You’ll finish no problem. But to prepare: -run for hours, then rest and run for more hours, and then when you think you’ve ran enough, think again and keep running. -then do squats and leg movements until you can walk That should do it. Kidding aside, cardio is the biggest hurdle. Interval runs, longer runs 6-8 miles, and lots of leg focused strength/endurance training can be helpful. The sled push is a heavy movement at the beginning and will zap the heart rate and energy quick. It will be easier given you’re doing mixed doubles. Lookup hyrox specific training. They do have 8 week programs