Limiting Factor: Legs or Lungs?

It seems to be the same thing for me. Maybe it's caused by going out too fast? Not sure.

My lungs are always the constraint for me. I do some hard workouts and quite a few mpw and my legs never get tired.

Played lots of basketball and skied which I think helped my legs a lot.

In healthy people under most conditions, the lungs are not the limiting factor. The ability of young lungs to move air is incredible. It is not unusual to see even moderately trained people able to move 140 liters of air per minute.

Conditions where this might not apply: altitude and severe smog

Asthmatics or others with lung disease

There is a very small percentage of people that will have issues with low perfusion from the RBCs traveling too fast past the alveoli. But they are most often elite females endurance athletes.

luv2run wrote:

In healthy people under most conditions, the lungs are not the limiting factor. The ability of young lungs to move air is incredible. It is not unusual to see even moderately trained people able to move 140 liters of air per minute.

Conditions where this might not apply: altitude and severe smog

Asthmatics or others with lung disease

There is a very small percentage of people that will have issues with low perfusion from the RBCs traveling too fast past the alveoli. But they are most often elite females endurance athletes.

I am not moving much air through my lungs. I take a breath maybe every 6-10 strides

You might need more work at lactate threshold if you are feeling your legs burn up, tempos always help with this as well as fartleks to an extent. Also if you just need strength, squats and other similar exercises are great.

You're in better shape than your teammates but they have stronger muscles. They are most likely more talented than you but have less training under their belt.

This is spot on. It may feel like your lungs are the limiting factor; however, that is rarely the case. The limitation is typically at the skeletal muscle level.

In reality, the muscles are nearly always the limiting factor. It's not that your lungs aren't intaking enough oxygen. On the contrary, they consume more oxygen than your body can use. So it's a case of how efficient your muscles are at using oxygen to create ATP (the molecule that creates movement [sorta]).

What happens, is once your that Oxygen-using energy system cannot create enough ATP to account for the demands of contraction, the non-oxygen energy system kicks in which is what creates loads of Lactic acid (again, sorta). This non-oxygen using system lasts only a short amount of time. So the limiting factor is always the efficiency of your exercise metabolism.

Hope that sorta makes sense. You can find the graphs of these if you look up:

ATP-PC system

Glycolysis

Oxidative phosphorylation

Had this come up back when I ran the 800m in college with my buddy who also ran the 800. He would say the only thing stopping him from running was faster were his legs at the end of a race, whereas for myself, it was always my lungs.

I think this is interesting and I find myself thinking about it a lot.

I am opposite of you these days, I feel that my engine is limiting me past a certain point whereas I feel my legs could keep going. I don't race on the track so I am talking a 5K distance on the road where I will feel like I need to slow some once I feel like either I am going to vomit or my lungs just can't take it. This depends on how hard I go out but usually in the last mile of the race. I know I can train and improve that to some extent but how much I guess you never know until you try.

You need to work on slowing down your lactic buildup.

You need to work on your speed endurance which will over time help with your concerns.

Don't listen to suggestions about taking certain "medication" and "wonder foods" they do not work.

8hundred wrote:

luv2run wrote:

In healthy people under most conditions, the lungs are not the limiting factor. The ability of young lungs to move air is incredible. It is not unusual to see even moderately trained people able to move 140 liters of air per minute.

Conditions where this might not apply: altitude and severe smog

Asthmatics or others with lung disease

There is a very small percentage of people that will have issues with low perfusion from the RBCs traveling too fast past the alveoli. But they are most often elite females endurance athletes.

I am not moving much air through my lungs. I take a breath maybe every 6-10 strides

That's literally impossible to sustain.

I'm not an exercise physiologist, but the experiences I've had where my legs gave out on me in a race before I really taxed my lungs were when I had not adequately rested before the race.

It could be helpful to take it down a notch in the last hard workout before your races. This could explain the discrepancy between you and your teammates if your muscles take longer to recover than them, or you are pushing harder than them in workouts.

Lol this man out here holding his breath. Seriously I think breathing once every other stride is deep breathing when running hard, 6-10 would lead to death.

benjamins wrote:

Lol this man out here holding his breath. Seriously I think breathing once every other stride is deep breathing when running hard, 6-10 would lead to death.

Interesting conversation.

When getting back into shape, I work for several months on nothing but aerobic training, meaning I run at a pace slow enough that my muscles are fully oxygenated at pace. Bottom line, very slow. I could use heart rate to keep pace in check (70% max HR is about right) but I've found that if I breath four steps in and four steps out, I will be at about the right pace. If I go too fast, I can't maintain that breathing pattern. I don't do it constantly, but it is a good mid-run check.

But for someone to try to race while maintaining that slow breathing pattern? Nope. No wonder his legs burn. As others have said, though, the lungs can take in much more oxygen than the body can utilize. The key is to maximize how efficiently the systems move and use oxygen.

You might study up on HADD TRAINING THEORY as discussed in earlier threads and in a PDF you will find if you Google that term.

You need too work on you're leg speed velocity.

Your welcome.

Back in high school my lungs were definitely by far the limiting factor. I wasn't as good as you, 16:50 in xc and 4:40 in track. But even in college when I got a little better (eg 15:07 on the track) legs were still never a limiting factor, all breathing. I think I'm naturally a pretty strong person, and I wrestled for a bunch of years which I think helped with leg strength.

As I've gotten older, and missed a few years here and there and have a more sedentary lifestyle (office job etc) it's more of a mix. I think it's because I've become more aerobically developed over time. I also think my legs have gotten weaker.

Not sure what you should make of all that, hopefully enough stories like this can start to paint a picture for you though.

yo yo bra wrote:

You need too work on you're leg speed velocity.

Your welcome.

^This.

I believe it's muscles, not lungs.

But not just leg muscles. When I had prepared properly, the limiting factor was my entire body's ability to deliver oxygen and process oxygen. It was not simply focused in the legs, and the lungs were working hard but not excessively so.

Fatigue in a distance race was more of a total body type of fatigue.. And this included compromised brain function (almost passing out, not being able to talk, seeing stars...)

Pushing against this overwhelming total fatigue is an essential part of distance running. Every part of your body, every fiber, every part of your being is involved.

This is where the mental aspects come into play. It seems like you move forward on guts, will and desire alone at some point.