In regards to to which type of training?
If you wish to train a particular skill in a player, the best way is to train just that position in which the skill gets training, e.g You have a player and wish to improve his outside defense, then train them for pressure as PG for that week. PG's who train in Pressure will more than likely get a pop in Outside Def compared to PG/SG training in Pressure. It's much more focused. So to answer your question ya, it does hurt development.
It can be a case of pick your poison, but if you don't give a particular player all the attention they you are slowing down his progress.
Does that make sense?
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