I am not familiar with the Up UP Down Down Workout in the HIIT section. Tried searching the Ebook and online. I jogged in place instead. Thanks
You start on your elbows in a plank position, then lift yourself up from your elbow with your right hand, then your left, then go back down on to your elbow with your right, then with your left and repeat, alternating each arm/hand you start with 🙂