Model parameters (mean±SD) for performance and HF spectral components of HRV.

Initial level: Initial basic level of performance and HF spectral component of HRV.k1 and k2 : multiplying factors respectively for the positive and negative component of performance and HF spectral component of HRV. τ1 and τ2 : time constants of decay for positive and negative components of performance and HF spectral component of HRV.tn : Critical period pre-competition in which training has a negative effect on performance (tn_P) and HF spectral component of HRV (tn_HF).tg : time pre-competition when training has maximum benefit.k1 and k2 are expressed in arbitrary units depending on units used to quantify training load, performance and HF spectral component of HRV.