To improve maximal endurance or strength performance, an optimal physiological training load is required. Post-exercise heart rate variability (HRV) has been shown to be a valid method to evaluate the training load 1,2. The main objective of this study was to determine whether the HRV and selective physiological indicators could assess cumulative metabolic and neuromuscular fatigue induced by the short-term high-intensity training blocks. Endurance and strength trained men (n=18) completed successively three different training blocks; high-intensity endurance, maximal strength and hypertrophy strength. Three consecutive high-intensity late-night exercise sessions followed by four days of recovery period before the new training block. WHO`s cycling fitness test, countermovement jump test, saliva cortisol concentrations, subjective perceived stress and subjective quality of sleep were measured at mornings before the training blocks and following mornings after the training sessions. Emfit sleep monitor measured HRV and sleep quality every night throughout the research period. Although subjects experienced the exercise sessions physically very demanding, no statistically significant differences were found between the single exercise sessions or between the training blocks in performance measurements (WHO`s cycling test and a countermovement jump test), cortisol levels, subjective stress and HRV. Statistically significant differences were not observed in sleep or relative portion of sleep phases during any training blocks. Some interesting trends were observed as RMSSD (Root Mean Square of the Successive R-R Differences) sleep score and sleep duration were systematically lower after training blocks than recovery periods. Based on this study, short-term high-intensity training blocks are well tolerated in athletes as they were not associated to significant physiological fatigue or associated with the disturbances in sleep quality or HRV. Probably greater training loads and/or longer training period are required in order to induce physiological changes in autonomic nervous system, cortisol concentration or sleep phases. Contact: Viberg, Tuulia; Ahtiainen, Juha: Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland; Aittokoski Timo: Emfit Oy, Jyväskylä, Finland
© Copyright 2020 19th International Symposium "Modern Science and Practice for Strength and Endurance Training" October 10-12, 2018. Veröffentlicht von Neuromuscular Research Center and Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä. Alle Rechte vorbehalten.