To quantify training intensity in 13 nationally ranked male distance runners, training heart rates, environmental factors, and motivational factors were recorded throughout a 6–8 wk period of normal training. Variation in motivational and environmental factors such as intended effort, terrain, and running with companions altered training session mean heart rates by up to 4·min−1 (standard deviation). Heart rates and blood lactate concentrations, recorded in a series of steady-state treadmill runs, were used to convert training session mean heart rates to mean training speeds (TS) and to derive a measure of the anaerobic threshold (AT, the treadmill speed at a blood lactate concentration of 4 mmol · 1–1). TS (15.6 ± 1.4 km · h−1, mean ± SD) was considerably lower than AT (20.2 ± 1.1 km·h−1) in all subjects (P < 0.001). Relative TS (TS expressed as a fraction of AT) differed significantly (P < 0.001) between subjects and correlated significantly with the distance of the event for which the subject was training (r = −0.59, P < 0.05). Relative TS may therefore be determined by the subject's or coach's perception of the appropriate intensity for the event. If the AT is the optimum training intensity, these subjects have considerable scope for improvement.