By "help" for your thighs and backside, I assume you mean slim them down. Exercising them will increase muscle tone, which will decrease their size some. The typical wisdom is that weight training builds muscle mass (strength), but aerobics enhances cardiovascular fitness (stamina). The third objective is flexibility -- so you need to stretch.

To answer your specific question about the effect of bike riding on your calves (I assume you ride a stationary bike) -- I do not think that bike riding works you calves very much. Body builders who want to work on their calves typically do a routine in which they go from a regular standing position to standing on their toes. If you do a few repetitions of that with weights, you really feel it in your calves. If you are bike riding, the bike will work your thighs, but I'm not so sure about your backside.

The other thing you should consider is that a good aerobics program combined with a careful weight control diet will probably achieve an overall slimming in time. Trying to "shape" your body by exercising certain muscle systems is very difficult, and is not likely to meet with much success. Body builders spend 5-6 hours a day every day to achieve some of that and in the end what they achieve is mostly determined by their genes and only in part by their efforts. Really successful body builders are just lucky they have the "right" genes.

You might find a book like "Fitness for Dummies" helpful in giving you a realistic perspective on what you can expect to achieve in your exercise program.

Well if you ride with high resistance you will build muscle, but if you lower resistance you will build nice tones without gaining weight...Have you seen any episodes of The Biggest Loser yet this season. You will laugh your heiny off :)

i agree with lildeborah. and i would add... i f you wanna increase your muscle mass, check out a book by Adam Zickerman. It's called the Power of 10: The Once-A-Week Slow Motion Fitness Revolution. It's a totally new appproach to building muscle mass. and it's the first time i actually noticed my muscle mass increasing. good luck!

My husband's main sorce of exercise has been bike riding,and he has ALWAYS had very nice,muscular thighs and a nice firm butt :)

"My husband's main sorce of exercise has been bike riding,and he has ALWAYS had very nice,muscular thighs and a nice firm butt :)"

Same here! My DH has done that 'Ride the Rockies', a six-day bike tour through the Rocky Mountains a few times.

One year, he rode with two other women. One had very well developed upper thighs. She was frustrated because she was always trying to slim them down.

Like another poster mentioned, you've got to do lots of reps. Put the pedal where you will have to stretch/elongate the leg, rather than ride like your on a BMX bike and 'build up' those thighs!

Bike riding is specially useful for removing belly fat and getting a flat hard stomach. It burn fat around abdominal region, hips and thighs. It is best to improve legs endurance power.