The effects of an increased calorie breakfast consumed prior to simulated match-play in Academy soccer players

Dietary analysis of Academy soccer players highlights that total energy and carbohydrate intakes are less than optimal, especially, on match-days. As UK Academy matches predominantly kick-off at ～11:00?h, breakfast is likely the last pre-exercise meal and thus may provide an intervention opportunity on match-day. Accordingly, the physiological and performance effects of an increased calorie breakfast consumed ～135-min before soccer-specific exercise was investigated. English Premier League Academy soccer players (n?=?7) repeated a 90-min soccer match simulation on two occasions after consumption of habitual (B_hab; ～1100?kJ) or increased (B_inc; ～2100?kJ) energy breakfasts standardised for macronutrient contributions (～60% carbohydrates, ～15% proteins and ～25% fats). Countermovement jump height, sprint velocities (15-m and 30-m), 30-m repeated sprint maintenance, gut fullness, abdominal discomfort and soccer dribbling performances were measured. Blood samples were taken at rest, pre-exercise, half-time and every 15-min during exercise. Although dribbling precision (P?=?.522; 29.9?±?5.5?cm) and success (P?=?.505; 94?±?8%) were unchanged throughout all time-points, mean dribbling speed was faster (4.3?±?5.7%) in B_inc relative to B_hab (P?=?.023; 2.84 vs 2.75?m?s^?1). Greater feelings of gut fullness (67?±?17%, P?=?.001) were observed in B_inc without changes in abdominal discomfort (P?=?.595). All other physical performance measures and blood lactate and glucose concentrations were comparable between trials (all P?>?.05). Findings demonstrate that Academy soccer players were able to increase pre-match energy intake without experiencing abdominal discomfort; thus, likely contributing to the amelioration of energy deficits on match-days. Furthermore, whilst B_inc produced limited benefits to physical performance, increased dribbling speed was identified, which may be of benefit to match-play.     

Mixed-methods pre-match cooling improves simulated soccer performance in the heat

This investigation examined the effects of three pre-match and half-time cooling manoeuvres on physical performance and associated physiological and perceptual responses in eight University soccer players during a non-motorised treadmill based individualised soccer-specific simulation [intermittent soccer performance test (iSPT)] at 30°C. Four randomised experimental trials were completed; following 30-min (pre-match) and 15-min (half-time) cooling manoeuvres via (1) ice slurry ingestion (SLURRY); (2) ice-packs placed on the quadriceps and hamstrings (PACKS); (3) mixed-methods (MM; PACKS and SLURRY concurrently); or no-cooling (CON). In iSPT first half, a moderate increase in total (Mean?±?Standard Deviation: 108?±?57 m, qualitative inference: most likely, Cohen’s d: 0.87, 90%CL: ±0.31), high-speed (56?±?46 m, very likely, 0.68?±?0.38) and variable run (15?±?5 m, very likely, 0.81?±?0.47) distance covered was reported in MM compared with CON. Additionally, pre-match reductions in thermal sensation (–1.0?±?0.5, most likely, –0.91?±?0.36), rectal (–0.6?±?0.1°C, very likely, –0.86?±?0.35) and skin temperature (–1.1?±?0.3°C, very likely, –0.88?±?0.42) continued throughout iSPT first half. Physical performance during iSPT first half was unaltered in SLURRY and PACKS compared to CON. Rectal temperature was moderately increased in SLURRY at 45-min (0.2?±?0.1°C, very likely, 0.67?±?0.36). Condition did not influence any measure in iSPT second half compared to CON. Only MM pre-match cooling augmented physical performance during iSPT first half, likely due to peripheral and central thermoregulatory factors favourably influencing first half iSPT performance. Further practical half-time cooling manoeuvres which enhance second half performance are still required.     

Intensities of exercise during match-play in FA Premier League referees and players

Abstract

The aim of the present study was to examine the relationship between intensities of exercise during match-play of elite-standard soccer referees with those of the players from the same match. Match analysis data were collected (Prozone® Leeds, UK) for 18 elite-standard soccer referees (age 26–49 years) on FA Premier League matches during the 2008/09 English FA Premier League season (236 observations). Running categories for referees and players were as follows: total distance covered (m); high-speed running distance (speed >19.8 km · h^?1); and sprinting distance (speed >25.2 km · h^?1). Analysis of the distance–time regression coefficients revealed no differences between the referees' and players' within-match rates of change for total distance covered (?0.594 ± 0.394 vs. ?0.713 ± 0.269 m · min^?1; P = 0.104), high-speed running (?0.039 ± 0.077 vs. ?0.059 ± 0.030 m · min^?1; P = 0.199), and sprinting (?0.003 ± 0.039 vs. ?0.021 ± 0.017 m · min^?1; P = 0.114). In addition, there were no differences between across-season rates of change for total distance (–26.756 ± 40.434 vs. ?20.031 ± 25.502 m per match day; P = 0.439) and sprinting (–9.662 ± 7.564 vs. ?8.589 ± 4.351 m per match day; P = 0.542). These results show that elite-standard soccer referees' intensities of exercise during match-play are interrelated with those of the players and thus demonstrate that referees are able to keep pace with the players during FA Premier League matches.     

Does maturation influence neuromuscular performance and muscle damage after competitive match-play in youth male soccer players?

Abstract

Poor neuromuscular control and fatigue have been proposed as a risk factor for non-contact injuries especially around peak height velocity (PHV). This study explored the effects of competitive soccer match-play on neuromuscular performance and muscle damage in male youth soccer players. 24 youth players aged 13-16y were split into a PHV group (?0.5 to 0.5y) and post PHV group (1.0–2.5y) based on maturity off-set. Leg stiffness, reactive strength index (RSI), muscle activation, creatine kinase (CK), and muscle soreness were determined pre and post a competitive soccer match. Paired t-tests were used to explore differences pre and post competitive match play and independent sample t-tests for between groups differences for all outcome measures. There was no significant fatigue-related change in absolute and relative leg stiffness or muscle activation in both groups, except for the gastrocnemius in the post PHV group. RSI, CK and perceived muscle soreness were significantly different after soccer match-play in both groups with small to large effects observed (ES:0.41–2.82). There were no significant differences between the groups pre match-play except for absolute and relative leg stiffness (P?<?0.001; ES?=?1.16 and 0.63 respectively). No significant differences were observed in the fatigue related responses to competitive match play between groups except for perceived muscle soreness. The influence of competitive match-play on neuromuscular function and muscle damage is similar in male youth around the time of PHV and those post-PHV indicating that other factors must contribute to the heightened injury risk around PHV.     

Fluctuations in running and skill-related performance in elite rugby union match-play

This study investigated end-game and transient changes in running activities and whether these were concomitantly associated with reductions in skill-related performance in senior international rugby union match-play. Altogether, 18 official matches were analysed (322 individual observations) using computerised video-based tracking and event coding (Amisco Pro^®, SUP, Nice, France). In forwards and backs, trivial to small reductions (% difference: ?2.1, ±1.3 to ?10.0, ±4.0%) in total distance and that covered at high speeds (>18.0?km?h^?1) occurred in the second- versus the first-half while there were trivial differences in skill-related performance measures (?2.3, ±4.5 to 7.5, ±14.0%). In both positions, small to moderate declines (?42, ±10 to ?21, ±7%) occurred in high-speed running in the final 10-min and 5-min periods versus mean values for all other 10-min and 5-min periods throughout the game while only small changes (?18, ±51 to 13, ±41%) in skill-related performance were observed. Trivial changes in running and skill-related performance (?11, ±74 to 7, ±39%) were observed in the 5-min period immediately following the most intense 5-minute periods of play compared to mean performance over the other 5-min periods. These findings suggest that international rugby union players were generally able to maintain skill-related performance over the course of match-play even when declines in running performance occurred.     

Are declines in physical performance associated with a reduction in skill-related performance during professional soccer match-play?

The aim of this study was to determine whether declines in physical performance in a professional soccer team during match-play were associated with reductions in skill-related performance. Computerized tracking of performance in midfield players (n = 11) showed that total distance and distance covered in high-speed running (>14.4 km · h?1) were greater in the first versus second half of games (both P < 0.001) and in the first versus the final 15 min of play (P < 0.05). Analysis of high-speed running across 5-min periods showed that more distance was covered in the first versus the final game period, and in the peak period of activity compared with the following period and game mean for other periods (all P < 0.05). Analysis of skill-related measures revealed no significant decline between halves, across 15-min intervals or in the 5-min period following that of peak high-speed activity compared with the game mean for other 5-min periods. In contrast, frequencies of passing, ball possessions, and duels were greater in the first 5-min than in the final 5-min period (P < 0.05). Neither physical nor skill-related performance was affected across three consecutive games within a period of ≤7 days. The results suggest that the players were generally able to maintain skill-related performance throughout games and when competing in successive matches within a short time.     

Analysis of repeated high-intensity running performance in professional soccer

Abstract

The aims of this study were twofold: (1) to characterize repeated high-intensity movement activity profiles of a professional soccer team in official match-play; and (2) to inform and verify the construct validity of tests commonly used to determine repeated-sprint ability in soccer by investigating the relationship between the results from a test of repeated-sprint ability and repeated high-intensity performance in competition. High-intensity running performance (movement at velocities >19.8 km · h^?1 for a minimum of 1 s duration) was measured in 20 players using computerized time–motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of six consecutive 6 s sprints separated by 20 s passive recovery intervals. In all players, most consecutive high-intensity actions in competition were performed after recovery durations ≥61 s, recovery activity separating these efforts was generally active in nature with the major part of this spent walking, and players performed 1.1 ± 1.1 repeated high-intensity bouts (a minimum of three consecutive high-intensity bouts with a mean recovery time ≤20 s separating efforts) per game. Players reporting lowest performance decrements in the repeated-sprint ability test performed more high-intensity actions interspersed by short recovery times (≤20 s, P < 0.01 and ≤30 s, P < 0.05) compared with those with higher decrements. Across positional roles, central-midfielders performed more high-intensity actions separated by short recovery times (≤20 s) and spent a larger proportion of time running at higher intensities during recovery periods, while fullbacks performed the most repeated high-intensity bouts (statistical differences across positional roles from P < 0.05 to P < 0.001). These findings have implications for repeated high-intensity testing and physical conditioning regimens.     

The appropriateness of training exposures for match-play preparation in adolescent schoolboy and academy rugby union players

The aim of this study was to compare the physical and movement demands between training and match-play in schoolboy and academy adolescent rugby union (RU) players. Sixty-one adolescent male RU players (mean ± SD; age 17.0 ± 0.7 years) were recruited from four teams representing school and regional academy standards. Players were categorised into four groups based on playing standard and position: schoolboy forwards (n = 15), schoolboy backs (n = 15), academy forwards (n = 16) and academy backs (n = 15). Global positioning system and accelerometry measures were obtained from training and match-play to assess within-group differences between conditions. Maximum data were analysed from 79 match files across 8 matches (1.3 ± 0.5 matches per participant) and 152 training files across 15 training sessions (2.5 ± 0.5 training sessions per participant). Schoolboy forwards were underprepared for low-intensity activities experienced during match-play, with schoolboy backs underprepared for all movement demands. Academy forwards were exposed to similar physical demands in training to matches, with academy backs similar to or exceeding values for all measured variables. Schoolboy players were underprepared for many key, position-specific aspects of match-play, which could place them at greater risk of injury and hinder performance, unlike academy players who were better prepared.     

A Coding System to Quantify Powerful Actions in Soccer Match Play: A Pilot Study

Purpose: The powerful activity profile of elite soccer match play has not been documented appropriately to inform specific maximal power assessment and development criteria. The aims of the current study were to develop a reliable soccer-specific powerful action (SSPA) notational analysis coding system that could be used to compare frequency and durations of powerful actions during elite youth soccer match play. Methods: Sixteen elite male English Premier League (EPL) Academy players (19 ± 1 yrs) were recorded by an individual camera during 16 competitive EPL U18 and U21 games. Video footage was analyzed using performance analysis software and SSPAs were coded according to the following categories: initial acceleration, leading acceleration, sprint, unilateral jump and bilateral jump. Results: The SSPA coding system demonstrated very good inter- and intra-rater reliability (kappa coefficients ≥ 0.827). Elite youth EPL soccer players undertook significantly more initial (31 ± 9) and leading (37 ± 12) accelerations than sprints (8 ± 3; p = .014, d = 1.7, and p < .001, d = 1.7, respectively) and jumps (6 ± 5; p = .002, d = 1.7 and p < .001, d = 1.7, respectively). Players performed a significantly greater number of initial and leading accelerations with action durations below 1.5 s compared to above 1.5 s (p = .001, d = 1.6, and p = .002, d = 1.4), respectively. Conclusions: Our SSPA coding system provides a reliable observational instrument for quantifying the frequency and duration of powerful actions performed during elite soccer match play. In our sample of elite youth soccer players, horizontal accelerations of short duration (< 1.5 s) from different starting speeds appear the most dominant powerful action in elite youth soccer match play.     

Body composition of English Premier League soccer players: Influence of playing position,international status,and ethnicity

Abstract

Body composition is a key consideration in the physical make-up of professional soccer players. The aims of the present study were to determine whether the body composition of professional soccer players varied according to playing position, international status or ethnicity, and to establish which variables best distinguished the soccer players from a reference group. Body composition was assessed using dual-energy X-ray absorptiometry in 64 male professional soccer players. Measured variables included bone mineral density and the relative amounts of lean and fat mass. Data were analysed using analysis of variance and stepwise discriminant function. The soccer players recorded better values than a reference group (n = 24) for all body composition compartments. Percent lean mass and bone mineral density were the variables best able to identify the soccer players (95.5% correctly classified). Differences in body composition were evident between goalkeepers and outfield players, but not between outfield playing positions. No differences were found on the basis of international status. The non-Caucasian players demonstrated significantly lower percent body fat (9.2 ± 2.0%) than the Caucasian players (10.7 ± 1.8%). It was concluded that body composition is important for elite soccer players, but that homogeneity between players at top professional clubs results in little variation between individuals.     

Contextual factors on physical demands in professional women’s soccer: Female Athletes in Motion study

The aim of this study was to examine the impact of contextual factors on relative locomotor and metabolic power distances during professional female soccer matches. Twenty-eight players (forwards, n?=?4; midfielders, n?=?12; defenders, n?=?12) that competed in a 90-min home and away match (regular season only). The generalised estimating equations (GEE) was used to evaluate relative locomotor and metabolic power distances for three contextual factors: location (home vs. away), type of turf (natural vs. artificial), and match outcome (win, loss and draw). No differences were observed for home vs. away matches. Moderate-intensity running (20.0?±?1.0?m?min^?1 and 16.4?±?0.9?m?min^?1), high-intensity running (8.6?±?0.4?m?min^?1 and 7.3?±?0.4?m?min^?1) and high-metabolic power (16.3?±?0.5?m?min^?1 and 14.4?±?0.5?m?min^?1) distances were elevated on artificial turf compared to natural grass, respectively. Relative sprint distance was greater during losses compared with draws (4.3?±?0.4?m?min^?1 and 3.4?±?0.3?m?min^?1). Overall physical demands of professional women’s soccer were not impacted by match location. However, the elevation of moderate and high-intensity demands while playing on artificial turf may have implications on match preparations as well as recovery strategies.     

Intensities of exercise during match-play in FA Premier League referees and players

The aim of the present study was to examine the relationship between intensities of exercise during match-play of elite-standard soccer referees with those of the players from the same match. Match analysis data were collected (Prozone? Leeds, UK) for 18 elite-standard soccer referees (age 26-49 years) on FA Premier League matches during the 2008/09 English FA Premier League season (236 observations). Running categories for referees and players were as follows: total distance covered (m); high-speed running distance (speed >19.8 km · h(-1)); and sprinting distance (speed >25.2 km · h(-1)). Analysis of the distance-time regression coefficients revealed no differences between the referees' and players' within-match rates of change for total distance covered (-0.594 ± 0.394 vs. -0.713 ± 0.269 m · min(-1); P = 0.104), high-speed running (-0.039 ± 0.077 vs. -0.059 ± 0.030 m · min(-1); P = 0.199), and sprinting (-0.003 ± 0.039 vs. -0.021 ± 0.017 m · min(-1); P = 0.114). In addition, there were no differences between across-season rates of change for total distance (-26.756 ± 40.434 vs. -20.031 ± 25.502 m per match day; P = 0.439) and sprinting (-9.662 ± 7.564 vs. -8.589 ± 4.351 m per match day; P = 0.542). These results show that elite-standard soccer referees' intensities of exercise during match-play are interrelated with those of the players and thus demonstrate that referees are able to keep pace with the players during FA Premier League matches.     

An exercise protocol that simulates the activity patterns of elite junior squash

Abstract

Squash is a popular racket sport that requires intermittent activity with frequent bursts of near maximal-intensity exercise. Consequently, effective physiological and thermoregulatory responses are important contributors to performance during squash match-play. Controlled field-based simulation protocols have been introduced in a growing number of sports, which allow sports scientists to investigate changes in physiology and the efficacy of various interventions in sport-specific contexts. This study aimed to develop an exercise protocol that simulates the physiological requirements of elite squash match-play. Eight elite junior squash players (age 16.2 ± 0.8 years, height 1.76 ± 0.06 m, body mass 61.3 ± 5.9 kg; mean ± s) completed the following in a randomized order: (1) a squash match against a player of similar standard and (2) a squash-specific incremental exercise protocol (multistage squash test [MST]) followed by the squash simulation protocol (SSP). The multistage squash test was continued for 18.0 ± 1.0 min and elicited near maximal post-MST heart rates, blood lactate concentrations and ratings of perceived exertion (198 ± 9 beats · min^?1, 5.7 ± 1.7 mmol · l^?1 and 18 ± 1, respectively). The SSP was 12.2 min in length compared with mean game length during competitive matches of 10.0 ± 1.6 min (P = 0.27). Peak heart rates were similar during the SSP and match-play (192 ± 11 and 189 ± 6 beats · min^?1, respectively; P = 0.44). Mean exercising heart rates were similar during the SSP (180 ± 8 beats · min^?1) and match-play (179 ± 13 beats · min^?1; P = 0.73). Peak blood lactate concentrations during the SSP and match-play were 3.5 ± 1.5 and 2.4 ± 1.2 mmol · l^?1 (P = 0.07), respectively. Peak ratings of perceived exertion during the SSP and match-play were similar (17 ± 2 and 17 ± 2, respectively; P = 0.64). It was concluded that the SSP closely replicated the demands of squash match-play in elite junior squash players. Furthermore, the SSP provides coaches and scientific support staff with a controlled squash-specific exercise protocol that has potential application in the objective investigation of a range of interventions such as training programmes, nutritional supplements and strategies to maintain core body temperature.     

The impact of in-season national team soccer play on injury and player availability in a professional club

This study investigated the impact of in-season national team duty on injury rates and player availability in a professional soccer club. Time-loss injuries and exposure time during club and national team duties were recorded prospectively over 5 seasons (2009–2014). A time-loss injury was sustained by 37.7% of squad members participating in national duty, all injuries occurring in match-play. The incidence (per 1000 h exposure) for national team player match-play injuries did not differ (P = 0.608) to that for all players in club competitions: 48.0 (95% CI 20.9–75.5) vs. 41.9 (95% CI 36.5–47.4), incidence rate ratio = 1.2 (CI: 0.8–2.4). The majority (58%) of national team injuries resulted in a layoff ≤1 week. Of all working days lost to injury generally, 5.2% were lost through injury on national duty. Injury incidence in the week following national duty was comparable (P = 0.818) in players participating or not: 7.8 (95% CI 3.6–12.0) vs. 7.1 (95% CI: 4.6–9.6), incidence rate ratio = 1.1 (CI: 0.7–2.7). While approximately 40% of participating players incurred a time-loss injury on national duty, no training injuries were sustained and injuries made up a negligible part of overall club working days lost to injury. Following duty, players had a similar injury risk to peers without national obligations.     

Muscle fatigue induced by exercise simulating the work rate of competitive soccer

Fatigue represents a reduction in the capability of muscle to generate force. The aim of the present study was to establish the effects of exercise that simulates the work rate of competitive soccer players on the strength of the knee extensors and knee flexors. Thirteen amateur soccer players (age 23.3±3.9 years, height 1.78±0.05?m, body mass 74.8±3.6?kg; mean±s) were tested during the 2000–2001 soccer season. Muscle strength of the quadriceps and hamstrings was measured on an isokinetic dynamometer. A 90?min soccer-specific intermittent exercise protocol, incorporating a 15?min half-time intermission, was developed to provide fatiguing exercise corresponding in work rate to a game of soccer. The exercise protocol, performed on a programmable motorized treadmill, consisted of the different intensities observed during soccer match-play (e.g. walking, jogging, running, sprinting). Muscle strength was assessed before exercise, at half-time and immediately after exercise. A repeated-measures analysis of variance showed significant reductions (P?<0.001) in peak torque for both the quadriceps and hamstrings at all angular velocities (concentric: 1.05, 2.09, 5.23 rad?·?s^?1; eccentric: 2.09 rad?·?s^?1). The peak torque of the knee extensors (KE) and knee flexors (KF) was greater before exercise [KE: 232±37, 182±34, 129±27, 219±41?N?·?m at 1.05, 2.09 and 5.23 rad?·?s^?1 (concentric) and 2.09 rad?·?s^?1 (eccentric), respectively; KF: 126±20, 112±19, 101±16, 137±23?N?·?m] than at half-time (KE: 209±45, 177±35, 125±36, 214±43?N?·?m; KF: 114±31, 102±20, 92±15, 125±25?N?·?m) and greater at half-time than after exercise (KE: 196±43, 167±35, 118±24, 204±43?N?·?m; KF: 104±25, 95±21, 87±13, 114±27?N?·?m). For the hamstrings?:?quadriceps ratio, significant changes were found (P?<0.05) for both legs, the ratio being greater before than after exercise. For fast?:?slow speed and left?:?right ratios, no significant changes were found. We conclude that there is a progressive reduction in muscle strength that applies across a range of functional characteristics during exercise that mimics the work rate in soccer.     

Influence of carbohydrate mouth rinsing on running and jumping performance during early morning soccer scrimmaging

Carbohydrate mouth rinse (CMR) is a novel method proposed to enhance endurance performance lasting ≤ 60 min. The current study examined the influence of CMR on anaerobic performance tasks in 11 collegiate female soccer players after an overnight fast. Athletes completed two experimental sessions, during which carbohydrate (CHO; 6% maltodextrin) or taste- and colour-matched placebo (PLA) mouth-rinse solutions were administered in a counterbalanced, double-blinded design. Three rounds of a 5-min scrimmage bout and series of performance tests including a single countermovement vertical jump (1VJ), a set of four consecutive vertical jumps, a 72-m shuttle run (SR72) and 18-m sprint comprised each trial. Thirst sensation (TS), session TS, ratings of perceived exertion (RPE) and session RPE were assessed as secondary outcomes. The first SR72 approached significance (p = 0.069), but no significant between-trials differences were observed for any of the mean performance tasks. The highest 1VJ scores did not differ for the first (CHO = 47.3 ± 3.4, PLA = 47.7 ± 3.5 cm; p = 0.43), second (CHO = 48.0 ± 4.1, PLA = 47.9 ± 3.5 cm; p = 0.82) or third bout (CHO = 47.4 ± 3.9, PLA = 48.1 ± 3.9 cm; p = 0.26). TS approached significance (p = 0.053) during the first bout. No significant differences (p > 0.05) were found for any of the perceptual variables. Current results fail to support ergogenic influence of CMR on anaerobic performance tasks in collegiate female athletes.     

Effects of treadmill versus overground soccer match simulations on biomechanical markers of anterior cruciate ligament injury risk in side cutting

This study aimed to investigate whether treadmill versus overground soccer match simulations have similar effects on knee joint mechanics during side cutting. Nineteen male recreational soccer players completed a 45-min treadmill and overground match simulation. Heart rate (HR) and rating of perceived exertion (RPE) were recorded every 5 min. Prior to exercise (time 0 min), at “half-time” (time 45 min) and 15 min post-exercise (time 60 min), participants performed five trials of 45° side-cutting manoeuvres. Knee abduction moments and knee extension angles were analysed using two-way repeated measures analysis of variance (α = 0.05). Physiological responses were significantly greater during the overground (HR 160 ± 7 beats ? min^?1; RPE 15 ± 2) than the treadmill simulation (HR 142 ± 5 beats ? min^?1; RPE 12 ± 2). Knee extension angles significantly increased over time and were more extended at time 60 min compared with time 0 min and time 45 min. No significant differences in knee abduction moments were observed. Although knee abduction moments were not altered over time during both simulations, passive rest during half-time induced changes in knee angles that may have implications for anterior cruciate ligament injury risk.