The purpose of this study was to measure performance and physiological indicators of exercise intensity during a graded exercise test (GXT) and a 30-min time trial (30TT) in road cyclists before and after aerobic training. Six Australian National Squad male road cyclists (MEAN± SD; 23.5± 1.5 yrs, 179.8± 3.1 cm, 69.5± 5.6 kg, 5.02± .41 L.min-1 O2 peak, 412.5± 28.2 W PPO), performed two GXTs and two maximal 30TTs before and after 2 months of early season training (3200-4800 km). Testing was performed on a magnetically braked cycle ergometer (Lode) and all cyclists had previously completed testing protocols. The GXT began at 100 W and increased 50 W every 5 min until exhaustion. For the 30TT cyclists produced the highest power output possible for 30-min. Every 5 min during both tests heart rate (HR), rating of perceived exertion (RPE), and blood lactate (HLA), pH, and bicarbonate (HCO3-) were measured. Threshold power output was determined during the GXT using the DMAX technique. Dependent variables were analysed using a series of paired t-tests. Significance was accepted when P<.10. Training was associated with the following changes during the GXT: increase in PPO (380± 40 to 413± 28 W, P<.10), increase in DMAX power (296± 42 to 327± 26 W, P<.10), decrease in DMAX lactate (4.1± 0.9 to 3.0+0.5 mM, P<.10) with no change in DMAX HR, DMAX O2, or O2peak. As expected, training improved the 30TT power (326± 27 to 350± 19 W, P<.10) but did not change 30TT HR (186± 5 to 183± 6 bpm, NS) or 30TT RPE (16.7± 0.9 to 17.0± 1.0 RPE units, NS). Surprisingly, the 30TT HLA increased (6.7± 1.6 to 8.2± 1.4 mM, P<.10), pH decreased (7.353± .019 to 7.307± .037 pH units, P<.10) and HCO3- decreased (18.5± 2.0 to 15.4± 1.5 mM, P<.10). In summary, male cyclists generally complete a maximal 30TT ~25 W above DMAX power, ~2-4 mM above DMAX HLA, and ~10-15 bpm above DMAX HR. Training improved DMAX power and 30TT power by 7-10%. Although 30TT HR and RPE were not influenced by training, 30TT HLA was higher (~1-2 mM) and pH and HCO3- were lower. Thus, training induced improvements in the HLA - Power curve (DMAX) appear to predict improvements in 30TT power but not 30TT HLA or pH, highlighting a difference between GXT and 30TT testing.
© Copyright 1999 5th IOC World Congress on Sport Sciences with the Annual Conference of Science and Medicine in Sport 1999. Alle Rechte vorbehalten.