BMX: Training routine for a beginner? At the ripe old age of 20, I finally moved to an area with a BMX track, so this summer I'm finally going to be able to follow my life-long dream of racing. Other than spending a lot of time riding daily and practicing on my home track, what other sort of training should I be doing? What muscles do I need to work, and what's an effective way of doing so (preferably without gym equipment)?
Off-bike? You might try out plyometric exercises. Plyometrics can help you improve your agility and power. In addition, you'd probably want to work on core strength.

I think that plyometrics would be helpful since BMX races are relatively short and rely a lot on agility and sprinting power.

You also mention that the track is too muddy for riding. So, you could do sprint intervals on pavement. Sprint intervals will improve your stamina and speed. An example would be something like this:


Ride easy for 10 minutes
Sprint for 30 seconds and work your way up to 2 minute sprints
Ride at a comfortable pace for 3 minutes
Repeat the sprint/comfortable pace cycle 4 to 6 times
Finish up by riding at an easy pace for another 10 minutes
Do this 2 or at most 3 times a week but NOT on consecutive days