A SEASON-LONG COMPARISON OF SOCCER REFEREE MATCH DEMANDS BETWEEN THE ENGLISH PREMIER LEAGUE AND CHAMPIONSHIP

Conference Poste

Seasonal Training-Load Quantification in Elite English Premier League Soccer Players

Purpose: To quantify the seasonal training load completed by professional soccer players of the English Premier League. Methods: Thirty players were sampled (using GPS, heart rate, and rating of perceived exertion [RPE]) during the daily training sessions of the 2011–12 preseason and in-season period. Preseason data were analyzed across 6 × 1-wk microcycles. In-season data were analyzed across 6 × 6-wk mesocycle blocks and 3 × 1-wk microcycles at start, midpoint, and end-time points. Data were also analyzed with respect to number of days before a match. Results: Typical daily training load (ie, total distance, high-speed distance, percent maximal heart rate [%HRmax], RPE load) did not differ during each week of the preseason phase. However, daily total distance covered was 1304 (95% CI 434–2174) m greater in the 1st mesocycle than in the 6th. %HRmax values were also greater (3.3%, 1.3–5.4%) in the 3rd mesocycle than in the first. Furthermore, training load was lower on the day before match (MD-1) than 2 (MD-2) to 5 (MD-5) d before a match, although no difference was apparent between these latter time points. Conclusions: The authors provide the 1st report of seasonal training load in elite soccer players and observed that periodization of training load was typically confined to MD-1 (regardless of mesocycle), whereas no differences were apparent during MD-2 to MD-5. Future studies should evaluate whether this loading and periodization are facilitative of optimal training adaptations and match-day performance

An examination of the training loads within elite professional football

The popularity of soccer throughout the world has led to the demand for a scientific approach to the preparation of players for competitive matches. Although previous researchers have attempted to understand the training demands undertaken by soccer players, limited information is known regarding the structure of training in soccer. At present research has focused on the frequency and duration of soccer training without using both objective and subjective measures of training load to systematically evaluate training practices in elite teams. Little is also known regarding the periodisation strategies employed by elite soccer teams across a competitive season and whether they follow traditional models of periodisation. With this in mind, the primary aim of this thesis is to therefore characterise the current training periodisation practices that exist in elite soccer using applied methods of training load assessment. The aim of the first study (Chapter 3) was to evaluate the use of Global Positioning Devices (GPS) for the measurement of soccer-specific activities to provide objective data for training load assessment. Findings from this study were applied to study 3 (Chapter 5) of the thesis. Firstly, a soccer-specific movement course was designed based on the movements exhibited by an elite soccer player during a competitive match using a multi-camera tracking system (ProZone®). Two moderately trained males performed 10 bouts of the soccer-specific track following familiarisation and a 10 minute standardised warm up. Both subjects wore two 10Hz GPS units inside a custom-made vest during all bouts of the track to determine both reliability and inter-unit reliability of the GPS devices. Data analysis revealed the reliability of the GPS devices was good for distance covered at lower velocities (0 – 4 m/s; CV% = 0.6 – 3.6%). However when the velocity of movement increased (> 4 m/s), the reliability of the units decreased (mean change from 13.8 to 33.6 CV%). Both total distance (mean CV% = 1.1%) and max speed (mean CV% = 2.7%) were both found to be highly reliable variables. However the devices demonstrated high levels of inter-unit reliability error due to an increase in systematic error with random distribution of data points between both devices for all variables measured. The data suggested that 10Hz GPS devices are reliable for the measurement of lower velocity (0 – 4 m/s) running. However, care must be taken when analysing data in higher velocity bands (> 4 m/s) due to the high ii error rates observed. The high inter-unit reliability error also suggests that 10Hz GPS devices cannot be used interchangeably between players in order to minimise the associated error. The aim of the second study (Chapter 4) was to quantify the reliability and validity of a portable vertical jump assessment tool (Optojump®) for use in the applied setting. Vertical jump assessment was utilised as a measurement tool to analyse the effect of training load on the neuromuscular system that was evaluated in study 4 (Chapter 6) of the thesis. Eleven healthy male subjects were familiarised to perform four separate common types of vertical jump test: countermovement with arm swing (CMJ-W), countermovement without arm swing (CMJ-WO), squat jump (SJ) and drop jump (DJ). Contact time, flight time and jump height were selected as variables for the study. For reliability assessment, all subjects performed 3 efforts of each jump type across 5 identical testing sessions (separated by minimum of 2 days). For validity assessment, subjects were asked to perform the same jump modalities as the previous investigation on one occasion while data was simultaneously collected from both a force plate (criterion instrument) and the Optojump photocells. The data revealed the Optojump device was highly reliable for the assessment of jump flight and height for CMJ-W, CMJ-WO, SJ and DJ (all CV% = 3.2 and 5.6%). However reliability of the device was reduced for the measurement of contact time with the DJ (CV% = 13.9%). Validity data revealed that all jump types and variables were highly valid in comparison to the force plate criterion measure (SEE% = 0.99). This study revealed that the Optojump device is highly reliable and valid for all jump types and variables, with the exception of contact time for DJ. Therefore the Optojump system may be used with confidence to detect within-group changes in applied assessments of vertical jump performance. Due to the high cost and lack of portability of laboratory-based force plates, the Optojump system is a viable alternative for accurate jump measurement and neuromuscular assessment. The CMJ-WO jump assessment was chosen for study 4 for comparison with previous research. The aim of the third study (Chapter 5) was to quantify the periodisation strategies employed by an elite professional soccer team throughout a competitive season. Training load data was collected from 37 elite outfield soccer players at one professional English soccer team over a 45 week period during the 2011-2012 domestic season. All players wore iii global positioning system (GPS) devices, heart rate (HR) belts and were asked to provide a rating of perceived exertion (RPE) for each training session to generate training load data. Players were assigned to one of 5 positional groups: central defender (CD), wide defender (WD), central midfielder (CM), wide midfielder (WM) and attacker (AT). The data was separated into the pre-season (6 weeks duration) and in-season (39 weeks duration) phases in order to investigate specific training periods recognised within the annual plan. The pre-season phase was further separated into weekly blocks for analysis of the structure employed in each specific microcycle. The in-season phase was divided into 6 x 6 week blocks for analysis of mesocycle structure. Within the in-season data, three separate microcycles (weeks 7, 24 and 39) were selected consisting of the same weekly training schedules to determine whether differences in microcycle training load pattern existed. In addition, the training data within a given microcycle was analysed to investigate the loading patterns in relation to number of days away from the competitive match fixture. Linear mixed modelling analysis revealed significant differences for total distance and average HR (P 0.05). Training load variables were significantly reduced on match day (MD) -1 (P 0.05) during in-season microcycles. CM players generally covered the most total distance compared to other positions. Defenders reported higher internal load values (average HR and RPE) compared to attackers during in-season training phases but such differences were not evident during pre-season. This study revealed that training load doesn’t appear to be systematically periodised across a competitive season in an elite soccer team. This may have practical implications for training planning, as monotonous training load prescription may lead to maladaptation in soccer players during a competitive season. This was the first study to systematically evaluate periodisation strategies in an elite soccer team, but further work is required to determine such practices at different soccer teams. The aim of the fourth study (Chapter 6) was to determine the neuromuscular response to a microcycle of soccer training in elite soccer players using vertical jump assessment via the Optojump device. Nine elite level youth soccer players from an U18 soccer academy team were recruited for the study. The players underwent four separate on-field soccer training sessions following familiarisation of all testing procedures. Players were assessed for CMJ iv (flight time and jump height) both pre and post each training session in order to determine any differences in neuromuscular status across a training microcycle. Training load data was analysed using GPS, HR and RPE and the relationship with the absolute change in CMJ performance was assessed. Data analysis revealed no significant difference in CMJ performance across the four separate training sessions leading into a competitive match (P > 0.05). Training load data was significantly reduced on MD-1 for all training load variables (with the exception of high speed distance). There was no relationship found between the absolute change in CMJ performance and training load variables (P > 0.05). This study suggested that neuromuscular status remains unaffected in soccer players during a typical microcycle of training. This may be due to the emphasis of fitness maintenance during the in-season phase in order to maximise recovery between matches resulting in the players becoming accustomed to repeated maintenance loading. In summary, the work undertaken from the studies in this thesis provides novel information in relation to the training loads within elite professional soccer in relation to periodisation strategies. Specifically, this is the first work to systematically examine the training load across a competitive soccer season using both objective and subjective measures. Methodological work in this thesis also highlighted the importance of quantifying and interpreting errors associated with measurement tools when using applied methods to quantify training load in soccer players. It was also found that neuromuscular status remained unchanged throughout a planned microcycle in preparation for a competitive match. These findings suggest that the way in which training periodisation is applied is of utmost importance as opposed to trying to use traditional models and methods. Due to the limitations of traditional periodisation and training load management in elite soccer, future work should focus on developing periodisation models unique to the competition demands of soccer

The use of GPS technology to quantify the game demands of elite youth soccer: implications for training design.

The transition from academy to the professional level is one of the pivotal key stages in the development of elite professional soccer players and our understanding of this process is incomplete (Mills et al. 2012). A comprehensive detailed assessment of elite youth players match performance is limited and a clear gap in the literature exists which has consequences for the development programs of academy players (Harley et al. 2010). Global positioning systems (GPS) have been developed for use within a sports context to measure distance and velocity, however the methods employed for determining accurate capture conditions has not been examined and rely solely on historical criteria established before its use in dynamic sports such as soccer. The studies contained in this thesis are designed to further examine how an increase understanding of the match demands of youth soccer through the use of GPS technology to allow the development of highly tailored training programs to maximise the development of youth players. The aim of the first study (Chapter 4) was to compare data collected using 5Hz GPS (MinimaxX, Catapult) and the ProZone™ (PZ) match analysis system and to establish satellite and Horizontal Dilution of Precision (HDOP) threshold limits to allow direct comparison between the two data sets. Ten elite outfield youth team players were monitored with PZ and GPS during a match and the data grouped into 10 minute capture periods and categorised into players who averaged a mean satellite lock of more than 5.5, 5, 4.5, and 4 over the ten minute period and a mean an HDOP of less than 1.8, 2, 3 and 4. The distance covered in each of the predetermined PZ speed categories were compared. The data showed significant differences (p 0.05) with small to large effect sizes. These data therefore suggested that for the accurate assessment of high velocity running (>4m/s) using GPS a HDOP threshold of 1.8 be used. Using the valid GPS capture conditions obtained in study 1, the aim of the second study (Chapter 5) was to quantify match play according to outfield playing position in elite youth soccer at a scholarship (U18) level and compare to First team players. Eleven Under 18 games were analysed using GPS. Total distance covered and the maximal sprinting speeds were comparable with first team players in addition to the type of sprint performed (leading or explosive). The very high intensity running distance was less than that of first team players (range 532 to 804m vs 632 to 1196m) with the youth performing less sprints (range 9 to 12 vs 23 to 44) and with each sprint over a longer distance (50% over 10m vs under 10m) . The data highlights that the acceleration profiles of youth players need to receive the greatest attention at Under 18 level for there to be successful progression to the elite level. By highlighting the discrepancy in the number of sprints and the distance covered by elite youth players the purpose of study three (Chapter 6) was to adapt the Draper and Lancaster test (ADL) to soccer specific distances and determine its reliability and ability to discriminate between different levels of players. The reliability of the total time of the ADL proved to be highly reproducible (TE = 0.17, ICC = 0.99, CV =0.7) along with the three sub-component tests (LE7m TE = 0.38, ICC = 0.93, CV = 1.6, 505 TE = 0.28, ICC = 0.96, CV = 1.3, and EX7m TE = 0.21, ICC = 0.98, CV =1.2). In assessing the validity of the ADL test the national players showed that they were significantly quicker in the ADL (mean diff = 0.41, t = 5.32, p < 0.005, CI = 0.25, 0.57, d = 1.4) the EX7m (mean diff = 0.19, t = 6.72, p < 0.005 , CI = 0.14, 0.25, d = 1.76) and 505 (mean diff = 0.14, t = 3.27, p < 0.005, CI = 0.05, 0.22, d = 0.86) sub component tests compared to the club level players but not in the 7mLE (mean diff = 0.05, t = 1.79, p = 0.08, CI = 0.01, 0.11, d = 0.47). The data demonstrate that the ADL test was reliable in test retest situations and a valid predictor of level of sport participation because it discriminated between players of lesser ability (club) and higher ability (national) and can be used in a football setting to assess the main fitness components (explosive speed, leading speed and agility) which have been highlighted as important in the elite game. Extending on this work, the aim of study 4 (Chapter 6) was to investigate the application of the A505 field test for the assessment of functional asymmetries of the lower limb. Measurement of the fastest time for each side was recorded along with the peak torque of the hamstrings and quadriceps measured on an isokinetic dynamometer. The data showed that there were significant differences recorded in three of the four categories of the dominant side movements, concentric extension (Mean difference = 44.18, t = 5.70, p <0.001, CI = 28.4, 60.1, ES = 1.57), concentric flexion (Mean difference = 4.17, t = 3.29, p = 0.003, CI = 1.58, 6.8, ES = 1.12) and eccentric extension (Mean difference = 35.71, t = 3.50, p = 0.001, CI = 14.9, 56.5, ES = 1.18) with the eccentric flexion group showing non-significant differences (Mean difference = 2.68, t = 1.73, p = 0.094, CI = -0.5, 5.8, ES = 0.66). The non-dominant side showed significant differences in all four, concentric extension (Mean difference = 37.07, t = 6.41, p <0.001, CI = 25.1, 49.0, ES = 1.51) concentric flexion (Mean difference = 4.14, t = 2.70, p = 0.011, CI = 1.0, 7.3, ES = 0.95), eccentric extension (Mean difference = 34.90, t = 3.49, p = 0.002, CI = 14.5, 55.3, ES = 1.18), and eccentric flexion (Mean difference = 2.20, t = 2.27, p = 0.031, CI = 0.2, 4.2, ES = 0.85). The results suggest that the use of the A505 field test can determine asymmetries during functional dynamic movements in elite youth soccer players when compared to isokinetic assessment and as imbalances may have functional consequences which can lead to injury, therefore there is a need to examine how best to correct these. Using the subjects from the previous chapter the aim of study 5 (Chapter 7) was to examine the effect of isolateral plyometrics (PT) and strength training (ST) to correct bilateral imbalances in youth academy players. Players were separated into a PT or WT group and performed training over six weeks. The non-dominant leg improved in its performance in the A505 field test whilst there was no improvement in the dominant leg. There was no overall difference between the training groups in either the dominant (f = 0.026, p = 0.619, CI = -0.043, 0.026 s, p2 = 0.013) or the non-dominant leg (f = 1.946, p = 0.179, CI = -0.064, 0.013 s, p2 = 0.093). However this partial improvement decreased the bilateral A505 ratio and it can be postulated, as suggested in the previous chapter, that this would reduce the likelihood of injury in the players. In summary, the work undertaken from the studies in this thesis provides novel information in relation to the measuring of match performance when using GPS and the application of this information to the programming of training programmes with elite youth soccer players. It has also examined and validated the use of a simple field test to highlight bilateral lower limb imbalances and possible training programs to improve the bilateral ratio and to maximise the development of youth players

Reliability of ‘in-season’ fitness assessments in youth elite soccer players: a working model for practitioners and coaches.

Purpose: To assess the reliability of a battery of field tests when performed around habitual training during one micro-cycle of the ‘in-season’ period in youth elite soccer players. Methods: n=19 English Premier League academy players (mean ± SD: age, 18.3±0.2 years; stature, 1.80±0.05 m; body mass, 76.5±7.5 kg; V̇O2 max; 62.3±4.38 ml·kg-1·min-1 Sum of 8 skinfolds; 64.8±17.4 mm) performed; ‘1RM half-back squat (HBS)’, ‘vertical jump’ (VJ), ‘Yo-Yo IR2’, ’5, 10 & 20 m, sprint’, ‘the agility T-test’ and a ‘repeated sprint ability’ assessments around their habitual ‘in-season’ training and match-play on two occasions. Typical error (TE), coefficient of variation (CV), the smallest worthwhile change (SWC) was then calculated between trials. Test usefulness was then calculated by comparing the ‘SWC’ to the TE and rated as; good, OK or marginal. The smallest difference needed to be considered real (MD), was also calculated using the equation (TE×1.96×√2). Results: Most assessments demonstrated relatively high levels of reproducibility (CV; 0.3 - 4.3 %) to witness an “almost certain beneficial change” (i.e.,>MD) changes of approximately 5% (RSAbest, RSAmean, 10m & 20m sprint, ‘agility T test’ and 1RM HBS), and 11.5% (VJ, 5m sprint, and Yo-Yo IR2) are needed. Conclusions: The present training and testing ‘model’ is reliable and could be used when evaluating the fitness of highly trained youth elite soccer players during the ‘in-season’ period

Effectiveness of a community football programme on improving physiological markers of health in a hard-to-reach male population: the role of exercise intensity

© 2015 Taylor & Francis. The present study evaluated the effectiveness of participation in recreational football during a community health programme, on physiological markers of health within a hard to reach population. Nine men (Age: 33 ± 9 years, Mass: 75.4 ± 13.7 kg, Height: 1.74 ± 0.07 m and Body Fat: 19 ± 2%) were recruited to participate in the study in collaboration with an English Premier League Football Club. Participants completed the 12-week football-based programme which included two coached football sessions each week. Physiological tests for blood pressure, resting heart rate, cholesterol and an anthropometrical test for body composition were completed at three time points during the study (Weeks – 1, 6 and 12) in an attempt to evaluate the impact of the intervention on health. During each training session, measurements of intensity (%HRmax, identified from the yoyo intermittent level 1 test), duration and rating of perceived exertion were made. The 12-week programme (mean HRmax throughout programme = 75 ± 4% beats min−1; mean RPE throughout programme = 6 ± 1) elicited few changes in physiological markers of health with the only significant change been a decrease in resting heart rate from weeks 6 to 12 (87 ± 22 beats min−1 at week-6, to 72 ± 17 beats min−1; p < 0.05). These data would suggest that the current community football-related health project was not effective in improving physiological markers of health, but was able to maintain their level of health. A lack of improvement may be due to the low intensity of sessions and a lack of coach education for the promotion of sessions that aim to improve health

Free-sugar, total-sugar, fibre and micronutrient intake within elite youth British soccer players: a nutritional transition from schoolboy to fulltime soccer player.

It is recommended that soccer players consume a high carbohydrate (CHO) diet to augment performance. However, growing evidence suggests that there is a link between high free-sugar (FS) intake (>5% total energy intake; TEI) and metabolic diseases. Furthermore, foods that are often high in sugar, such as processed foods, are typically lacking in nutrient quality. We therefore analysed total- and FS, dietary fibre and micronutrient intake of players from an English Premier League academy under(U) 18 (n=13); U15/16 (n=25); U13/14 (n=21) using a 7-day food diary. Data was compared to current UK dietary reference value (DRV) for free-sugar via a t-test. The U13/14s (1018 %) and U15/16s (1130 %) both consumed higher amounts of free-sugar in comparison to the UK DRV of 5% TEI 5% (P<0.01), conversely, the U18s did not exceed the DRV (513 %). Furthermore, FS intake of the U18s was significantly lower than the U13/14s and U15/16s (P<0.01). Dietary fibre was below the DRV (25g/d for U13/14 & U15/16s; 30g/d for U18s) for all squads (19.04.7; 19.68.3; 17.14.2 g/d, respectively), but not different between squads. Additionally, micronutrient reference intakes were generally met. In conclusion, we provide novel data on dietary sugar, fibre and micronutrient intake within elite youth soccer players. We report an apparent 'nutritional transition' from schoolboy to fulltime soccer player, with U18s showing a significantly lower intake of sugar in comparison to younger squads, and a similar intake of FS to the UK DRVs. Practitioners should target improving player education around sugar and fibre consumption

Football in the community schemes: Exploring the effectiveness of an intervention in promoting healthful behaviour change

This study aims to examine the effectiveness of a Premier League football club’s Football in the Community (FitC) schemes intervention in promoting positive healthful behaviour change in children. Specifically, exploring the effectiveness of this intervention from the perspectives of the participants involved (i.e. the researcher, teachers, children and coaches). A range of data collection techniques were utilized including the principles of ethnography (i.e. immersion, engagement and observations), alongside conducting focus groups with the children. The results allude to the intervention merely ‘keeping active children active’ via (mostly) fun, football sessions. Results highlight the important contribution the ‘coach’ plays in the effectiveness of the intervention. Results relating to working practice (i.e. coaching practice and coach recruitment) are discussed and highlighted as areas to be addressed. FitC schemes appear to require a process of positive organizational change to increase their effectiveness in strategically attending to the health agenda

Acute simulated soccer-specific training increases PGC-1α mRNA expression in human skeletal muscle

The aim of the current study was to quantify oxygen uptake, heart rate and molecular responses of human skeletal muscle associated with mitochondrial biogenesis following an acute bout of simulated soccer training. Muscle biopsies (vastus lateralis) were obtained from nine active men immediately pre-completion, post-completion and 3 h post-completion of a laboratory-based soccer-specific training simulation on a motorised treadmill. The soccer-specific simulation was a similar intensity (55 ± 6% (Formula presented.)) and duration (60 min) as that observed in professional soccer training (e.g. standing 41%, walking 37%, jogging 11%, high-speed running 9% and sprinting 2%). Post-exercise, muscle glycogen decreased (Pre; 397 ± 86 mmol∙kg−1 dw, Post; 344 ± 64 mmol∙kg−1 dw; P = 0.03), plasma lactate increased (P −1, non-esterified fatty acids and glycerol increased (P −1 and 145 ± 54 μmol∙L−1, respectively. PGC-1α mRNA increased (P = 0.009) fivefold 3 h post-exercise. We provide novel data by demonstrating that soccer-specific training is associated with increases in PGC-1α mRNA. These data may have implications for practitioners in better understanding the metabolic and muscle responses to soccer-specific training protocols in the field