When you start training for Tough Mudder (assuming your not training year round) you will most likely find time is your biggest problem. Your going to need to follow a realistic training program to get you where you need to be for the event.
But if your like most people you will end up waiting till the last minute to start training. I would say at a minimum to get in some sort of shape you are going to need 4-8 weeks.
Assuming you are not in the best shape possible, the thing you are going to be have to be careful about is pushing yourself too hard.
If you REALLY are out of shape you are going to have a difficult time at Tough Mudder. No question about it. If you try and rush your training the end result is your going to hurt yourself. You will go balls-to-the-wall one day and then be so sore you can’t walk the next day.
As long as you have at least 4 weeks to go before the event you will have a chance to get into decent shape. Find a 3-4 month training program and start from the beginning. You want to get your body used to physical activity. You will not be able to get into Tough Mudder shape so just do the best you can.
If you can only run a mile at most, what you should do is then run a quarter mile, walk a quarter mile. In a Tough Mudder you will need to run/walk 10-12 miles. Just getting the total distance in with a combination of walking and running is the most important thing.
Besides running you are going to be using almost all of your muscle groups. Hopefully you are a member of a gym. If so you need to take full advantage of ALL of the equipment. Crossfit training will do you well. The combination of working out and cardio is the best thing you can do.
Don’t forget swimming if you have access to a pool. Swimming is an awesome cardio workout that doesn’t have the impact on your legs that jogging does.
Good luck and remember just finish the race and not worrying about your time will make it much easier.
– Robert Walsh