Mental blocks in sports? Resources? Ideas?

[Dmmetler]

DD11 has been stuck on tumbling for awhile. We moved to a new coach this summer, and she started making progress again, and got a move she'd been working on for awhile, but the second time she did it at cheer, she didn't manage it, and hasn't been able to do it since. She hasn't had a fall or injury-just is scared that she will fail again, which sets her up to fail.  Even the thought of trying makes her start to tear up and hyperventilate. Yesterday, when her coach was right by her, she could do it, and didn't need assistance, but the second she tried on her own, her form fell apart and she just couldn't do it. Any good resources on helping get past those mental blocks?

[AmandaVT]

Which skill is it? (I coached gymnastics for awhile)

[Dmmetler]

Really, it's anything going backwards, but specifically she needs her back walkover for a routine this season-and as soon as it was programmed, she lost it. She has the same thing with her back handspring, where she can do it as long as a coach is there, but will/cannot throw it by herself. Meanwhile, she can throw front walkovers, handsprings, and even tucks (on a spring floor or tumble track-she hasn't tried them on a regular floor yet) without trouble.