Why is cycling making my legs bigger?

Question

I used to run 8k/5 days a week for 2 years then i took a year and a half off and was lazy and dieted, but from dieting i got unhealthy and loss muscle and was just thin. Since I stopped dieting 2 months ago and started cycling (3-5 hours a day with a lot of uphill/5days a week... for work) I can't seem to fit any of my pants and my legs are getting bigger.. what is going on?

Answer 1

Gaining muscle.  Cycling will definitely tone your body but at the same time, builds muscle, especially biking uphill.  

Answer 2

Well it short lenghted tiny thingos in your legs.  

Answer 3

Stick to 80-90 rpms and it puts less pressure on your legs. Higher gears, hills you build muscle...

If you want to look like a biker, stick to 80-90 otherwise your calves will hit your water bottle... like me...

Answer 4

Are you thick? Cycling heavily relies on the muscles in your legs, if you're doing some lengthy rides of course the muscles in your legs are going to get bigger.

Answer 5

  In cycling I am not sure.But I think it has something to do with toneing your leg muscle.