Leg vs lung burns....what is the science?
 

had a good ride today but experienced burning lungs after TT attempt to test fitness but later as I was seated grinding bigger gears up hills 1 mile climb legs burned but not lungs.
both were good steady strong efforts.
what determines which goes first.

You want Science?
 

Search university sports physiology post graduate or masters degree theses, probably not going to find people having done the detailed studies hanging out here.

I know it's simplified to say, but aerobic effort uses up the lungs, anaerobic effort uses up the legs. Very generally, cyclists tend to have more aerobic fitness than anaerobic capacity. We can (mostly) all ride for hours and hours, but many people can't ride standing for more than 20-30 seconds.

Level of fitness/conditioning will tell you what's what, but only after a couple of hours. Speaking only about myself, I can still mash at low cadence when I'm nearly exhausted, but trying to maintain say 95rpm past the 100 mile mark is not in my deck of cards.

Duplicate threads merged.

Burning legs, need more blood and oxygen to flush the lactate? Burning lungs, running in overdrive?

the difference? cadence, elevation

High weight, low reps = strength, power workout.
Low weight, high reps = endurance

Science? There's the scientific method, which nobody here is following, and there's the current body of scientific knowledge, which is to say, the current theories that we know are mostly wrong but are the best we have at the moment. And of course those are debated because that's how it works.

Anything citing science and hawking pickle juice derivatives or any such for-profit product is not science, it's marketing.

AFAIK there are issues with the various theories for gravity, for example, but we use what we have because it's the best we have. That ain't sexy, unless you're using the uncertainty to hawk your anti-gravity ankle bracelets.

Lungs burn because they can't deliver as much oxygen as the body needs. Muscles burn because they didn't get as much blood flow as they need. Maybe some studies somewhere, funded by some national sports program, but I don't know you'll find them.

I'm going to go ride my bike now, and collect one subjective data point.

thanks.
I just wanted some info since it is something of a conundrum....

Since I been weightlifting on/off since I was a teen most of the time when I am bike riding it is seems my lungs are failing and not my legs. Being about 5' 5", 215 lbs and oh 85 lbs or so overweight hills are murder on my lungs. My legs have no problem climbing the hills, but I am gasping like crazy for air. I started doing more hill training to try to improve my riding performance rather than just going on longer rides. I started at doing just 5 miles that was on a very hilly bike path, felt way harder and more exhausting than a 20 - 30 mile mostly flat ride at a 12-14 mile/hr clip. I ride a steel Schwinn Mountain bike. I worked up to intervals and got up to repeating that course 4 times for a total of 20 miles up/down hills for a days workout. It is absolute murder on my lungs but I do see improvement in my lungs not failing so much, my legs don't seem to be the problem and are only a little sore the next day.

Interesting topic. I was thinking about this as well lately. I will speak from experience, not any scientific expertise.

To maintain the same power on a trainer, if I am pushing a higher gear with low cadence I feel more pain in my quads, but my breathing and heart beat slows down, whereas pushing a lower gear at higher cadence increases my breathing (and heart beat) but reduces the pain I feel in my quads. There is almost always a sweet spot right in the middle of the two that feels great when I hit that perfect gear/cadence/power balance.

My lungs blow up after a max effort sprint, drowning feeling. Legs are totally fine.
Same goes for climbing, lungs give up before the legs.
On flats, I sometimes have to coast a few secs, because too much lactate in legs, but then my lungs are fine.

my lungs went into crazy land felt like I was suffocating.....actually scary for few mins but once I calmed down road well . I hit the climb felt strong no issues breathing pushed hard but legs burned like nutz.
just curious about the science of why.

Cant compute.

Interesting, I had a similar observation, mine was when going uphill my hear rate was never that high but my lungs were burning and I was gasping for breath. Looking back, my legs were also definitely not at their maximum, so that is the same situation as for you.

On hills when I go for PR attempts my lungs still give out first, but HR is now 4-5 bpm higher and legs seem fine. Where legs hurt is in interval training sessions on flat/rolling terrain. Depending on length of intervals, the last 2-4 in a training session can really put the pain in my legs while my lungs seem fine. The less fresh I am, e.g. long Sunday ride then Tuesday interval session and legs haven't recovered yet, the more the legs hurt, too.

anaerobic vs aerobic, gear inches, cadence, etc...

That was what I was working on, standing on the pedals. Some say dancing on the pedals. I tried another approach.

First when watching the pro riders, its usually intense when attacking on the climbing stages. But what if a rider is not attacking and just wanted to see "how far" the standing (dancing) can go?

So far, it seems that the weight of the rider is doing maybe more than 50% of the work when "dancing". So, I tried to slow it down, the cadence I mean. Intentionally go "slow motion" and trying to keep the quads from being used by using a straight leg approach. That is, instead of a slight knee bend, the leg is kept straight at the top of the pedal stroke. What happens, is the quads do very little work and the body weight is deployed to push down the pedal.

That's how a rider can go for minutes while standing. Of course, you give up speed and all that. Any practical applications to a new skill? When the grade reaches 12% and you don't feel like racing against yourself, and you have enough cassette cluster to do it, then maybe.

Adaptation. Burning lungs are adapting to higher harder efforts. Burning legs are adapting to harder longer efforts. Both suck. Until after recovery. Then you do it again. It always hurts. You just go faster.

From a practical standpoint, successful racers learn pretty quickly that low-load, high-cadence near-maximal efforts are much easier to recover from than high-load, low-cadence efforts (or, in sprints, high-load, high-cadence efforts).

The latter is what is meant when racers refer to "burning matches"---you can only do a few of those high-load efforts per ride before you're done for the day (see the Grand Tour videos where riders like Jens Voight pull at the head of a strung-out peloton on Alpine climbs as long as they can and then pull to the side and limp to the finish line, hoping to make it there before the time cutoff).

Since anaerobic cell respiration takes place without oxygen, simple biology, the lungs are not keeping up with the demands of the cells. Aerobic respiration takes place with oxygen so during aerobic exercise the lungs are able to supply the demands of the cells.

All I know is, burning lungs are building capacity. I remember the first time in the bathtub I sank under the water and waited for my lungs to complain. And waited, and waited...