Improving Preflight Technique on Yurchenkos
Midwest Gymnastics uses this drill explained by Alison Lim to improve the preflight on Yurchenko vaults. All you need is a few mats on a tumble track and a soft landing surface.
Lim notes that this is a drill that she has seen successfully transfer over to the actual vault because the gymnasts are able to truly feel the proper positions.
Check out a couple more vault drills here:
Punch Back Drill for Yurchenko Vaults
Vault Blocking Drill for Max Rise off the Table