Best drills/exercises for developing leg power?

What are the best drills/exercises for developing the power for the bigger tumbling skills like double fronts and double backs?

I do standing jumps onto a vault, I can do about sternum height from standing and can do a standing front somersault. Haven't tried a standing back yet, need to make sure I've got someone to support me for that!

i can just about land a double front. Haven't tried a double back.

Hi LeeLee,

The single leg squat progressions from F1 and the Tumbling One progressions. Those courses are excellent for conditioning!

Thanks for the replies.  These are my current drills:

1.  Tumbling back tucks up onto a 5ft. stack of mats.
2.  Running front tucks up onto a 5ft. stack of mats.
3.  Standing back tucks, front tucks, and arabians up onto a 3ft. stack of mats.
4.  Weighted 1 leg squats jumps.
5.  Weighted 1 leg lunge jumps.
6.  Box drop rebounds.
7.  Box snapdowns to rebounds, back tucks, layouts, fulls.

I spread these out across the week.

I've had success with kettlebell goblet squats

I also use exercises from Coach Sommers:  Senders - A Dynamic Leg Strength Series post.