New approaches to obtaining individual peak height velocity and age at peak height velocity from the SITAR model.

•Three new methods, the model method, the quadratic function method and the numerical method, for calculating the individual peak height velocity (PHV) and the age at peak height velocity (APHV) from the SITAR model, are proposed and compared.•When the growth curves of all individuals are well fitted by the SITAR model, the quadratic function method is more superior since it does not produce unreasonable APHV estimates compared to the model method and costs less computation time compared to the numerical method.•When the growth curves of some individuals are not well fitted by the SITAR model, the numerical method should be adopted for getting most robust estimates of PHV and APHV.•The model method generates unreasonable APHV estimates, particularly when the growth curves are not well fitted.