Yurchenko's, since the introduction of the Vault Table in 2002, have come a long way. In most cases, this has meant it has become a more widely trained and performed Vault. With this greater representation in performance has come a surge in performance related mistakes as lower level coaches are often pursuing this complex and intricate element sometimes at the risk of not fully understanding the mechanics of successful interaction between the phases of the vault.
Before the 'Table', little girls around the age of 10 were rarely performing this complex Vault. Only the most competent and knowledgeable coaches were teaching and pursuing the element with the athletes at the forefront of gymnastics competition. I recently went to a Level 8, 9 and 10 competition in the greater Washington D.C. area and the majority of girls now are progressing into backward entry vaulting. For better or for worse - what a shift!
The reason the Yurchenko is a complex vault boils down to a number of reasons - the top two being the transition of forward momentum to backward momentum occurs prior to hitting the springboard and secondly, the pre-flight if performed correctly, should eventually be a blind occurrence.
The transition from forward momentum into backward momentum, or the round off, takes a great deal of patience to refine and master when running at full speed - especially for young gymnasts. Very often there are directional mistakes due to problems with the hurdle and spacing of the run up. With these directional mistakes, loss of power into the round off inevitably occurs. More often than not, this loss of power will lead to improper angles onto the springboard causing the gymnast to lean too far forward. The lean of the body forward will cause the pre-flight to become high in trajectory.
The irony here is that, with a higher trajectory pre-flight, comes a greater visual ability to see and focus on the table prior to making hand contact. All too often, this visual sight makes the gymnast feel comfortable and actually allows a properly timed push through the shoulder girdle region. The major problem is, this heightened sense of 'block' timing becomes irrelevant as the problem with high trajectory is the gymnast will make contact with the hands on the table 'on the way down' rather then rising like a staircase, on the way up. The only choice the gymnast has upon this conclusion is to direct power in the downward manner.
Mastering the process of making the hand contact with the table while the body is still rising takes years of practice with even the most physically prepared gymnast. If your gymnasts take a few seasons to continue to perform handsprings I would say - don't fret. In the meantime they can train this complex vault and master the essential elements of successful performance. In the long run, they will be performing the properly executed Yurchenko, while those fast tracked Yurchenko's will proverbially 'be on the way down'. Good luck!