Core Forge is a Level IV workout that will test your VO2 Max to the limit and push your quads against the very edge of their ability to perform. It focuses on lower body strength and core but it also works all the other abdominal muscle groups and, seeing how it is Burpees that power it, it manages to deliver a burn to your lower body muscles and a massive load to your lungs. Since it's time based speed of execution is key to maintain momentum and quality in the workout. Pay attention to EC.