Russell, M, Sparkes, W, Northeast, J, Cook, CJ, Love, TD, Bracken, RM, and Kilduff, LP. Changes in acceleration and deceleration capacity throughout professional soccer match-play. J Strength Cond Res 30(10): 2839–2844, 2016—As the acceleration and deceleration demands of soccer are currently not well understood, this study aimed to profile markers of acceleration and deceleration capacity during professional soccer match-play. This within-player observational study required reserve team players from a Premier League club to wear 10-Hz Global Positioning System units throughout competitive matches played in the 2013–14 competitive season. Data are presented for players who completed 4 or more games during the season (n = 11), and variables are presented according to six 15-minute intervals (I1–6: 00:00–14:59 minutes, 15:00–29:59 minutes, 30:00–44:59 minutes, 45:00–59:59 minutes, 60:00–74:59 minutes, and 75:00–89:59 minutes, respectively). During I6, the distance covered (total, per minute, and at high intensity), number of sprints, accelerations (total and high intensity), decelerations (total and high intensity), and impacts were reduced compared with I1 (all p ≤ 0.05). The number of high-intensity impacts remained unchanged throughout match-play (p > 0.05). These findings indicate that high-intensity actions and markers of acceleration and deceleration capacity are reduced in the last 15 minutes of the normal duration of match-play. Such information can be used to increase the specificity of training programs designed for soccer players while also giving further insight in to the effects of 90 minutes of soccer-specific exercise. Interventions that seek to maintain the acceleration and deceleration capacity of players throughout the full duration of a soccer match warrant investigation.

Background In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~ 60% of energy intake, 5–8 g·kg− 1·d− 1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~ 1.6 g·kg− 1·d− 1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 g.kg− 1·d− 1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150–400 Kcal·h− 1 (carbohydrate, 30–50 g·h− 1; protein, 5–10 g·h− 1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450–750 mL·h− 1 (~ 150–250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., > 575 mg·L− 1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety.

In this study, we examined the reliability and construct validity of new soccer skills tests. Twenty soccer players (10 professional and 10 recreational) repeated trials of passing, shooting, and dribbling skills on different days. Passing and shooting skills required players to kick a moving ball, delivered at constant speed, towards one of four randomly determined targets. Dribbling required players to negotiate seven cones over 20 m. Each trial consisted of 28 passes, 8 shots, and 10 dribbles. Ball speed, precision, and success were determined for all tests using video analysis. Systematic bias was small (<9% in all measures) and all outcome measures were similar between trials. Test–retest reliability statistics were as follows: ball speed (passing, shooting, dribbling; coefficient of variation [CV]: 6.5%, 6.9%, 2.4%; ratio limits of agreement [RLOA]: 0.958 ×/÷ 1.091, 0.990 ×/÷ 1.107, 0.993 ×/÷ 1.039), precision (passing, shooting, dribbling; CV: 10.0%, 23.5%, 4.6%; RLOA: 0.956 ×/÷ 1.147, 1.030 ×/÷ 1.356, 1.000 ×/÷ 1.068), and success (passing, shooting, dribbling; CV: 11.7%, 14.4%, 2.2%; RLOA: 1.017 ×/÷ 1.191, 0.913 ×/÷ 1.265, 0.996 ×/÷ 1.035). Professional players performed better than recreational players in at least one outcome measure for all skills. These findings demonstrate the reliability and validity of new soccer skill protocols.

Evious muscular contraction, commonly occurs after heavy resistance exercise. However, this method of inducing PAP has limited application to the precompetition practices (e.g., warm-up) of many athletes. Very few studies have examined the influence of plyometric activity on subsequent performance; therefore, we aimed to examine the influence of alternate-leg bounding on sprint acceleration performance. In a randomized crossover manner, plyometric-trained men (n = 23) performed seven 20-m sprints (with 10-m splits) at baseline, ∼15 seconds, 2, 4, 8, 12, and 16 minutes after a walking control (C) or 3 sets of 10 repetitions of alternate-leg bounding using body mass (plyometric, P) and body mass plus 10% (weighted plyometric, WP). Mean sprint velocities over 10 and 20 m were similar between trials at baseline. At ∼15 seconds, WP impaired 20-m sprint velocity by 1.4 ± 2.5% when compared with C (p = 0.039). Thereafter, 10- and 20-m sprint velocities improved in WP at 4 minutes (10 m: 2.2 ± 3.1%, p = 0.009; 20 m: 2.3 ± 2.6%, p = 0.001) and 8 minutes (10 m: 2.9 ± 3.6%, p = 0.002; 20 m: 2.6 ± 2.8%, p = 0.001) compared with C. Improved 10-m sprint acceleration performance occurred in P at 4 minutes (1.8 ± 3.3%, p = 0.047) relative to C. Therefore, sprint acceleration performance is enhanced after plyometric exercise providing adequate recovery is given between these activities; however, the effects may differ according to whether additional load is applied. This finding presents a practical method to enhance the precompetition practices of athletes....

Purpose: This study examined the effects of exercise-induced fatigue on soccer skills performed throughout simulated match play.Methods: Fifteen academy soccer players completed a soccer match simulation (SMS) including passing, dribbling, and shooting skills. Precision, success rate, and ball speed were determined via video analysis for all skills. Blood samples were obtained before exercise (preexercise), every 15 min during the simulation (15, 30, 45, 60, 75, and 90 min), and 10 min into half-time.Results: Preliminary testing confirmed test-retest repeatability of performance, physiological, and metabolic responses to 45 min of the SMS. Exercise influenced shooting precision (timing effect: P = .035) and passing speed (timing effect: P = .011), such that shots taken after exercise were 25.5 ± 4.0% less accurate than those taken before exercise and passes in the last 15 min were 7.8 ± 4.3% slower than in the first 15 min. Shot and pass speeds were slower during the second half compared with the first half (shooting: 17.3 ± 0.3 m·s^-1 vs 16.6 ± 0.3 m·s^-1, P = 0.012; passing: 13.0 ± 0.5 m·s^-1 vs 12.2 ± 0.5 m·s^-1, P = 0.039). Dribbling performance was unaffected by exercise. Blood lactate concentrations were elevated above preexercise values throughout exercise (time of sample effect: P < .001).Conclusions: These findings demonstrate that soccer-specific exercise influenced the quality of performance in gross motor skills, such as passing and shooting. Therefore, interventions to maintain skilled performance during the second half of soccer match play are warranted.