Sometimes gymnasts that are beginning to learn Kasamatsu or Tsukahara type vaults may get confused and go for a landing on the knees instead of the feet. This is a serious mistake that can cause a knee injury on a hard surface. Before the gymnasts try on a regular vaulting surface or even on resi mats over the pit, they must demonstrate a consistent ability to land feet first in loose foam.
"Throwing the head out" is a very common mistake that does not add any technical or presentational value to this skill.
When spotting new gymnasts on backhandsprings we must keep our head further back away from them to avoid getting hit if they open the arms too much.