Mental blocks are garbage.
I've coached in the role of assistant, choreographer, volunteer, and now head coach off and on for the past 17 years and I've NEVER, not one time, EVER, had a kid develop a mental block. If you coach a program with kids who have mental blocks, or are the parent of a child with a mental block, one of two things is guaranteed to be true: They've either been trained to be mentally weak, or they have come up through their skills without proper progressions and have been rushed to improve faster than they should have been.
Train your kids to be mentally tough ATHLETES, instead of cheer divas, and use proper progressions as they develop their skills, and mental blocks will be nonexistent in your world too.