It is said that climbing hills is excellent training for a cyclist. It isn't much fun but I have to agree, it is good training. I have discovered it to be true. Many of the miles I've ridden this year were in hilly regions. All that climbing has built up my strength and helped me lose pounds. Now I have found another kind of beneficial training. Riding a tandem bike really gives you a good workout. I think the miles I am riding on the tandem are doing more for my strength and endurance that the miles I can ride on my single. When I get back on the single for a ride after several mornings riding tandem, I can really feel a difference in strength. I don't think it will take very long for me to create even bigger gains by riding it.