21-15-9 workouts are one of my favorites because the hardest part is at the beginning, and once you get through that first set, it's smooth sailing because the end is in sight! Here's how this one works:
1. 21 Ab-wheels. For these you'll want to roll the wheel away from you as far as you can, and then zip it back in towards you. Then, 21 Wall Balls (Here's how to do wall balls). Then, 21 Russian Split Squats (you can do these with or without dumb bells. I am using 20lbs in each hand).
2. Repeat the same thing, doing fifteen repetitions of each movement.
3. Repeat the same thing, doing nine repetitions of each movement.
That's it! Enjoy and let me know how it goes for you down in the comments section below!