Can I Prevent Delayed Onset Muscle Soreness?
While DOMS is common and annoying, it is not a necessary part of getting into shape. There are many things you can do to prevent, avoid and shorten DOMS. Here are a few tips:
* Warm up thoroughly before activity
* Cool down completely after exercise
* Perform easy stretching before
* Perform thorough flexibility exercises after exercise, while the muscles are warm
* Start with easy to moderate activity and build up your intensity over time
* Avoid making sudden major changes in the type of exercise you do
* Avoid making sudden major changes in the amount of time that you exercise
That was from that link.
Either that, or you probably need to up the intensity.