Wprime
W': work capacity above critical power/speed.
W': work capacity above critical power/speed.
Usage
Wprime(object, session = NULL, quantity = c("expended", "balance"), w0,
cp, version = c("2015", "2012"), meanRecoveryPower = FALSE,
parallel = FALSE, ...)
Arguments
- object
A
trackeRdata
object.- session
A numeric vector of the sessions to be used, defaults to all sessions.
- quantity
Should W'
'expended'
or W''balance'
be returned?- w0
Inital capacity of W', as calculated based on the critical power model by Monod and Scherrer (1965).
- cp
Critical power/speed, i.e., the power/speed which can be maintained for longer period of time.
- version
How should W' be replenished? Options include
'2015'
and'2012'
for the versions presented in Skiba et al. (2015) and Skiba et al. (2012), respectively. See Details.- meanRecoveryPower
Should the mean of all power outputs below critical power be used as recovery power? See Details.
- parallel
Logical. Should computation be carried out in parallel? If
TRUE
computation is performed in parallel using the backend provided toforeach
. Default isFALSE
.- ...
Currently not used.
Details
#' Skiba et al. (2015) and Skiba et al. (2012) both describe an exponential decay of \(W'\) expended over an interval \([t_{i-1}, t_i)\) if the power output during this interval is below critical power:
$$W_exp (t_i) = W_exp(t_{i-1}) * exp(nu * (t_i - t_{i-1}))$$
However, the factor nu differs: Skiba et al. (2012) describe it as \(1/\tau\) with \(\tau\) estimated as
$$tau = 546 * exp(-0.01 * (CP - P_i)) + 316$$
Skiba et al. (2015) use \((P_i - CP) / W'_0\). Skiba et
al. (2012) and Skiba et al. (2015) employ a constant recovery power
(calculated as the mean over all power outputs below critical
power). This rationale can be applied by setting the argument
meanRecoveryPower
to TRUE
. Note that this uses
information from all observations with a power output below
critical power, not just those prior to the current time point.
Value
An object of class trackeRWprime
.
References
Monod H, Scherrer J (1965). 'The Work Capacity of a Synergic Muscular Group.' Ergonomics, 8(3), 329--338.
Skiba PF, Chidnok W, Vanhatalo A, Jones AM (2012). 'Modeling the Expenditure and Reconstitution of Work Capacity above Critical Power.' Medicine & Science in Sports & Exercise, 44(8), 1526--1532.
Skiba PF, Fulford J, Clarke DC, Vanhatalo A, Jones AM (2015). 'Intramuscular Determinants of the Abilility to Recover Work Capacity above Critical Power.' European Journal of Applied Physiology, 115(4), 703--713.
Examples
# NOT RUN {
data('runs', package = 'trackeR')
wexp <- Wprime(runs, session = c(11,13), cp = 4, version = '2012')
plot(wexp)
# }