How to lose Lean Mass

[SDTRI619]

I have been competing in endurance races since 1997 and have not really lost a lot of weight during those times. The lowest weight I have acheived was 165 pounds and have about 8% body fat. Now, I would like to lose some of that lean mass so that I can weigh less and be more competitive.

I know I should increase cardio which will catabolize my muscles. However, all I did for training for my IRONMAN race was cardio. Total mileage on the swim per week was 4 miles, 300-500 miles per week on the bike, and at least 50-60 miles per week running. I did not do any weight training and reduced my carb intake. The most caloric intake I took during this training was around 3500 calories (easily burned more then that while riding a bike for 5-6 hours). I was still unable to get below 165 pounds.

Any ideas?

Thanks