Noninvasive determination of the anaerobic threshold in canoeing, cross-country skiing, cycling, roller, and ice-skating, rowing, and walking.

The relationship between velocity (V) and heart rate (HR) was determined in four canoeists, 42 cross-country skiers, 73 cyclists, nine ice-skaters, 10 roller-skaters, 32 rowers, and 20 walkers. The athletes were asked to increase their work intensity progressively, from low to submaximal velocities; HRs were determined by ECG in roller-, ice-skating, and walking, or read on a cardiofrequency meter in canoeing, cross-country skiing, cycling, and rowing. In all the athletes examined the linearity of the V-HR relationship was maintained up to a submaximal speed (deflection velocity, Vd), beyond which the increase in work intensity exceeded the increase in HR. Vd and anaerobic threshold (AT), determined through blood lactate measurements, were coincident in 19 athletes (6 cross-country skiers, 3 cyclists, 2 roller-skaters, 3 rowers, and 5 walkers). Vd was correlated with the average speeds maintained in walking (20 km, n = 13, r = 0.88), cross-country skiing (15 km, n = 20, r = 0.80; 30 km, n = 8, r = 0.82; 12 km, n = 7, r = 0.86; 11 km, n = 7, r = 0.86) and cycling (1,000 m flying-start, n = 68, r = 0.83), thus showing that AT is a limiting factor in these aerobic events.