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Purpose: The aims of this study were to (1) assess the concurrent validity of global positioning systems (GPSs) against a radar device to measure sprinting force–velocity (F–v) profiles and (2) evaluate the interunit reliability of 10-Hz GPS devices (Vector S7, Catapult Innovations). Methods: Sixteen male elite U18 rugby union players (178.3 [7.6] cm; 78.3 [13.2] kg) participated. Two 50-m sprints interspersed with at least 5 minutes of recovery were completed to obtain input (maximal sprint speed and acceleration time constant τ) and output (theoretical maximal horizontal force, sprinting speed, and horizontal power) F–v profile variables. Sprint running speed was concurrently measured with a radar and 2 GPS units placed on the upper back of each player. Concurrent validity and interunit reliability analyses were performed. Results: Moderate to nearly perfect correlations were observed between radar and GPS-derived F–v variables, with small to large typical errors. Trivial to small coefficients of variation were found regarding the GPS interunit reliability. Conclusion: The GPS devices tested in this study represent a valid and reliable alternative to a radar device when assessing sprint acceleration F–v profiles in team-sport players. [ABSTRACT FROM AUTHOR]

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 x 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 a-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. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the relationship between matchday wellness status and a technical–tactical performance construct during rugby match-play. One hundred and thirty-three male rugby union players (73 forwards and 60 backs) from five under-18 national squads who participated in the under-18 Six Nations competition completed a subjective wellness questionnaire on each matchday morning. Players subjectively rated each item (sleep quality, fatigue, muscle soreness, stress and mood) on a five-point Likert scale to calculate their daily wellness status (i.e. difference between matchday and baseline perceived wellness). Technical–tactical performance during match-play was quantified by coding individual key performance indicators (e.g. number of carries, number of tackles). Partial least squares correlation analysis (PLSCA) was employed to compute the latent variables of perceived wellness status (X matrix) and technical–tactical performance (Y matrix) for each player observation (n = 271). The latent variables are a construct of each variable group, enabling higher dimensional data to be visualised more simply. Linear mixed-effect models were later conducted to assess the relationships between the latent variables. The effect of perceived wellness status on technical–tactical performance was statistically significant in forwards (p =.042), not statistically significant in backs (p =.120) and accounted for 4.9% and 1.9% variance in the technical–tactical performance construct, respectively. The findings of this study suggest that perceived wellness status can influence technical–tactical match performance, but the practical significance of these findings should be interpreted with caution given the amount of variance in technical–tactical performance accounted by the models. [ABSTRACT FROM AUTHOR]

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. Purpose: To monitor the changes in physical performance in elite team-sport players during a 3-wk taper after a preseason training camp. Methods: 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. Results: At Post, no single peak performance was observed for maximal lowerlimb 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

It is widely recognised that the physical demands in rugby sevens are high especially in comparison to the 15-aside version. The aim of this study was to assess fluctuations in physical performance (running and contact loads) in international rugby sevens competition. Altogether, 32 matches played by an international team in the HSBC World Sevens Series were analyzed (63 match-observations). Players wore a validated GPS device (SensorEverywhere, France) sampling at 16Hz while an operator coded every contact action (tackles, collisions, mauls, scrums) using video analysis software (SportsCode, USA). Running load was assessed using total distance travelled (m), individually determined high-speed distance (covered at velocities > maximal aerobic speed, m) and very-high speed distance (covered at velocities > 85% maximal sprinting speed, m). The frequency of accelerations (actions > 2.5 m⋅s-2) and high-intensity actions (HIA, sum of high- velocity runs, accelerations and contact-related actions, n) were also calculated. A magnitude-based inferential approach to statistics was adopted and effect sizes quantified. Findings showed: 1) a small decrease in high-speed distance and number of accelerations performed during the second- versus the first-half of play suggesting a decline in running performance. (2) a moderately higher total distance and high-speed distance covered during the first and final 1-min period compared to the average for other 1-min periods, suggesting a specific reverse 'J-shape' pacing profile 3) a most likely decrease in total distance, high-speed running, and to a lesser extent the number of accelerations declined following the peak 1-min period of the game. These findings provide pertinent information on changes in running performance over the course of international sevens and have implications for physical conditioning strategies. [ABSTRACT FROM AUTHOR]