ABSTRACT:Maviel, C, Vercruyssen, F, Duché, P, Bourdin, S, Morin, J-B, and Couderc, A. In-season individualized resisted sprint session improves in-situ acceleration-speed profile in professional rugby backs. J Strength Cond Res XX(X): 000-000, 2026-This study aimed to evaluate how resisted sprint training sessions with individualized load calibration influence the in-situ acceleration-speed profile in professional rugby. Recent findings highlight the importance of individualized load prescription based on the force-velocity profile and horizontal propulsive power, both closely linked to sprint performance in rugby. Two groups of professional rugby backs were examined: a control group (CG, n = 11, 2023-2024 season) and an experimental group (EG, n = 17, 2024-2025 season). The CG completed standard in-season training with no resisted sprint work, whereas the EG performed a resisted sprint protocol using the 1080 Sprint system calibrated to 50% of each player's maximal sprint velocity (S0), derived from the preintervention in-situ acceleration-speed profile. Sprint sessions were performed once per week and consisted of four 15 m resisted sprints at a constant target velocity. Significant improvements were observed in the EG for propulsive power (4.5 ± 3.0%, p < 0.001), S0 (2.7 ± 2.1%, p < 0.001), and maximal acceleration (1.8 ± 2.7%, p = 0.03), whereas no significant changes were found in the CG. These findings suggest that implementing individualized resisted sprint training sessions is a promising strategy to improve in-situ sprint mechanical outputs during the competitive season.

Purpose : To examine the effect of repeated-sprint training in hypoxia (RSH) on oxygenation kinetics in the vastus lateralis muscle using statistical parametric mapping during repeated treadmill sprints in world-class female Rugby Sevens players. Methods: All players performed 4 repeated-sprint cycle-training sessions in either normobaric hypoxia (RSH, exercise, and interset rest at inspired oxygen fraction of 10.6% and 20.9%, respectively; n = 12) or normoxia (n = 11) during a 9-day training camp before international competition. Repeated-sprint ability (8 × 5-s treadmill sprints with 25-s recovery) was assessed preintervention and postintervention in normoxia only. Continuous assessment of tissue saturation index (TSI) in the vastus lateralis muscle was conducted using near-infrared spectroscopy. Results : There was a difference in TSI signal amplitude between conditions during the last second of the 5-second sprint phase and the first 3.7 seconds of the 25-second recovery phase. In the RSH group, TSI magnitude during the sprints and recovery phases was lower after compared with before the intervention (from 4.3 to 8.7 s; P < .001). The cumulated distance covered in sprints 1 to 8 significantly increased from preintervention to postintervention (pooled values: +1.9% [3.0]%; P = .019), regardless of the condition ( P = .149). Conclusion: Statistical parametric mapping analysis revealed a noticeable change in TSI in the RSH group toward the end of both the active and the early recovery phase of a normoxic repeated-treadmill-sprints test, whereas no differences were detected in the normoxic group postintervention. Despite improvements in repeated-sprint ability in both groups, addition of severe hypoxia during repeated-sprint training did not yield further performance enhancement.

Potential estimation (PE) in rugby union traditionally emphasizes physical, anthropometric, and biological attributes to distinguish between playing positions. Forwards are typically characterized by greater strength and power, whereas backs rely more on speed and agility. However, how these differentiators evolve across developmental stages remains underexplored. This study aimed to examine age-related changes in discriminative variables influencing positional differentiation across U14, U16, and U18 categories. A total of 139 national level male rugby players were assessed: U14 (n = 64), U16 (n = 51), and U18 (n = 24). Anthropometric data (height, body mass, body mass index (BMI)), maturity status (Y-PHV, MO), sprint performance (T10, T30), and horizontal force-velocity (F-v) profiling were collected. ANOVAs and post hoc analyses explored differences across age and position. Decision tree models identified key discriminative variables, and a feature importance analysis was performed, complemented by a recurrence analysis. Findings revealed significant age- and position-related differences (p < 0.05). BMI and maturity variables were the most relevant at U14, while sprint and F-v metrics gained importance with age. In U18, physical performance indicators such as peak power, theoretical maximal horizontal force, and slope force velocity emerged as dominant. These results suggest a transition from anthropometric to performance-based differentiation across age groups, offering key insights for refining PE strategies in youth rugby.

The aim of this study was to determine the minimum playing time in matches required to produce reliable acceleration - speed (AS) profiles from global navigation satellite system (GNSS) data. The playing time of 25 professional rugby union players was recorded using GNSS technology and segmented into four sections from 40, 80, 120 and 160 minutes of play. For each interval, the impact of integrating new match data on the AS profile was assessed, aiming to identify the saturation point where additional data did not induce significant changes in the profile outputs. A repeated measures ANOVA and Bonferroni post-hoc tests were applied to examine the variations of AS profile between time intervals. This led to identify the saturation point for assessing "robust" values of theoretical maximum acceleration (A0) and maximum speed (S0). A substantial lack of significant effect was observed for A0 (p = 1.00) and S0 (p = 0.99) in the section of 160 minutes, with an intra-subject variability of 1.50 and 1.20% for A0 and S0, respectively. Determining AS profiles for rugby players is essential for monitoring performance in training and match contexts. Our findings indicate that an equivalent of two full rugby union matches is required to generate a reliable AS profile.

ABSTRACT Purpose The objective of this study is to investigate the effectiveness of novel repeated-sprint training in hypoxia (RSH) protocol, likely maximizing hypoxic stimulus (higher than commonly used) while preserving training quality (interset rest in normoxia). Methods Twenty-three world-class female rugby sevens players performed four repeated-sprint training sessions (4 sets of 5 × 5-s cycle sprints—25-s intersprint recovery and 3-min interset rest) under normobaric hypoxia (RSH, exercise and interset rest at FiO2 of 10.6% and 20.9%, respectively; n = 12) or normoxia (repeated-sprint training in normoxia; exercise and interset rest at FiO2 of 20.9%; n = 11) during a 9-d training camp before international competition. Repeated-sprint ability (8 × 5-s treadmill sprints—25-s recovery), on-field aerobic capacity, and brachial endothelial function were assessed pre- and postintervention. Results Arterial oxygen saturation (pooled data: 87.0% ± 3.1% vs 96.7% ± 2.9%, P < 0.001) and peak and mean power outputs (sets 1 to 4 average decrease: −21.7% ± 7.2% vs −12.0% ± 3.8% and −24.9% ± 8.1% vs −14.9% ± 3.5%; both P < 0.001) were lower in RSH versus repeated-sprint training in normoxia. The cumulated repeated-sprint distance covered significantly increased from pre- to postintervention (+1.9% ± 3.0%, P = 0.019), irrespective of the condition (P = 0.149). On-field aerobic capacity did not change (all P > 0.45). There was no significant interaction (all P > 0.240) or condition main effect (all P > 0.074) for any brachial artery endothelial function variable. Only peak diameter increased (P = 0.026), whereas baseline and peak shear stress decreased (P = 0.014 and 0.019, respectively), from pre- to postintervention. Conclusions In world-class female rugby sevens players, only four additional repeated-sprint sessions before competition improve repeated-sprint ability and brachial endothelial function. However, adding severe hypoxic stress during sets of repeated sprints only did not provide supplementary benefits.

ABSTRACT:Couderc, A, Gabbett, TJ, Piscione, J, Robineau, J, Peeters, A, Igarza, G, Thomas, C, Hanon, C, and Lacome, M. Repeated high-intensity effort activity in international male Rugby Sevens. J Strength Cond Res 35(6): 1720-1726, 2023-Rugby Sevens is characterized by repeated high-intensity accelerations, sprinting, and collisions, commonly referred to as repeated high-intensity effort (RHIE) activity. Although repeated acceleration and sprinting activity of Rugby Sevens has been investigated, to date, no study has investigated the repeated running and collision activity of international Rugby Sevens during competitive events. In this study, 15 elite players competed in 44 matches during the HSBC World Sevens Series. Global positioning systems and match analysis software were used to quantify the frequency of repeated running and collision efforts. High acceleration (≥2.5 m·s -2 ), high speed (above maximal aerobic speed), sprint (above 85% of maximal sprint speed), and collision efforts (tackles, ruck, and contact) were considered as high-intensity effort activities. An RHIE bout was defined as 3 or more high-intensity efforts with less than 21 seconds recovery between efforts. The difference between positional groups (forward and backs) and first and second halves was compared using magnitude-based inferential statistics. One hundred twelve individual match observations were analyzed. On average, players performed 27 high-intensity effort events across the game. The distribution of high-intensity efforts included the following: 37% collisions, 34% accelerations, 27.5% high-velocity running, and 1.5% sprints. An average of 3.7 RHIE bouts was performed per player. The difference in high-intensity efforts and number of RHIE bouts performed were trivial/small when compared between first and second halves, and between forward and back positional groups. Repeated high-intensity effort bouts play an important role in the activity profile of elite Rugby Sevens players. This study could provide a framework for performance analysts and coaches to analyze match-related performance of elite Rugby Sevens players, taking into account both the high-intensity running and collision components of the game. Coaches should implement training interventions to ensure the maintenance of RHIE performance during competitive events.

PURPOSE:In women's rugby, players regularly interchange between the rugby sevens (R7) and rugby union (RU) formats. Yet, the game demands and particularly the physical aspects respective to both formats vary and players must be able to respond accordingly. The aim of this study was to compare peak running demands in R7 and RU players.METHODS:A total of 51 international women players participated. HSBC World Sevens Series (n = 19) and Six Nations Rugby Union tournament matches (n = 10) were analyzed for a total of 437 individual match observations. Global positioning systems were utilized to measure total (in meters) and high-speed (above 16 km·h-1, in meters) distance and frequency of accelerations (above 2.5 m·s-2, n) during different rolling-average periods (1-7 min) to obtain peak running activity values. Power law modeling was used to obtain slope and intercept. For all variables, peak values and the value at the 90th percentile (P90) were analyzed.RESULTS:No intercept difference (P = .25; -0.12 ± 0.17) was observed between formats for total distance (161 vs 155 m·min-1). In contrast, R7 players reported a higher intercept (P = .01; -0.29 ± 0.17) for high-speed distance (66 vs 51 m·min-1), while the intercept was higher (P = .01; 0.31 ± 0.20) in RU for accelerations performed (6.1 vs 5.4 n·min-1). Regarding P90, higher values (P < .001) were observed in R7 for total and high-speed distance and accelerations.CONCLUSIONS:While peak overall intensity was similar, P90 on the high-speed spectrum was higher in R7. Information on the most demanding match-play periods specific to both women's rugby formats can inform training specificity by tailoring sessions to ensure sufficient exposure to these peak demands and, consequently, aid transitioning between formats.

Introduction The study aimed to interpret the evolution of the physical performance of rugby sevens and rugby union French international players from 2009 to 2020. Methods 631 players from the French national teams were divided into three groups: forwards, backs and sevens. The performances evaluated were anthropometric characteristics, strength tests (1 RM bench press and 1 RM pull-up), aerobic capacity (YoYo IR1 test) and speed tests (10 m, 20 m and 50 m). The best performance of each player over a two-year period was kept for the analysis. Fluctuations were observed across the decade. Results The anthropometric characteristics of female rugby sevens players tend to be taller and lighter than rugby union players. In rugby sevens, a moderate increase in maximal aerobic capacity was observed while sprint performances remained similar. Improvements in height and weight were observed over the last 10 years in rugby union players with a difference between the position. A moderate increase in sprinting performances and strength were observed both in backs and forwards. Discussion The overall improvement of strength and conditioning performances and anthropometrical evolution reflects the rugby environment characterized by the arrival of professional contracts and the structuration process of the clubs which allows a better quality of training and easier access to the infrastructures of the very high level.

PURPOSE:To investigate the effect of cycling-based repeated-sprint training in hypoxia versus in normoxia on single overground running sprint performance and associated force-velocity (F-V) profile in world-class female rugby sevens players. METHODS:Eighteen world-class female rugby sevens players were randomly assigned to repeated-sprint cycling training in normobaric hypoxia (n = 9) or normoxia (n = 9) groups. Training consisted of 4 sessions of repeated-sprint cycling training in normobaric hypoxia or in normoxia (4 × 5 × 5-s cycle sprints-25-s intersprint recovery performed in simulated altitude of ∼5000 m or in normoxia with 3-min interset rest in normoxia for both groups) in addition to rugby sevens training and strength and conditioning sessions within a 9-day intervention period before an international competition. Before and 1 day after the intervention, single 50-m overground running "all-out" sprint performance and associated F-V-related mechanical output were assessed. RESULTS:No interaction (group × time; all P > .088), time effect (before vs 1 d after; all P > .296), or group effect (repeated-sprint cycling training in normobaric hypoxia vs in normoxia; all P > .325) was detected for 50-m overground running sprint performance and any derived F-V profiling variables. CONCLUSIONS:Four sessions of repeated-sprint training either in hypoxia or in normoxia performed over 9 days had no influence on single 50-m overground running sprint performance and associated F-V profile. In world-class female rugby sevens players, the intervention (training camp before an international competition) might have been too short to induce measurable changes. It is also plausible that implementing a similar program in players with likely different F-V profile may result in negligible mechanical effect.

BACKGROUND:This study compared the physical performance of National female rugby sevens players selected or not selected to form the Brazilian National Olympic team.METHODS:Thirty women rugby sevens players from the Brazilian National team (15 Olympic and 15 non-Olympic athletes) participated in this study. Tests were performed on consecutive days, in the following order: day 1) standing long jump (SLJ); squat and countermovement jumps (SJ and CMJ); and one-repetition maximum test in the bench-press, prone-row, and parallel squat exercises; day 2) 40-m linear sprint; Pro-agility and L-drill change of direction tests; and Yo-Yo intermittent recovery test level 1 (IR1). The differences between groups in all variables examined were analyzed using the independent t test and effect sizes (ES).RESULTS:Greater jump performances were noticed for the Olympic players in all jump tests compared to the non-Olympics (ES=0.95, ES=1.05, and ES=0.93, for SLJ, SJ, and CMJ, respectively; P<0.05). Olympics revealed shorter sprint times than non-Olympics in 40-m distance (ES=0.88; P<0.05). Higher one-repetition maximum in the bench-press and Yo-Yo IR1 distance were also observed for the Olympics in comparison to non-Olympic players (ES=0.65 and 0.93, respectively; P<0.05).CONCLUSIONS:Lower-body power, upper-body strength, maximal sprint velocity and aerobic fitness were found to be important for distinguishing between Olympic and non-Olympic female rugby sevens players. Coaches and practitioners should prioritize the development of these physical qualities in these team-sport athletes.

Headline E lite Rugby Sevens match play is characterized by high intensity running, accelerations, decelerations and collisions (11), and repeated high-intensity efforts (4, 5). Due to the popularity of Rugby Sevens, tournaments are played worldwide, including in hot and humid environments (e.g. 45°C in Sydney during Sevens 2020). When training or competing in the heat, physiological strain can lead to impairments in endurance exercise capacity (9). Elevated whole-body temperature can also impair repeated sprint performance through a reduction in arterial oxygen delivery, greater reliance on anaerobic energy provision and accelerated accumulation of atomic hydrogen (6). Such heat related physiological impairments could impact performance in Rugby Sevens. Training strategies to mitigate the effects of heat stress on physical performance should be explored in the context of Rugby Sevens. If such strategies are effective, they could help staff and players to adequately prepare for the next Olympic Games in Tokyo, where similar conditions will be encountered (10). Recently, equipped with an environmental chamber (hypoxia, heat and relative humidity), the French Rugby Union investigated the potential effect of high-intensity interval training (HIIT) performed in the heat before the 2019 Dubai Sevens tournament.

This study describes asymmetry in the main running mechanical variables during repeated treadmill sprints in elite female athletes and examines whether inter-limb differences in sprinting mechanics increase with fatigue. Eighteen elite female players (French national Rugby Sevens team) performed 8 × 5-s sprints (25-s rest) on an instrumented motorised sprint treadmill. The group mean 'symmetry angle' (SA) scores were ~1-2% for contact time (1.6 ± 0.6%), aerial time (2.1 ± 0.8%), step frequency (1.3 ± 0.5%) and step length (1.6 ± 0.6%). Mean vertical and horizontal forces, vertical and leg stiffness presented SA values of 1.7 ± 1.5%, 2.4 ± 1.2%, 2.6 ± 0.2% and 2.5 ± 0.2%, respectively. The SA scores were ~2-8% for duration of braking (6.9 ± 5.0%) and propulsive (6.5 ± 4.4%) phases, peak braking (6.5 ± 2.5%) and propulsive (1.6 ± 0.9%) forces as well as net (5.8 ± 5.6%), braking (7.7 ± 5.3%) and propulsive (2.7 ± 1.6%) impulses. However, there was no influence of sprint repetition number on SA scores for tested variables (P > 0.05). In elite female Rugby Sevens players, there was no noticeable difference in asymmetries for the great majority of stride mechanical variables during repeated treadmill sprints.

Rugby sevens, a sport new to the Olympics, features high-intensity intermittent running and contact efforts more than short match durations, normally 6 times across 2 to 3 d in a tournament format. Elite rugby sevens seasons often include over a dozen competitive tournaments over less than 9 months, demanding deliberate and careful training-stress balance and workload management alongside development of the necessary physical qualities required for competition. Focus on running and repeated power skills, strength, and match-specific conditioning capacities is advised. Partial taper approaches in combination with high-speed running (>5 m/s from GPS measures) before and between tournaments in succession may reduce injury rates and enhance performance. In a sport with substantial long-haul intercontinental travel and repetitive chronic load demands, management of logistics including nutrition and recovery is inclusive of the formula for success in the physical preparation of elite rugby sevens athletes.

Purpose: To investigate the running demands and associated metabolic perturbations during an official rugby sevens tournament. Methods: Twelve elite players participated in 7 matches wearing GPS units. Maximal sprinting speed (MSS) and maximal aerobic speed (MAS) were measured. High-intensity threshold was individualized relative to MAS (>100% of MAS), and very-high-intensity distance was reported relative to both MAS and MSS. Blood samples were taken at rest and after each match. Results: Comparison of prematch and postmatch samples revealed significant (P < .01) changes in pH (7.41-7.25), bicarbonate concentration ([HCO3-]) (24.8-13.6 mmol/L), and lactate concentration ([La]) (2.4-11.9 mmol/L). Mean relative total distance covered was 91 +/- 13 m/min with similar to 17 m/min at high-intensity. Player status (whole-match or interchanged players), match time, and total distance covered had no significant impact on metabolic indices. Relative distance covered at high intensity was negatively correlated with pH and [HCO3-] (r = .44 and r = .42, respectively; P < .01) and positively correlated with [La] (r = .36; P < .01). Total distance covered and distance covered at very high intensity during the 1-min peak activity in the last 3 min of play were correlated with [La] (r = .39 and r = .39, respectively; P < .01). Conclusions: Significant alterations in blood-metabolite indices from prematch to postmatch sampling suggest that players were required to tolerate a substantial level of acidosis related to metabolite accumulation. In addition, the ability to produce energy via the glycolytic energy pathway seems to be a major determinant in match-related running performance.

PURPOSE:To compare the sensitivity of a sprint vs a countermovement-jump (CMJ) test after an intense training session in international rugby sevens players, as well as analyze the effects of fatigue on sprint acceleration.METHODS:Thirteen international rugby sevens players completed two 30-m sprints and a set of 4 repetitions of CMJ before and after a highly demanding rugby sevens training session.RESULTS:Change in CMJ height was unclear (-3.6%; ±90% confidence limits 11.9%. Chances of a true positive/trivial/negative change: 24/10/66%), while a very likely small increase in 30-m sprint time was observed (1.0%; ±0.7%, 96/3/1%). A very likely small decrease in the maximum horizontal theoretical velocity (V0) (-2.4; ±1.8%, 1/4/95%) was observed. A very large correlation (r = -.79 ± .23) between the variations of V0 and 30-m-sprint performance was also observed. Changes in 30-m sprint time were negatively and very largely correlated with the distance covered above the maximal aerobic speed (r = -.71 ± .32).CONCLUSIONS:The CMJ test appears to be less sensitive than the sprint test, which casts doubts on the usefulness of a vertical-jump test in sports such as rugby that mainly involve horizontal motions. The decline in sprint performance relates more to a decrease in velocity than in force capability and is correlated with the distance covered at high intensity.

Ce travail de thèse s’inscrit dans le cadre de travaux menés en sciences du sport. Basé sur l’exploration des caractéristiques physiques et physiologiques, les performances techniques et physiques des joueurs de l’équipe de France de Rugby à 7, ont été étudiées au travers de l’analyse de tournois internationaux.Dans une première étude, nous avons observé l’impact de variables contextuelles sur les performances physiques et techniques des joueurs en match. Les résultats démontrent que le niveau de l'adversaire ainsi que le résultat du match influencent l’activité des joueurs.Ces derniers sont susceptibles de réaliser de meilleures performances physiques au cours de match dont l’issue est favorable. En effet, les joueurs augmentent la distance totale parcourue dans un match contre un adversaire plus faible. Pour la première fois en Rugby à 7, nous avons montré que les performances techniques sont elles aussi influencées lorsque les joueurs de l’équipe de France jouaient contre une équipe plus forte. En effet, nous avons observé des diminutions du nombre de passes et de situations où les joueurs sont porteurs de balle.Au travers d’une approche physiologique, une deuxième étude a appréhendé les réponses métaboliques individuelles des joueurs de l’équipe de France durant un tournoi international. Les résultats ont montré des relations significatives entre les concentrations de lactate et les pics d’activité enregistrés dans les trois dernières minutes de jeu, ce qui suggère que la capacité à fournir de l'énergie via la voie de la glycolyse est une exigence fondamentale dans cette discipline. L'équilibre acido-basique modifié de façon significative en fin de match, indique que les joueurs doivent être capables de tolérer un niveau important d'acidose due à une forte sollicitation énergétique lors des matchs internationaux.Enfin, notre dernière étude s’est centrée sur les actions de haute intensité effectuées en match. Ces derniers résultats de recherche ont permis de démontrer qu’un joueur réalise en moyenne ~26 actions de haute intensité par match. De plus et pour la première fois dans cette discipline, nous avons montré qu’environ 4 séquences de répétitions d’actions de haute intensité sont comptabilisées en match, dont la durée moyenne est d’environ 40 secondes et comprennent des temps de récupérations inférieurs à 9 secondes. Ainsi, le Rugby à 7 peut être considéré comme un sport collectif de répétitions d’efforts intenses.Pour conclure alors, ces travaux de thèse vont permettre aux entraîneurs et préparateurs physiques de Rugby à 7, de pouvoir s’inspirer de nos résultats pour planifier et mettre en œuvre des entraînements spécifiques aux exigences du Rugby à 7.