I am on week 15 this is the most thorough workout I have ever done. I am 55 years old and rode 3000 miles by Nov. 1. My riding buddy started P90X in the spring and I watched his riding improve all summer. I thought I was in pretty good shape last fall after doing a double century in southeastern Ohio but this program kicked my butt the first month. I have been staying with the exercise program and doing my own nutrition. I work out on my trainer a couple times a week and get in a run or two also. I feel like I am in better shape than I have been in years and look forward to getting back on the road!