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We examined the sensitivity and time-course of recovery of neuromuscular and perceptual player monitoring measures to U-18 English Premier League academy football match play. Eighteen players performed maximal posterior chain, hip adductor and abductor isometric strength tests, countermovement jumps (CMJ) and provided self-report wellbeing scores around eight competitive league home games: 1 day before (MD-1), pre-match (MD-PRE), post-match (MD-POST) and two (MD+2) and three (MD+3) days post-match. A permutational multivariate analysis of variance and post hoc univariate analyses of variance were used to examine match-induced responses to monitoring variables. Between MD-1 and MD-POST, we observed small to moderate reductions to the adductor and abductor peak force and maximal impulse and IPCS peak force; small reductions to CMJ jump height (JH) (flight time), eccentric peak force and eccentric deceleration rate of force development and moderate to large reductions to perceived fatigue, muscle soreness and mood. No match-induced changes were observed for CMJ flight time: contraction time or eccentric duration. Posterior chain, abductor, CMJ and self-report measures normalised by MD+3 but adductor peak force remained compromised at MD+3 (ES = small). Posterior chain, adductor and abductor peak isometric force and maximal impulse; CMJ JH, eccentric peak force and eccentric deceleration rate of force development and perceived fatigue, muscle soreness and mood are sensitive to match-induced fatigue. Since adductor peak force remained compromised at MD+3, it is apparent that players might not achieve complete neuromuscular recovery within 3 days of match play, and that the adductor muscle group might be particularly vulnerable to match-induced fatigue., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Purpose: To examine the test–retest reliability of countermovement jump (CMJ) and isometric strength testing measures in elite-level under-18 and under-23 academy football players. Methods: A total of 36 players performed 3 maximal CMJs and isometric abductor (IABS), adductor (IADS), and posterior chain (IPCS) strength tests on 2 separate test days using dual force plates (CMJ and IPCS) and a portable strength testing device (IABS and IADS). Relative (intraclass correlation coefficient) and absolute (coefficient of variation, standard error of the measurement, and minimal detectable change [MDC%]) reliabilities for 34 CMJ, 10 IABS, 10 IADS, and 11 IPCS measures were analyzed using between-sessions best, mean, and within-session methods. Results: For all methods, relative reliability was good to excellent for all CMJ and all IADS measures and poor to good for all IABS and IPCS measures. Absolute reliability was good (ie, coefficient of variation < 10%) for 27 (best) and 28 (mean) CMJ variables and for 6 (IABS and IADS) and 2 (IPCS) isometric measures. Commonly used CMJ measures (jump height, eccentric duration, and flight-time:contraction-time ratio) had good to excellent relative reliability and an MDC% range of 14.6% to 23.7%. Likewise, commonly used isometric peak force measures for IABS, IADS, and IPCS had good to excellent relative reliability and an MDC% range of 22.2% to 26.4%. Conclusions: Commonly used CMJ and isometric strength measures had good test–retest reliability but might be limited by their MDC%. Rate-of-force-development measures (for all isometric tests) and impulse measures (IPCS) are limited by poor relative and absolute reliability and high MDC%. MDC% statistics should be considered in the context of typical responsiveness. [ABSTRACT FROM AUTHOR]

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 (R 2 = 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. [ABSTRACT FROM AUTHOR]