The role of motion analysis in elite soccer

The optimal physical preparation of elite soccer (association football) players has become an indispensable part of the professional game especially due to the increased physical demands of match-play. The monitoring of players’ work-rate profiles during competition is now feasible through computer-aided motion analysis. Traditional methods of motion analysis were extremely labour intensive and were largely restricted to university- based research projects. Recent technological developments have meant that sophisticated systems, capable of quickly recording and processing the data of all players’ physical contributions throughout an entire match, are now being used in elite club environments. In recognition of the important role motion analysis now plays as a tool for measuring the physical performance of soccer players, this review critically appraises various motion analysis methods currently employed in elite soccer and explores research conducted using these methods. This review therefore aims to increase the awareness of both practitioners and researchers of the various motion analysis systems available, identify practical implications of the established body of knowledge, while highlighting areas that require further exploration

A time-motion analysis of elite women's hockey - implications for fitness assessment and training

To-date no large scale studies have been published that have used player tracking technology to investigate continuous time-motion analysis in the modern era of Women’s field hockey during Elite level International\ud competition to investigate positional differences and inform fitness training and testing. A new computerised time-motion analysis method, Trak Performance was used to analyse individual player movement (n = 54) from\ud 18 International Women’s hockey matches (18 defenders, 18 midfielders, 18 forwards). Overall analysis identified distance covered 9.1 ± 1.6 km, of which 74.7 ± 9.0% was covered in low intensity activity of stationary, walking and\ud jogging, 3.9 ± 2.4% match time was spent stationary. Mean sprint distance of 12.7 ± 1.7 m, with an average of 26.7 ± 11.5 s between each sprint. Positional differences were identified for the mean percentage of time spent, distances\ud covered in locomotion activity, the mean duration of rest between sprint bouts, the frequency of sprints and work to rest ratios. The majority of contrasts in movement characteristics occur between the defensive players and other outfield positions. Analysis of repeated-sprint ability revealed forwards undertake a significantly greater amount of 16 ± 9. Modern hockey dispels traditional positional roles with tactics and the more fluid nature of attacking plays requiring a more versatile player. Fitness assessment/training should therefore resemble the intermittent nature of the game with sprint recovery\ud periods reflecting the different positional demands

Current methods of soccer match analysis

Ha sido realizada una revisión de 86 artículos, con el objetivo de analizar a través de los estudios más recientes los beneficios y limitaciones de los nuevos sistemas para el análisis del futbolista durante el partido, debido a que las mayores exigencias en el rendimiento del fútbol moderno está obligando a replantearse cuáles son sus demandas físicas, así como los modelos de planificación y los métodos de entrenamiento tradicionales. Los resultados muestran que el vídeo análisis asistido por ordenador para la codificación de los patrones de movimiento y la tecnología GPS se presentan como herramientas de gran utilidad para conocer mejor la carga física del jugador, mientras que el diseño observacional facilita la evaluación del comportamiento técnico-táctico del futbolista y el equipo. Como conclusión podemos decir que hemos observado sin embargo una metodología diferente entre las opciones comerciales disponibles y una tecnología ubicada todavía en una etapa inicial de desarrolloA review of 86 references has been made, in order to analyze through the most recent studies the benefits and limitations of the new systems for the analysis of soccer player during the match, due to the fact that the greater performance requirements of modern soccer is forcing to review his physical demands, as well as planning models and traditional training methods. The results show that the computer-aided video analysis for coding movement patterns and the GPS technology are presented as very useful tools for a better understanding of the players physical load, whereas the observational design facilitates assessment of the technical-tactical behavior of the soccer player and the team. In conclusion we can say that we have however observed a different methodology among the available commercial options and a technology still placed at an initial stage of development

Technical demands of soccer match-play in the English Championship

The aim of this study was to investigate the effect of match-play on the performance of technical actions in professional soccer players. Using computerized notational analysis, technical performance was quantified for the outfield players of one team during the 2010/2011 English Championship season. This retrospective study evaluated temporal patterns in the performance of players who completed more than 10 games (n=10). Total possessions and number of ball distributions were lower in the second versus the first half of match-play (10 ± 7%, P=0.010 and 11 ± 8% P=0.009,respectively). Analysis across 15-min intervals revealed reductions during the last 15-min of match-play in the total number of possessions (0:00-14:59 min: 11.8 ± 1.9 vs.75:00-89:59 min: 9.5 ± 1.7, P<0.05) and distributions (0:00-14:59 min: 10.9 ± 2.3 vs.75:00-89:59 min: 8.7 ± 2.1, P<0.05). The number of touches taken per possession, number of challenges, percentage of challenges won, length of forward distributions and percentage success of distributions were all similar between halves and across 15-min intervals. These results demonstrate that match-specific factors reduced total possessions and number of passes in the second half of match-play. Coaching staff could use this information to inform team tactics and technical training sessions

Influence of opposition team formation on physical and skill-related performance in a professional soccer team

This study examined the influence of opposition team formation on physical and skill-related performance in a professional soccer team. Performance in forty-five French League 1 matches played over three competitive seasons (2007-08, 2008-09, and 2009-10) was analysed using multi-camera computerised tracking. Players (n=21) in the reference team (using a 4-3-3/4-5-1 formation) were analysed in matches against three opposition team formations: 4-4-2 (11 games), 4-3-3/4-5-1 (16 games) and 4-2-3-1 (18 games). Performance was compared for defending and midfield units as a whole and individually across four positions: fullbacks, central-defenders and central- and wide-midfielders. Collectively, players covered a greater total distance (p<0.05) and distance in low/moderate-intensity running (0-14.3km/h) (p<0.05) in matches against a 4-2-3-1 compared to a 4-4-2 formation. Distance covered in high-intensity (14.4-19.7km/h) and very high-intensity running (≥19.8km/h) was not affected by opposition formation. In contrast, players covered more distance in total high-intensity performance (≥14.4km/h) when the reference team was in possession against a 4-4-2 compared to a 4-2-3-1 formation (p<0.05) while more distance was run at these speeds when the reference team was out of possession against a 4-2-3-1 (p<0.01) and a 4-3-3 (p<0.05) compared to a 4-4-2 formation. Players ran less distance at low/moderate intensities in the second- versus first-half of matches against all three formations (p<0.01 to p<0.05) whereas total distance and high-intensity performance was unaffected. None of the measures of physical performance across the individual playing positions were affected by opposition team formation. Skill-related performance varied according to opposition formation: players as a whole performed more passes versus a 4-4-2 than a 4-2-3-1 (p<0.01), ground and aerial duels versus a 4-2-3-1 compared to a 4-4-2 (both p<0.01); 1-touch passes versus a 4-2-3-1 compared to a 4-4-2 (p<0.01) and a 4-3-3/4-5-1 (p<0.05). The mean number of touches per possession was highest versus a 4-4-2 compared to a 4-3-3/4-5-1 (p<0.01) and a 4-2-3-1 (p<0.01). While skill-related performance across the four individual playing positions was generally unaffected by opposition team formation, mean pass length was greater in central-midfielders against a 4-4-2 compared to 4-3-3/4-5-1 (p<0.05) and 4-2-3-1 (p<0.01) formations. In general, these findings suggest that physical performance in the reference team was not greatly affected by opposition team formation. In contrast, skill-related demands varied substantially according to opponent formation and may have consequences for tactical and technical preparation and team selection policies

Analysis of repeated high-intensity running performance in professional soccer

The aims of this study conducted in a professional soccer team were two-fold: to characterise repeated high-intensity movement activity profiles in official match-play; b) 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 for a minimum of 1-s duration) in 20 players was measured using computerised time motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 out of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of 6 consecutive 6s sprints separated by 20s passive recovery intervals. In all players, the majority of consecutive high-intensity actions in competition were performed after recovery durations ≥61s, 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 3 consecutive high-intensity with a mean recovery time ≤20s 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 (≤20s, p<0.01 and ≤30s, p<0.05) compared to those with higher decrements. Across positional roles, central-midfielders performed a greater number of high-intensity actions separated by short recovery times (≤20s) 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

U-SAFT⁹⁰ simulates the internal and external loads of university-level soccer match play

Motion analysis has become more prevalent in contemporary soccer research, particularly within the elite sector. The study of motion-profiles can be used for identifying patterns in soccer match performance regarding both physical and technical elements. Deducing movement patterns and internal and external loading through in-depth study, it may then be possible to simulate competitive match-play specific to squad or individual needs. Modern technology allows match performance to be broken down into specific periods that subsequently enables the examination of work rate. Changes in work-rate may indicate fluctuations in performance which can also heighten the risk of injury and susceptibility to conceding to opponents. As a result, preparatory, conditioning and nutritional interventions can be employed directed towards sustaining performance levels.This thesis will firstly look at motion profiles of competitive soccer in an amateur population in order to quantify the internal and external physical demands and variation in work-rate compared to those previously scrutinised in elite soccer. The following experimental chapter utilises motion analysis data to create and validate a squad soccer-specific exercise protocol (SSEP) to use as a simulation of soccer match-play in both rehabilitation and laboratory settings.Motion analysis was determined with a 5Hz Global Positioning System to analyse total, high-intensity and sprint distance as well as producing mechanical ‘Accumulated Player Load’ values through an in-built accelerometer. This data was combined with concurrent heart rate data during matches to provide a measure of internal physiological load. Total distance was found to range between 7223-12158m, with an average of 9423m for the squad, declining 6% between halves (P 0.05).The findings in this thesis suggest patterns of physical demands in competitive amateur match play are similar to those of elite soccer, in terms of total, high-intensity and sprint distances but fall in the lower part of the range previously reported in motion-analysis studies. Changes in work-rate possibly due to fatigue are evident in motion profiles of amateur soccer players, similar to those observed in professionals. Furthermore heart rate analysis suggested cardiovascular strain is also high.Competitive amateur match-play can be simulated effectively with respect to inducing the same internal and external loads associated with a 90 minute soccer match. The implications of such findings are that the USAFT⁹⁰ can be used to simulate the locomotor, physiological and mechanical demands of amateur soccer matches in controlled environments. This may be useful for rehabilitation purposes and testing intervention strategies to gauge effect on performance. Future research should address positional differences and examine the effect of fatigue on work-rate in more detail for university-level soccer. This would accommodate individual and positional capabilities that were not simulated in USAFT⁹⁰

The development of a novel rugby league match simulation protocol

The effectiveness of recovery interventions following prolonged multiple sprint team sports matches has rarely been studied despite the potential for exercise-induced muscle damage to adversely affect training in the days following games. The lack of research related to this topic is probably owing to the wide variability that exists in the movement demands of players between matches and the impact that this has on the subsequent rate and magnitude of recovery which makes it difficult to detect meaningful differences when conducting research with small sample sizes. Therefore, the purpose of this thesis was to develop a rugby league-specific match simulation protocol that replicates the movement demands, physiological responses and subsequent recovery from matches in order to study the effectiveness of recovery interventions. Hence, two time-motion analysis studies were conducted using a semi-automated image recognition system to inform the development of the rugby league match simulation protocol (RLMSP). Whilst mean total distance covered over the duration of the match was 8,503 m, ball in play and stoppage work-to-rest ratios were 1:6.9 and 1:87.4, respectively, for all players. Furthermore, a significant decline in high and very high intensity running locomotive rates were observed between the initial and final 20 min periods of the match. Thus a RLMSP was devised to replicate the overall movement demands, intra-match fatigue and recovery from a senior elite rugby league match. Not only was there a low level of variability in the movement demands during the RLMSP over consecutive trials, but with the exception of creatine kinase, the rate and magnitude of recovery following the RLMSP was similar to that that has been published following competitive matches. Therefore, the RLMSP devised in this thesis may be a more appropriate research tool for assessing the effectiveness of recovery interventions following match related exercise than following actual match play.Sponsored by Warrington Wolves Rugby League Football Clu

The validity, reliability and sensitivity of utilising a wearable GPS based IMU to determine goalkeeper specific training demands

Despite the plethora of football focused literature, there is still very little known about the training practices of the goalkeeper (GK). The development of portable Global Positioning System (GPS) and Inertial Measurement Unit (IMU) devices ensured physical activities can be accurately measured within the training environment. The integration of inertial sensor fusion algorithms has allowed the IMU the ability to also detect non-locomotive activities that are specific to a sport. This technology is shown to be a valid method of analysis for the demands of an outfield football player, however, similar research into the GK position is required. Thus, the aim of this study was to investigate the validity, reliability and sensitivity of utilizing a wearable GPS based IMU to determine goalkeeper specific training demands. A total of 123 event variables were recorded via OptimEye G5 GPS units over 14 sessions from 6 professional GKs during the 2017-2018 Scottish Premiership season. GPS data was collected as part of normal daily monitoring and compared against corresponding computerized notational analysis of the same training sessions. Event variables were split into specific IMU events by a GK specific algorithm: Total Dives (TD), Dives Right (DvR), Dives Left (DvL), Dive Returns (DR) and Jumps. The intra-unit variation was derived from reproducibility of trends within the difference between GPS and corresponding Video Analysis (VA) counts. Unit sensitivity was investigated according to the relationship between average DR times and countermovement jump (CMJ) and ballistic press-up (BP) results which corresponded to lower and upper body velocity at peak power (m/s) respectively. There was no significant difference (p0.05). Bland Altman 95% Limits of Agreement (LOA) show minimal variation for TD (-3.6 to 5.6), DvL (-1.75 to 4.04) and DvR (-3.38 to 3.13). However, DR (-13 to 12.6) and Jumps (-8.8 to 15.7) showed much wider LOA and variation from VA counts. Intra-unit variability was significantly different across all metrics with GPS units, over-estimating movement event counts compared to VA counts. Inter-unit sensitivity suggested that CMJ and lower body velocity at peak power (m/s) performance had the greatest correlation (r=0.992) with average DR times compared to BP and upper body velocity at peak power (r=0.684) and CMJ + BP combined (r=0.603). Based on these findings, the sensitivity of the OptimEye G5 GPS to count GK specific events was almost perfect (r = 903), however, the specificity of the IMU algorithm to distinguish the different movements was questionable. Jumps were significantly over- estimated, and in the meantime, we would suggest using video footage to compliment GPS data for accurate longitudinal analysis. This study provided novel information regarding the DR action, of which the lower body muscular profile plays the dominant part in. Although there are limitations within this study, these investigations should only act as the first step in understanding if the GPS coupled IMU has a place in accurately determining the training demands of a goalkeeper