These are probably one of the best overall movements you can do to help prepare yourself for obstacle course racing or any course in general. When I first started doing burpees I could barely do 10 in a row. Now I can easily do 50+ in a row. There are days I've done 100 or so in a row before taking a break. Theres nothing better!
Some of the muscles worked during a burpee include trapezoids, lower back, pectorals, deltoids, triceps, hamstrings, glutes, calves, quadriceps, and abdominals. They hit a lot of muscle groups. Imagine if you add a weight vest to this exercise. It can be very intense experience to say the least!
Burpees are an aerobic exercise that keeps you heart rate up at a maximum rate. They improve cardiovascular endurance, so muscle fatigue during longer workouts or races is decreased the more you do them. Because you’re using your full body when doing burpees and because they’re such an intense workout, the burpee is one of the best exercises to burn fat. So you can easily see the benefit of doing Burpees.
Burpees also can be modified to be more intense in so many ways giving you even more variation if you so choose.
Some variations include:
Adding a push up
Adding a push up with a leg raised
Doing squat thrust
Performing a explosive jump at the end
Adding a pull up after the burpee
A renegade burpee
Clean and press burpee
The list can literally go on. I sometimes even do a Burpee into a Bench Jump.
In closing Burpees are one of the best movements you can do to develope the conditioning and endurance you will need on the course!