Description
Generate a vector of W' balance values from time and power data. The
underlying algorithm is published in Skiba et al. (2012).Usage
Wbal(data, time = "timer.s", pwr = "power.W", CP, .string = FALSE)
Arguments
data
a data.frame/matrix object with time and power columns.
time
character; name of the time (seconds) column in data.
pwr
character; name of the power (watts) column in data.
CP
a critical power value for use in the calculation.
.string
are column name arguments given as character strings? A
backdoor around non-standard evaluation. Mainly for internal use.
Value
- A numeric vector of W' balance values, in kilojoules.
Details
The algorithm used here, while based on Dr Phil Skiba's model, differs in
that values are positive as opposed to negative. The original published model
expressed W' balance as W' minus W' expended, the latter recovering with an
exponential time course when P < CP. An issue with this approach is that an
athlete might be seen to go into negative W' balance. Hence, to avoid
assumptions regarding available W', this algorithm returns W' expended (and
its recovery) as positive values; i.e. a ride is begun at 0 W' expended, and
it will increase in response to supra-CP efforts.References
Skiba, P. F., W. Chidnok, A. Vanhatalo, and A. M. Jones. Modeling
the Expenditure and Reconstitution of Work Capacity above Critical Power.
Med. Sci. Sports Exerc., Vol. 44, No. 8, pp. 1526-1532, 2012.
http://www.ncbi.nlm.nih.gov/pubmed/22382171{PubMed link}.