If I don’t have a back ext. what would you recommend for posterior for youth?
Nordics and Single Leg Jefferson Curls and then progressing to seated GM and RDL as they start accessing weights. Sled drive, Back Ext, Seated GM, RDL, Nordic, J curl, 6 nice basic posterior options per ATG Pro, many variations within. (Realize layer 4, for example, is deadlifts as a whole, or squats as a whole, each of which has many variations)
So there’s a lot to work with and equipment never really stops you from results.