The impact of detraining on cardiac autonomic function and specific endurance and muscle power performances of high level endurance runners.
BACKGROUND The purpose of this study was to analyze the effects of four weeks of training cessation (TC) on specific endurance performance, resting and postexercise heart rate variability (HRV) and neuromuscular capacities of high level endurance runners. METHODS Eighteen endurance runners, 8 men and 10 women (25.5+ 7.5 years; 166.9+ 7.6 cm; 54.2+ 6.9 kg) took part in this study. The 3000 m time trial performance, resting HRV, 5' 5' test, squat and countermovement jumps (SJ and CMJ, respectively) and mean propulsive power in the jump squat exercise relative to body mass (MPP JS REL) were performed pre and immediately following the 4 week TC. The inference based on magnitudes were used to analyze the differences between pre and post values. RESULTS The time in the 3000 m time trial was almost certainly higher after TC. A very likely decrease was noticed in the resting HRV Index after the TC period. The differences in all variables analyzed during the 5' 5' test were rated as unclear. No differences were observed in SJ and CMJ comparing the pre and post moments of TC, while the MPP JS REL was very likely improved after the TC period. CONCLUSIONS The resting HRV accompanied the reductions in the specific endurance performance while the 5' 5' test variables did not. The lack of training stimulus led to improvement in the MPP JS REL, possibly due to the withdrawal of specific endurance training, which strongly concurs with neuromuscular performance.
The Journal of sports medicine and physical fitness