There's also that study where kids trying to throw a ball into a basket from a specific distance improved quicker if they practiced throwing from two different

There's also that study where kids trying to throw a ball into a basket from a specific distance improved quicker if they practiced throwing from two different distances, different from the one that was tested, than those practicing only the tested distance. Edit: I think this is it: http://www.ncbi.nlm.nih.gov/pubmed/662537 http://www.ncbi.nlm.nih.gov/pubmed/662537