Worst Case Scenarios in Soccer Training and Competition: Analysis of Playing Position, Congested Periods, and Substitutes.

Aim : To understand mean (WCS mean ) and peak (WCS peak ) worst case scenarios within training and game play in male professional soccer. Methods : Thirty-one ( n  = 31) first team players were monitored across 37 matches and 14 MD-3 sessions. Playing status was distinguished, football drills analyzed, and performance explored in long-period: >6 days, moderate-period: 5-6 days, and congested-period: ≤4 days. Relative total distance (TD), high-speed running distance (HSRD, >19.8 km·h -1 ), sprint distance (SD, >25.2 km·h -1 ), accelerations/decelerations (A+D, >3 m·s -2 ), accelerations (Acc, >3 m·s -2 ), and decelerations (Dec, >-3 m·s -2 ) were measured as well as Maximum acceleration (Max Acc; m·s -2 ) and deceleration (Max Dec; m·s -2 ). Results : Analysis of variance found differences between matches and training in WCS mean for TD, HSRD, SD, and Max Dec in all positions ( p  < .001; partial η 2  > .275). Fullbacks displayed differences between match and training in Max Acc (moderate ESs; p  < .001), while center backs and central midfielders in Max Dec (large ESs; p  > .05). Main effects of playing status were discovered for all metrics except Max Dec ( p  < .001; partial η 2  > .124). Analysis showed differences between long- and congested-period for A+D and Dec (large ESs; p  ≤ .05). Conclusions : Findings provide more insights into short peak intensity demands of soccer showing that the maximum high velocity action of acceleration and deceleration is not being replicated in training. Nonstarters lack maximum intensity exposure in matches (WCS peak ) increasing the gap between training and competition even higher during congested fixture periods.