You can't beat cycling for both building muscle and cardio.
Stewart Cohen/Lifesize/Getty Images
Every year you may catch a glimpse of the Tour de France on TV or you may notice the road cyclists that hit your local byways in packs of wild colors on the weekends as they log mile after mile on their bikes. But the one thing you probably won't see much of are bulky legs.
Cycling is one of the best cardio activities around, torching calories at a fast clip. And it's also one of the best ways to tone the muscles in your legs, as well as your glutes, for a great-looking lower half.
How you shape those leg muscles while cycling is entirely up to how you you ride, how long you ride, and what sex you are.
The Muscles Hard at Work
Every time you jump into the saddle, whether you're a road cyclist, mountain biker, or just out for an afternoon cruise on a one-speed, your power is in pedaling, which means your legs benefit the most from your workout.
By far, your quads and hamstrings are the two muscle groups that work the hardest when you cycle. Every time you push down on your pedal, you engage those muscles. Your calf muscles, too, are getting a workout as they help with the overall pushing effort, and especially come into play when you're out of the saddle and pushing uphill.
Rounding out the muscle groups are your glutes, which provide the foundational force to your cycling effort.
Cardio vs. Building Muscle
If bulking up your legs is your endgame, then cycling is not an ideal path to that goal because of the cardio component, which is good news for those who want to build and tone leg muscle without creating tree stumps out of their legs.
Cycling torches calories and builds muscle at the same time, which means that the net effect is one of toning rather than bulking. Moderate cycling for anyone who weighs between 130 and 205 pounds burns from 472 to 745 calories an hour.
As you burn those calories, you're also building new muscles in your legs, especially if you're new to cycling, but that muscle may replace fat. Now, instead of jiggly thighs, you can have firm and toned legs thanks to stronger hamstrings and quads. Not to mention, your newly-toned hind end and calves will perfectly frame your shapely thighs.
The Roads Traveled
One of the greatest influences on how you build leg muscles during cycling is how you ride. If you're chugging up single-track trails on your mountain bike, you'll be building muscle at a far faster rate (not to mention burning calories), than if you were taking a spin around the park.
And the farther and longer you go, the more leg muscles you'll build. Here, again, the effect of burning calories at the same time will offset bulkier legs, which is why those Tour de France riders look like they weigh less than 100 pounds soaking wet.
The Gender Factor
The final factor in whether, and how, you build leg muscles while cycling has to do with your gender. If you're a male, you'll build muscle far more quickly than females, because your muscles are genetically predisposed to bulking up, thanks to your testosterone. Women, with their almost negligible amounts of testosterone, won't bulk up nearly as much.
If well-toned, muscular legs are your goal, cycling can't be beat. And the toning doesn't end at the top of your legs, as you build your glutes and some upper body strength, too. If bulky thighs are what you're after, hit the gym as well as your bike for beefier legs.