Using a general purpose spreadsheet software package to estimate exponential plus constant model fits for blood lactate concentration versus work rate data

  • Ian Cook
  • Gerrit J van Wyk

Abstract

The objective of this analysis was to evaluate the accuracy of a standard spreadsheet software package to estimate best-fit parameters for an exponential plus constant model (y=a+b.e cx) applied to blood lactate concentration versus work rate data. During an incremental cycle test, blood lactate concentrations were measured in six endurance-trained athletes. A spreadsheet (Microsoft® Excel) and a dedicated curvefitting software programme (GraphPad Prism®) were used to obtain model coefficients, model fit parameters, interpolated work rate at a fixed blood lactate concentration (WR 4mmol/l) and work rate at a curve gradient of 1 mmol/l per watt (WRdy/dx=1). Model coefficients and model fit parameters were identical to the sixth decimal place for four subjects and differed by ≤0.000006 in two subjects. WR4mmol/l differed by <0.003 watts in five subjects, while a difference of <1 watt was found for one subject. WRdy/dx=1 differed by 0.0018 watts in only one subject. These findings suggest that a general purpose spreadsheet software package can be used by sport and exercise physiologists to accurately determine model coefficients, model fit parameters, WR4mmol/l and WRdy/dx=1.

South African Journal for Research in Sport, Physical Education and Recreation Vol. 28(2) 2006: 27-37
Published
2006-10-06
Section
Articles

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print ISSN: 0379-9069