"Just" Cardio

I often read "You won't gain muscle by just doing cardio" but what exercise IS just cardio? Running and cycling build leg muscles, rowing builds them all over, as does swimming, I can't think of any sport where the cardio aspect is balanced with some strengthening effect. So what is "just" cardio? Air punching?

most likely cardio will actually burn muscle and make them smaller (look at marathon runners, no muscle and they run all the time) Cardio breaks muscle down, not build it up.

It's not so much building muscle as leaning muscle. You won't get "bigger" doing cardio, and in fact if you're trying to strength train cardio will actually inhibit your muscle growth (from info by the ISSA).

Cardio WILL build muscle! If it didn't my thighs wouldn't be pure muscle since the only work I really do on my legs is running (and running is cardio).

My point is, running has a cardiovascular effect (which is what people mean by cardio - it causes your heart rate to rise), but it also has a strengthening effect (what people call weights) as your legs are weight bearing. As most people hit the ground with some force, the strengthening effect of running is actually quite a lot (the force going through each of my legs when I land is my weight, 133lbs, at around 3Gs, that is a LOT of force, equivalent to a huge weight).

I was just saying that regardless of what people say - I believe that cardio CAN build muscle. I know people say it won't, but I see how different my thighs are pre-running and post-running. They are pure muscle now. So, yes, I do believe that cardio can build muscle.

Is their "pure" cardio? Well, I highly doubt it. Since everything you'd be doing would be weight bearing.

I often read "You won't gain muscle by just doing cardio" but what exercise IS just cardio? Running and cycling build leg muscles, rowing builds them all over, as does swimming, I can't think of any sport where the cardio aspect is balanced with some strengthening effect. So what is "just" cardio? Air punching?

most likely cardio will actually burn muscle and make them smaller (look at marathon runners, no muscle and they run all the time) Cardio breaks muscle down, not build it up.

What I am saying is how can there be such a things as pure "cardio"? I can't think of any exercise that raises your heart rate with no muscular force. And muscular force WILL build muscle.

but running acutally burns muscle, not builds it, so yes there may be a strength element to it but in "real" strength training you can not do 1000's of reps without a rest yet you do with cardio exercises, so it is not really strength training at all and the multiple reps may even make your muscles smaller, not larger.

I often read "You won't gain muscle by just doing cardio" but what exercise IS just cardio? Running and cycling build leg muscles, rowing builds them all over, as does swimming, I can't think of any sport where the cardio aspect is balanced with some strengthening effect. So what is "just" cardio? Air punching?

most likely cardio will actually burn muscle and make them smaller (look at marathon runners, no muscle and they run all the time) Cardio breaks muscle down, not build it up.

When I read the OP I thought, "of course it builds muscle, just look at marathon runners" because their legs are all muscle. Then I read this. I think there is a real big divide on these boards as to just how bulky a muscle has to be before it's considered a muscle.

I am not disagreeing that running builds muscle. Absolutely it does. No runner would disagree with you. What I am saying is that running ISN'T "just" cardiovascular exercise. It has a weight aspect too. As does almost every sport, so the people who say "Cardio doesn't build muscle" are kind of missing the point, because pure cardio is nigh on impossible.

I am a runner and I disagree, running for most people (unless you are a genetic abnormality) will not build muscle, and if you are in a caloric deficit will actually burn muscle off of your body.

Cardio WILL build muscle! If it didn't my thighs wouldn't be pure muscle since the only work I really do on my legs is running (and running is cardio).

My point is, running has a cardiovascular effect (which is what people mean by cardio - it causes your heart rate to rise), but it also has a strengthening effect (what people call weights) as your legs are weight bearing. As most people hit the ground with some force, the strengthening effect of running is actually quite a lot (the force going through each of my legs when I land is my weight, 133lbs, at around 3Gs, that is a LOT of force, equivalent to a huge weight).

I think you are absolutely correct. It's pretty much impossible to work your heart (cardio) without stressing your muscles.

cardio tones muscle, and yes you will lose muscle if you don't eat properly. With that being said, you will uncover all the muscle that you already have if you were to only do cardio. If you are trying to burn any amount of fat, you need to do cardio quite a bit. If you want to build your muscles, you would need some sort of lifting routine in order to fatigue those muscles properly.

Now that just isn't true. You don't need a specific "lifting routine" to build muscle. You have to have a weight aspect to your exercise regime, but that can be rowing, cycling, press ups, rock climbing, any one of 100s of sports that have a similar effect. Look at olympic swimmers. They have incredible bodies, and not from lifting weights.

Olympic swimmers all lift weights as part of their training program.

cardio tones muscle, and yes you will lose muscle if you don't eat properly. With that being said, you will uncover all the muscle that you already have if you were to only do cardio. If you are trying to burn any amount of fat, you need to do cardio quite a bit. If you want to build your muscles, you would need some sort of lifting routine in order to fatigue those muscles properly.

Now that just isn't true. You don't need a specific "lifting routine" to build muscle. You have to have a weight aspect to your exercise regime, but that can be rowing, cycling, press ups, rock climbing, any one of 100s of sports that have a similar effect. Look at olympic swimmers. They have incredible bodies, and not from lifting weights.

Or tennis player's legs. I'm sure tennis is probably considered cardio, but D*** those tennis dudes have some fantastic legs.

Cardio does not build muscle. Why? Because running,cycling and the like recruit slow twitch muscle fibers, lifting weights recruits fast twitch muscle fibers. ST muscle fibers do not hypertrophy very much (maybe 5% of of what fast twitch does).

99% of the "building muscle" people think is happening when they run or cycle is a combination of just simply lowering BF% and muscle being more dense. A lean leg will look larger than a fat leg even if the measurements prove that wrong. FT and ST muscle fibers will become more dense with training and will make the muscle feel harder but in fact they may not be larger.

The one exception is sprinters and that's because sprinting activates fast twitch fibers.

From what I've read you have to put a load on the muscle equal to or greater than 60% of the maximum load it can handle to recruit a significant amount of FT muscle fibers to see a significant amount of hypertrophe.

Running (outside of sprints) will not do that.

Cardio does not build muscle. Why? Because running,cycling and the like recruit slow twitch muscle fibers, lifting weights recruits fast twitch muscle fibers. ST muscle fibers do not hypertrophy very much (maybe 5% of of what fast twitch does).

99% of the "building muscle" people think is happening when they run or cycle is a combination of just simply lowering BF% and muscle being more dense. A lean leg will look larger than a fat leg even if the measurements prove that wrong. FT and ST muscle fibers will become more dense with training and will make the muscle feel harder but in fact they may not be larger.

The one exception is sprinters and that's because sprinting activates fast twitch fibers.

Hmm, I think that all sounds interesting. But it doesn't explain my Zumba legs.

Sure it does. More lean=look more muscular. More dense=feels a lot harder.

Simple as that. I would seriously doubt your legs got bigger doing Zumba unless you gained weight.

cardio tones muscle, and yes you will lose muscle if you don't eat properly. With that being said, you will uncover all the muscle that you already have if you were to only do cardio. If you are trying to burn any amount of fat, you need to do cardio quite a bit. If you want to build your muscles, you would need some sort of lifting routine in order to fatigue those muscles properly.

Now that just isn't true. You don't need a specific "lifting routine" to build muscle. You have to have a weight aspect to your exercise regime, but that can be rowing, cycling, press ups, rock climbing, any one of 100s of sports that have a similar effect. Look at olympic swimmers. They have incredible bodies, and not from lifting weights.

Olympic swimmers all lift weights as part of their training program.