RELATIONSHIPS BETWEEN POSTCOMPETITION BLOOD LACTATE CONCENTRATION ANDAVERAGE RUNNING VELOCITY OVER 100-M AND 200-M RACES

The relationships between anaerobic glycolysis and average velocity (( $) over bar upsilon) sustained during sprint running were studied in 1 2 national level male sprinters. A blood sample was obtained within 3 min of the completion of semi-finals and finals in the 100-m and 200-m Cameroon national championships and blood lactate concentration ([la( -)](b)) was measured. The 35-m times were video-recorded. The 100-m an d 200-m [la(-)](b) were 8.5 (SD 0.8) and 10.3 (SD 0.8) mmol.l(-1), res pectively. These were not correlated with the performances. Over 200 m [la -]b was correlated with the ($) over bar upsilon sustained over t he last 165 m (r=0.65, P<0.05). In the 9 athletes who participated in both the 100-m and 200-m races, the difference between the [la(-)](b) measured at the end of the two races was negatively correlated to the difference in ($) over bar upsilon sustained over the two races (r=0.7 6, P>0.02). Energy expenditure during sprint running was estimated fro m the [la(-)](b) values. This estimate was mainly based on the assumpt ion that a 1 mmol.l(-1) increase in [la(-)](b) corresponds to the ener gy produced by the utilization of 3.30 ml O-2.kg(-1). The energy cost of running was estimated at 0.275 (SD 0.02) ml O-2.kg(-1).m(-1) over 2 00-m and 0.433 (SD 0.03) ml O-2.kg(-1).m(-1) over 100-m races. These r esults would suggest that at the velocities studied anaerobic glycolys is contributes to at least 55% of the energy expenditure related to sp rint running. However, the influence of both mechanical factors and th e contribution of other energy processes obscure the relationship betw een [la(-)](b) and performance.