Today's workout calls for you to do a huge number of repetitions, but don't be scared. Embrace the challenge! For the 50-rep movements, choose a weight that will allow you to perform some fairly big sets—at least 15 reps—before you have to rest. If you can do all 50 reps without taking a break, the weight is too light. However, if you can only perform 4-5 reps per set, your weight selection is far too heavy. Rest only when you have to. When you do rest, keep it short.
Before you start the workout, watch the video above so you know how to perform the movements!