby Union.

The aim of this study was to describe the incidence, severity and type of shoulder injuries resulting from match play in adult community rugby union between 2009-2013. A total of 254 time-loss shoulder injuries were reported, an overall incidence of 2.2 per 1 000 h (95% CI: 1.9 to 2.4), and a mean injury severity of 9.5 weeks missed (95% CI: 8.2 to 10.8). The semi-professional group had an incidence of 2.8 injuries per 1 000 h (95% CI: 2.2 to 3.5), which was higher than the recreational group at 1.8 injuries per 1 000 h (95% CI: 1.4 to 2.2, p=0.004). The incidence of acromioclavicular joint injury for semi-professional players was 1.2 per 1 000 h (95% CI: 0.8 to 1.6); which was significantly higher than the incidence of this injury type in recreational players (0.5 per 1 000 h 95% CI: 0.3 to 0.7, p=0.002). Overall, back row players sustained the highest incidence of all shoulder injuries for a given playing position, 2.9 injuries per 1 000 h (95% CI: 2.2 to 3.6). The tackle was the main event associated with injury. Injury prevention programs and coaching strategies that consider tackle technique and physical conditioning of the shoulder region are therefore considered important.

Spinal muscle activity in simulated rugby union scrummaging is affected by different engagement conditions.

Biomechanical studies of rugby union scrummaging have focused on kinetic and kinematic analyses, while muscle activation strategies employed by front-row players during scrummaging are still unknown. The aim of the current study was to investigate the activity of spinal muscles during machine and live scrums. Nine male front-row forwards scrummaged as individuals against a scrum machine under "crouch-touch-set" and "crouch-bind-set" conditions, and against a two-player opposition in a simulated live condition. Muscle activities of the sternocleidomastoid, upper trapezius, and erector spinae were measured over the pre-engagement, engagement, and sustained-push phases. The "crouch-bind-set" condition increased muscle activity of the upper trapezius and sternocleidomastoid before and during the engagement phase in machine scrummaging. During the sustained-push phase, live scrummaging generated higher activities of the erector spinae than either machine conditions. These results suggest that the pre-bind, prior to engagement, may effectively prepare the cervical spine by stiffening joints before the impact phase. Additionally, machine scrummaging does not replicate the muscular demands of live scrummaging for the erector spinae, and for this reason, we advise rugby union forwards to ensure scrummaging is practiced in live situations to improve the specificity of their neuromuscular activation strategies in relation to resisting external loads.

The influence of an artificial playing surface on injury risk and perceptions of muscle soreness in elite Rugby Union.

This prospective cohort study investigated the influence of an artificial playing surface on injury risk and perceptions of muscle soreness in elite English Premiership Rugby Union players. Time loss (from 39.5 matches) and abrasion (from 27 matches) injury risk was compared between matches played on artificial turf and natural grass. Muscle soreness was reported over the 4 days following one match played on each surface by 95 visiting players (i.e., normally play on natural grass surfaces). There was a likely trivial difference in the overall injury burden relating to time-loss injuries between playing surfaces [rate ratio = 1.01, 90% confidence interval (CI): 0.73-1.38]. Abrasions were substantially more common on artificial turf (rate ratio = 7.92, 90% CI: 4.39-14.28), although the majority of these were minor and only two resulted in any reported time loss. Muscle soreness was consistently higher over the 4 days following a match on artificial turf in comparison with natural grass, although the magnitude of this effect was small (effect sizes ranging from 0.26 to 0.40). These results suggest that overall injury risk is similar for the two playing surfaces, but further surveillance is required before inferences regarding specific injury diagnoses and smaller differences in overall injury risk can be made.

Force production during maximal effort bend sprinting: Theory vs reality.

This study investigated whether the "constant limb force" hypothesis can be applied to bend sprinting on an athletics track and to understand how force production influences performance on the bend compared with the straight. Force and three-dimensional video analyses were conducted on seven competitive athletes during maximal effort sprinting on the bend (radius 37.72 m) and straight. Left step mean peak vertical and resultant force decreased significantly by 0.37 body weight (BW) and 0.21 BW, respectively, on the bend compared with the straight. Right step force production was not compromised in the same way, and some athletes demonstrated substantial increases in these variables on the bend. More inward impulse during left (39.9 ± 6.5 Ns) than right foot contact (24.7 ± 5.8 Ns) resulted in 1.6° more turning during the left step on the bend. There was a 2.3% decrease in velocity from straight to bend for both steps. The constant limb force hypothesis is not entirely valid for maximal effort sprinting on the bend. Also, the force requirements of bend sprinting are considerably different to straight-line sprinting and are asymmetrical in nature. Overall, bend-specific strength and technique training may improve performance during this portion of 200- and 400-m races.

Pre-binding prior to full engagement improves loading conditions for front-row players in contested Rugby Union scrums.

We investigated the effect of a "PreBind" engagement protocol on the biomechanics of contested Rugby Union scrummaging at different playing levels. "PreBind" requires front-row props to take a bind on opposing players prior to the engagement, and to maintain the bind throughout the scrum duration. Twenty-seven teams from five different playing levels performed live scrums under realistic conditions. Video analysis, pressures sensors, and inertial measurement units measured biomechanical outcomes as teams scrummaged following different engagement protocols: the CTPE (referee calls "crouch-touch-pause-engage"), the CTS ("crouch-touch-set"), and the PreBind ("crouch-bind-set") variants. PreBind reduced the set-up distance between the packs (-27%) and the speed at which they came into contact by more than 20%. The peak biomechanical stresses acting on front rows during the engagement phase were decreased in PreBind by 14-25% with respect to CTPE and CTS, without reducing the capability to generate force in the subsequent sustained push. No relevant main effects were recorded for playing level due to within-group variability and there were no interaction effects between playing level and engagement protocol. Pre-binding reduced many mechanical quantities that have been indicated as possible factors for chronic and acute injury, and may lead to safer engagement conditions without affecting subsequent performance.

The influence of playing level on the biomechanical demands experienced by rugby union forwards during machine scrummaging.

This study investigated machine scrummaging at different playing levels in rugby union and analysed kinetic factors that might influence performance and injury risk. Thirty-four forward packs from six different playing levels scrummaged against an instrumented scrum machine under real environmental conditions. Applied forces were measured in three orthogonal directions. The peak (SD) of the overall compression forces during engagement ranged between 16.5 (1.4) kN (International-Elite) and 8.7 (0.1) kN (Women), while sustained compression forces spanned between 8.3 (1.0) kN (International) and 4.8 (0.5) kN (Women). The peak of the overall vertical force during the initial engagement phase was between -3.9 (0.7) kN (Elite) and -2.0 (1.0) kN (School), and the range of lateral forces was between 1.8 (0.3) kN (International) and 1.1 (0.3) kN (School). Forces measured across all playing levels, particularly during initial engagement, were generally higher than those measured in the most commonly cited previous studies. This increase may be due to a combination of changes in modern scrummaging technique, changes in players' anthropometrics, and experimental conditions that better respect ecological validity. The magnitude of the measured forces is in the range of values that studies on cadaveric specimens have indicated as potentially hazardous for (chronic) spine injuries.

Measurement error in estimates of sprint velocity from a laser displacement measurement device.

This study aimed to determine the measurement error associated with estimates of velocity from a laser-based device during different phases of a maximal athletic sprint. Laser-based displacement data were obtained from 10 sprinters completing a total of 89 sprints and were fitted with a fifth-order polynomial function which was differentiated to obtain instantaneous velocity data. These velocity estimates were compared against criterion high-speed video velocities at either 1, 5, 10, 30 or 50 m using a Bland-Altman analysis to assess bias and random error. Bias was highest at 1 m (+ 0.41 m/s) and tended to decrease as the measurement distance increased, with values less than + 0.10 m/s at 30 and 50 m. Random error was more consistent between distances, and reached a minimum value (±0.11 m/s) at 10 m. Laser devices offer a potentially useful time-efficient tool for assessing between-subject or between-session performance from the mid-acceleration and maximum velocity phases (i. e., at 10 m and beyond), although only differences exceeding 0.22-0.30 m/s should be considered genuine. However, laser data should not be used during the first 5 m of a sprint, and are likely of limited use for assessing within-subject variation in performance during a single session.

Strategies for maintaining a handstand in the anterior-posterior direction.

PURPOSE: The purpose of this analysis was to determine the contributions made by wrist, shoulder, and hip joint torques in maintaining a handstand. METHODS: Handstand balances (N = 6) executed on a force plate and recorded with two genlocked video cameras were subjected to inverse dynamics analysis to determine anterior-posterior joint torques at the wrists, shoulders, and hips. Multiple regression analyses were conducted to investigate which of the joint torques were influential in accounting for anterior-posterior whole-body mass center (CM) movement. RESULTS: Results demonstrated that, in general, all calculated joint torques contributed to CM movement. In a number of trials, wrist torque played a dominant role in accounting for CM variance. Ostensibly, superior handstand balances are characterized by important contributions from wrist torques and shoulder torques with little influence from hip torques. In contrast, hip torques were found to be increasingly influential in less successful balances. CONCLUSIONS: It is concluded that multiple joints are utilized in maintaining a handstand balance in the anterior-posterior direction, and there appears to be two joint involvement strategies, which supports similar findings from postural research on normal upright stance.