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This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p <.01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p <.01). Caffeine gum did not influence any other variables (p >.05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study is to investigate biomechanical and physiological responses to soccer-specific exercise incorporating an extra-time period (ET) and assess the test-retest reliability of these responses. Methods: Twelve soccer players performed 120 min of soccer-specific exercise. Tri-axial (PL[subscript Total]) and uni-axial PlayerLoad™ in the vertical (PL[subscript V]), anterior-posterior (PL[subscript A-P]), and medial-lateral (PL[subscript M-L]) planes were monitored using a portable accelerometer. Likewise, respiratory exchange ratio (RER) was recorded throughout exercise. At the end of each 15-min period, players provided differential ratings of perceived exertion for legs (RPE-L), breathlessness (RPE-B) and overall (RPE-O), and capillary samples were taken to measure blood lactate (BLa) concentrations. The soccer-specific exercise was completed twice within 7 days to assess reliability. Results: A main effect for time was identified for PL[subscript Total] (p = 0.045), PL[subscript V] (p = 0.002), PL[subscript A-P] (p = 0.011), RER (p = 0.001), RPE-L (p = 0.001), RPE-O (p = 0.003), and CMJ (p = 0.020). A significant increase in PL[subscript Total] (234 ± 34 au) and decrease in RER (0.87 ± 0.03) was evident during 105-120 versus 0-15 min (215 ± 25 au; p = 0.002 and 0.92 ± 0.02; p = 0.001). Coefficients of variations were <10% and Pearson's correlation coefficient demonstrated moderate-to-very strong (0.33-0.99) reliability for all PL variables, RPE-B, BLa, and RER. Conclusions: These results suggest that mechanical efficiency is compromised and an increased rate of lipolysis is observed as a function of exercise duration, particularly during ET. These data have implications for practitioners interested in fatigue-induced changes during ET.

Purpose: To assess the training load, energy expenditure, dietary intake, and sleep quality and quantity of junior tennis players during a tennis training camp. Methods: Ten junior academy tennis players (14 [1] y) completed a 6-day camp with daily morning and afternoon training. Players wore accelerometer watches to measure activity energy expenditure and sleep. Global positioning system units were worn to monitor external training load (distance covered, maximum velocity, and PlayerLoad™). Dietary intake was obtained from a food diary and supplementary food photography. Results: Players covered significantly more distance and had higher PlayerLoad™ during morning sessions than afternoon sessions (5370 [505] m vs 4726 [697] m, P <.005, d = 3.2; 725 [109] a.u. vs 588 [96] a.u., P <.005, d = 4.0). Players also ran further (5624 [897] m vs 4933 [343] m, P <.05, d = 1.0) and reached higher maximum velocities (5.17 [0.44] m·s−1 vs 4.94 [0.39] m·s−1, P <.05, d = 0.3) during simulated match play compared with drill sessions. Mean daily energy expenditure was 3959 (630) kcal. Mean energy intake was 2526 (183) kcal, resulting in mean energy deficits of 1433 (683) kcal. Players obtained an average of 6.9 (0.8) hours of sleep and recorded 28 (7) nightly awakenings. Conclusions: Junior academy tennis players failed to achieve energy balance and recorded suboptimal sleep quantity and quality throughout the training camp. [ABSTRACT FROM AUTHOR]

Polyphenol consumption has become a popular method of trying to temper muscle damage. Cocoa flavanols (CF) have attracted attention due to their high polyphenol content and palatability. As such, this study will investigate whether an acute dose of CF can aid recovery following exercise-induced muscle damage. The study was a laboratory-based, randomized, single-blind, nutrient-controlled trial involving 23 participants (13 females and 10 males). Participants were randomized into either control ∼0 mg CF (n = 8, four females); high dose of 830 mg CF (CF830, n = 8, five females); or supra dose of 1,245 mg CF (CF1245, n = 7, four females). The exercise-induced muscle damage protocol consisted of five sets of 10 maximal concentric/eccentric hamstring curls and immediately consumed their assigned drink following completion. To measure muscle recovery, maximal voluntary isometric contraction (MVIC) of the knee flexors at 60° and 30°, a visual analog scale (VAS), and lower-extremity function scale were taken at baseline, immediately, 24-, 48-, and 72-hr postexercise-induced muscle damage. There was a main effect for time for all variables (p < .05). However, no significant differences were observed between groups for all measures (p ≥ .17). At 48 hr, there were large effect sizes between control and CF1245 for MVIC60 (p = .17, d = 0.8); MVIC30 (p = .26, d = 0.8); MVIC30 percentage change (p = .24 d = 0.9); and visual analog scale (p = .25, d = 0.9). As no significant differences were observed following the consumption of CF, there is reason to believe that CF offer no benefit for muscle recovery when ingested acutely. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to profile the physiological, physical, and biomechanical responses during walking football. A total of 17 male participants (aged 66 ± 6 years) participated. Heart rate; blood lactate; accelerometer variables (biomechanical load [PlayerLoad™], changes of direction); and rating of perceived exertion were measured. Participants mean percentage of maximum heart rate was 76 ± 6%during the sessions, with rating of perceived exertion across all sessions at 13 ± 2. Blood lactate increased by ~157% from presession (1.24 ± 0.4 mmol/L) to postsession (3.19 ± 1.7 mmol/L; p ≤ .0005). PlayerLoad™ values of 353 ± 67 arbitrary units were observed, as well as ~100 changes of direction per session. In conclusion, walking football is a moderate- to vigorous-intensity activity. The longitudinal health benefits of walking football remain to be elucidated, particularly on bone health, cardiovascular fitness, and social and mental well-being. [ABSTRACT FROM AUTHOR]

Purpose: The extra-time (ET) period of soccer is competed during fixture congested schedules with often limited recovery time between matches. The aim of this study was to assess muscle damage recovery following 90- and 120-min (i.e., incorporation of ET) of simulated soccer match-play. Methods: Twelve semiprofessional soccer players completed 90 and 120-min treadmill-based soccer-specific exercise in a counterbalanced order. Creatine kinase (CK), creatinine, urea, aspartate aminotransferase, perceived muscle soreness, pain pressure threshold, reactive strength index, countermovement jump height, and isokinetic strength assessments of eccentric knee flexors at 60, 180 and 270 deg‧s−1 were taken at baseline and immediately-, 24, 48 and 72-hr post-exercise to assess recovery. Results: No significant between-trial interactions except for CK were found. Pairwise comparisons detected a 53% increase in CK at 24-hr (455 ± 29 μ∙L−1) following 120-min of simulated match-play vs. the corresponding post 90-min time-point (299 ± 29 μ∙L−1; p <.01). The 120-min trial caused a 58% higher CK response at 72-hr (244 ± 25 μ∙L−1) vs. post 90-min comparisons (154 ± 29 μ∙L−1; p =.02). No interaction effects were detected for any other recovery variables. Creatine kinase and perceived muscle soreness remained elevated up to 72-hr in both trials (p <.01). Conclusions: These data indicate that 120 min of simulated soccer match-play delays the time-course of CK recovery up to 72-hr post-match. However, 120 min of simulated soccer has no additional impact on functional recovery and perceived muscle soreness vs. 90 min. Recovery should be investigated following 90- and 120-min of actual match-play.Trial registration The study was pre-registered on the Open Science Framework (DOI: 10.17605/OSF.IO/VGU6T Date: 10/06/2019). [ABSTRACT FROM AUTHOR]

Purpose : The aim of this study was to investigate thigh musculature excitation and torque generation in response to soccer-specific exercise incorporating an extra-time (ET) period. Methods : Twelve semiprofessional soccer players performed 120-min treadmill-based soccer-specific exercise. Surface electromyography (EMG) signals for the rectus femoris (EMG RF ) and biceps femoris (EMG BF ) were measured as the mean response across a pre-determined 10-second sprint bout during each 15-min block of exercise. Peak eccentric torque of the knee flexors (eccKF) and concentric torque of the knee extensors (conKE) were recorded across angular velocities of 60, 180, and 270 deg∙s -1 immediately pre- and post-exercise. Tri-axial PlayerLoad™ (PL-T) was monitored throughout exercise and defined across vertical (PL-V), anterior-posterior (PL-AP), and medial-lateral (PL-ML) planes of motion. Results : A reduction in normalized EMG RF amplitude was evident at 105‒120 min, versus 0‒15 min (-12.5%; p =  .037), 15‒30 min (-12.5%; p =  .047), and 45‒60 min (-14%; p =  .030). Peak torque of the eccKF was significantly reduced from pre- to post-exercise at 60 (-7.7%; p = .018), 180 (-10.5%; p = .042), and 270 deg∙s -1 (-7.5%; p = .034). A main effect for time was identified for PL-T ( p < .010), PL-V ( p = .033), and PL-AP ( p < .010). Conclusions : These findings suggest that muscle excitation of the rectus femoris is reduced during ET, accompanied with a deficit in the torque generation of the knee flexors following 120 min of soccer-specific activity. Practitioners should adequately condition players for the additional ET period by incorporating exercises into training schedules that develop fatigue-resistant eccentric hamstring strength to minimize injury risk.

The aim of this investigation was to profile the physiological, physical, and biomechanical responses during walking football. A total of 17 male participants (aged 66 ± 6 years) participated. Heart rate; blood lactate; accelerometer variables (biomechanical load [PlayerLoad™], changes of direction); and rating of perceived exertion were measured. Participants mean percentage of maximum heart rate was 76 ± 6% during the sessions, with rating of perceived exertion across all sessions at 13 ± 2. Blood lactate increased by ∼157% from presession (1.24 ± 0.4 mmol/L) to postsession (3.19 ± 1.7 mmol/L; p ≤ .0005). PlayerLoad™ values of 353 ± 67 arbitrary units were observed, as well as ∼100 changes of direction per session. In conclusion, walking football is a moderate- to vigorous-intensity activity. The longitudinal health benefits of walking football remain to be elucidated, particularly on bone health, cardiovascular fitness, and social and mental well-being.