The tracking of morning fatigue status across in-season training weeks in elite soccer players

Thorpe RT, Strudwick AJ, Buchheit M, Atkinson G, Drust B and Gregson W. The tracking of morning fatigue status across in-season training weeks in elite soccer players. IJSPP, In Press. Full text here

Purpose: To quantify the mean daily changes in training and match load and any parallel changes in indicators of morning-measured fatigue across in-season training weeks in elite soccer players.
Methods/ Following each training session and match, ratings of perceived exertion (RPE) were recorded to calculate overall session load (RPE-TL) in 29 English Premier League players. Morning ratings of fatigue, sleep quality, muscle soreness, as well as sub-maximal exercise heart rate (HRex), post-exercise heart rate recovery (HRR%) and variability (HRV) were also recorded. Data were collected for a median duration of 3 weeks (range: 1-13) and reduced to a typical weekly cycle including a weekend match day. Data were analysed using within-subjects linear mixed models.
Results: RPE-TL was approximately 600 AU (95%CI: 546-600) higher on match day vs the following day (P<0.001). RPE-TL progressively decreased by ˜ 60 AU per day over the 3 days prior to a match (P<0.05).  Morning-measured fatigue, sleep quality and soreness tracked the changes in RPE-TL, being 35-40% worse on post-match day vs pre-match day (P<0.001).  Perceived fatigue, sleep quality and soreness improved by 17-26 % from post-match day 1 to day 3 with further smaller (7-14%) improvements occurring between post-match day 4 and pre-match day (P<0.01). There were no substantial or statistically significant changes in HRex, HRR% and HRV over the weekly cycle (P>0.05).
Conclusions: Morning-measured ratings of fatigue, sleep quality and muscle soreness but not HR-derived indices are sensitive to the daily fluctuations in session load experienced by elite soccer players within a standard in-season week.
Key Words-Training, Performance, Wellness, Recovery