Rugby Union Players Research Articles

Increases in DXA-Derived Visceral Fat Across One Season in Professional Rugby Union Players: Importance of Visceral Fat Monitoring in Athlete Body Composition Assessment

Introduction: In rugby, the average player body mass has increased by approximately 25% since 1955. Visceral adipose tissue (VAT) is associated with low grade inflammation, and chronic diseases, such as cardiovascular diseases. The purpose of this study was to investigate changes in VAT in relation to other indices of body composition, across 1 season in professional rugby. Methodology: One hundred and sixteen male rugby union players’ (age: 26.2 ± 4.6 y, BMI: 29.40 ± 3.22 kg.m2) total body composition dual energy X-ray absorptiometry scans from 4 time points across the season (baseline, preseason, midseason, and postseason) were analyzed. Players were grouped by playing position, forwards (n = 65) and backs (n = 51). Players followed individually tailored diet plans. Results: Mean baseline VAT was 404.67 ± 229.43 g (forwards: 469.36 ± 263.16 g, backs: 311.40 ± 121.15 g). Total mass, lean mass, body fat percentage (%BF), and VAT were greater in forwards than backs at all 4 timepoints. Meaningful increases in VAT across the season, were observed in 37.5% of backs and 53.6% of forwards. There was a positive linear relationship between lean mass and total mass, up to 116.04 kg total mass. Beyond this threshold, lean mass accumulation reduced and %BF and VAT mass increased. There were significant relationships between %BF, VAT, and BMI (p < 0.001), but no physiological relevant pattern was discerned. Conclusions: Despite regular high-intensive exercise and individually tailored dietary control across a professional rugby season, players from both playing positions demonstrated increases in VAT, although the cause remains unknown. Our findings indicate the importance of monitoring VAT in athletes alongside standard measures of body composition. Additionally, our findings suggest there may be an upper threshold of body mass beyond which lean mass may not increase further and instead %BF and VAT are more likely to accumulate. Further research is required to identify how increasing player size may impact long-term cardiometabolic health given the known links between VAT and cardiometabolic risk.

Descriptive epidemiology of injuries in Japanese male collegiate rugby union players

To the best of our knowledge, most previous studies regarding the epidemiology of injuries in rugby union (rugby) players have focused on professional players. Therefore, data on injuries in collegiate rugby players in Japan is limited. The purpose of this study was to conduct a prospective injury survey of Japanese male collegiate rugby players over several years and to analyze the injuries that occurred during matches and training according to field position, type of injury, and mechanism of injury. This prospective study initially registered 128 rugby players from one university club. The occurrence of injuries was recorded by athletic trainers during the rugby seasons between 2017 and 2019. The total injury rate (IR) was 7.26 injuries/1000 player-hours (1000 PHs). The match IR (122.73 injuries/1000 PHs) was almost 31.9 times higher than the training IR (3.84 injuries/1000 PHs). Ankle sprains/ligament injuries (17.7%; 1.28 injuries/1000 PHs) were the most common injuries, in addition to acromioclavicular joint injuries in forwards and hamstring strain injuries in backs. The most common injury mechanism was tackling (16.4%). Injury characteristics differed according to field position; therefore, preventive measures according to field position are necessary. Moreover, the high number of tackle injuries suggests that improved tackle skills would help reduce injuries. The IR among Japanese collegiate rugby players was higher than that reported previously. Injury prevention training for collegiate players is necessary to reduce the number of injuries.

Current practices in the management of anterior glenohumeral instability in rugby union players

BackgroundRugby has the highest incidence of traumatic injuries of any sport, and glenohumeral injuries result in the lengthy delay in return to play. The purpose of this study is to survey surgeons from the American Shoulder and Elbow Surgeons (ASES), and the British Elbow and Shoulder Society (BESS) to evaluate the current state of management of anterior glenohumeral instability, and compare the differences in practices. MethodsA survey of surgeons from ASES and BESS was conducted. Treatment options were proposed in a variety of clinical scenarios of glenohumeral instability. The time of immobilization post-operatively, return to play, and attitudes on current contact regulations. Results were compared using the chi-square test or t-test. ResultsNinety-seven surgeons responded to the survey. There was a significant difference in treatment between ASES and BESS surgeons in the setting of primary dislocation (p < 0.05), but not recurrent dislocation (p > 0.05). The period of immobilization following injury and surgery was different between both treating groups. There was a significant difference in return to play between ASES and BESS surgeons with arthroscopic stabilization and open Bankart repair (p < 0.05), but not following conservative treatment or the Latarjet procedure (p > 0.05). ConclusionsThere remains wide variance on the management of glenohumeral instability in rugby union players among surgeons. While immobilization times post-operatively were similar, the BESS surgeons were more confident in allowing earlier return to play. There is also a significant concern that contact levels should be regulated to protect player safety. Level of evidenceLevel 4 (case series).

Objective sleep patterns and validity of self-reported sleep monitoring across different playing levels in rugby union.

Growing evidence highlights that elite rugby union players experience poor sleep quality and quantity which can be detrimental for performance. This study aimed to i) compare objective sleep measures of rugby union players between age categories over a one week period, and ii) compare self-reported measures of sleep to wristwatch actigraphy as the criterion. Two hundred and fifty-three nights of sleep were recorded from 38 players representing four different age groups (i.e. under 16, under 18, senior academy, elite senior) in a professional rugby union club in the United Kingdom (UK). Linear mixed models and magnitude-based decisions were used for analysis. The analysis of sleep schedules showed that U16 players went to bed and woke up later than their older counterparts (small differences). In general, players obtained seven hours of sleep per night, with trivial or unclear differences between age groups. The validity analysis highlighted a large relationship between objective and subjective sleep measures for bedtime (r = 0.56 [0.48 to 0.63]), and get up time (r = 0.70 [0.63 to 0.75]). A large standardised typical error (1.50 [1.23 to 1.88]) was observed for total sleep time. This study highlights that differences exist in sleep schedules between rugby union players in different age categories that should be considered when planning training. Additionally, self-reported measures overestimated sleep parameters. Coaches should consider these results to optimise sleep habits of their players and should be careful with self-reported sleep measures.

Orofacial trauma and mouthguard use in Brazilian rugby union players.

Rugby union represents a high-risk sport for orofacial trauma due to its impact collisions and repetitive tackles. The aim of this study was to investigate the prevalence of orofacial trauma according to mouthguard use among a sample of Brazilian rugby union players. An online questionnaire was sent to the 16 best rugby union clubs in Brazil. The questionnaire contained questions about the training history of each athlete, prevalence of orofacial trauma, and details about mouthguard use. Only participants who reported using a mouthguard were selected for this analysis. A total of 244 individuals were included. The prevalence of orofacial trauma was 34.4%, and 61.9% of them did not wear a mouthguard at the time of the incident. The only type of mouthguard reported was the pre-fabricated ("boil and bite" and "ready-to-wear") type. A stronger association was observed between the reason for using a mouthguard and the outcome, whereas a lower proportion of trauma was observed among individuals who claimed mandatory mouthguard use at the gym/sport (20.0%). Time since the respondent started playing rugby union and who instructed them to use a mouthguard were not associated with orofacial trauma. Prevalence of orofacial trauma was high among this sample of rugby union players from Brazil, even with the use of pre-fabricated mouthguards. This study encourages further investigation on the use of custom-made mouthguards in rugby union and the role of coach/physical educators to reduce the prevalence of orofacial trauma.

The Physical Characteristics of Elite Female Rugby Union Players

This study explored the anthropometric and body composition characteristics of elite female rugby union players, comparing between and within different playing positions. Thirty elite female rugby union players (25.6 ± 4.3 y, 171.3 ± 7.7 cm, 83.5 ± 13.9 kg) from New Zealand participated in this study. Physical characteristics were assessed using anthropometric (height, body mass, skinfolds) and body composition (dual-energy X-ray absorptiometry) measures. Forwards were significantly taller (p < 0.01; d = 1.34), heavier (p < 0.01; d = 2.19), and possessed greater skinfolds (p < 0.01; d = 1.02) than backs. Forwards also possessed significantly greater total (p < 0.01; d = 1.83–2.25) and regional (p < 0.01; d = 1.50–2.50) body composition measures compared to backs. Healthy bone mineral density values were observed in both forwards and backs, with significantly greater values observed at the arm (p < 0.01; d = 0.92) and femoral neck (p = 0.04; d = 0.77) sites for forwards. Tight-five players were significantly heavier (p = 0.02; d = 1.41) and possessed significantly greater skinfolds (p < 0.01; d = 0.97) than loose-forwards. Tight-five also possessed significantly greater total body composition measures (p < 0.05; d = 0.97–1.77) and significantly greater trunk lean mass (p = 0.04; d = 1.14), trunk fat mass (p < 0.01; d = 1.84), and arm fat mass (p = 0.02; d = 1.35) compared to loose-forwards. Specific programming and monitoring for forwards and backs, particularly within forward positional groups, appear important due to such physical characteristic differences.

Sport Concussion Assessment Tool: Fifth Edition Normative Reference Values for Professional Rugby Union Players.

To describe distributions and establish normative ranges for new or changed subcomponents of the Sports Concussion Assessment Tool (SCAT)-5. Cross-sectional study. Professional Rugby Union players performing 2017 preseason baseline SCAT-5 testing. Subcomponent tests newly introduced or changed in the SCAT-5. The 10-word immediate and delayed recall tests and the rapid neurological screen. Thousand two hundred three players were included in complete case analyses. The 10-word immediate recall test [median score 15, interquartile range (IQR) 15-22, range 3-30] showed an asymmetrical, bimodal distribution. The delayed recall test (median score 7, IQR 5-9, range 0-10) demonstrated a left skewed distribution. The diplopia and reading/following instruction tests of the neurological screen were performed normally by virtually all participants (98.5% and 99.6%, respectively). Normative classification ranges for each SCAT-5 subcomponents of interest were determined. The increased spread of scores, with improved midrange centering, suggests that the increase to 10-word list lengths should improve the performance of immediate and delayed recall tests. Normative ranges will provide a distribution against which postinjury SCAT-5 scores can be compared and interpreted.

Does the initial level of horizontal force determine the magnitude of improvement in acceleration performance in rugby?

This study aimed to observe the effect of 8 weeks of resisted sled training (RST), with optimal loading for maximal power output production and initial levels of force, on the magnitude of improvement in sprint performance and individual sprint mechanical outputs in female amateur rugby union players. The study examined the horizontal Power-Force-Velocity profile (P-F-V profile), which provides a measure of the athlete’s individual balance between force and velocity capabilities (Sfv), theoretical maximum force (F0), theoretical maximum velocity (V0), maximum power (Pmax), the maximum ratio of force (Rfmax) and rate of decrease in ratio of force (Drf). Thirty-one participants (age = 23.7 ± 3.3years, BM = 69 ± 9Kg, height = 167.5 ± 5.2 cm) were divided into a control group and two experimental groups; forwards (FG) and backs (BG). For 8 consecutive weeks (16 sessions), all groups performed the same training programme: 2 sets of 5 × 30 m, but athletes assigned to FG and BG ran towing a resisted sled attached to their waists, with optimal loading for maximal power output production. Both FG and BG significantly improved (p ≤ 0.05) in 5 and 20 m sprint performance, and in the mechanical properties related to the horizontal P-F-V profile. The correlation between the initial level of horizontal strength and the magnitude of improvement in Pmax also suggests that higher levels of horizontal force may lead to greater adaptations in RST. The P-F-V profile is a useful field method for identifying the weakest mechanical variable in rugby players during sprinting and enabling the prescription of individualized training programmes according to specific running performance.

Probiotic supplementation elicits favourable changes in muscle soreness and sleep quality in rugby players

Probiotic supplementation may offer team sport athletes a range of benefits beyond the immune and gastrointestinal systems. ObjectivesTo examine the effects of a probiotic formulation on perceptual markers of sleep quality and quantity, and muscle soreness, leg heaviness and motivation in elite rugby union athletes. MethodsA double-blind randomised controlled trial involving 19 elite male rugby athletes was conducted over 17 weeks encompassing both domestic and international competition. Psychometric variables and salivary biomarkers were assessed twice a week. Athletes were assigned either a daily probiotic (Ultrabiotic 60™) and Saccharomyces boulardii (during international competition) or a placebo. Associations between psychometric scores for perceptual and salivary biomarkers of sleep (melatonin) and inflammation C-reactive protein (CRP) were investigated. ResultsMuscle soreness was ∼0.5 units lower (F(1, 343)=42.646, p<0.0001) and leg heaviness scores ∼0.7 units lower (F(1, 334)=28.990, p<0.0001) in the probiotic group compared to the placebo group. Across both groups, as self-reported muscle soreness scores and salivary CRP concentrations increased, sleep quantity, quality and motivation scores decreased. Conversely as muscle soreness scores and CRP decreased, sleep quantity and quality, and motivation scores improved. ConclusionsA long-term programme of probiotic supplementation in international-level rugby union players may yield favourable effects on self-reported muscle soreness and sleep quality associated with muscle soreness during training and competitions.

The relationship between collision metrics from micro-sensor technology and video-coded events in rugby union.

This study aimed to determine the relationship between collision metrics from a commercially available micro-sensor technology unit (MST) and the count of collisions coded by expert video analysts in professional rugby union. Forty-four professional rugby union players wore MST units during match play. We analyzed 245 combined data files from 11 competitive matches, resulting in the inclusion of a total of 9202 individual collision events. Collision metrics (the count of collisions and the Collision Load™) were analyzed via the manufacturer's software. Each match was also video recorded and evaluated by two expert video analysts. Pearson's correlation coefficients were used to determine the relationship between the count of collisions coded by the expert video analysts, and both MST collision metrics. One-way ANOVA was used to determine whether differences in the Collision Load™ for individual collision events existed between different playing positions. Very large-nearly perfect correlations were observed between the count of collisions coded by the expert video analysts and both MST collision metrics (the count of collisions: r=0.91, 90% CI=0.89-0.93; the Collision Load™: r=0.89; 90% CI=0.87-0.91). Differences in the Collision Load™ for individual collision events were identified between different playing positions. Collision metrics registered by the MST software relate very strongly with the count of collisions coded by expert video analysts. The typical Collision LoadTM per individual collision event varies depending on player position. The application of automated collision detection for rugby union appears feasible.

High Prevalence of Cannabidiol Use Within Male Professional Rugby Union and League Players: A Quest for Pain Relief and Enhanced Recovery.

Rugby is characterized by frequent high-intensity collisions, resulting in muscle soreness. Players consequently seek strategies to reduce soreness and accelerate recovery, with an emerging method being cannabidiol (CBD), despite anti-doping risks. The prevalence and rationale for CBD use in rugby has not been explored; therefore, we recruited professional male players to complete a survey on CBD. Goodness of fit chi-square (χ2) was used to assess CBD use between codes and player position. Effects of age on use were determined using χ2 tests of independence. Twenty-five teams provided 517 player responses. While the majority of players had never used CBD (p < .001, V = 0.24), 26% had either used it (18%) or were still using it (8%). Significantly more CBD use was observed in rugby union compared with rugby league (p = .004, V = 0.13), but player position was not a factor (p = .760, V = 0.013). CBD use increased with players' age (p < .001, V = 0.28), with mean use reaching 41% in the players aged 28 years and older category (p < .0001). The players using CBD primarily used the Internet (73%) or another teammate (61%) to obtain information, with only 16% consulting a nutritionist. The main reasons for CBD use were improving recovery/pain (80%) and sleep (78%), with 68% of players reporting a perceived benefit. These data highlight the need for immediate education on the risks of CBD, as well as the need to explore the claims regarding pain and sleep.

Match loads of university rugby union players between the 2016 and 2018 Varsity Cup competitions.

Rugby union is a popular and continuously growing sport globally. With the advance of technology, practices have been implemented to quantify the match running demands of rugby union players. The aim of this study was to analyse the match loads of rugby union players between the 2016 and 2018 Varsity Cup competitions. The sample consisted of 562 match observations of male university rugby union players competing in the Varsity Cup tournaments. The backline players ran significantly longer total distances (5105 m; p = 0.001; ES = 0.49); have greater high-speed running (496 m; p = 0.001; ES = 1.03), very high-speed running (260 m; p = 0.001; ES = 1.50) and sprint distances (117 m; p = 0.001; ES = 1.32) than forward players. Backline players also accumulated a high number of metres per minute (238 ± 94; p = 0.001; ES = 0.46), total Player Load (488 ± 203; p = 0.001; ES = 0.31), RHIE (9 ± 8; p = 0.001; ES = 0.75) and number of accelerations (4 ± 5; p = 0.001; ES = 0.49). These findings may assist coaches to develop player position specific training programmes to meet the physical demands of rugby.

Sensitivity, reliability and construct validity of GPS and accelerometers for quantifying peak periods of rugby competition.

Training prescription and monitoring of team-sport athletes rely on accurate quantification of player movement. Our aim was to determine the sensitivity, reliability and construct validity of measures derived from a wearable device incorporating Global Positioning System (GPS) and accelerometer technology to quantify the peak periods of rugby competition. Match movement data were collected from 30 elite and 30 sub-elite rugby union players across respective competitive seasons. Accelerometer and GPS measures were analysed using a rolling average to identify peak movement for epochs ranging from 5 to 600 seconds. General linear mixed modelling was used to quantify the effects of playing position and match-half on the peak movement and variabilities within and between players represented reliability of each measure. Mean positional differences and match-half changes were assessed via standardisation and magnitude-based decisions. Sensitivity of measures was quantified via evaluation of ("signal") and typical error of measurement ("noise"). GPS and accelerometer measures had poor sensitivity for quantifying peak movement across all epochs and both levels of rugby union competition (noise 4× to 5× the signal). All measures displayed correspondingly low reliability across most epochs and both levels of competition (ICC<0.50). Construct validity was evident in mean differences between playing positions and match halves that were consistent with expected activity profiles in rugby union. However, it was clear from the pattern of differences across epoch durations and levels of competition that GPS and accelerometer measures provided different information about player movement. The poor sensitivity and low reliability of GPS and accelerometer measures of peak movement imply that rugby union players need to be monitored across many matches to obtain adequate precision for assessing individuals. Although all measures displayed construct validity, accelerometers provided meaningful information additional to that of GPS. We recommend using accelerometers alongside GPS to monitor and prescribe match respresentative training.

Clarifying the structure of serious head and spine injury in youth Rugby Union players.

This study aimed to clarify the cause of rugby head and spinal cord injuries through a network centrality analysis of 14-year (2004-2018) longitudinal data in Japan. The study hypothesis is that understanding the causal relationship among the occurrence of serious injuries, the quality of player experience and play situation as a network structure could be possible to obtain practical knowledge on injury prevention. In this study, bipartite graphs are used to make it easier to understand the situation of players and injuries. This would also help to elucidate more characteristic subgroup. A network bipartite graph and subgroup (cluster) analyses were performed to clarify the injured players' experience and the cause of injury. We used the algorithm of R program, IGRAPH, clustering edge betweenness. For subgroup extraction, the modularity Q value was used to determine which step to cut. The Japanese rugby population was 93,873 (2014-2018 average), and 27% were high school students. The data showed that careful attention would be particularly needed for groups of inexperienced Japanese high school players. Our study suggests that we should consider introducing rules that prohibit "head-on collisions" in youth rugby.

Convergent Validity, Reliability, and Sensitivity of a Running Test to Monitor Neuromuscular Fatigue.

To investigate the convergent validity, reliability, and sensitivity over a week of training of a standardized running test to measure neuromuscular fatigue. Twenty male rugby union players were recruited for the study, which took place during preseason. The standardized running test consisted of four 60-m runs paced at ~5 m·s-1 with 33 seconds of recovery between trials. Data from micromechanical electrical systems were used to calculate a running-load index (RLI), which was a ratio between the mechanical load and the speed performed during runs. RLI was calculated by using either the entire duration of the run or a constant-velocity period. For each type of calculation, either an individual directional or the sum of the 3 components of the accelerometer was used. A measure of leg stiffness was used to assess the convergent validity of the RLI. Unclear to large relationships between leg stiffness and RLI were found (r ranged from -.20 to .62). Regarding reliability, small to moderate (.47-.86) standardized typical errors were found. The sensitivity analysis showed that the leg stiffness presented a very likely trivial change over the course of 1 week of training, whereas RLI showed very likely small to a most likely large change. This study showed that RLI is a practical method to measure neuromuscular fatigue. In addition, such a methodology aligns with the constraint of elite team-sport setup due to its ease of implementation in practice.

Shoulder functional status in rugby union players with and without history of shoulder problems

ObjectivesTo assess the effects of (1) rugby union practice, (2) history of injury managed nonoperatively, and (3) history of injury managed operatively on shoulder functional status in male rugby union players. DesignCross sectional study. SettingClinical. Participants86 male athletes were assigned into four groups: multisport athletes, rugby union players without shoulder problems, with history of shoulder injury managed nonoperatively and with history of shoulder injury managed operatively. Main outcome measuresSI-RSI questionnaire, maximal isometric glenohumeral internal and external rotator strength, unilateral seated shot put test, upper quarter Y balance test. ResultsHealthy players presented higher internal (p = 0.03) and external (p = 0.04) rotator strength than multisport athletes. History of shoulder injury managed nonoperatively did not impair physical abilities but limited player’s psychological readiness (p < 0.001). After 4.5-months, shoulder stabilization surgery impaired maximal muscle strength and upper quarter body stability and mobility (p < 0.001 for all). ConclusionsThe shoulder functional status in rugby union player presented increased glenohumeral rotator strength when compared to non-collision sport athletes. In rugby union players, psychological concerns remained in the long-term after a shoulder injury managed nonoperatively, and psychological and physical readiness seemed not be reached at 4.5 months postoperatively to respond to rugby union practice demand.

Combining Blood Flow Restriction Training With Heat To Maximize Hypertrophy And Strength In Rugby Players

PURPOSE: We assessed whether blood flow restriction (BFR) training with the addition of heat stress (BFRH) improves hypertrophy, muscle strength and sport-specific physical performance in rugby union players, compared to BFR training alone. METHODS: Nineteen elite U23 rugby union male players were randomly assigned to BFRH (n = 7), BFR (n = 6) or traditional high-load resistance training (CON, n = 6) groups. BFRH and BFR groups trained twice weekly for 3 weeks using BFR exercise (half squat, 4 sets of 30-15-15-15 repetitions at 30% 1 maximum repetition (1RM) with 30 s of passive recovery; 50% of resting arterial occlusion pressure) in hot (37°C) and cool (22°C) conditions, respectively. Before and after the intervention, thigh circumference, half squat 1RM, squat jump force-velocity profile, and performance in vertical jump, sprint and repeated-sprint ability (RSA) tasks were measured. Muscle damage marker (creatine kinase) was measured before and after (0.1-24 h) the first and last training session. RESULTS: Thigh circumference significantly increased (P<0.001) from pre- to post-training in both BFRH (+6%, P<0.001) and BFR (+4%, P<0.05). Significant time × group interaction revealed improvement in half squat 1RM (+12% and +19%, P<0.01) and maximal force component (+102% and +116%, P<0.001) of the force-velocity profile for BFRH and BFR. Vertical jump performance did not change. 10-m sprint (-5% and -3%, P<0.001) and RSA best and total times (both -2%, both P≤0.001) improved similarly in BFRH and BFR. Although not significant, muscle damage was lowered after the last session in BFRH only. No pre- to post-training changes occurred in CON. CONCLUSIONS: Combining BFR training with heat stress can potentially induce hypertrophy and improve rugby union-specific physical performance while also inducing lower muscle damage than BFR training alone. Such gains could be of benefit during competitive period or rehabilitative setting.

The Influence of Functional Flywheel Resistance Training on Movement Variability and Movement Velocity in Elite Rugby Players.

The aim of this study was to identify the changes in movement variability and movement velocity during a six-week training period using a resistance horizontal forward–backward task without (NOBALL) or with (BALL) the constraint of catching and throwing a rugby ball in the forward phase. Eleven elite male rugby union players (mean ± SD: age 25.5 ± 2.0 years, height 1.83 ± 0.06 m, body mass 95 ± 18 kg, rugby practice 14 ± 3 years) performed eight repetitions of NOBALL and BALL conditions once a week in a rotational flywheel device. Velocity was recorded by an attached rotary encoder while acceleration data were used to calculate sample entropy (SampEn), multiscale entropy, and the complexity index. SampEn showed no significant decrease for NOBALL (ES = -0.64 ± 1.02) and significant decrease for BALL (ES = -1.71 ± 1.16; p < 0.007) conditions. Additionally, movement velocity showed a significant increase for NOBALL (ES = 1.02 ± 1.05; p < 0.047) and significant increase for BALL (ES = 1.25 ± 1.08; p < 0.025) between weeks 1 and 6. The complexity index showed higher levels of complexity in the BALL condition, specifically in the first three weeks. Movement velocity and complex dynamics were adapted to the constraints of the task after a four-week training period. Entropy measures seem a promising processing signal technique to identify when these exercise tasks should be changed.

Acute effects of Running Anaerobic-based Sprint Test with different loads in amateur Rugby Union players

The aim of this study was to compare the acute effects of the Running Anaerobic-based Sprint Test (RAST) with different loads in physiologic and neuromuscular parameters. 12 amateur rugby union players performed the RAST, with heart rate (HR) and blood lactate concentration ([LAC]) measurements pre, post and 5 min post RAST, squat jump (SJ), countermovement jump (CMJ), 10 m (S10) and 20 m (S20) sprints pre and post RAST. These procedures were carried out during three sessions, randomly performed in different conditions: no load (NL), load with 13% (L13) or 25% (L25) of body mass. Between loads, peak power in RAST and mean power were statistically different, with lower in L25 condition. Between moments, significant differences were observed with decrease in HR, increase in [LAC] for pre, post and 5 min post, respectively, and performance decrease in CMJ and S10, without load vs moment interaction. In addition, between loads, with exception of power produced in RAST, no significant differences were observed for any variable. Therefore, despite the differences in power production during RAST, it is concluded that RAST performed with or without loads of either 13 or 25% of body mass induces similar acute effects in both physiologic and neuromuscular parameters. Le but de cet article était de comparer les effets aigus du test Sprint basé sur anaérobie (RAST) avec différentes charges de paramètres physiologiques et neuromusculaires. Douze joueurs amateurs de rugby à XV ont effectué le RAST, avec des mesures de la fréquence cardiaque (HR) et de la concentration en lactate sanguin ([LAC]) avant, après et 5 minutes après le RAST, squat jump (SJ), contre-mouvement (CMJ), 10 m (S10) et 20 m (S20) sprints avant et après RAST. Ces procédures ont été réalisées au cours de trois séances, effectuées au hasard dans différentes conditions : sans charge (NL), charge avec 13 % (L13) ou 25 % (L25) de masse corporelle. Entre les charges, la puissance de pointe dans RAST et la puissance moyenne étaient statistiquement différentes, avec une condition inférieure à L25. Entre les moments, des différences significatives ont été observées avec une diminution de la FC, une augmentation de [LAC] pour le pré, le post et le post 5 min, respectivement, et une diminution des performances en CMJ et S10, sans interaction charge/moment. De plus, entre les charges, à l’exception de la puissance produite dans RAST, aucune différence significative n’a été observée pour aucune variable. Par conséquent, malgré les différences de production d’énergie pendant le RAST, il est conclu que le RAST effectué avec ou sans charges de 13 ou 25 % de la masse corporelle induit des effets aigus similaires dans les paramètres physiologiques et neuromusculaires.

Physical and Fitness Characteristics of Elite Professional Rugby Union Players.

This study explored the physical and fitness characteristics of elite professional rugby union players and examined the relationships between these characteristics within forwards and backs. Thirty-nine elite professional rugby union players from the New Zealand Super Rugby Championship participated in this study. Body composition was measured using dual-energy X-ray absorptiometry alongside anthropometrics. Fitness characteristics included various strength, power, speed, and aerobic fitness measures. Forwards were significantly (p ≤ 0.01) taller and heavier than backs, and possessed greater lean mass, fat mass, fat percentage, bone mass, and skinfolds. Forwards demonstrated greater strength and absolute power measures than backs (p = 0.02), but were slower and possessed less aerobic fitness (p ≤ 0.01). Skinfolds demonstrated very large correlations with relative power (r = −0.84) and speed (r = 0.75) measures within forwards, while backs demonstrated large correlations between skinfolds and aerobic fitness (r = −0.54). Fat mass and fat percentage demonstrated very large correlations with speed (r = 0.71) and aerobic fitness (r = −0.70) measures within forwards. Skinfolds, fat mass, and fat percentage relate strongly to key fitness characteristics required for elite professional rugby union performance. Individual and positional monitoring is important due to the clear differences between positions.