SOS is a fast-moving, hard-hitting HIIT workout that demands explosion and consistent pressure throughout each set. Stay on your toes throughout your Jumping Jacks routine and make sure you also always land on the ball of the foot after each Jump Knee Tuck. bring your knees to your chest with Jump Knee Tucks and move as explosively as you can within the 10 sec segment of the workout. You will feel the burn and there is always fatigue to battle against. Then again this is the kind of workout you may need rescue from, and that's before you add EC.