To produce mean velocities of 50 % , 55 % , and 60 % of vLTP1 , running speeds were calculated as 18.6 0.7 km/h ( 93.4 % vVO ( 2max ) ) , 20.2 0.6 km/h ( 101.9 % vVO ( 2max ) ) , and 22.3 0.7 km/h ( 111.0 % vVO ( 2max ) ) , which gave a mean blood lactate concentration ( La ) of 1.09 0.31 mmol/L , 1.57 0.52 mmol/L , and 2.09 0.99 mmol/L , respectively .