I practice Feldenkrais which is partly about improving coordination of movement and practicing things slowly is one of the major ideas behind that. I watched an online talk earlier this week talking about the 'Weber-Fechner-Henneman Movement Optimization Cycle' as an explanation behind that. I haven't scrutinised the science - but there's info on page 28 of this PDF: https://www.feldenkraisguild.com/files/Journal_30.pdf