Fig 1.
Study design showing timing of different tests. Time point 0 weeks indicates start of treatment (rHuEPO or placebo) for all participants. GXT, graded exercise test; TT, time trial test; RR, road race.
Fig 2.
Graphical representation of lactate threshold concepts.
Example of a blood lactate curve with the location of the different lactate threshold concepts for this particular curve. Open circles: observed blood lactate values at each exercise intensity; Black curve: third-order polynomial; Grey dashed line: baseline; Green circle and arrow: LT1, observer-determined first rise in blood lactate; Yellow circle and arrow: LT2, first observed blood lactate value more than 1 mmol/L above baseline; Pink circle and arrow: LT3, minimum lactate equivalent (blood lactate divided by power) plus 1.5 mmol/L; Purple circle and arrow: LT4, first blood lactate value that shows an increase of at least 1 mmol/L; Orange circle and arrow: LT5, minimum lactate equivalent (blood lactate divided by VO2); Brown circle and arrow and dashed line: LT-4mmol, value at 4 mmol/L; Red circle and arrow and dashed line: Dmax, value with the maximum perpendicular distance to the polynomial from the dashed line; Blue circle and arrow and dashed line: Dmax-mod, value with the maximum perpendicular distance to the polynomial from the dashed line.
Fig 3.
CONSORT flowchart.
Table 1.
Subject disposition.
Table 2.
Mean lactate threshold concept power output.
Table 3.
Cronbach’s alpha for each lactate threshold concept.
Table 4.
Predictive value of lactate threshold concepts.
Fig 4.
Linear regression lactate threshold concept power and average race power.
Linear regression of lactate threshold power and average race power per LT concept for all subjects depicting linear regression line (solid line) and 95% confidence interval (dotted lines). r2: R-squared or coefficient of determination is the proportion of the variance in the dependent variable that is predictable from the independent variable.
Table 5.
Reported correlations between LT concepts and endurance performance.