Muscular Endurance vs. Aerobic Endurance?
Could someone please explain to me the difference between muscular endurance and aerobic endurance, specifically as it relates to the following observations, if at all:
On a ride, in aero position, holding around 160 watts, I can go all day at around 78-82 RPM's. My HR stays at around 138 bpm. Any time I try to increase my cadence to 90+, I fatigue after about 2 minutes and have to either sit up, lower my cadence, or just coast to recover. Strange thing is that even though I'm fatigued, my HR stays around 135-138. I almost feel after 2 minutes @ 90+ rpm that I've just finished an FTP interval. But my power hasn't gone up, my HR is still low.
Is this what is referred to as muscular endurance vs. aerobic endurance? Do I conclude from above that I have good aerobic fitness but poor muscular endurance? Or is there something else going on? If this is the case, what do I do to develop muscular endurance?
Comments
To confirm, you have power and when you do ^this^ your power does change?
Maybe some smart science-y types can weigh in...
Power stays the same, increase cadence. This requires changing gears which I do.
Seems like Friel and (Training Peaks for that matter) make up a lot of things that may or may not be scientific/physiology-based.
I think there may be some utility in taking something like "fitness" and breaking it into different (largely made up) components to describe how things change as you become more fit. But I think it also clouds the issue and makes people, especially triathletes, think that they have to earn the right to go faster by building some special sauce first, then another special sauce, etc, especially with regards to the bike.
For instance, I can pedal all day at "X-Watts", but after a long time with a continued steady HR, my legs begin to cramp and my quads weaken and I just can't hold the watts anymore. My leg strength is my limiter and I need to work on my "Muscular Endurance". Or said a different way, I have better "Aerobic Endurance" than "Muscular Endurance". [FWIW, this has always been my personal issue with cycling...]
Other people have the opposite problem. They can pedal all day at "X-Watts", but eventually their HR starts to rise (but their legs still feel okay). Eventually their heart feels like it's going to explode out of their chest and that makes them slow down. This person would have greater "Muscular Endurance" than "Aerobic Endurance". These same people often have a hard time lowering their HR at the beginning of the bike after the swim (my own theory anyways with no science behind that).
When most people slow during an IM run, it's because they over-cooked the bike or the early part of their run. Interestingly, if you look at most "average people's" files from either their bike or especially their IM run, you'll see that their HR actually goes down over the course of the run. Their legs simply can't move fast enough to make their HR go up in the last 8 miles of the run (provided it's not overly hot of course as that is a totally different kind of stressor on your Cardiovascular or aerobic system.
It took me 5 IM's and a TON of training to get to the point (mentally and physically) that my Muscular Endurance was high enough relative to my Aerobic Endurance that I could make my HR climb over the last 8 miles of my run. If you look at some of the really fast guys in the Haus (T. Cronk, Al Truscott, Coach P, etc. etc. etc.) they are able to "not slow down" at the end of their IM run as they push their HR higher and higher throughout the day. They have learned the "art" of balancing both their Muscular Endurance and Aerobic Endurance to optimize their energy/speed throughout the course of a long day.
Now to your cadence question, I think that's slightly different. Theoretically, riding at a higher cadence shifts some of the burden to your Aerobic system from your muscular system. Since "most people" (not named Truscott/Cronk/McCrann/etc) are limited by their legs (Muscular System) at the end of the run, it is good practice to save them as long as possible by calling on your Aerobic System to do more of the work on your bike. But your issue is quite acute and happens so quickly, that likely (as Coach Rich points out), you just have to get your body used to it. It should adapt fairly quickly. I had this same issue with running a while back. It was exhausting to run at a high cadence/turnover. But over a couple of months I forced myself to do it and it just became "normal" after a few months. This is way to fast of a time for my "aerobic endurance" to dramatically improve. So I'll chalk it up to my body adapting to a higher turnover.
My advice, do some sets at much higher cadence. Even as high as like 110. work these in and deal with being a bit tired at first. Eventually (think over months) this will just be normal and your results will be better off for it. Or you could just become an absolute MONSTER on the bike like Coach P (or many pro's) for instance and have legs so strong that you can mash at 80 rpm's for 5 hours and still have strong enough legs to crush a 3:10 IM marathon... My guess is it'll be a quicker/easier path to learn to ride at a higher cadence first (then eventually build the monster legs to go along with it...).
Boy, a lot going on in this question. First, I agree with Rich that the categories ME and AE are metaphors to help some folks understand the various components of the energy production system. If you do your training, your entire energy production system improves. It's fun for some of us to delve into what's happening at the cellular level as our physiology improves, but you don;t really need to understand that to improve it. So I'm not gonna go into that difference unless someone says they *really* want to know about it.
On to the observation that inspired Victor to ask his question" "Why am I less able to sustain (say) 160 watts @ 90 rpm than @ 80. Rich again is pointing in the right direction - "You're just not as used to it." Here's my theory on what might be going on. You're a big guy, right Victor? Meaning your legs are a lot heavier than, say mine, @ my 145 lbs. So if we're both slamming 160 watts into our pedals, you are probably "wasting" a lot more energy than I am simply to lift those knees up and down, and spin those feet in circles - they simply weigh more than mine. Each time you do that is an energy drain; the more times you do it in a minute, the more energy you are expending that is not going to move your bike forward.
That's also part of the theory about why East Africans are faster at longer running races: they often have lower limbs, especially from the knee down, which are simply smaller than is common among, say, many Europeans. Smaller calves, less mass to move through each step, less energy "wasted", more energy available for moving forward. As a general rule, no matter what your ethnic/geographic background, the smaller your calves, the faster your running potential, even compared to otherwise similarly sized individuals.
On the plus side, when well-trained, you will be able to generate a LOT more watts than I can, simply because you have more muscle mass than I do.
Is this on a trainer or outside? I've found on the trainer for the same power, a lower cadence seems much easier to me and more sustainable. Outside, my natural cadence comes up without any effort. I think that is pretty common.
Aerobic Endurance = Z2
Muscular Endurance = Z3
My understanding is Aerobic Endurance is higher cadence working the cardiovascular system more , Muscular Endurance would be lower cadence working muscle strength.... Either way , for me it falls into the "try not to think about it too much" camp....I think for racing , low VI RR's , etc our job is to simply find the best sustainable power for the duration , that will produce the least amount of stress (HR) to our body..... I think our bodies are pretty smart ,will naturally default to the correct cadence/HR overtime to find this most efficient power/cadence/HR combination.... Try working with just power displayed (No cadence or HR viewed for entire wko) look at the data later....
Having said that I really like Rachel's comment about task specific adaptations.... For training it makes sense to try to figure out what may be your limiter and work that area.... I also like the theory of working the low end and the high end (of your averages) to trigger different systems and adaptations... IOW if your avg cadence is 80 , some low cadence work at 60-65 and some high cadence work at 100-110..... but not much of either just something to trigger those different systems/muscles...
@Rachel ... interesting comparison on trainer vs. outside.... I'm exactly the opposite having a slower cadence outside than on the trainer.... However most of my trainer rides are in ERG mode where I naturally find a higher cadence on for some reason...
@Al - You make a lot of sense just looking at my anatomy. You are correct, I'm a big guy (but shrinking). Makes sense that spinning a big honkin' leg round and round is going to be more difficult than a little leg. Why do you think the expenditure of that "wasted energy" at a higher RPM is not reflected in my HR. Seems my HR tracks predictably with my watts. I've observed that while I'm fatiguing at higher cadence, my HR is not going up. Maybe if I could hold it through that fatigue and not sit up, slow cadence, or coast, my HR would eventually go up/catch up with the extra wasted effort getting my large legs up.
Along those lines, again being a big (but shrinking) guy, I wonder if the top of my thighs bumping up into my (shrinking) belly also bleeds energy that is wasted every time the opposite foot is pushing down on the pedal. On the recovery side, my leg is in contact with my abdomen at that top of the thigh. Would it be beneficial to do something with my fit while I continue to lose weight? I'm already running 165mm crank arms which I think helps a lot. Wonder if a couple degreed on my stem, bringing my cockpit up just a bit might be worth looking at. I'll say this. I'm feeling better and better on my bike every pound I lose and I'm definitely not going to be this size for much longer. So, maybe I just keep training, keep working on the weight, and let this cadence3, watts, leg size, most efficient power/cadence/HR combination just work itself out, like @Tim says.
I think JWs explanation above is an interesting one. what slows you down? leg strength or cardio issues (the need to catch your breath)
Like @Rich said, I think I just need to do more of what makes me uncomfortable and just train. It'll come.
Thanks again.
I also tend to think of the issue as varying cadence for a given power output. The lower the cadence, the more "muscular" and the higher the cadence, the more "aerobic".
In general I think it is just good cycling skills to be able to generate a given power output over a wide range of cadences. In the end I think most cyclists just self select an optimal cadence and learn to improve power over time at that cadence level.
I've heard that for triathletes it makes sense to have bike cadence similar to run cadence as it makes the transition from one to the other just that much easier. Haven't read anything substantial on it, but it seems reasonable to me.
Science seems to say that there is no real value to low cadence work. See here: http://www.ncbi.nlm.nih.gov/pubmed/24550843
A lot of coaches still seem to prescribe the low cadence stuff. I think some are just going off of Friel's work. Others have told me they have read some of the negative reports, but believe that in the world outside the lab, they really do work.
My last thought on the issue would be to make sure that training work matches racing work on cadence. So don't sit on a trainer at 100 rpm all the time and ride your triathlon at 80 rpm. Practice specificity.
http://trisutto.com/come-in-spinner-the-bike-cadence-debate/
http://trisutto.com/top-gear-the-bike-cadence-debate-continued/
Good blog posts, Tim. Thanks. Lots to consume. Think my biggest takeaway till is just train. Have fun like Sutton says, just figuring out what woks best for you.