Perform 1 pull-up during the 1st minute. Perform 2 pull-ups during the 2nd minute. Continue to add 1 pull-up every minute until failure. Once you fail move on to push-ups, but continue with the same number (e.g. if you fail trying to get seven pull-ups on the seventh minute, perform 8 push-ups on the 8th minute and then 9 push-ups on the 9th minute). Once you fail move on to sit-ups and then squats. Your score is the last round you were able to complete.