Physical and Fitness Characteristics of Elite Professional Rugby Union Players

Head Acceleration Events During Tackle, Ball-Carry, and Ruck Events in Professional Southern Hemisphere Men's Rugby Union Matches: A Study Using Instrumented Mouthguards

OBJECTIVES

Describe head acceleration events (HAEs) experienced by professional male rugby union players during tackle, ball-carry, and ruck events using instrumented mouthguards (iMGs).

DESIGN

Prospective observational cohort.

METHODS

Players competing in the 2023 Currie Cup (141 players) and Super Rugby (66 players) seasons wore iMGs. The iMG-recorded peak linear acceleration (PLA) and peak angular acceleration (PAA) were used as in vivo HAE approximations and linked to contact-event data captured using video analysis. Using the maximum PLA and PAA per contact event (HAEmax), ordinal mixed-effects regression models estimated the probabilities of HAEmax magnitude ranges occurring, while accounting for the multilevel data structure.

RESULTS

As HAEmax magnitude increased the probability of occurrence decreased. The probability of a HAEmax ≥15g was 0.461 (0.435-0.488) (approximately 1 in every 2) and ≥45g was 0.031 (0.025-0.037) (1 in every 32) during ball carries. The probability of a HAEmax >15g was 0.381 (0.360-0.404) (1 in every 3) and >45g 0.019 (0.015-0.023) (1 in every 53) during tackles. The probability of higher magnitude HAEmax occurring was greatest during ball carries, followed by tackles, defensive rucks and attacking rucks, with some ruck types having similar profiles to tackles and ball carries. No clear differences between positions were observed.

CONCLUSION

Higher magnitude HAEmax were relatively infrequent in professional men's rugby union players. Contact events appear different, but no differences were found between positions. The occurrence of HAEmax was associated with roles players performed within contact events, not their actual playing position. Defending rucks may warrant greater consideration in injury prevention research.

Seasonal Variation and Positional Differences in Anthropometry, Strength, and Power Characteristics in English Premiership Women's Rugby Union Players

ABSTRACT

Yao, X, Austerberry, A, Bishop, C, Wilson, L, Chiang, C-Y, and Turner, A. Seasonal variation and positional differences in anthropometry, strength, and power characteristics in English premiership women's rugby union players. J Strength Cond Res 38(5): 924-931, 2024-Women's rugby is a collision sport that relies heavily on body composition and physical characteristics of strength and power to achieve competitive success. Furthermore, the seasonal nature presents a variety of physical challenges that can cause fluctuations in a player's physical development. Therefore, the purpose of this study was to determine the differences in anthropometry, strength, and power characteristics between forwards and backs in women's rugby union athletes in England and to identify changes throughout a season. Forty-seven players were recruited from the English premiership women's rugby during the 2020-2021 season. Players were split into forwards and backs and underwent body composition testing by dual-energy X-ray absorptiometry and strength and power tests (countermovement jump, drop jump [DJ], and isometric midthigh pull) on 3 separate occasions (preseason, midseason, postseason). Overall, forwards had significantly ( p < 0.01) higher body mass, fat mass, lean mass [LM], bone mineral content, and take off momentum, and backs had significantly higher ( p < 0.01, d > 0.5) jump height, reactive strength, and shorter DJ contact time. When observing seasonal changes, there were statistically significant differences ( p < 0.01) or moderate-to-large practical differences ( d > 0.5) in LM, reactive strength index modified, time to take-off, and DJ flight time [FT] among forwards when comparing 3 testing time frames. For backs, statistically significant differences ( p < 0.01) or moderate-to-large practical differences ( d > 0.5) were reported in LM and DJ FT throughout the season. In conclusion, the strength and power testing and characteristics shown in this study could support coaches and junior women's rugby athletes to have a basic understanding of English premiership physical standards.

The Development of a Resting Metabolic Rate Prediction Equation for Professional Male Rugby Union Players

Determining resting metabolic rate (RMR) is an important aspect when calculating energy requirements for professional rugby union players. Prediction equations are often used for convenience to estimate RMR. However, the accuracy of current prediction equations for professional rugby union players remains unclear. The aims of this study were to examine the RMR of professional male rugby union players compared to nine commonly used prediction equations and develop and validate RMR prediction equations specific to professional male rugby union players. One hundred and eight players (body mass (BM) = 102.9 ± 13.3 kg; fat-free mass (FFM) = 84.8 ± 10.2 kg) undertook Dual-energy X-ray Absorptiometry scans to assess body composition and indirect calorimetry to determine RMR. Mean RMR values of 2585 ± 176 kcal∙day-1 were observed among the group with forwards (2706 ± 94 kcal·day-1), demonstrating significantly (p < 0.01; d = 1.93) higher RMR compared to backs (2465 ± 156 kcal·day-1), which appeared to be due to their higher BM and FFM measures. Compared to the measured RMR for the group, seven of the nine commonly used prediction equations significantly (p < 0.05) under-estimated RMR (-104-346 kcal·day-1), and one equation significantly (p < 0.01) over-estimated RMR (192 kcal·day-1). This led to the development of a new prediction equation using stepwise linear regression, which determined that the strongest predictor of RMR for this group was FFM alone (R2 = 0.70; SEE = 96.65), followed by BM alone (R2 = 0.65; SEE = 104.97). Measuring RMR within a group of professional male rugby union players is important, as current prediction equations may under- or over-estimate RMR. If direct measures of RMR cannot be obtained, we propose the newly developed prediction equations be used to estimate RMR within professional male rugby union players. Otherwise, developing team- and/or group-specific prediction equations is encouraged.

The associations between anthropometric characteristics and nutritional parameters in male elite rugby union players

The objective was to analyse the associations between anthropometric characteristics and diet in male rugby players according to the playing position. A cross-sectional study was developed. The forwards had higher body weight (107 kg) and fat mass (FM; 12%) than the backs (87.8 kg and 8.47%, respectively) (p < 0.05). The quality of diet needs to improve (KIDMED value of 5.87 and 6.36 for forwards and backs, respectively). Nutritional imbalances, such as deficits in carbohydrates, fibre, calcium, magnesium and vitamin D, and excess of fats, saturated fatty acid, cholesterol and sugars were found. Carbohydrates and proteins intake were significant associated (p < 0.05) with a minor FM. Forwards with a KIDMED index of less than 8 had a significantly higher FM than those who maintained an optimal diet (p < 0.05). The diet of rugby players should be more in line with dietary recommendations and take into account the player position to optimise sports performance.

Physical Fitness Tests as Predictors of High-Intensity Running Performance in Rugby

Understanding the physical fitness elements that influence high-intensity running ability during rugby matches is crucial for optimizing player performance and developing effective training strategies. In this study, we aimed to investigate the relationships between various physical fitness components and high-intensity running ability in rugby. For this purpose, 60 Japanese university rugby players were randomized into four groups and two matches were played. The participants were monitored in two matches, and their running abilities were assessed using GPS sensors. The running time was divided into three running velocity categories: distance run at ≤5.4 km/h (low-intensity running); distance run at 5.5~17.9 km/h (medium-intensity running), and distance run at ≥18.0 km/h ≤(high-intensity running) and backs and forwards were evaluated separately. To determine which physical fitness test is more predictive of performance, we decided to correlate several physical test performances with the running time intensities during the matches. Independently of the position, the high-intensity running time correlated with the repeated sprint ability (RSA) and the 40 m sprint speed. The results suggest that RSA measured in the field is the most important high-intensity running ability predictor during a match for both positions.

Dietary Intakes of Elite Male Professional Rugby Union Players in Catered and Non-Catered Environments

In professional rugby union, it is common for players to switch between catered and non-catered dietary environments throughout a season. However, little is known about the difference in dietary intake between these two settings. Twelve elite male professional rugby union players (28.3 ± 2.9 y, 188.9 ± 9.5 cm, 104.1 ± 13.3 kg) from the New Zealand Super Rugby Championship completed seven-day photographic food diaries with two-way communication during two seven-day competition weeks in both catered and non-catered environments. While no significant differences were observed in relative carbohydrate intake, mean seven-day absolute energy intakes (5210 ± 674 vs. 4341 ± 654 kcal·day^-1), relative protein (2.8 ± 0.3 vs. 2.3 ± 0.3 g·kgBM·day^-1) and relative fat (2.1 ± 0.3 vs. 1.5 ± 0.3 g·kgBM·day^-1) intakes were significantly higher in the catered compared to the non-catered environment (respectively) among forwards (n = 6). Backs (n = 6) presented non-significantly higher energy and macronutrient intakes within a catered compared to a non-catered environment. More similar dietary intakes were observed among backs regardless of the catering environment. Forwards may require more support and/or attention when transitioning between catered and non-catered environments to ensure that recommended dietary intakes are being achieved.

Differences in Adiposity Profile and Body Fat Distribution between Forwards and Backs in Sub-Elite Spanish Female Rugby Union Players

The purpose of this study was to analyze the adiposity profile and the body fat distribution in 56 sub-elite female rugby union players involved in the Spanish National Women's Rugby Union Championships. The participants included in this study, which was the first to analyze sub-elite players, show thinner skinfolds, lower fat mass, and lesser fat percentage than previously reported for elite female rugby union players. Forwards were heavier and had higher body mass index (BMI) and fat mass, thicker skinfolds, and higher fat percentage than back players. Forwards also possessed significantly greater total fat-free mass than backs. All these differences were applicable only to players under 25 years of age. A negative correlation between age and both abdominal and lower extremity fat was found in forward players but not in the backs. Both Yuhasz and Faulkner equations tended to underestimate fat percentage in comparison to Reilly equation. Although Yuhasz equation provided higher systematic error, random error was lower in comparison to Faulkner equation. This study shows the relevance of analyzing and monitoring adiposity in female rugby union players to optimize adaptation to the sports requirements of different playing positions and age.

Topical Review: Perceptual-cognitive Skills, Methods, and Skill-based Comparisons in Interceptive Sports

SIGNIFICANCE

We give a comprehensive picture of perceptual-cognitive (PC) skills that could contribute to performance in interceptive sports. Both visual skills that are low level and unlikely influenced by experience and higher-level cognitive-attentional skills are considered, informing practitioners for identification and training and alerting researchers to gaps in the literature.Perceptual-cognitive skills and abilities are keys to success in interceptive sports. The interest in identifying which skills and abilities underpin success and hence should be selected and developed is likely going to grow as technologies for skill testing and training continue to advance. Many different methods and measures have been applied to the study of PC skills in the research laboratory and in the field, and research findings across studies have often been inconsistent. In this article, we provide definitional clarity regarding whether a skill is primarily visual attentional (ranging from fundamental/low-level skills to high-level skills) or cognitive. We review those skills that have been studied using sport-specific stimuli or tests, such as postural cue anticipation in baseball, as well as those that are mostly devoid of sport context, considered general skills, such as dynamic visual acuity. In addition to detailing the PC skills and associated methods, we provide an accompanying table of published research since 1995, highlighting studies (for various skills and sports) that have and have not differentiated across skill groups.

Competition Nutrition Practices of Elite Male Professional Rugby Union Players

Thirty-four elite male professional rugby union players from the New Zealand Super Rugby championship completed dietary intakes via the Snap-N-Send method during a seven-day competition week. Mean seven-day absolute energy intake was significantly higher for forwards (4606 ± 719 kcal·day⁻¹) compared to backs (3761 ± 618 kcal·day⁻¹; p < 0.01; d = 1.26). Forwards demonstrated significantly higher mean seven-day absolute macronutrient intakes compared to backs (p < 0.03; d = 0.86–1.58), but no significant differences were observed for mean seven-day relative carbohydrate (3.5 ± 0.8 vs. 3.7 ± 0.7 g·kg·day⁻¹), protein (2.5 ± 0.4 vs. 2.4 ± 0.5 g·kg·day⁻¹), and fat (1.8 ± 0.4 vs. 1.8 ± 0.5 g·kg·day⁻¹) intakes. Both forwards and backs reported their highest energy (5223 ± 864 vs. 4694 ± 784 kcal·day⁻¹) and carbohydrate (4.4 ± 1.2 vs. 5.1 ± 1.0 g·kg·day⁻¹) intakes on game day, with ≈62% of total calories being consumed prior to kick-off. Mean pre-game meal composition for all players was 1.4 ± 0.5 g·kg⁻¹ carbohydrate, 0.8 ± 0.2 g·kg⁻¹ protein, and 0.5 ± 0.2 g·kg⁻¹ fat. Players fell short of daily sports nutrition guidelines for carbohydrate and appeared to “eat to intensity” by increasing or decreasing energy and carbohydrate intake based on the training load. Despite recommendations and continued education, many rugby players select what would be considered a “lower” carbohydrate intake. Although these intakes appear adequate to be a professional RU player, further research is required to determine optimal dietary intakes.

Short and long-term differences in anthropometric characteristics and physical performance between male rugby players that became professional or remained amateur

Objective

The objective of this study was to investigate which anthropometric and physical performance variables characterised players that advanced to professional teams (professionals) and how these variables changed over time, compared to those that did not secure professional contracts (i.e. remained amateurs).

Methods

Differences in anthropometry, strength, speed, power and intermittent running ability in 83 male rugby players collected between 2015 and 2019 were determined using repeated measures analysis.

Results

When arriving for the first year of the program, forwards that went on to become professional players were older (0.4 ± 0.3 yr, mean ± 95% CI, p = 0.004), heavier (4.6 ± 2.5 kg, p < 0.001) and stronger (range 6.2-16.4%) than forwards that remained amateur. Professional forwards were also slower at sprinting (range -2.7-2.9%, p < 0.001) and had lower Yo-Yo IRT L1 (-10.8%, p = 0.03). When first arrived on the program, professional backs were taller (3.5 ± 1.8 cm, p < 0.001), heavier (4.6 ± 2.4 kg, p < 0.001) and faster over 20 m (-1.9 ± 1.7%, p = 0.03) and 30 m (-1.7 ± 1.6%, p = 0.04) compared to amateurs. Compared to amateurs, professionals had a smaller increase in body mass (-4.2 ± 2.0%, p < 0.001) and greater improvement in sprinting (3.7, 2.8, 2.8% over 10, 20 and 30-m, respectively) and Yo-Yo IRT L1 (14.7 ± 11.0%, p = 0.05) over 3 years training.

Conclusion

Characteristics that are likely to assist players in becoming professionals include being older, heavier, taller and stronger.

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.