Tracking Morning Fatigue Status Across In-Season Training Weeks in Elite Soccer Players

Abstract

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 (s-RPE) were recorded to calculate overall session load (RPE-TL) in 29 English Premier League players from the same team. Morning ratings of fatigue, sleep quality, delayed-onset muscle soreness (DOMS), as well as sub-maximal exercise heart rate (HRex), post-exercise heart rate recovery (HRR%) and variability (HRV) were also recorded prematch day and one, two and four days post-match. Data were collected for a median duration of 3 weeks (range:1-13) and reduced to a typical weekly cycle including no mid-week match and a weekend match day. Data were analysed using within-subjects linear mixed models.Results: RPE-TL was approximately 600 AU (95%CI: 546-644) 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 DOMS 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 DOMS improved by 17-26% from post-match day to three days post-match with further smaller (7-14%) improvements occurring between four days post-match 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 DOMS are clearly more sensitive than HR-derived indices to the daily fluctuations in session load experienced by elite soccer players within a standard in-season week.

The Influence of Changes in Acute Training Load on Daily Sensitivity of Morning-Measured Fatigue Variables in Elite Soccer Players

“…9 The use of simple perceived ratings of wellness is an efficient and practical approach to determining the fatigue status of elite team sport athletes. [8][9][10]30 Previous observations on elite soccer players showed a moderate-to-strong significant correlation between the players perceived rating of fatigue and the previous days total high-speed-running distance (r = -.51; P < .001). 9 Furthermore, the slope of the regression model indicated that every ~400-m increase in total high-speed-running distance led to a 1-unit decrease (eg, a player may change from very poor level of fatigue to very, very poor level of fatigue after an additional ~400-m total high-speedrunning distance) in fatigue with 37% of the variance in training load explained by all the statistically significant predictors.…”

“…34 In the current study, only two match days were included in the sample of 17 days, consequently, the limited match exposure and training intensity may not have been sufficient to influence muscle soreness and sleep quality. In a previous study from the same population of players, match demands accounted for ~40% of total weekly load, moreover, perceived ratings of wellness were found to be lowest on the day postmatch, 10 further showing the debilitating effects of a match on fatigue status. Indeed, the average daily training load in the current study (RPE-TL 361) is considerably lower than that reported during an AFL preseason training camp (RPE-TL 746) where daily readings of muscle soreness and sleep quality were associated with changes in load.…”

“…18,19 All devices were activated 15 minutes before the data collection to allow acquisition of satellite signals. 20 The minimum acceptable number of available satellite signals was 8 (range [8][9][10][11]. 21 Players wore the same GPS device for each session to avoid interunit error.…”

“…Furthermore, in the same population, only perceived ratings of wellness were sensitive to within-week fluctuations in match and training load during typical in-season competition weeks. 10 Collectively, these findings demonstrate that these measures, particular perceived ratings of wellness, show promise as acute, simple, noninvasive assessments for tracking the fatigue status of elite team-sport athletes.Physiological adaptation to training is the culmination of repeated daily applications of training load. 11…”

“…9,10 The questionnaire comprised 3 questions relating to perceived sleep quality (coefficient of variation [CV] 13%), muscle soreness (CV 9%), and fatigue (CV 12%). 9 Each question scored on a 7-point Likert scale with scores of 1 to 7 with 1 and 7 representing very, very poor (negative state of wellness) and very, very good (positive state of wellness), respectively.…”