When we are powering up a hill, and our legs are in pain – do we know why? What’s the mechanism for it? Is the lactic acid idea debunked?

I was wondering, because since running I am not breathing particularly hard at any point when cycling, it’s the leg pain that limits me.

My understanding is that Lactic Acid build up isn’t debunked. There was a study put forth that claimed the idea was a construct, but this has in turn been responded to by another study that claims there were flaws in the considerations.

The long and short of it is that the muscles in your legs worked by running and cycling are different, but the muscles in respiratory system are the same, hence you feeling the benefit aerobically, but not in leg power/endurance. I THINK

Ask Jens!

[video]http://www.youtube.com/watch?v=W2GXeHbsG40[/video]

Have done a few lactate tests there is definitely a good correlation between pain and lactate level in my legs!

Ooh, has the idea of lactic acid build up been disregarded?? if so I’d like to know what causes the pain as I thought it was lactic acid…

I get pain when cycling up hills hard or sprinting, I don’t get it on a long run at slower pace for example.

Lactate and Lactic acid are not the same thing.

Don’t worry about what is causing the burning sensation. The most commonly recommended appropriate course of action is to build your aerobic capabilties as best you can to avoid “the burn”

The most commonly recommended appropriate course of action is to build your aerobic capabilties as best you can to avoid “the burn”

Really?

Even if I want to improve my burst sprinting ability? 20W on my lactate threshold power of say 320W is quite a lot, but it’s not much on top of my 1300W peak power….

Hmmm, I think, or rather thought, aerobically that i was pretty capable (maybe I’m confusing aerobic and endurance), so how do I best improve this?? It seems, no matter the training, shortish but sharp\hard bursts and I’m in pain…

Well if your short effort intensity is limited by pain, you’ll always be in pain when you do it by definition. As someone (possibly/probably Jens) said about cycling – it never hurts any less, you just get faster.

My colleague who is a pretty decent rider recently bought a power meter and discovered that whilst his functional threshold power (1 hour) is currently at the high end of Cat 3 but his max burst power is somewhere around that of a typical untrained rider 🙂 No wonder he prefers TTs 🙂

I think you’re refering to “anerobic”.

Lactate is produce at and above functional threshold. The greater your threshold the more power you put out before “the burn”.

What Jens refers to is an ability to discount mentally the physical message your body is givving you. Physically, its saying “your reaching my limits, please stop before you damage something!”. If you can switch this off mentally there’s a fair bit of tolerance before you physically cant continue.

Again, I THINK.

Really?

Even if I want to improve my burst sprinting ability? 20W on my lactate threshold power of say 320W is quite a lot, but it’s not much on top of my 1300W peak power….

Yep….

Here are two lactate tests I did many, many years ago. One for at the start of the base phase (3 months of just 250 miles/week at Zone 2) and the other is at the end of it.

Blue line is blood lactate level (left axis), magenta line is HR (right axis). X axis is Watts.

Before by brf, on Flickr

After by brf, on Flickr

Note that the lactate level at what was my top end, 300W, has dropped loads (from 11 to 6 ml/l) even though I’d done no riding at that level….

Correct, Kryton.

Footflaps – shame you didn’t continue to exhaustion on those. I’m not talking about ‘top end’ as in functional threshold, I’m talking about top-end as in absolute max burst power.

That’s a good point molgrips 🙂 when you say it like that. I had just hoped that as I trained the point the pain occured would be longer..

You will be going faster at that point though, but if you only ride alone you never notice this and you think you’re not getting anywhere.. until you ride with your mates and leave them standing which is immensely satisfying 🙂

What Jens refers to is an ability to discount mentally the physical message your body is givving you. Physically, its saying “your reaching my limits, please stop before you damage something!”. If you can switch this off mentally there’s a fair bit of tolerance before you physically cant continue.

Again, I THINK.

What’s known as the central governor theory of fatigue.
http://en.wikipedia.org/wiki/Central_governor

My understanding is that the muscle tissues develop lactic acid tolerance. Hence the need to ‘feel the burn’…

Footflaps – shame you didn’t continue to exhaustion on those. I’m not talking about ‘top end’ as in functional threshold, I’m talking about top-end as in absolute max burst power.

Absolute max means very little in terms of cycling performance.
Are you a track sprinter? Unless it is a very short event, aerobic fitness is always key.

Just going back to your original post as well…

because since running I am not breathing particularly hard at any point when cycling, it’s the leg pain that limits me.

Have you tried increasing your running pace or are you consistently running at the same effort over longer distances?

Leg pain in cycling, for me, comes in different forms.
Long threshold intervals @ 100% FTP are uncomfortable by their very nature. As are Vo2 efforts of appx 106%-120%, in much the same way. Its muscle exhaustion that limits how long your can output a set power for. The muscle can only do so much work.

Absolute maximal anaerobic efforts normally leave me unable to physically turn the cranks for a few minutes afterwards. Short 1 mile TT sprints, 1 minute hill climb TT sort of thing.

To me these feel like holding your breath sort of pain, like the muscles are being starved of oxygen, as ultimately they are. But at the end of the day it is still muscle exhaustion, just via a quicker route.

Absolute max means very little in terms of cycling performance.

Hm.. yes.. but 10 or even 30s max can be important in MTBing for those short sharp hills, and in road for sprint finishes (I imagine anyway – not road raced 🙂 )

Have you tried increasing your running pace or are you consistently running at the same effort over longer distances?

Most of my running is intervals, not really interested in anything over 10km.

molgrips – Member

Hm.. yes.. but 10 or even 30s max can be important in MTBing for those short sharp hills, and in road for sprint finishes (I imagine anyway – not road raced )

But they won’t be maximal efforts, even for those durations, or else you will get to the top 2 seconds before the guys riding within themselves who will then cruise off into the distance as you cry at your legs…

Of course the same goes for road racing sprints. You need to be there for it to count so your aerobic ability is still key, but yes being able to produce the big numbers at the death is important. It still won’t be as big a number as you could produce fresh.

Anyway. This is all digression from the original question of whats causing the pain.
Its razor blades.

no idea about maxpower, zones and other stuff but when climbing and sprinting/pushing hard it’s my lungs that do me in before my legs start to give up. Same with running too, legs only start to give me gyp after a long ride/run. WHat’s that down to then? (none smoker BTW presume that would make a difference)

Hm.. yes.. but 10 or even 30s max can be important in MTBing for those short sharp hills

Racing or just social riding?

Not sure of the chemistry involved but Spin classes have massively improved my performance in this area. Not necessarily in the burning sensation – thats just due to how hard your working your muscles and as you get fitter you up the resistance/power so you still get the burn (the burn is good!) – but when i’ve got the burn my ability to still produce good power and continue through the burn for longer has significantly increased. Also the recovery has improved greatly – less of the jelly legs thing after a real hard workout and the ability to keep going after a short rest.

Racing or just social riding

Racing. And I do intend to do some track sprinting when I get to build up the Dolan frame in my garage 🙂

http://velonews.competitor.com/2014/02/training-center/on-the-bike/lactic-acid-myths-debunked_316899

http://velonews.competitor.com/2014/02/training-center/on-the-bike/pointcounterpoint-lactic-acid-debunked_317172

I followed Joe Friels guide for MTB racing. It did seem to work (for me). Although I’ve not raced seriously nor trained since 2007.

http://www.mtbbritain.co.uk/MTB_training_bible.html