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Purpose: This investigation examined the longitudinal changes and interrelationships of salivary and self-report monitoring measures across a professional football season., Methods: Measures were collected biweekly from 18 senior professional male players across a 6-wk preseason and eight 5-wk in-season mesocycles and analyzed using a linear mixed-effects model., Results: Analysis identified a small (P = 0.003) cross-season suppression of salivary immunoglobulin A, small reductions to salivary α-amylase (P = 0.047) and salivary cortisol (P = 0.007), and trivial changes to salivary testosterone (P > 0.05). The testosterone/cortisol ratio typically responded inversely to changes in player workload. Self-report measures of fatigue (P = 0.030), sleep quality (P = 0.003), and muscle soreness (P = 0.005) improved (ES = small) across the first half of the season. Fatigue and sleep measures were most consistently related to hormonal measures (R2 = 0.43-0.45). For these relationships, increases in cortisol were associated with compromised self-report responses, whereas increases in testosterone/cortisol were associated with improved responses. Nonlinear relationships were identified for fatigue with immunoglobulin A (P = 0.017; ES = trivial) and testosterone (P = 0.012; ES = trivial), for sleep quality with testosterone (P < 0.001; ES = trivial), for muscle soreness with testosterone (P = 0.012; ES = trivial), and for the self-report inventory sum with testosterone (P = 0.027; ES = trivial). For these relationships, self-report responses were optimal at mean immunoglobulin A and testosterone levels, and very low levels (-2 SD) exerted the most compromising effects., Conclusions: Players can experience a chronic cross-season suppression of mucosal immunity. Salivary immunoglobulin A, testosterone, cortisol, and testosterone/cortisol measures relate to self-report measures of fatigue, sleep quality, and muscle soreness. In-season reductions in testosterone, cortisol, and testosterone/cortisol or increases in cortisol among elite football players could be used to indicate the need for reduced workload, which might lead to improved well-being., (Copyright © 2020 by the American College of Sports Medicine.)

Biomarkers relating to player "stress balance," immunological (ie, immunoglobulin-A), and hormonal (ie, testosterone and cortisol [T:C]) status are now commonly used in football. This article is our critical review of the scientific literature relating to the response of these measures to player load and their relationships with player health. The commonly reported relationship between immunoglobulin-A and training or match load highlights its sensitivity to changes in psychophysiological stress and the increased risk of compromised mucosal immunity. This is supported by its close relationship with symptoms of upper respiratory tract infection and its association with perceived fatigue in football players. Testosterone and cortisol concentrations and the testosterone–cortisol ratio are sensitive to changes in player load, but the direction of their response is often inconsistent and is likely influenced by player training status and non-sport-related stressors. Some evidence indicates that sustained periods of high training volume can increase resting testosterone and that sustained periods of low and high training intensity can increase resting cortisol, compromising the testosterone–cortisol ratio. These findings are noteworthy, as recent findings indicate interrelationships between testosterone, cortisol, and testosterone:cortisol and perceived measures of fatigue, sleep quality, and muscle soreness in football players. Variability in individual responses suggests the need for a multivariate and individualized approach to player monitoring. Overall, we consider that there is sufficient evidence to support the use of salivary immunoglobulin-A, testosterone, cortisol, and testosterone:cortisol measures as part of a multivariate, individualized player monitoring system in professional football. [ABSTRACT FROM AUTHOR]

We examined how summated training and match load measures relate to salivary immunological and hormonal profile changes in professional football players. Data were collected from 18 elite-level professional male football players from one English Championship team across a complete 40 wk competitive season. Daily training (micro-technology) and match (computerised tracking) measures of total, high-speed and high-metabolic load running distance and sprint, acceleration, deceleration and sRPE load were converted into exponentially weighted moving average "acute" (7d), "chronic" (28d) and acute:chronic composite load measures. Bi-weekly morning saliva samples were analysed for immunoglobulin-A, alpha-amylase, testosterone, cortisol and testosterone:cortisol. A two-stage data reduction technique using partial least squares modelling and a backward stepwise selection procedure determined the most parsimonious model for each salivary variable. Testosterone had non-linear relationships with chronic total (P = 0.015; Cohen's D: large), high-metabolic load (P = 0.001;small) and high-speed (P = 0.001;trivial) running distance and linear relationships with chronic sRPE (P = 0.002;moderate ↓) and acute:chronic high-speed running distance (P = 0.001; trivial ↑). Cortisol had a non-linear relationship with chronic high-speed running distance (P = 0.001;trivial). Testosterone:cortisol had non-linear relationships with chronic decelerations (P = 0.039;small) and chronic summated acceleration and deceleration load (P = 0.039;small). Non-linear relationships typically indicated optimal hormonal responses at squad mean loads. No load variables clearly related to salivary immunoglobulin-A or alpha-amylase changes. We conclude that chronic total and high-intensity load measures relate to hormonal changes and might be useful indicators of player readiness. Acute load variables were not related to immunological or hormonal changes and consequently, should not be used as surrogate measures of player readiness in isolation. [ABSTRACT FROM AUTHOR]