Worried About Getting Bulky Thighs?

Here's how to put those fears to rest for good.


It’s one of the biggest worries women have about indoor cycling; sometimes it even prevents them from committing to these high-octane workouts: The fear of developing bulky thighs. Few women on the planet want to develop thicker thighs and the mainstream media has fed this trepidation with warnings that indoor cycling gives you bulky legs, claims that are completely unfounded, according to Jennifer Sage, founder of the Indoor Cycling Association.

Here’s the truth: This is unlikely to happen for several reasons. For one thing, the ability to build bulky muscle mass is more of a guy thing, and it’s highly dependent on genetic factors; most women simply don’t have the testosterone levels that would allow their muscles to bulk up even with weight training. For another thing, with indoor cycling workouts, while there are certainly times when you’ll be pushing a fair amount of resistance as you simulate climbing a hill, these climbs are usually pretty short-lived, lasting only a matter of minutes, which isn’t enough time to build larger quad muscles. The rest of the time, you’ll be pedaling at a fast pace, against lighter resistance, in order to build speed and stamina.

For a real-life reality check, consider the body type of professional road cyclists: They tend to be on the lean side and while their leg muscles are well defined, perhaps even chiseled, they’re certainly not “bulky.” And there’s a reason for this, according to Shannan Lynch, Ph.D., director of education at Mad Dogg Athletics, Inc., which owns and licenses the Spinning® brand: Intense cycling requires a large proportion of fast-oxidative glycolytic muscle fibers, which allow a rider to pedal for a long time, pedal fast, and explode with energy at the right moments without tiring too quickly, she explains.

Thicker muscle fibers only develop as a result of continuously heavy resistance loads—and that’s just not the way things roll with indoor cycling workouts.   

What you will get with regular indoor cycling workouts is greater muscle definition in your legs (think: shapely, toned gams), a bang-up workout for your heart and lungs, an endorphin rush and a mood boost, and a chance to burn loads of calories (400 to 600 in a 45-minute class).

If slimming down is one of your goals, indoor cycling can help you get there as long as you don’t compensate for the tremendous calorie burn by eating whatever you want to. (Some cyclists find their post-workout hunger kicks into overdrive; it’s fine to refuel with a healthy snack after your ride but portion control is essential).

Regular indoor cycling sessions really can change your body for the better. In a 2010 study, researchers from the University of Palermo in Italy had previously sedentary, overweight women engage in three indoor cycling sessions per week for 12 weeks. After 36 sessions, the women lost an average of 3.2 percent of their body weight and 5 percent of their body fat, and they increased their lean muscle mass by 2.6 percent; meanwhile, their body measurements decreased. The proof is in the numbers!

The bottom line: If you enjoy indoor cycling, don’t let your worries about getting bulky thighs prevent you from engaging in these workouts, especially since they happen to be great for your body and mind.

If you want to go the extra mile to ensure that you don’t develop massive muscles, complement your indoor cycling workouts with exercises—like Pilates and yoga—that elongate your muscles. In the meantime, feel free to climb on the bike and ride away from your worries, knowing that you’ll develop lower body strength and endurance and great-looking legs.

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