I was formerly an elite youth rower, so I have a pretty big upper body, which of course I don't really need for cycling. Any tips for losing this muscle? I have already cut my upper body weight lifting. Thanks all.

Cutting out the lifting is probably the best bet. Another thing to add would be to start mixing in some running with your cycling. It will help your metabolism focus on your lower body strength.

As far as running goes, stick with longer runs (over 30 minutes) and take it easy. Runners call these workouts - long slow runs. I spend 45-120 minutes once or twice a week doing these (after you have built up to that length of time). No sprinting....this utilizes to much upper body strength.

The running will also help with your aerobic endurance.

I'll second running for sure, also focus more on long base type rides (which at this point of the season most people are doing anyways.) Riding for over 5 hours, or as long as you can.

Losing muscle is quite difficult but not lifting weights, running or doing any aerobic, fat burning type of exercise will help.

Whilst lifting weights are important (if done correctly however) to everybody on a training programme it is vital for those above the age of 35 years approx however as as we age we lose around 1-2 lbs of muscle mass each year. So strength training and lifting weights helps us maintain and keep our muscle mass up so that joints, muscles, tendons and ligaments are supported enough for the rigours of your particular sport (in our case, cycling).

Running will help lose muscle mass and more importantly body fat quicker than most exercise due to the high impact of the exrcise. But be careful as if you have not run before regulary the chance of injury may be quite high. Be sensible with it if you are going to start running and start at an easy time period first... maybe 15 mins jogging. Do this 2-3 times week for about 4 weeks. If this is ok then increase the time to 20 mins or 30 mins. Maybe do 1 longer run each week of up to an hour but you have to build to this time gradually.
The majority of your running should be off road also if running is not your key sport and just an added cross training benefit. This will limit the stresses and strains on your body especially around the knees, hips, and back.

Just sticking to 1 pace however is ok, but maybe vary it once a week and add a few 'pick ups' or 'surges' on the end. This will keep things more interesting and stop you getting stale or bored and even make you run faster but over a long period rather than a 'quick fix'.

At the end of the day if you want to get fitter to ride... then ride your bike!
If you want to lose muscle... stop the weights and focus on endurance, aerobic type rides mixed with a little speed work each week. You will then adapt slowly and you will slim down, tone up and get 'lean 'n' mean'!
Stick to a healthy diet also eating 4-6 meals a day and your on your way!

Keep at it and don't go for the 'quick fix!'. The fitter athletes take years to get to their goals NOT weeks or even months!
Good luck.
Mark

Id say keep on doing some sort of upperbody training especialy back/stomach area where many cyclist are very weak
and there are some theories that your body when it starts to produce lactic acid it uses other muscles to"cancel out" the lactic acid
so if you got a decent uppebody you should last longer when you go on red in a race

run run run

best way to lose muscle mass as well as body fat, which is ultimately what you are trying to do - mark has some excellent advice in his post

as a water polo player I have the same problem, a very big upper body although those drafting behind love it

perry is also right - lactic acid produced in working muscles is also oxidised in non-working muscles as well!