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Will Running Cause Bulky Thighs?

You Asked: Will Running Cause Bulky Thighs?

Dear Fit,
I've been trying to lose weight for a while now, and only have about 30 minutes to work out each day. Walking hasn't really affected the scale as much as I'd like, so a friend suggested I start running instead. Do I have to worry about getting huge, muscular, and bulky thighs?
— Looking to Lose

I think it is great that you're kicking it up a notch when it comes to fitness. Your concern is a common one since running mostly works the lower body. To find out if you need to worry about your thighs, just


Running will in no way bulk up your quads into huge masses of muscle. Since running is a great way to burn calories (which is what you need to do if you're trying to lose weight), it'll actually help you lose fat from all over, including from your thighs and bum. So on the contrary, it'll help your thighs look slimmer, not bulkier. Think about photos you've seen of marathoners like this one from the 2009 Boston Marathon. Do any of them have thick thighs?

Running will also tone your booty, quads, hamstrings, calves, and shins, so once you start shedding pounds, it'll reveal sculpted and shapely muscles. The same goes for biking and hiking. These cardio activities will burn calories and tone beautifully without adding bulk. I would suggest you look into ChiRunning. This technique helps you run more efficiently, which helps you avoid overworking your quads.


Join The Conversation
amandaaa amandaaa 8 years
i have never been much of a runner, but recently i have forced myself to do it more often in order to lose weight/tone up...after having run fairly regularly for a few weeks, my legs have toned up tremendously. my calf muscles are very noticeable and i have nice lines on the sides of my thighs. much better than fat!
courtneyd courtneyd 8 years
mamasitamalita, that's awfully judgmental. I too worry about getting bulky thighs because it's one of the places on my body that never seems to slim down. I already have a hard time finding jeans and pants and shorts that will fit because the thighs are always too tight - so I either end up with pants that are too large, or pants that look like sausage casing around my thighs if I don't buy widelegs or relaxed fit. So even though I love strength training, I force myself to do more cardio (which I don't really enjoy nearly as much) because I know that is one way to help keep them from getting too bulky. Also, the chirunning link doesn't work. I would love to see what that's all about.
rockinchica88 rockinchica88 8 years
Running shouldn't be causing more injuries than other activities. It is just that it encompasses the whole body without aid of any other objects like a bike or climbing stairs. also it is high impact. So because it encompasses the whole body you have to have a great gait so one muscle isn't working for another and setting you off balance. I have been struggling with this for a couple months because i tend to lock my knees when i run which is causing weak ankles. But it can happen anywhere in your body. But because of running causing me to fix my gait, posture and balance my fitness level has skyrocketed.
wanderlusting wanderlusting 8 years
I started running in January. My thighs ARE larger. But that's the way I am built - I have a disability with my feet that throws everything off course. As a result, my calves are spindly and weak (and can NEVER gain muscle) and my thighs are huge from doing all the work. It has been that way since I was born. So running does make my thighs larger, while spinning makes them thinner. Either way though, they are only large because I am gaining muscle and not shedding enough fat. If I lost all my horrible fat, then my legs would still be large, but toned and muscular and I don't mind that at all!
darc5204 darc5204 8 years
I think the article is too "this is what you want to hear" and agree with the other commenters. How muscular running makes you look partly depends on body type, and it doesn't give you skinny model legs. Nothing at all wrong with that; most of the runners I know look pretty spectacular!
lemuse20 lemuse20 8 years
I think the reason why you see some runners with bulky legs is because they weight train to build muscle.
aimeeb aimeeb 8 years
Things like this are what make me weary to start running.
mydiadem mydiadem 8 years
Depends on your body type, why don't you just try running and see how it goes? If you feel its making you bulky then switch to something else. Personally running causes more injuries and does bulk up my legs moreso than other forms of fitness like stairs and bike. And if you do a mix of different things and not just run or walk then you'll be working lots of different muscles and be stronger overall.
cmd0610 cmd0610 8 years
haha mamasita- well said! if u want to be thin and healthy you've gotta take the muscle along with it right, and isn't being toned and having muscles a good thing (and good for increasing resting metabolism also right?) . . .
michlny michlny 8 years
Running is a great way to burn through calories, thereby reducing the jiggly thighs and firming them into slender beauties :)! A good idea is to cross train - Jumping Rope is a GREAT way to burn calories in a short time!!
livetolove livetolove 8 years
running toned my thighs--I love them muscular and strong, who cares about bulkiness! Bulk = muscle, get over it!
mamasitamalita mamasitamalita 8 years
so this is a woman (I assume) who wants to be thin and muscle free. sigh. embrace fitness baby
cmd0610 cmd0610 8 years
for me running slimmed by thighs but bulked up by calves- i think everyone is going to have a unique reaction, but i think when it comes to exercise the important thing is to think about all the great benefits (losing weight amongst those!) and not to focus on where u will build muscle- as if that's a bad thing?!?!?!!
TidalWave TidalWave 8 years
This is the lamest excuse not to exercise I've ever heard
bigestivediscuit bigestivediscuit 8 years
I think it depends on your body type. But I've never heard of running causing bulky thighs. All of my friends who run have really nice lean legs, which is one of the reasons why I run.
plus_2_kid plus_2_kid 8 years
I think it really depends on your body type. Also, long slow runs would better better than short sprints. Look at elite sprinters - they DO have large thighs, but that's because of the weight training they do as well. Running + yoga is the magic combination for me. Strengthening, cardio, toning and stretching. I love how my legs and butt look when I'm doing both regularly together. Lean and toned. Of course, I'm now pregnant and *trying* to learn to love my increasing booty. I still don't get why my thighs are getting huge when the baby's in my belly! ;)
Crisonce Crisonce 8 years
i used to run and bike and switched to focus on my yoga daily, since then my thighs have been shrinking... in my case, running did bulk me up compared to my body as a yogi
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