Leg Muscle Strength can't keep up with Cardio Growth

[slimindn1219]

Hello,

  This is my first time posting to this bored and I am relativly inexeperienced in fitness.   I have been making a lot of progress lately (235 down to 220) in about a month, but I am starting to hit a problem I have hit in the past.  My heart muscles are growing much faster than my leg muscles, making it extremely difficult to maintain a high heart rate during excercise.  2 weeks ago, I did a half an hour on the elliptical and burned 537 calories, yesterday I did an hour and only burned 555 ( according to my fitbit charge HR).  I try to keep escalating the resistance on the elliptical, but honestly it just makes my legs hurt more and does not seem to challenge me significantly more aerobically.  I know the obvious suggestion is to do different activties, but I have some limitations.  I have a bad knee and lower back and it makes taking classes pretty hard (altough I do them occasionally) and the row machine impossible.  The stationary bike seems to burn almost no calories at all. Honestly I really enjoy getting a cardio workout in, I love the feeling and calm after I sweat, so its more than just burning calories and losing weight, it makes me feel so much better and calms me emotionally, but my leg muscles just can't seem to keep up.

Any and all suggestions, greatly appreciated.  I'm 5'11 30 year old male if that matters.

Thanks in advance!

[ErinScott]

I understand what you are going through. There are times when I feel like I could go much longer, but my legs, or arms, are just done. I would add in some (gentle) body weight exercises to strength your leg muscles in addition to your cardio.

If you have access to a pool, I'd also really suggest you take up swimming. It's a great cardio workout and you use your full body to do it. It's good if you have bad knees, or back too as there is no impact. I have a bad cervical spine and find I can push myself in the pool, further than I can doing land activities as it will lead to less neck pain. I also do aqua aerobics, and would suggest you check those classes out too. You will do lots of leg strengthening exercises there, as well as cardio, but there is little to no impact so you can squat and jump, and do jumping jacks without the pressure on your spine and knee. My legs have gotten a lot stronger since I've started doing aqua, and I love that I can do stuff in the water that I wouldn't be able to do otherwise.

[VinceD]

My first suggestion would be to try and do some strength training for your legs.  With a bad knee some things may be out, but even partial squats or leg presses could help build some leg strength.  Farmer's carries may be easier on the knees.  Basically carriying weights, dumbells or other weights, for a distance.  Carry a dumbell in each hand from one side of the gym to the other and back.  Builds leg strenght in addition to grip, shoulders, etc.  Another suggestion would be walkiing on the treadmill set to an incline.  Set an incline that does not bother the knee too much but gives the needed extra effort.

[PaleoCrossfit]

Squats.

[Dominique]

I think there's some confusion about "muscle growth". The cardiac muscle (your heart) won't "grow" from one month of exercise, even if you are entirely new to exercising. Your cardio fitness, however, may have improved. If the same effort results in a lower heart rate, it just means your heart has become more efficient: it's able to pump the same amount of blood using fewer beats per minute. That's good!

As to your "leg muscles" not growing fast enough (to keep up with your stronger heart): first of all, your leg muscles (and other squeletal muscles) aren't going to grow in any significant manner in one month time, especially not from cardio training alone, and especially not if you're on a restrictive diet. The knee problem you mentioned sounds more serious than the alleged insufficient leg muscle growth. Your improved cardio fitness would allow you to train longer (and therefore burn more calories), but you'd have to find "knee-friendly" activities.

Regarding HR, don't be obsessed by the "fat burning zone": any elevation of your HR during exercise will have you burn more calories (and with that, fat). You may also want to incorporate some strength training into your regimen, so as to maximize fat loss and minimize muscle loss.

[Dominique]

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@PaleoCrossfit wrote:

Squats.

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Hmm, I'm not sure it's the best exercise for someone who has a bad knee...

[larrypo09]

Don't ignore your body...you need to build in a rest day (or two) into your schedule and allow your legs time to recover. 

[ponydoc]

Actually, as a cardiac researcher I can tell you that the Myocardium (Heart muscle) does enlarge with training.  It's called hypertrophy and it is why your heart pumps more efficiently.  This can start to occur very early in a new fitness regime (changes can happen in weeks).  Athletes do have slightly larger and heavier hearts than their sedantary counterparts. 

As for the cardiovascular endurance surpasing your leg strength, I had the same issue when I first started running.  The answer is strength training.  I would find a trainer who can build you a routine that will take into account your knee injury

[Heybales]

So true, it's easier to improve aerobically than it is lose weight, which is the problem right now.

Existing muscle strength can't push hard enough to give the same workout to the heart muscle, or to keep progressing in intensity.

And this example is exactly why the HRM ability to estimate calorie burn can be very inaccurate.

Your HR has gone down in exercise, but if doing the same level of work with same weight, you are burning the same calories as before, but going by lower HR, it would appear not.

But, also in this case of being out of shape, you were likely getting inflated calorie burn before, now you are probably closer to reality.

You can keep strengthening the muscle you got though, unless you were really a couch potato there is probably some room for improvement left.

Same as the first many months lifting is about engaging the nervous system more and using all you got better, well before body feels a need to add more.

But eventually you could reach a point where more muscle is the only solution to going harder to make a workout for the heart.

So strength training as mentioned before. Sadly in a diet gains will be few and far between, if any depending on how extreme your diet is.

[Marcy]

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@ponydoc wrote:

Actually, as a cardiac researcher 

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"Equine" cardiac researcher? Just curious because of your profile name.

[ponydoc]

You are sharp!  Yes I am a veterinary cardiac researcher.  My main interest is exercise-associated cardiac physiology/pathology.  I do, however, delve into human exercise physiology as it is very relevant and I enjoy working with people on the human side.

[Dominique]

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@ponydoc wrote:

Actually, as a cardiac researcher I can tell you that the Myocardium (Heart muscle) does enlarge with training.  It's called hypertrophy and it is why your heart pumps more efficiently.

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Sure, but how much hypertrophy of the cardiac muscle is likely to occur in merely a month of training, which is what the OP reported?

[ponydoc]

Depends on the intensity of training and the duration of his work-outs.  Young males can have especially rapid and pronounced changes.  Hard to say as it will vary between individuals but hypertrophy will occur in a matter of a few weeks.  Right now the main differences in his endurance will be the result of differences in buffering ability and increased plasma volume.  However, he will likely also have a degree of cardiac hypertrophy that is contributing. 

[TandemWalker]

Hi @slimindn1219 - Interval training could do the trick you know. The next time you do your one-hour ellipical workout, go at your normal pace for 3 minutes; and increase the pace for the next 3; and keep cycling through like this for the whole duration of your workout.

Also, if you can, find something else to do; don't do elliptical every day. Get on the stationary bike, or the rowing machine, do something different.  What's happening, IMHO not as an expert but just a regular Joe, is that your body has gotten used to a certain level of physical exertion. Intervals will fool your  metabolism and cause your hear rate to go through peaks and throughs, and you will inevitably burn more. Avoiding routine and having more than one exercise type in your took kit will also help keeping your metabolism challenged. You don't have to take my word for the benefit of interval training - just Google it and you'll find plenty on the subject.

Hope this helps. Have a great day.

 TW  

[Marcy]

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@ponydoc wrote:

You are sharp!  Yes I am a veterinary cardiac researcher.  My main interest is exercise-associated cardiac physiology/pathology.  I do, however, delve into human exercise physiology as it is very relevant and I enjoy working with people on the human side.

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Thanks for clarifying that your research does include human physiology. You picked up on where my thought was going.  🙂