Subscribe to RSS
Reliability and Validity of a Continuous Incremental Treadmill Protocol for the Determination of Lactate Threshold, Fixed Blood Lactate Concentrations, and V̇O2max
14 March 2008 (online)
Fifteen male runners were tested on two occasions to determine the reliability of a continuous incremental level running treadmill protocol (C), with 3-min stages, for lactate threshold (LT) and fixed blood lactate concentration (FBLC) (2.0 mM, 2.5 mM, 4.0 mM) assessment. Test-retest (T-RT) reliability coefficients for velocity at LT, 2.0 mM, 2.5 mM, and 4.0 mM were r = 0.89,0.91,0.95, and 0.95, respectively (velocity ranged from 215.3 m/min at LT to 273.6 m/min at 4.0 mM). Mean differences in T-RT velocity values ranged from 0.7 m/min (at LT) to 6.0 m/min (at 2.5 mM; 252.3 m/min vs 258.3 m/min; NS)and the standard errors of measurement were less than ± 10.0 m/min. Similar results were observed for V̇O2, with T-RT r values ranging from r = 0.82 (at LT) to r = 0.88 (at 2.0 mM) (V̇O2 ranged from 47.2 ml/kg · min-1 at LT to 60.9 ml/ kg · min-1 at 4.0 mM; V̇O2 peak = 65.6 ml/kg · min-1). Mean differences in T-RT V̇O2 values were less than 1.4 ml/kg · min-1 (NS) and the standard errors of measurement were less than ± 2.95 ml/kg · min-1. Interinvestigator and intrainvestigator reliability coefficients were high and ranged from r = 0.91 to r = 0.99. Validity of C was assessed in an additional 16 male runners who completed C and a criterion discontinuous (D) protocol (using a series of 10-min stages) for LT and FBLC assessment. Results indicated that C and D resulted in similar V̇O2 and velocity values at LT and FBLC. For V̇O2, correlations ranged from r = 0.75 (V̇O2LT) to r = 0.90 (V̇O2 2.5 mM and V̇O2 4.0 mM) with SEE ranging from ±1.99 to ±3.58 ml/kg · min-1. For velocity, correlations ranged from r = 0.87 to r = 0.97 with SEE ranging from ± 6.5 m/min to ± 13.1 m/min. It was concluded that a continuous horizontal treadmill protocol using 3-min stages results in reliable and valid measurement of velocity and V̇O2 at LT and FBLC of 2.0 mM, 2.5 mM, and 4.0 mM.
Onset of blood lactate accumulation (OBLA) - lactate threshold - V̇O2max