Leg muscles.

Hey, i have heard this differently from alot of people, so i just wanted to ask, i was told that riding your bike only tones your leg muscles but doesent make them bigger, but then someone else told me it does make them bigger,it makes more sense that it would make them bigger considering your using your leg muscles...But i dont know, i just want to know, because i dont work my legs that much in the gym, mainly because i dont like doing leg stuff that much, but i do ride my bike alot, so if this is enough then thats sweet, if not then i guess ill have to start working my legs more. by the way i got really strong legs, o and im pretty sure biking uses all the muscles in your legs but im not sure. I was also told you use your back muscles while bike riding.

Well, any balanced workout should incorporate leg and back exercises.  These exercises are actually the key to increased overall bulk, not just in the legs and back.  So add squats/leg press and deadlift into what you do now.  Riding a bike is an aerobic exercise, not an anaerobic.  Aerobic exercises involve working in an oxygenated state.  For example, long distance running: You are breathing while you are using your leg muscles.  Aerobic exercises uses slow twitch muscle fibers.  If you want to see impressive legs, take a look at fixed gear bicyclists.  However, this kind of exercise really will not make you stronger, it will merely give you more endurance.

Squat 385, Bench 235, Deadlift 450 @ 181.

Squat to become beast.

I want to get really big leg muscles, but i want to be a fast runner still, will this slow me down?