Step aerobics good for quads and calfs.

Cycling, I guess for you, moutain bike riding would work well. Plus doing leg work in the weight room would help too.

Ryan.

For your leg exercise. Lean against a wall and lower your back (keep it straight!) until your legs are at 90 degrees, aim to do 10 reps 3 sets.

For your calfs, hold onto something for balance and perform calf raises one leg at a time, so you end up on your tippy toes. Aim for 20-30 reps 3 sets.

Improve your lung capacity -- aerobic conditioning!