Purpose: The purpose of this study was to investigate the effect of alterin
g the initial running speed (RS) in the incremental portion of the lactate
minimum test on the lactate minimum speed (LMS). Methods: Eight well-traine
d endurance runners (mean +/-SD age 29.0 +/- 5.4 yr, body mass 72.0 +/- 5.6
kg, (V) over dot O-2max 63.1 +/- 3.8 mL.kg(-1) min(-1))completed a standar
d incremental treadmill rest for the assessment of the lactate threshold (L
T) and (V) over dot O-2max and eight lactate minimum tests. Following a per
iod of supramaximal exercise, subjects were allowed 8 min of recovery to al
low blood [lactate] to peak. Subjects then undertook eight randomly-assigne
d incremental treadmill tests from different initial running speeds (3.0, 2
.5, 2.0, 1.5, 1.0, and 0.5 km.h(-1) below the predetermined RS-LT, at the R
S-LT, and at 1.0 km.h(-1) above the RS-LT) with RS increased by 1.0 km.h(-1
) every 5 min until volitional fatigue. Blood samples for the determination
of blood [lactate] were taken at the end of each stage and the LMS was det
ermined by fitting a spline function to the data. Results: No LMS could be
determined for the two highest initial RS conditions. For the other conditi
ons, the LMS was significantly affected by the initial RS used in the incre
mental test and varied from 13.8 +/- 0.7 km.h(-1) with an initial RS of 3.0
km.h(-1) below the RS-LT, to 15.8 +/- 0.8 km.h(-1) with an initial RS of 0
.5 km.h(-1) below the RS-LT. The LMS was significantly different from the R
S-LT (15.4 +/- 0.8 km.h(-1)) (P < 0.05), except when the incremental test s
tarted at 1.0 or 1.5 km.h(-1) below the RS-LT. Conclusions: These results s
uggest that the LMS rest is not a valid method for estimation of the LT sin
ce it is profoundly influenced by the starting speed selected for the incre
mental portion of the rest.