When searching the web, I see a lot of different opinions when it comes to how to train for a mud race. While my experience is limited (completed in two races so far), I think the number one thing to work on is your long distance running capacity. And while I'm working on that as we speak, I'm also a big fan of Beachbody routines like P90X, Insanity, Asylum, and their new routine Body Beast. So my goal is to come up with a training program using Beachbody routines while incorporating long distance running. Currently my routine is as follows:
Day 1 - Body Beast & 5k speed run
Day 2 - Insanity
Day 3 - Body Beast & 5k speed run
Day 4 - Insanity
Day 5 - Body Beast & Long run
Day 6 - Insanity
Day 7 - Rest
Now I didn't include the specific routines in the above schedule. Instead, I just follow the wall calendars that comes with the programs and cross the days off as I complete them. So I still complete the routines, but it takes me twice as long because I'm doing two routines at the same time. For those who don't have the above routines, you can substitute Body Beast with P90x or Tony Horton One on Ones & you can substitute Insanity with Asylum.
The mud races have a lot of obstacles that requires upper body strength, so that's where the benefit of doing a strength based program like Body Beast or P90X comes into play.
But the mud races also have obstacles that are high intensity in nature. A lot of people do Crossfit & the Spartan Workout of the Days have a lot of Crossfit principles to them. While Insanity is not Crossfit, it's the closest Beachbody program available. I find the High Intensity Interval Training (HIIT) in Insanity routines helps on obstacles that you need a burst of energy to get through.
I'm real excited about my training program and I'm glad I didn't have to leave my home gym & Beachbody progams (which I love).