Moving forward on the saddle

edited June 2007 in Road beginners

I have been commuting for a couple of weeks, this is the third week. It is only 3 miles each way. Downhill to work and uphill on the way home. I have noticed on the last 3/4 rides I have been getting slower and moving forwasrd on thr saddle. As far as I can tell my position on the bike is pretty good. So was wondering why I was moving forward. Is there a weakness somewhere? I haven't been doing any other exercise other than cycling. Do I need to work my core?


Rich (A commuter at last)