Assessment of Fatigue and Recovery in Male and Female Athletes After 6 Days of Intensified Strength Training

Christian Raeder, Thimo Wiewelhove, Rauno Álvaro De Paula Simola, Michael Kellmann, Tim Meyer, Mark Pfeiffer, Alexander Ferrauti

This study aimed to analyze changes of neuromuscular, physiological and perceptual markers for routine assessment of fatigue and recovery in high-resistance strength training. Fourteen male and nine female athletes participated in a six-day intensified strength training micro-cycle (STM) designed to purposefully overreach. Maximal dynamic strength (estimated one-repetition maximum [1RMest]; criterion measure of fatigue and recovery), maximal isometric strength (MVIC), countermovement jump (CMJ) height, multiple rebound jump (MRJ) height, jump efficiency (RSI), muscle contractile properties using tensiomyography including muscle displacement (Dm), delay time (Td), contraction time (Tc) and contraction velocity (V90), serum concentration of creatine kinase (CK), perceived muscle soreness (DOMS) and perceived recovery (PPC) and stress (MS) were measured pre and post the STM and after three days of recovery. After completing the STM, there were significant (p<0.05) performance decreases in 1RMest (%Δ±90% confidence limits, ES=effect size; - 7.5±3.5, ES=-0.21), MVIC (-8.2±4.9, ES=-0.24), CMJ (-6.4±2.1, ES=-0.34), MRJ (- 10.5±3.3, ES=-0.66), and RSI (-11.2±3.8, ES=-0.73.) as well as significantly reduced muscle contractile properties (Dm, -14.5±5.3, ES=-0.60; V90, -15.5±4.9, ES=-0.62). Following three days of recovery, a significant return to baseline values could be observed in 1RMest (4.3±2.8, ES=0.12), CMJ (5.2±2.2, ES=0.28) and MRJ (4.9±3.8, ES=0.32), whereas RSI (-7.9±4.5, ES=-0.50), Dm (-14.7±4.8, ES=-0.61) and V90 (-15.3±4.7, ES=-0.66) remained significantly reduced. The STM also induced significant changes of large practical relevance in CK, DOMS, PPC and MS pre to post-training and after the recovery period. The markers Td and Tc remained unaffected throughout the STM. Moreover, the accuracy of selected markers for assessment of fatigue and recovery in relation to 1RMest derived from a contingency table was inadequate. Correlational analyses also revealed no significant relationships between changes in 1RMest and all analyzed markers. In conclusion, mean changes of performance markers and CK, DOMS, PPC and MS may be attributed to STM-induced fatigue and subsequent recovery. However, given the insufficient accuracy of markers for differentiation between fatigue and recovery, their potential applicability needs to be confirmed at the individual level.