It's amazing how much the abdominals get worked from picking yourself up. One of the things I learned while getting up, is the correct way to get up. For me not getting up with my head forward torwards my attacker is what I had to work on. Even if not for takedowns, basic falling and rolling is important. Another there a lot of great sacrifice falls to be had later on. The one I love is the (you grab) two handed lapel grab, kick the legs up and turn away from your attacker while up around chest level. There's always a counter to everything though.