If you're looking to build core strength to help you get into more athletic poses like handstand, here's one way you can start. This quick core video incorporates hollow rocks and sit ups into a hiit style workout of 21, 15 and 9 repetitions. By the end, you should definitely be feelin' it! Let me know how it goes for you down in the comments section below, and if you need more core stuff, check this out as well.