This helped me a lot! (I am a gymnast, not a coach!)
I would just run and punch in front of my bedroom door, and try to hit the very top.. (Does this make sense?)
Then once I got used to jumping so high..I ran, punched, and tried to hit the ceiling! This really helped with getting the whole "Going up" part...which will give you more height..
When she is working them at gym... Tell her to find something in the gym (that is higher than the door), I use a trophy or fan..
1. Run, hurdle, punch
2. Reach your hands up to the object
3. Keep stretching up! (Only watch that object!)
4. Once you feel like its coming down, hollow below your ribs to make it round..and kick yours heals to your butt!
5. As you are landing, find that object again, and watch it! *Good luck!!
To sum this up...Spot a high object, and watch it the whole time its in sight..
P.s. The higher the object, the higher the tuck!