Should I worry about my leg muscles bulking up...

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tanya1282
tanya1282 Posts: 20
in Fitness and Exercise
I heard some girls complain that their thigh and calf muscles become bulky from a lot of running. I remember when I played soccer in high school, I had bigger thighs than I liked even though I was slim overall. I like to run but I am worried about my thighs becoming bulky, I just want them to slim down. I read on other websites that I need to do endurance cardio.
Currently, I like to do interval training on the treadmill about twice a week with no incline. I run for 4 minutes at 6mph and then walk for 2 minutes at 3 mph and repeat that 5 times. On other days, I go on the elliptical for 30-40 minutes or ride a bike for 40-50 minutes.
Should I change my treadmill workout to just steady jogging for 30 minutes? I want to lose weight and slim down my thighs without getting bulky legs. Any suggestions?

Replies

  • kimmerroze
    kimmerroze Posts: 1,330 Member
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    Cardio actually eats your muscles... along with your fat... so its acutally good for slimming down...

    as far as people saying thier muscles bulk up... they aren't bulking up they are just becoming more defined... mine have looked like they have bulked up but in actuality when I measure them they are smaller.
  • cloggsy71
    cloggsy71 Posts: 2,208 Member
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    Your thighs will only become 'bulky' if you train for 'explosive' speed (i.e. like a sprinter)

    Long distance runners (like marathon runners) have long lean muscles which is better for stamina!

    It might also be worth looking at cycling as a form of training too!
  • ashleynicoleb
    ashleynicoleb Posts: 376 Member
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    Cardio actually eats your muscles... along with your fat... so its acutally good for slimming down...

    as far as people saying thier muscles bulk up... they aren't bulking up they are just becoming more defined... mine have looked like they have bulked up but in actuality when I measure them they are smaller.

    Agreed. I wouldn't worry about running "bulking" you up. The effect is actually the opposite in my experience.
  • natskedat
    natskedat Posts: 570 Member
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    The type of muscle fiber you build will depend on the type of running you do. Muscles required for explosive sports (sprints, kicking a ball, powerlifting, etc.) are shorter and thicker, while muscle fibers needed for energy over a longer period (distance running) are longer and thinner. The shape of your muscle will likely resemble the shape of the majority of muscle fibers your recruit, use, and build. Remember though, that much of your body shape, size, and development is genetic. It's not predetermined, but your genetics will in large part influence they way your body develops as you engage in different sports.

    Hope this helps!
  • Sarahr73
    Sarahr73 Posts: 454 Member
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    Cardio actually eats your muscles... along with your fat... so its acutally good for slimming down...

    as far as people saying thier muscles bulk up... they aren't bulking up they are just becoming more defined... mine have looked like they have bulked up but in actuality when I measure them they are smaller.

    My calves have done the same. You can see the muscle more now and it looks like it would be bigger, but in reality they are smaller just more defined.
  • natskedat
    natskedat Posts: 570 Member
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    Cardio actually eats your muscles... along with your fat... so its acutally good for slimming down...

    as far as people saying thier muscles bulk up... they aren't bulking up they are just becoming more defined... mine have looked like they have bulked up but in actuality when I measure them they are smaller.

    This is not true. When properly fed before, during, and after exercise, your muscles will not consume themselves. If your muscles consume themselves for energy, you are not supplying enough carbohydrates to your muscles for the work you are requiring from them. Keeping your heart rate in the range of 55-70% of your maximum heart rate will consume fat, as your muscles will use your fat for fuel. Keeping your heart rate in the range of 70-85% will cause your body to switch fuel sources, changing from fat to glycogen plus a small amount of fat.

    When properly nourished, you will not destroy lean body mass during cardiovascular work.
  • Rebeccasluckyduck
    Rebeccasluckyduck Posts: 168 Member
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    My legs bulk up, both my thighs and my calves. They're definitely more defined and toned, but they do get bigger. Yes, I've measured them to find out, but it's more the way my pants fit. I put on a pair of capris yesterday that I wore just a few weeks ago and they are tight on my legs and loose on my waist.

    I usually run 5-8 miles at a time during my off season and when I start training (just started again) I'll work up to 11 - 15 on a long run. I guess it also depends on your body type. I'm just not a long, lean runner. My son isn't either. He's actually training for a marathon to build his quads for football. It works for him playing on the line. However, he eats enough to not lose the weight from running.

    Cycling will definitely build your legs up - this is from experience also. I just started that again this week so I know my days of cute capris are out the window. I'll spend my summer in skirts or shorts.
  • Cmccracken1
    Cmccracken1 Posts: 326 Member
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    i have lost 4 inches off my thighs with running. i jogg moderate pace, 5mph sometime 6 for up to 60 mins. i have no complaints about the size of my thighs now they are tone and i feel good about it.
  • tanya1282
    tanya1282 Posts: 20
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    Keeping your heart rate in the range of 55-70% of your maximum heart rate will consume fat, as your muscles will use your fat for fuel. Keeping your heart rate in the range of 70-85% will cause your body to switch fuel sources, changing from fat to glycogen plus a small amount of fat.

    When properly nourished, you will not destroy lean body mass during cardiovascular work.

    So I should aim for 55-70% of my maximum heart rate to burn more fat? So around 106 to 135 bpm for me. When I workout it's more like 160bpm so I think I will try and do more moderate exercise but for a longer period of time.
  • natskedat
    natskedat Posts: 570 Member
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    Yes! It may not seem like you're getting that "burn" that we're so used to, but in the end, you're strengthening your heart muscle, and as it becomes stronger, your body will be able to do more at that rate. You'll notice in a few weeks that you've lost serious inches without exhausting yourself, as well. Some ultramarathoners run an entire race without raising their heart rate above 130. It's a great way to build endurance.

    Hope that answers your question.
  • cloggsy71
    cloggsy71 Posts: 2,208 Member
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    Yes! It may not seem like you're getting that "burn" that we're so used to, but in the end, you're strengthening your heart muscle, and as it becomes stronger, your body will be able to do more at that rate. You'll notice in a few weeks that you've lost serious inches without exhausting yourself, as well. Some ultramarathoners run an entire race without raising their heart rate above 130. It's a great way to build endurance.

    Hope that answers your question.

    This in turn will reduce your resting heart rate too...

    Lance Armstrong (at his peak) had a resting heart rate of 32 bpm!
  • kdiamond
    kdiamond Posts: 3,329 Member
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    My thighs (measured mid thigh) were 19 1/2 inches when I didn't lift and weighed 102 pounds. I also used to use that stupid elliptical trainer like it was going out of style.

    Now my thighs are 18 1/2 inches and I weigh 110, plus deadlift at 135 pounds and squat at 100 pounds. I also do sprinting. I don't do cardio in the technical sense. Lifting heavy leaned me out and made my legs smaller and more sculpted.

    Just some food for thought.
  • arac007
    arac007 Posts: 4
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    ever since I started doing treadmill with an incline of 10% I found my legs bulked up and my pants became tighter.

    now I do the elliptical my pants are still tight. and the weight is not coming down in spite of one hour of treadmill per day. any advise on how to make my legs thinner?
  • Lyadeia
    Lyadeia Posts: 4,603 Member
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    On a calorie deficit, the more I run (and the more weight I lift, for that matter) the leaner I become...the opposite of "bulking up."

    Far too many women think that exercise will make them bulky. It's an irrational fear. It's like refusing to drive a car because you think you'll magically become a champion Nascar driver.
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
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    Cardio actually eats your muscles...

    Whilst this is not complete nonsense, it's not far short...

    All exercise draws fuel from a variety of sources, with the vast majority coming from readily available, and easily replenished, sources like muscle glycogen.

    The body isn't going to start cannibalising muscle tissue unless one is routinely training for endurance events, without any effort to refuel between training sessions.
    as far as people saying thier muscles bulk up... they aren't bulking up they are just becoming more defined...

    Subject to the type of running that one is doing, and diet, there can easily be increased muscle size, coupled with the improved definition as a result of fat loss. Running is a weight bearing activity, and in the same way as any other weight bearing activity will cause damage to the musles, connective tissue and the bones. The healing process exploits the nutrients to repair the damage, but the type and nature of the repair process does depend on the training that one is doing.

    Lots of highest intensity short distance work does lead to more bulk than lots of medium to high intensity medium to longer distance work. Hillwork will develop the quads as well, providing some strength balance.

    Essentially, as long as one is eating in deficit or around maintenance then there is unlikely to be a significant increase in muscle size.

    I'd second the view above about cycling as well as running, it compensates for muscle imbalance by developing the quads and glutes, as well as providing some higher intensity work with less impact on the joints.
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
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    Currently, I like to do interval training on the treadmill about twice a week with no incline. I run for 4 minutes at 6mph and then walk for 2 minutes at 3 mph and repeat that 5 times. On other days, I go on the elliptical for 30-40 minutes or ride a bike for 40-50 minutes.
    Should I change my treadmill workout to just steady jogging for 30 minutes? I want to lose weight and slim down my thighs without getting bulky legs. Any suggestions?

    You're not getting any benefit from interval training until you establish a solid aerobic base.

    I would suggest that you focus for now on increasing your time on your feet, as long as you can already do 30 minutes start adding time until you're running for an hour at a time, that will help you increase your average speed. If you can't sustain 30 minutes at 6mph then use a progressive interval plan to get to that stage, then increase the duration.

    Once you can routinely workfor 60 minute you'll be in a better position to start benefiting from interval training. As long as you're in deficit or at maintenance you won't see significant muscle development, although you should see more definition as the bodyfat percentage reduces.
  • learnerdriver
    learnerdriver Posts: 298 Member
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    my experience- legs have lost but annoying tummy still hanging in there...

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