Tumbling downhill is standard progression for beginners — but I know it could be used much more with advanced athletes. Speed training, similar to that used by sprinters.
The best apparatus I ever built was a 40ft tumbling floor, slanted at about 10 degrees, constructed out of plywood. (I wish I had a photo.) It worked great!
For fun, tumble downhill on sand or grass.
George Novak, Ica, Peru. The world’s highest sand dunes.
Gymnastics Coaching.com 