Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players.

Russell, M, Reynolds, NA, Crewther, BT, Cook, CJ, and Kilduff, L. Physiological and performance effects of caffeine gum consumed during a simulated half-time by professional academy rugby union players. J Strength Cond Res 34(1): 145-151, 2020-Despite the prevalence of caffeine (CAF) as an ergogenic aid, few studies have examined the use of caffeinated gums, especially during half-time in team sports. The physiological (blood lactate and salivary hormone concentrations) and performance (repeated sprints and cognitive function) effects of consuming CAF gum during a simulated half-time were examined. Professional academy rugby union players (n = 14) completed this double-blind, randomized, counterbalanced study. After pre-exercise measurements, players chewed a placebo (PLC) gum for 5 minutes before a standardized warm-up and completing repeated sprint testing (RSSA1). Thereafter, during a 15-minute simulated half-time period, players chewed either CAF (400 mg; 4.1 ± 0.5 mg·kg) or PLC gum for 5 minutes before completing a second repeated sprint test (RSSA2). Blood lactate, salivary testosterone and cortisol concentrations, and indices of cognitive function (i.e., reaction time and Stroop test) were measured at baseline, pre-RSSA1, post-RSSA1, pre-RSSA2, and post-RSSA2. Sprint performance was not affected by CAF (p = 0.995) despite slower sprint times after the first sprint of both RSSA tests (all p < 0.002). After half-time, salivary testosterone increased by 70% (+97 ± 58 pg·ml) in CAF vs. PLC (p < 0.001), whereas salivary cortisol remained unchanged (p = 0.307). Cognitive performance was unaffected by time and trial (all p > 0.05). Although performance effects were absent, chewing CAF gum increased the salivary testosterone concentrations of professional rugby union players over a simulated half-time. Practitioners may, therefore, choose to recommend CAF gum between successive exercise bouts because of the increases in salivary testosterone observed; a variable associated with increased motivation and high-intensity exercise performance.

FIFA 11+: an effective programme to prevent football injuries in various player groups worldwide-a narrative review.

In 2009, FIFA promoted and disseminated the FIFA 11+ injury prevention programme worldwide. Developed and studied by the FIFA Medical Assessment and Research Centre (F-MARC), the programme was based on a randomised controlled study and one countrywide campaign in amateur football that significantly reduced injuries and healthcare costs. Since the FIFA 11+ launch, key publications have confirmed the preventive effects of the programme and have evaluated its performance effects in female as well as male amateur football players. Furthermore, implementation strategies of this prevention programme have also been studied. The goal of this narrative review was to summarise the available scientific evidence about the FIFA 11+ programme. While FIFA continues to disseminate and implement FIFA 11+ among its Member Associations, adaptations of the injury prevention programme for children and referees have been developed and are currently being evaluated.

Respiratory muscle specific warm-up and elite swimming performance.

BACKGROUND: Inspiratory muscle training has been shown to improve performance in elite swimmers, when used as part of routine training, but its use as a respiratory warm-up has yet to be investigated. AIM: To determine the influence of inspiratory muscle exercise (IME) as a respiratory muscle warm-up in a randomised controlled cross-over trial. METHODS: A total of 15 elite swimmers were assigned to four different warm-up protocols and the effects of IME on 100 m freestyle swimming times were assessed.Each swimmer completed four different IME warm-up protocols across four separate study visits: swimming-only warm-up; swimming warm-up plus IME warm-up (2 sets of 30 breaths with a 40% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); swimming warm-up plus sham IME warm-up (2 sets of 30 breaths with a 15% maximum inspiratory mouth pressure load using the Powerbreathe inspiratory muscle trainer); and IME-only warm-up. Swimmers performed a series of physiological tests and scales of perception (rate of perceived exertion and dyspnoea) at three time points (pre warm-up, post warm-up and post time trial). RESULTS: The combined standard swimming warm-up and IME warm-up were the fastest of the four protocols with a 100 m time of 57.05 s. This was significantly faster than the IME-only warm-up (mean difference=1.18 s, 95% CI 0.44 to 1.92, p<0.01) and the swim-only warm-up (mean difference=0.62 s, 95% CI 0.001 to 1.23, p=0.05). CONCLUSIONS: Using IME combined with a standard swimming warm-up significantly improves 100 m freestyle swimming performance in elite swimmers.

The effect of coach and player injury knowledge, attitudes and beliefs on adherence to the FIFA 11+ programme in female youth soccer.

BACKGROUND: Injury knowledge and beliefs influence uptake of prevention programmes, but the relationship between knowledge, beliefs and adherence remains unclear. AIM: To describe injury knowledge and beliefs among youth female soccer coaches and players, and to identify the relationship between these factors, different delivery strategies of the FIFA 11+ programme and adherence. METHODS: A subcohort analysis from a cluster-randomised controlled trial of 31 female soccer teams (coaches n=29, players (ages 13-18) n=258). Preseason and postseason questionnaires were used to assess knowledge and beliefs. Teams recorded FIFA 11+ adherence during the season. RESULTS: At baseline, 62.8% (95% CI 48.4% to 77.3%) of coaches and 75.8% (95% CI 71.5% to 80.1%) of players considered 'inadequate warm-up' a risk factor for injury. There was no effect of delivery method (OR=1.1; 95% CI 0.8 to 1.5) or adherence (OR=1.0; 95% CI 0.9 to 1.1) on this belief. At baseline, 13.8% (95% CI 1.3% to 26.4%) of coaches believed a warm-up could prevent muscle injuries, but none believed it could prevent knee and ankle injuries. For players, 9.7% (95% CI 6.1% to 13.3%), 4.7% (95% CI 2.1% to 7.3%) and 4.7% (95% CI 2.1% to 7.3%) believed a warm-up would prevent muscle, knee and ankle injuries, respectively. Years of playing experience were negatively associated with high adherence for coaches (OR=0.93; 0.88 to 0.99) and players (OR=0.92; 0.85 to 0.98). CONCLUSIONS: There were gaps in injury knowledge and beliefs, which differed for coaches and players. Beliefs did not significantly affect adherence to the FIFA 11+, suggesting additional motivational factors should be considered.

Preconditioning Strategy in Rugby-7s Players: Beneficial or Detrimental?

PURPOSE: Preconditioning strategies are considered as opportunities to optimize performance on competition day. While investigations conducted in rugby players on the effects of a morning preconditioning session already exist, additional work is warranted. The aim of this study was to monitor changes in physical and psychophysiological indicators among international Rugby-7s players following a priming exercise. METHODS: In a randomized crossover-design, fourteen under-18 international Rugby-7s players completed, at 8:00am, a preconditioning session consisting of a warm-up followed by small-sided games, accelerations and 2 x 50-m maximal sprints (Experimental) or no pre-loading session (Control). Following a 2-hour break, the players performed a set of six 30-m sprints and a Rugby-7s match. Recovery-stress state and salivary stress-markers levels were assessed before the preloading session (Pre), immediately after (Post-1), before the testing session (Post-2) and after (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 to 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 alpha-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 pre-conditioning session.

Variabilidade do lactato sanguíneo em resposta a nados de aquecimento e de máxima intensidade / Variability of blood lactate in response on heating and maximum intensity swim

Os objetivos do presente estudo foram (1) verificar as concentrações de lactato no sangue e sua variabilidade em resposta à intensidade característica de aquecimento e em resposta à máxima intensidade de nado; (2) verificar o comportamento das concentrações de lactato ao longo do tempo, e (3) testar a correlação entre valores de pico de concentração de lactato com o desempenho em 200 m nado crawl. Participaram 13 nadadores competitivos, com experiência de, no mínimo, 4 anos na modalidade. Foram obtidas amostras de sangue arterializado que foram analisadas com aparelho portátil para mensuração de lactato Accusport (Roche) em quatro momentos distintos: após 15 min de repouso em decúbito dorsal (M1), após 800 m nadados em intensidade de aquecimento (M2), um (M3) e três minutos (M4) após 200 m nadados em máxima intensidade no estilo crawl. O desempenho na distância de 200 m foi transformado em unidades pontuais (DESP) a fim de comparação com outros estudos. Os resultados apontaram para maiores concentrações de lactato em M3 e M4 em comparação à M1 e M2). Alta variabilidade inter e intra-indivíduos foi verificada. Nenhuma correlação entre desempenho e concentração de lactato sanguíneo foi encontrada. As diferenças inter individuais devem ser levadas em consideração quando se busca estudar o metabolismo energético em natação.

The objectives of this study were (1) to verify the concentrations of lactate in the blood and its variability in response to the characteristic intensity of warming up and response to maximum intensity in swim, (2) to verify the behavior of lactate concentrations over time, and (3) to test the correlation between peak values of lactate concentration and performance in 200 m crawl. Subjects were 13 competitive swimmers, with experience of at least four years in the sport. Samples of arterial blood were obtained and analyzed through a portable device for lactate measurement Accusport (Roche) from four different times: after 15 min rest in the supine position (M1), after 800 m intensity heating swimming(M2), one (M3) and three minutes (M4) after a 200 m at maximum intensity swimming in front crawl stroke. The performance at the distance of 200 m was transformed on units (DESP) to compare to other studies. The results pointed to higher lactate concentration values in M3 and M4 when compared to M1 and M2. High variability within and between individuals were found. None correlation between performance and blood lactate concentration was found. The inter-individual differences should be taken into consideration when seeking to study energy metabolism in swimming.