Application of small and large-sided games to youth rugby union: A match demands approach

Rugby union (RU) is a highly demanding and a global contact sport that combines physical, technical, and tactical characteristics. This team sport is practiced by players of all ages and backgrounds on various levels of play. To meet the demands of rugby competition, a multifactorial approach to training has been applied in practice. One training method that has risen to prominence for its reported benefits of contextualising and concurrently training all aspects of high-intensity intermittent field-based sports such as RU, is small-sided games (SSG). Most research on these training forms has been conducted on soccer players and tends to confirm its benefits. Emerging evidence in the rugby codes is heavily focussed on rugby league senior players, often on the elite level. Rugby union has shown scarce evidence for SSG training in senior players, but the knowledge regarding youth players is lagging. The aim of this thesis was therefore to investigate the application of SSG to RU, clarify their characteristics in youth players, and evaluate their suitability in function of developing and preparing players for competition. The initial literature review in Chapter 2 outlines that the physical, physiological, and kinematic demands of rugby competition are high, and vary according to the cohorts investigated, such as for playing level and position. In addition, emerging evidence showed that the match demands of youth differ between age groups, and from those in senior players. This preliminary investigation showed scant evidence of SSG efficacy and utility for improving physical performance but the research regarding the effects of SSG design was scarce and demonstrated incoherent methodology. The systematic review of the body of literature in Chapter 4 used PRISMA methodology to establish that five out of seven initial studies examining the effects of SSG were at critical risk of bias, and a further two were at moderate risk. Despite moderate to good methodological quality (52-98%), these findings imply two studies provide sound evidence for a non-randomized study but cannot be considered comparable to a well-performed randomized trial, and five studies are objectively too problematic to provide any useful evidence and should not be included in any future synthesis of the literature. Within these studies, the lack of a focussed line of investigation was identified as a key weakness. Initial results of the review indicated that various SSG designs influence the outcomes differently for different cohorts, and that fewer players and larger pitches could increase demands. However, no evidence was available for the design of SSG in youth RU players. Recent evolutions in the relevant literature revealed that seven additional studies have expanded the knowledge but show a similar disparity in methods, hampering the ability to extrapolate clear and applicable conclusions for SSG design, especially in youth players. In Chapter 5 and Chapter 6, a worldwide e-survey study (n=115) discussed the application of SSG in RU practice. These results confirmed the notion that SSG are widely used in practice, with 85% of practitioners, applying SSG regularly across all levels of play and in all age categories. Technical skill (26%), fun (25%), physical conditioning (18%), and tactical training (17%) were established as the main targeted objectives. The specific design of SSG was related to practitioners’ characteristics such as playing level, coaching experience, practitioner role, target age group, player sex, and geographical location. Most practitioners used two or three bouts of three to seven-a-side SSG, with a 1:1 to 5:1 work-rest ratio, for short durations (2-10 minutes). Tackle (37%), touch (36%), and wrapping (28%) were commonly implemented rules. However, school and lower-level coaches used longer bouts and tackle rules on less variable pitch sizes, for fun and technical skill, more often than higher-level coaches, who preferred shorter-duration bouts with touch rules and more extreme pitch sizes, primarily for physical conditioning. Overall, 3v3, 5v5, and 7v7 were determined to be the most popular top-three SSG formats. We established that SSG design should be evidence-based and reflect the needs and challenges of the specific performance context. In Chapter 7, a cross-sectional experimental study was conducted on NZ secondary school-age RU players (n= 158; age 14.8 ± 1.4; height 174.5 ± 7.5 cm; mass 77.2 ± 17.1 kg). Four age groups (U14, U15, U16, U18) randomly played 3v3, 5v5, or 7v7 on a small (S= 25x35 m), medium (M= 35x50 m), or large (L=50x70 m) pitch, for three bouts of four minutes with three minutes of active recovery. Kinematic, physiological, and physical data were captured using microsensor devices, alongside ratings of perceived exertion (RPE) and injury incidence. Multiple multivariate and univariate analyses found that player number and pitch size are the main elemental SSG design factors driving performance outcomes, followed by player age category and bout sequencing. The results showed that the isolated effect of increasing player numbers decreased kinematic and physiological demands, while an increase in pitch size mainly increased kinematic but not physiological demands. However, design factors mutually affected each other’s influence and select performance measures, such as sprint frequency, showed greater resistance to changes in format. Moreover, the innovative approach of the study in Chapter 7 integrated the SSG design constraints and demonstrated that maximising relative playing area (i.e., 3v3-L) maximises most kinematic, physiological, and physical performance measures. These findings further suggested that various SSG formats between ~350 and 583 m2·player-1, and for some measures as little as 175 m2·player-1, can produce running demands of approximately 94 m∙min-1 of relative distance (RD) and 145 m of high-intensity running distance (HIRD). Intensity measures across all youth showed an RPE of 15 and an average heart rate (HRAVG) of ~83% HRMAX for the highest-reaching full SSG format (3v3-L). Nevertheless, only 1.1 ± 1.2 minutes per bout and 4.3 ± 3.8 minutes per SSG (~24%) were spent above 90% HRMAX, an intensity often deemed necessary for promoting cardiovascular adaptation. Bout 1 was shown to yield greater performance than subsequent bouts, mainly in formats with the most extreme relative pitch sizes. However, RPE increased with every bout in all SSG formats. Differences between age groups were identified that were performance measure-specific, non-linear in evolution, and non-uniform. A conservative injury incidence of 59.8 per 1000 player-hours was found. The match demands of rugby sevens (7s) were investigated in Chapter 8, showing a continuous high-intensity profile. Youth players demonstrated high kinematic demands with RD of 111 m·min-1, 3 sprints·min-1, and 252 m HIRD. Match intensity resulted in an HRAVG of 90% HRMAX, with up to 58% of game time above 90% HRMAX. These youth match demands were established to be greater than their international peers, senior 7s games, and elite-level cohorts. Of note, U15 demonstrated greater kinematic and physiological demands than their U19 counterparts. In Chapter 9, the demands of fifteen-a-side matches were investigated, showing a more intermittent high-intensity profile. Approximately 87% of match distance was covered at low speeds (<50% VTOP) with an HRAVG of 87% HRMAX, and up to 88% of game time was performed above 80% HRMAX. Kinematic demands showed 73 m·min-1 of RD, 1.4 sprints·min-1, and 410 m HIRD. Performance was largely maintained between playing halves and differences between forwards and backs mainly related to relative performance. These demands converged towards and even surpassed those of the senior game and some elite-level cohorts. In conclusion, this doctoral thesis contributes novel evidence to the body of knowledge that deepens the understanding of the application of SSG to youth RU players, relative to match demands in 7s and fifteen-a-side matches. This knowledge is important as it provides a standardised benchmark to apply concrete SSG guidelines for targeting general and specific outcomes in RU practice. This benchmark can be used to contrast with higher-level competition demands and thereby forming the foundation of a developmental pathway by progressively targeting these performance standards. Based on our research, standardised SSG with greater relative pitch area generally increase acute kinematic, physiological, and physical demands in U14 to U18 RU players. However, important nuances exist between individual performance measures on the one hand, and between age categories on the other. These nuances require further research and SSG prescription necessitates an age group and outcome measure-specific approach (i.e., exact physical, physiological, kinematic, technical and/or tactical variables), which can be optimised by practitioners implementing constraint manipulation within their specific context. The kinematic, physiological, and physical match demands of NZ secondary school-level competition are very high and may adequately prepare players for senior and higher-level rugby. Small-sided game training as delivered in this investigation can be used as a safe and solid basis for general conditioning of youth players and to prepare them for most movement demands of RU competition. To obtain optimal match preparation, SSG design should be modulated using the prescriptions presented in this thesis and expanded on by experimenting with additional design elements taken from best-practice, cross-code, and cross-sport SSG research. To meet full competition demands, SSG training should furthermore be complemented by other training modalities to attain the requisite and complete high-intensity cardiovascular and movement performance outputs of fifteen and seven-a-side youth rugby competition.
The University of Waikato
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