Two days of simulated CrossFit competition affect autonomic nervous system but not anaerobic power or fatigue

BACKGROUND: We examined changes in autonomic nervous system function, anaerobic power, and fatigue over two days of simulated CrossFit competition in CrossFit athletes. In addition, we determined the relationship between these internal training load variables and variables characterizing two weeks of tapering preceding the competition. METHODS: In total, 21 participants (intervention group, N.=10, INT; control group, N.=11, CON) completed the assessments. INT performed the assessments at baseline (pre-day 1), during the competition (post-day 1 and pre-day 2), and after the competition (post-day 2), while CON performed only the baseline assessments. RESULTS: Autonomic nervous system function, anaerobic power, and fatigue did not differ between the beginning of day 1 and day 2. Autonomic nervous system function was impaired at the end of each day. Anaerobic power and fatigue did not change during either day. CONCLUSIONS: Finally, the two training weeks preceding the two days of simulated competition were related to anaerobic power but not autonomic nervous system function or fatigue. CrossFit coaches and athletes should be aware of the limited effects of step taper on heart rate variability and fatigue.