Purpose: During heavily congested schedules, professional soccer players can experience exacerbated fatigue responses, which are thought to contribute to an increased risk of injury. Given that match-induced residual fatigue can last up to 72 hours, many coaches naturally prioritize recovery in the days immediately following match day. While it is intuitive for coaches and training staff to decrease the amount of auxiliary training practices to focus on recovery, prescribing upper-body resistance training on the day after match play has recently emerged as a specific training modality in this context. While these sessions may be implemented to increase training stimulus, there are limited data available regarding the efficacy of such a practice to improve recovery kinetics. Methods: In this narrative review, the authors look at the theoretical implications of performing upper-body resistance training on the day after match play on the status of various physiological and psychological systems, including neuromuscular, metabolic, hormonal, perceptual, and immunological recovery. Results: The available evidence suggests that in most cases this practice, as currently implemented (ie, low volume, low intensity), is unlikely to be complementary (ie, does not accelerate recovery) but is potentially compatible (ie, does not impair recovery). Conclusion: Overall, because the perception of such sessions may be player dependent, their programming requires an individualized approach and should take into account match dynamics (eg, fixture scheduling, playing time, travel).
Angelo Sabag, Ric Lovell, Neil P. Walsh, Nick Grantham, Mathieu Lacome, and Martin Buchheit
Pauline Clavel, Eve Tiollier, Cédric Leduc, Marina Fabre, Mathieu Lacome, and Martin Buchheit
Purpose: To assess the concurrent validity of a continuous blood-glucose-monitoring system (CGM) postbreakfast, preexercise, exercise, and postexercise, while assessing the impact of 2 different breakfasts on the observed level of validity. Methods: Eight nondiabetic recreational athletes (age = 30.8 [9.5] y; height = 173.6 [6.6] cm; body mass = 70.3 [8.1] kg) took part in the study. Blood glucose concentration was monitored every 10 minutes using both a CGM (FreeStyle Libre, Abbott, France) and finger-prick blood glucose measurements (FreeStyle Optimum) over 4 different periods (postbreakfast, preexercise, exercise, and postexercise). Two different breakfasts (carbohydrates [CHO] and protein oriented) over 2 days (2 × 2 d in total) were used. Statistical analyses included the Bland–Altman method, standardized mean bias (expressed in standardized units), median absolute relative difference, and the Clarke error grid analysis. Results: Overall, mean bias was trivial to small at postbreakfast (effect size ± 90% confidence limits: −0.12 ± 0.08), preexercise (−0.08 ± 0.08), and postexercise (0.25 ± 0.14), while moderate during exercise (0.66 ± 0.09). A higher median absolute relative difference was observed during exercise (13.6% vs 7%–9.5% for the other conditions). While there was no effect of the breakfast type on the median absolute relative difference results, error grid analysis revealed a higher value in zone D (ie, clinically unsafe zone) during exercise for CHO (10.5%) compared with protein (1.6%). Conclusion: The CGM device examined in this study can only be validly used at rest, after both a CHO and protein-rich breakfast. Using CGM to monitor blood glucose concentration during exercise is not recommended. Moreover, the accuracy decreased when CHO were consumed before exercise.
Cédric Leduc, Jason Tee, Mathieu Lacome, Jonathon Weakley, Jeremy Cheradame, Carlos Ramirez, and Ben Jones
Purpose: To investigate the convergent validity, reliability, and sensitivity over a week of training of a standardized running test to measure neuromuscular fatigue. Methods: 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. Results: 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. Conclusions: 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.
Bruno Marrier, Alexandre Durguerian, Julien Robineau, Mounir Chennaoui, Fabien Sauvet, Aurélie Servonnet, Julien Piscione, Bertrand Mathieu, Alexis Peeters, Mathieu Lacome, Jean-Benoit Morin, and Yann Le Meur
Purpose: Preconditioning strategies are considered opportunities to optimize performance on competition day. Although investigations conducted in rugby players on the effects of a morning preconditioning session have been done, additional work is warranted. The aim of this study was to monitor changes in physical and psychophysiological indicators among international Rugby-7s players after a priming exercise. Methods: In a randomized crossover design, 14 under-18 international Rugby-7s players completed, at 8:00 AM, a preconditioning session consisting of a warm-up followed by small-sided games, accelerations, and 2 × 50-m maximal sprints (Experimental), or no preloading session (Control). After a 2-h break, the players performed a set of six 30-m sprints and a Rugby-7s match. Recovery–stress state and salivary stress-marker levels were assessed before the preloading session (Pre), immediately after the preloading session (Post 1), before the testing session (Post 2), and after the testing session (Post 3). Results: Experimental–Control differences in performance across a repeated-sprint test consisting of six 30-m sprints were very likely trivial (+0.2, ±0.7%, 3/97/1%). During the match, the total distance covered and the frequency of decelerations were possibly lower (small) in Experimental compared with Control. Differences observed in the other parameters were unclear or possibly trivial. At Post 2, the perceived recovery–stress state was improved (small difference) in Experimental compared with Control. No difference in salivary cortisol response was observed, while the preconditioning session induced a higher stimulation of salivary testosterone and α-amylase. Conclusions: The players’ ability to repeat sprints and physical activity in match play did not improve, but their psychophysiological state was positively affected after the present preconditioning session.
Bruno Marrier, Julien Robineau, Julien Piscione, Mathieu Lacome, Alexis Peeters, Christophe Hausswirth, Jean-Benoît Morin, and Yann Le Meur
Peaking for major competition is considered critical for maximizing team-sport performance. However, there is little scientific information available to guide coaches in prescribing efficient tapering strategies for team-sport players.
To monitor the changes in physical performance in elite team-sport players during a 3-wk taper after a preseason training camp.
Ten male international rugby sevens players were tested before (Pre) and after (Post) a 4-wk preseason training camp focusing on high-intensity training and strength training with moderate loads and once each week during a subsequent 3-wk taper. During each testing session, midthigh-pull maximal strength, sprint-acceleration mechanical outputs, and performance, as well as repeated-sprint ability (RSA), were assessed.
At Post, no single peak performance was observed for maximal lower-limb force output and sprint performance, while RSA peaked for only 1 athlete. During the taper, 30-m-sprint time decreased almost certainly (–3.1% ± 0.9%, large), while maximal lower-limb strength and RSA, respectively, improved very likely (+7.7% ± 5.3%, small) and almost certainly (+9.0% ± 2.6%, moderate). Of the peak performances, 70%, 80%, and 80% occurred within the first 2 wk of taper for RSA, maximal force output, and sprint performance, respectively.
These results show the sensitivity of physical qualities to tapering in rugby sevens players and suggest that an ~1- to 2-wk tapering time frame appears optimal to maximize the overall physical-performance response.
Anthony Couderc, Claire Thomas, Mathieu Lacome, Julien Piscione, Julien Robineau, Rémi Delfour-Peyrethon, Rachel Borne, and Christine Hanon
To investigate the running demands and associated metabolic perturbations during an official rugby sevens tournament.
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.
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 ~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).
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.
Bruno Marrier, Yann Le Meur, Julien Robineau, Mathieu Lacome, Anthony Couderc, Christophe Hausswirth, Julien Piscione, and Jean-Benoît Morin
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.
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.
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).
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.
Bruno Marrier, Yann Le Meur, Cédric Leduc, Julien Piscione, Mathieu Lacome, Germain Igarza, Christophe Hausswirth, Jean-Benoît Morin, and Julien Robineau
Purpose: To describe the training periodization in rugby sevens players competing in the World Rugby Sevens Series during a non-Olympic season. Methods: Workload data were collected over a 33-wk period in 12 male players participating in a full competitive season. Workload was quantified using session rating of perceived exertion and global positioning system–derived data during training and competition. Self-reported well-being was assessed using a questionnaire. Each variable was analyzed weekly and through 5 mesocycles (preseason, in-season 1–4), each of which ended with competition blocks. Results: The perceived load decreased throughout the season for the full squad (−68% [26%] between preseason and final competitive block, large effect) and when unavailable players were removed from the analysis (−38% [42%], moderate). Weekly perceived load was highly variable, with a typical periodization in 4 phases during each mesocycle (regeneration, training overload, taper, and competition). During the preseason, the workload was higher during the overload training phase than during the competitive period (range: +23% to +59%, large to very large, for the distance covered above individual maximal aerobic speed and the number of accelerations). This observation no longer persisted during the season. The well-being score decreased almost certainly from in-season 3 (moderate). Conclusions: These results highlighted the apparent difficulty in maintaining high-load training periods throughout the season in players engaged on the World Rugby Sevens Series despite ∼4–7 training weeks separating each competitive block. This observation was likely explained by the difficulties inherent to the World Rugby Sevens Series (risk of contact injury, calendar, and multiple long-haul travel episodes) and potentially by limited squad-rotation policies.
Cedric Leduc, Dan Weaving, Cameron Owen, Mathieu Lacome, Carlos Ramirez-Lopez, Maj Skok, Jason C. Tee, and Ben Jones
Purpose: Sleep is recognized as an important recovery strategy, yet little is known regarding its impact on postmatch fatigue. The aims of this study were to (1) describe sleep and postmatch fatigue, (2) understand how sleep is affected by contextual and match factors, and (3) assess how changes in sleep can affect postmatch fatigue. Methods: Twenty-three male rugby union players were monitored across 1 season (N = 71 player–match observations). Actigraphy was used during preseason to establish baseline sleep quality and quantity. Sleep was then measured 1 and 2 days after each match day (MD + 1 and MD + 2). Global positioning systems, notational analysis, and rating of perceived exertion represented external and internal load from matches. Subjective wellness and a standardized run were used to characterize postmatch fatigue 2 days prior (baseline) and at MD + 1 and MD + 2. Linear mixed models established the magnitude of change (effect size [ES]) between baseline, MD + 1, and MD + 2 for sleep and postmatch fatigue. Stepwise forward selection analysis ascertained the effect of match load on sleep and the effect of sleep on postmatch fatigue. Each analysis was combined with magnitude-based decisions. Results: Sleep characteristics and neuromuscular and perceptual postmatch fatigue were negatively affected at MD + 1 and MD + 2 (ES = small to very large). Kickoff and travel time had the greatest effect on sleep (ES = small). Wellness and soreness were influenced by sleep (fall-asleep time and fragmentation index) and collisions, respectively (ES = small). Conclusion: Sleep quality and quantity were affected independently of the match load (ie, running activity) sustained, and changes in sleep marginally affected postmatch fatigue.
Sebastien Racinais, Julien D. Périard, Julien Piscione, Pitre C. Bourdon, Scott Cocking, Mohammed Ihsan, Mathieu Lacome, David Nichols, Nathan Townsend, Gavin Travers, Mathew G. Wilson, and Olivier Girard
Purpose: To investigate whether including heat and altitude exposures during an elite team-sport training camp induces similar or greater performance benefits. Methods: The study assessed 56 elite male rugby players for maximal oxygen uptake, repeated-sprint cycling, and Yo-Yo intermittent recovery level 2 (Yo-Yo) before and after a 2-week training camp, which included 5 endurance and 5 repeated-sprint cycling sessions in addition to daily rugby training. Players were separated into 4 groups: (1) control (all sessions in temperate conditions at sea level), (2) heat training (endurance sessions in the heat), (3) altitude (repeated-sprint sessions and sleeping in hypoxia), and (4) combined heat and altitude (endurance in the heat, repeated sprints, and sleeping in hypoxia). Results: Training increased maximal oxygen uptake (4% [10%], P = .017), maximal aerobic power (9% [8%], P < .001), and repeated-sprint peak (5% [10%], P = .004) and average power (12% [14%], P < .001) independent of training conditions. Yo-Yo distance increased (16% [17%], P < .001) but not in the altitude group (P = .562). Training in heat lowered core temperature and increased sweat rate during a heat-response test (P < .05). Conclusion: A 2-week intensified training camp improved maximal oxygen uptake, repeated-sprint ability, and aerobic performance in elite rugby players. Adding heat and/or altitude did not further enhance physical performance, and altitude appears to have been detrimental to improving Yo-Yo.