Team Behavior and Performance: An Exploration in the Context of Professional Rugby Union.

PURPOSE: To explore complex system behavior and subsequent team performance in professional rugby union. METHODS: Here, we present 2 studies. In the first, we used global positioning system technology to measure player clustering during stoppages in play in nearly 100 games of professional rugby union to explore team (complex system) behavior and performance. In the second, we measured stress hormones (cortisol and testosterone) prior to team meetings and analyzed these relative to amount of time and the frequency with which players looked at peer presenters, as well as subsequent training performance, to explain how stress may lead to behaviors observed in the first study and subsequent match performance. RESULTS: No link between player clustering during stoppages of play and performance was observed. When players (complex system agents) demonstrated greater levels of stress (as indicated by greater cortisol-awakening response and a greater decline in testosterone-to-cortisol ratio across the morning), they tended to look at peer presenters more; however, training quality declined (P = .02). Correlational analysis also showed that training quality was related to testosterone-to-cortisol ratio (P = .04). CONCLUSIONS: Team behavior is complex and can be unpredictable. It is possible that under stress, complex system agents (ie, rugby union players) look at (and cluster toward) their teammates more; however, meaningful interaction may not necessarily occur. Furthermore, while complex system (team) analysis may be valuable strategically in rugby union in the context of describing behavior, without understanding "how" or "why" intrateam/interagent behaviors emerge it may have little meaning.

Acute Performance, Daily Well-Being, and Hormone Responses to Water Immersion After Resistance Exercise in Junior International and Subelite Male Volleyball Athletes.

ABSTRACT: Horgan, BG, Tee, N, West, NP, Drinkwater, EJ, Halson, SL, Colomer, CME, Fonda, CJ, Tatham, J, Chapman, DW, and Haff, GG. Acute performance, daily well-being and hormone responses to water immersion after resistance exercise in junior international and subelite male volleyball athletes. J Strength Cond Res 37(8): 1643-1653, 2023-Athletes use postexercise hydrotherapy strategies to improve recovery and competition performance and to enhance adaptative responses to training. Using a randomized cross-over design, the acute effects of 3 postresistance exercise water immersion strategies on perceived recovery, neuromuscular performance, and hormone concentrations in junior international and subelite male volleyball athletes ( n = 18) were investigated. After resistance exercise, subjects randomly completed either 15-minute passive control (CON), contrast water therapy (CWT), cold (CWI), or hot water immersion (HWI) interventions. A treatment effect occurred after HWI; reducing perceptions of fatigue (HWI > CWT: p = 0.05, g = 0.43); improved sleep quality, compared with CON ( p < 0.001, g = 1.15), CWI ( p = 0.017, g = 0.70), and CWT ( p = 0.018, g = 0.51); as well as increasing testosterone concentration (HWI > CWT: p = 0.038, g = 0.24). There were trivial to small ( p < 0.001-0.039, g = 0.02-0.34) improvements (treatment effect) in jump performance (i.e., squat jump and countermovement jump) after all water immersion strategies, as compared with CON, with high variability in the individual responses. There were no significant differences (interaction effect, p > 0.05) observed between the water immersion intervention strategies and CON in performance ( p = 0.153-0.99), hormone ( p = 0.207-0.938), nor perceptual ( p = 0.368-0.955) measures. To optimize recovery and performance responses, e.g., during an in-season competition phase, postresistance exercise HWI may assist with providing small-to-large improvements for up to 38 hours in perceived recovery (i.e., increased sleep quality and reduced fatigue) and increases in circulating testosterone concentration. Practitioners should consider individual athlete neuromuscular performance responses when prescribing postexercise hydrotherapy. These findings apply to athletes who aim to improve their recovery status, where postresistance exercise HWI optimizes sleep quality and next-day perceptions of fatigue.

Performance Analysis in Rugby Union: a Critical Systematic Review.

BACKGROUND: Performance analysis in rugby union has become an integral part of the coaching process. Although performance analysis research in rugby and data collection has progressed, the utility of the insights is not well understood. The primary objective of this review is to consider the current state of performance analysis research in professional rugby union and consider the utility of common methods of analysing performance and the applicability of these methods within professional coaching practice. METHODS: SPORTDiscus electronic database was searched for relevant articles published between 1 January 1997 and 7 March 2019. Professional, male 15-a-side rugby union studies that included relevant data on tactical and performance evaluation, and statistical compilation of time-motion analysis were included. Studies were categorised based on the main focus and each study was reviewed by assessing a number of factors such as context, opposition analysis, competition and sample size. RESULTS: Forty-one studies met the inclusion criteria. The majority of these studies measured performance through the collection and analysis of performance indicators. The majority did not provide context relating to multiple confounding factors such as field location, match location and opposition information. Twenty-nine performance indicators differentiated between successful match outcomes; however, only eight were commonly shared across some studies. Five studies considered rugby union as a dynamical system; however, these studies were limited in analysing lower or national-level competitions. CONCLUSIONS: The review highlighted the issues associated with assessing isolated measures of performance, lacking contextual information such as the opposition, match location, period within match and field location. A small number of studies have assessed rugby union performance through a dynamical systems lens, identifying successful characteristics in collective behaviour patterns in attacking phases. Performance analysis in international rugby union can be advanced by adopting these approaches in addition to methods currently adopted in other team sports.

Sleep and Salivary Testosterone and Cortisol During a Short Preseason Camp: A Study in Professional Rugby Union.

Purpose: To examine changes in, and relationships between, sleep quality and quantity, salivary testosterone, salivary cortisol, testosterone-to-cortisol ratio (T:C), and self-reported muscle soreness during a residential-based training camp in elite rugby players. Methods: Nineteen male rugby players age 26.4 (3.9) years, height 186.0 (9.4) cm, and weight 104.1 (13.4) kg (mean [SD]) participated in this study. Wrist actigraphy devices were worn for 8 nights around a 4-d training camp (2 nights prior, during, and 2 nights after). Sleep-onset latency, sleep duration, sleep efficiency, and waking time were measured. Participants provided saliva samples during camp on waking and again 45 min later, which were then assayed for testosterone and cortisol levels. They also rated their general muscle soreness daily. Results: Little variation was observed for sleep quality and quantity or testosterone. However, significant differences were observed between and within days for cortisol, T:C, and muscle soreness (P < .001). Few relationships were observed for sleep and hormones; the strongest, an inverse relationship for sleep efficiency and T:C (r = -.372, P < .01). Conclusions: There may be no clear and useful relationship between sleep and hormone concentration in a short-term training camp context, and measures of sleep and testosterone and cortisol should be interpreted with caution because of individual variation. Alterations in hormone concentration, particularly cortisol, may be affected by other factors including anticipation of the day ahead. This study adds to our knowledge that changes in hormone concentration are individual and context specific.