Time course of performance changes and fatigue markers during intensified training in trained cyclists

1 Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; 2 School of Human Movement Studies, Queensland University of Technology, Kelvin Grove, Queensland 4059, Australia; and 3 Department of Human Physiology and Sportsmedicine, Vrije Universiteit Brussel, B-1050 Brussels, Belgium To study the cumulative effects of exercise stress and subsequent recovery on performance changes and fatigue indicators, the training of eight endurance cyclists was systematically controlled and monitored for a 6-wk period. Subjects completed 2 wk of normal (N), intensified (ITP), and recovery training. A significant decline in maximal power output (N = 338 ± 17 W, ITP = 319 ± 17 W) and a significant increase in time to complete a simulated time trial (N = 59.4 ± 1.9 min, ITP = 65.3 ± 2.6 min) occurred after ITP in conjunction with a 29% increase in global mood disturbance. The decline in performance was associated with a 9.3% reduction in maximal heart rate, a 5% reduction in maximal oxygen uptake, and an 8.6% increase in perception of effort. Despite the large reductions in performance, no changes were observed in substrate utilization, cycling efficiency, and lactate, plasma urea, ammonia, and catecholamine concentrations. These findings indicate that a state of overreaching can already be induced after 7 days of intensified training with limited recovery. cycling; overtraining; overreaching; overload