title: Physical Demands During Contextualised Peak Intensity Periods: Analysis of Transitional Play, High-Pressure Activities and 30-second Worst-Case Scenarios in Elite Football
Creators: name: Bortnik, Lukasz
Publisher: name: University of Central Lancashire
Year: 2024

description: Transitional activities (TA’s) and high-pressure actions are the key phases of play in modern football. They present a broad context within game play, as they depict actions in/out of possession as well as represent tactical offensive and defensive team collective movements and behaviours. A detailed definition of these tactical moments is presented in Table 2 and 3, which can be found in Chapter 3 (page 86-87). Previous studies have not explored the physical demands during transitions in football and most authors have reported whole and average match GPS-derived data neglecting fluctuations of intensity across 90-min. These shorts bouts of high-intensity periods could expose players to the highest physical outputs within a contemporary match play. The increased body of knowledge on TA’s might provide new multivariate insights about physical demands of
competition and offer more effective team/individual contextualised training design that integrates physical and technical-tactical aspects in practical settings. Therefore, the primary aim of this thesis was to analyse short and specific blocks of activities commonly observed in football matches and determine their impact on external load metrics to optimise physical preparation of players, enhance performance, and potentially reduce injury risk.

Chapter 3 analysed the mean and peak team physical demands during transitional activities and compared them to the 90-min averages. Chapter 4 explored physical demands across different playing positions during these phases. Players were categorised to the following positional groups: center backs (CB), full backs (FB), central defensive midfielders (CDM), central midfielders (CM), central attacking midfielders (CAM), wingers (W), and attackers (A). The aims of Chapter 5 and Chapter 6 were to analyse the effect of contextual variables (match half, match outcome, and 15min blocks) on locomotor and mechanical metrics and investigate repeated high-intensity specific efforts (clusters) during these key periods of play. Frequency, type, duration, and recovery periods between clusters of transitional activities (CTA) were also determined. Chapter 7 investigated 30-second peak intensity periods also referred to as the worst-case-scenarios (WCS) within training and game play. The aim was to compare commonly selected football specific drills to the competition WCS demands, establish the effect of position, playing status (starters vs. non-starters), and different recovery periods between games (long vs moderate vs congested) on match day physical performance during 30-second peak phases.

Findings demonstrated largely elevated physical metrics when contextualised into transitions, especially in relation to high-velocity activities, which were 7-9 times greater when compared to the whole match averages. It was revealed that during football matches players could be frequently exposed (n = 50 ± 11.1) to short maximum physical outputs (transitions) lasting around 10 seconds. Moreover, 66% of all transitions were identified as clusters (CTA), which means more than 2 TA’s occurred within 1 min. Additionally, all locomotor metrics (high velocity) were found to be insufficiently imposed in training across all playing positions. It was also shown that the congested fixtures could have a detrimental effect on mechanical metrics and the gap between training and competition for maximum intensity periods could even be greater in substitute players.

Such information could help practitioners prescribe position specific high-velocity and high-intensity exposures within a weekly microcycle to better prepare players for short and specific peak intensity periods experienced in official matches. Practitioners should move away from training design guided only by 90-minute averages and focus more on condensed match demands in practical settings to counteract the detrimental effects of fatigue on the second half physical performance. Isolated running based drills in conjunction with transitional games during team and/or top-up conditioning sessions would be highly recommended based on these findings.

This thesis provides novel data about short specific and contextualised maximum intensity periods. The chapters presented in this work contribute to the body of existing knowledge and provide further valuable insights into the physical demands of professional football. Collectively therefore, they should serve as high importance to practitioners. Coaches are encouraged to apply these findings and adopt practical recommendations presented in Chapter 8 in team and individual training prescription.