Author(s): VAN DYCK, M., LIEVENS, M., BOONE, J., GHIJS, M., BOURGOIS, J.G., VERMEIRE, K., BOURGOIS, G., COLOSIO, A.L., CAEN, K., Institution: GHENT UNIVERSITY, Country: BELGIUM, Abstract-ID: 2051

INTRODUCTION:
The aim of this study was to characterize W recovery kinetics in response to a partial W depletion. We hypothesized that W recovery following partial depletion would be better described by a two-phase than a one-phase exponential model.
METHODS:
Nine healthy men performed a ramp incremental test, three to five constant load trials to determine critical power and W, and ten experimental trials, each consisting of two constant load work bouts (WB1+WB2) interspersed by a recovery interval. In WB1, participants were subjected to a 25% or 75% W depletion (DEP25%+DEP75%) and subsequently recovered for 30,60,120,300 and 600s. WB2 was performed to exhaustion and used to calculate the observed W recovery (WOBS). WOBS was fitted using a monoexponential and a biexponential model. For each model, the root mean square error (RMSE) and the Akaike information criterion (AICc) was calculated to evaluate their goodness-of-fit.
RESULTS:
ΔAICc favoured the use of a monoexponential model for both DEP25% (-15.6) and DEP75% (-23.3), despite a lower RMSE for the biexponential model (DEP25%:0.4%vs.3.2% and DEP75%:3.8%vs.1.0%). Time constants (Tau) and amplitudes (A) derived from the monoexponential model were: Tau=32±11s and A 31±2.5% for DEP25% and Tau=81±16s and A=58.1±3.8% for DEP75%. WOBS values were strongly correlated between both depletion conditions (r=0.92) and significantly associated with V̇O2peak, CP and GET (r=0.67-0.77).
CONCLUSION:
The present study results demonstrate that a biexponential model fit does not outperform a simple exponential model to describe W recovery following a partial depletion. Also, our findings confirm that W recovery is positively associated with aerobic fitness, and that a single and fixed time constant does not work to model W recovery across different levels of depletion.