On the empirical substantiation of the definition of "Deliberate Practice" (Ericsson et al., 1993) and "Deliberate Play" (Côté et al., 2007) in youth athletes - Güllich, A.; Faß, L.; Gies, C.; Wald, V. (Journal of Expertise, 2020)
Keywords: youth; long-term performance build-up; training; training planning; training session; organizing; definition; theory; USA; junior sports; training science