Whether the gymnast is aware of these or not, there are four major sources of fear in the gym which feed balking and lost skills.
In everything that we do, we learn by making mistakes and failing. In most other sports, this learning process is non-eventful. You miss a shot, hit a ball into the net, strike out, or drop the ball, etc. In gymnastics, however, when you make a mistake, there can be scary consequences! You can have a scary fall, get banged up or bruised, or sustain an injury. In this way, Gymnastics is a unique sport because there is always the potential of getting hurt.
Add to this, the fact that as you progress up through the levels in this sport, the degree of skill difficulty rises and so also does your chances of sustaining an injury. As a consequence, fear is almost a constant companion for the competitive gymnast. Whether it's a fear of a release move, going backwards on floor or beam, a new vault or a dismount, I know of no other factor in this sport that can kill an athlete's joy, drive a coach to distraction and totally confound the athlete's parents than the fear-driven loss of skills.