Validation of a LiDAR-based player tracking system during football-specific tasks

Exploring turn demands of an English Premier League team across league and knockout competitions over a full season

Turns are key performance actions in soccer, but can also induce high mechanical loads resulting in tissue damage or injury. This study aimed to quantify the turn demands of an elite English Premier League soccer team. Turning data were obtained from 49 soccer matches (2022-23 season), from a single team that played 35 Premier League, 5 UEFA Europa League, 5 League Cup and 4 FA Cup matches using Sportlight LiDAR technology. Turns were analysed from 29 players who were categorised in playing position groups: goalkeeper (GK), central defenders (CD), full-backs (FB), central-midfielders (CM), wide-midfielders (WM), central-forwards (CF). Turn categories: high (120-180°), medium (60-119°) and low (20-60°) angled, and very high (>7.0ms-1), high (5.5-7.0ms-1), medium (3.0-5.5ms-1), and low (<3.0ms-1) entry speed (ES) was analysed. Primary findings show, on average, per match, CM performed more total turns (~35), than all other playing positions. Additionally, CM performed significantly more low and medium entry speed and high angled turns than other outfield positions. There were no significant differences between turn frequencies and turn characteristics in different competitions (p >0.05). The turning demands of soccer appear to vary significantly between player position. These findings may help inform position-specific return-to-play protocols, physical preparation strategies, drill design and rehabilitation programmes.

Frequency and intensity of change of directions in German Bundesliga soccer

The aim of this study was to investigate the change of direction (COD) frequencies and intensities of high-performance soccer players of the German Bundesliga independent of tactical and match context. COD data were collected from 18 German Bundesliga soccer teams (season 2016-2017; 308 fixtures) by an optical tracking system (OTS) (TRACAB). CODs were tracked using a modified algorithm and were sub-categorized by entry velocity (<3.0 m⋅s-1, 3.0-5.5 m⋅s-1, 5.5-7.0 m⋅s-1 and >7.0 m⋅s-1) and COD angle (20-59°, 60-119° and 120-180°). COD metric frequencies were compared between playing positions (goalkeepers, centre backs, full-backs, central midfielders, wide midfielders, and strikers). In general, regardless of entry velocity or COD angle, central midfielders consistently executed the highest number of COD actions during matches compared to the other playing positions. About ≈ 55% and ≈ 38% of CODs were <3.0 m⋅s-1 and <5.5 m⋅s-1, whereas ≈ 7% were >5.5 m⋅s-1. The distribution of COD angle types was ≈ 5% for 20-59°, ≈25% 60-119° and ≈ 70% for 120-180° COD angles. Our data provide insights into the COD demands of high-performance soccer in the German Bundesliga in terms of entry velocity and COD angles and their combination based on a large dataset of OTS data, which provides insights to facilitate the development of physical conditioning strategies, position-specific external load management, and multidirectional speed training with adequate test battery selection and return-to-play protocols for soccer players.

Challenges and considerations in determining the quality of electronic performance & tracking systems for team sports

Electronic performance & tracking systems (EPTS) are commonly used to track the location and velocity of athletes in many team sports. A range of associated applications using the derived data exist, such as assessment of athlete characteristics, informing training design, assisting match adjudication and providing fan insights for broadcast. Consequently the quality of such systems is of importance to a range of stakeholders. The influence of both systematic and methodological factors such as hardware, software settings, sample rate and filtering on this resulting quality is non-trivial. Highlighting these allows for the user to understand their strengths and limitations in various decision-making processes, as well as identify areas for research and development. In this paper, a number of challenges and considerations relating to the determination of EPTS validity for team sport are outlined and discussed. The aim of this paper is to draw attention of these factors to both researchers and practitioners looking to inform their decision-making in the EPTS area. Addressing some of the posited considerations in future work may represent best practice; others may require further investigation, have multiple potential solutions or currently be intractable.

What are the significant turning demands of match play of an English Premier League soccer team?

This study aimed to compare the significant turning demands of English Premier League soccer match play relative to playing position using LiDAR technology. Turning data were collected from an English Premier League soccer team (2020-2021 season; 18 fixtures) using a Sportlight® LiDAR tracking system. Turns were tracked during match play, sub-categorised by entry speed (<3.0, 3.0-5.5, 5.5-7.0 and >7.0 m/s) and turning angle (Low: 20-59°; Medium: 60-119°; High: 120-180°). Turning metric frequencies were compared between playing positions (centre backs, full-backs, central midfielders, wide midfielders, and central forwards). On average, per match, central midfielders performed more total turns (~38 vs ~18-27), turns with entry speeds <3.0 (~15 vs ~7-10) and 3.0-5.5 m/s (~21 vs ~8-15) and low (~4 vs ~1-2), medium (~10 vs ~3-6) and high angled turns (~24 vs ~12-18) compared to all other playing positions (p ≤ 0.001, d = 0.96-2.74). Approximately, 90% of turns during matches were performed with entry speeds <5.5 m/s and ~63-70% were high angled turns. This study provides unique insights into the turning demands of English Premier League soccer matches , which can be used to inform position-specific physical preparation strategies, turning testing battery selection, agility drill construction, and rehabilitation and return to play standards.