I just found this article on Bicycling magazine on some core exercises you can do at home, in between bike days. Note that some of the exercises require that you have a stability ball.

Bicycling Magazine – Core: Here’s how to train the most important muscles for cycling.

As with all exercises, the author notes that it should always be coupled with a proper diet. I’ve recently read an article about osteopoenia in cyclists, so make sure to also drink your milk or take your calcium supplements.

The naivety of youth and junk bikes versus new technology and an old fat rider: “What’s your money on?

Does this mean that I need to bike even harder?

Here’s the link on some essential cross-country techniques.