I originally got into biking due to a running injury and found it to be different and challenging in it's own right. However, I would be amiss if I didn't recognize the benefits of cycling on my running fitness, now that I do both. I have noticed that my lung capacity has improved faster and better on the bike than by training harder "on my feet". My quads are much stronger now, and match more evenly with my muscular hamstrings. The biggest improvement I see from these factors is hill climbing. I used to dread running hills. Today, I was delighted to find myself flying up them - feeling lighter than air, because I'm not dragging a 35 pound bike loaded with work gear. Amazing! While I had to build up my fitness differently for both running and cycling, I am now starting to see the symbiotic fitness benefits of being both a cyclist and a runner.
Anyone else find that cycling has boosted other fitness-related activities or sports in particular ways? Have other activities helped your cycling?