Carbonfiberboy 

I always thought there was something to this, then ran across this study:
https://www.academia.edu/69727748/Mu...ength_capacity

From this study, it seems as though the stronger the rider, the more they spread their pedal force over a larger arc. Thus at the same power as a weaker rider, their maximum pedal force is lower. IME that increases endurance. BTW, studies which equate endurance performance with 20k-40k time trial times are not looking at what some of us call endurance. I associate "endurance" with double imperial centuries and up. Even a double metric is not much of an endurance test - from my experience with same..

I've noticed that if I begin to press the ball of my foot against the shoe sole before TDC and then contact the heel cup of my shoe before BDC, at the same force and cadence, my power goes up, duh. Or reduce force and get the same power. I've been strength training for decades and it's worked. It's not about maximum pedal force for me, rather it's about minimum pedal force. And of course strength training helped my sprint, most noticeably my hill sprints. That was just for fun, but I think the ability to push hard through more of the pedal stroke at hill climbing cadence makes one faster.

The thing left unexplored in the study is "Why?" Why would strength training have this effect? One would think that one would simply stomp harder on the pedals, maybe have a reduction in arc.

Hermes

MoAlpha What do you think of Academia.EDU? They want an email to register. It is unclear how much vetting of papers occur and their overarching goal is that research should be free.

chaadster

Is that what it said? I didn't read it really closely and perhaps missed the discussion about application of torque throughout the stroke, but it does say\:

Therefore in stronger cyclists force applied on the pedals at low cadence
corresponds to a lower percentage of the maximum strength capacity allowing them to recruit
more type I fiber more economically; on the opposite, weaker cyclists need to increase pedal
rate to decrease the force applied on the pedals. Thus in stronger cyclists at submaximal
intensities we can hypothesize that an increase in energy cost with pedal cadence is mainly
related to the increase in internal work or ventilation whereas in weaker cyclists the relationship
between cadence and energy cost results from both optimal force applied on the pedals and
internal or ventilation work.

So yeah there's efficiency in strength, but provided the effort is submaximal and a lower proportion of total power capacity.

terrymorse 

In case you don't want to get an account at academia.edu to read that paper, here's a free PDF, courtesy of sci-hub:

https://sci-hub.ru/https://doi.org/1...in.2006.07.007

Carbonfiberboy 

I evidently didn't read it closely enough: I thought the earlier the burst started, the longer it would last. Oh well. I was just out on my rollers again, paying closer attention to burst duration. My VL and BF burst starts very early, maybe at TDC or close to it and short as described, but my RF burst is very long, about from where the VL and BF ends until past BDC and thus reduces burst levels on the quads. Too bad they didn't include the semitendinosus, as mine is larger and seems to be more active then my RF.

Your quoted paragraph certainly explains why strength training increases endurance on long rides or events, regardless of what's firing when.

Ric Stern

Previous research (Coyle et al 1991) used force instrumented pedals and they showed that better cyclists (national/international) stomped down more and pulled up less compared to less good cyclists (regional/county/state -- i'm not sure of the exact terminology).
your endurance (whether that's an event that is >90-secs - yes seconds, or one that is some sort of ultra endurance event lasting multiple hours to days) is affected by a variety of factors, which include in no particular order:
*FTP
*VO2max
*psychological factors
*nutrition
*training status
*etc

If you take an event such as The Transcontinental Race (an extreme ultra event taking the winner around 10 days or so) a large ability to do well is simply related to their FTP. This is also apparent for really short endurance events (e.g. anything from about 90-secs onwards). For most athletes once an exercise lasts for 90-secs or more it's primarily fuelled by your aerobic system such that by the time you're exercising maximally for 4-mins about 80% of the energy is derived aerobically.

So, on average, if you took two cyclists who weighed the same, and one athlete had an FTP that was say 4 W/kg and the other had 6 W/kg then the 6 W/kg athlete will be significantly better from 90-secs thru to multiple days. (This is on average, you WILL find examples that disagree with that). On the other hand two cyclists of the same mass with 4.0 and 4.1 W/kg it's anyone's guess who would be better at a variety. of different durations. Fatigue (and thus endurance) is multifactorial.

Note, that i've ignored differences in CdA for these illustrative purposes.

PeteHski

I found this article very useful in relation to pedalling technique and it’s associated myths and folklore.

https://www.cyclefit.co.uk/journal/c...ling-technique

1. don’t overthink it
2. don’t pull up!

Ric Stern

exactly my points (see the Coyle paper). I can't recall if Jeff was involved in the study or not (i don't have the paper to hand), but JB has produced some great stuff

PeteHski

👍
I really liked your post and how endurance really hinges on a few simple parameters. For me endurance events are usually tough mountainous Gran Fondos and my performance largely depends on my basic power metrics (FTP, VO2 max power) and how well conditioned my gut is for carb processing while riding hard for 4-10 hours.

Pedalling technique doesn’t really figure in my book. The only thing I do is try to maintain a reasonably high cadence as I do have a tendency to let my cadence drop off if I don’t concentrate. In training I sometimes ride 5-10 rpm higher than my natural cadence just to reinforce my muscle memory. I find that it makes my normal cadence feel easier straight afterward. I also train at low cadence for steep climbs. This is the only time that I feel maximal leg strength may have some influence on my pedalling and endurance. Cranking up a long 20% slope does start to feel like gym work, but I’m still always limited by the engine rather than the legs! I always end up hitting my HR limiter well before my legs are physically incapable of turning over the cranks.

Ric Stern

It's worth understanding that a higher rather than a lower cadence is less efficient at a given power output, and that training at low cadence (for steep hills) is *ineffective* for building strength. This is because even though it may feel like you are strength limited at low cadence, you're not (presuming you're able bodied). For eg at 400 W at 50 revs/min on 172.5 mm cranks your average effective force is 443 N between both legs, which is about 45 kg (about 100 lb). It's highly likely that your weight is much more than this and you can e.g. stand on one leg, or walk upstairs unaided. Presuming your pedalling is roughly equally shared between each leg, then the average effective force is 22.5 kg for each leg, with a peak force about 1.9 times higher than the average force (i.e., about 43 kg per leg). of course, if you're unable to sustain 400 W and you ride at a lower power then the average effective force would be reduced (eg at 300 W it's about 330 N, at 200 W about 220 N all at 50 revs/min). Conversely, if you can ride at 60 revs/min instead of 50, then your AEPF at 400 W would decrease to ~ 370 N, etc.

If you want to increase your leg strength (and you should want to - both for health and performance) then strength exercises in the gym are the way forward.

Unless there's something wrong with your heart, then your HR doesn't limit your legs. It may seem that way, but HR is a dependent variable, while power is the independent variable. HR is only part of the equation - there are changes that occur in cardiac output due to changes in stroke volume. Of course, as your exercise intensity increases, and your HR increases there's a multitude of physiological issues going on which cause fatigue in many ways. These are significantly harder to measure than either HR or power and for most of us the only physiological metric we can see is HR and so we often feel that it's that causing the fatigue/slowing down/drop off in performance etc

PeteHski

Very interesting thanks. I see HR as the red flag when I'm pushing hard, whether on a hill or flat. Once I go over FTP my HR starts to creep up until it eventually maxes out (which happens quicker the further above FTP I ride) and then I'm forced to back off and recover a little. Once my HR starts to come down I can start to push on again, but usually at a reduced power level. If I'm fatigued toward the end of a long ride, my HR stays lower but I find myself power limited.

For example yesterday I did a Zwift ride ending with a full gas climb up Leith Hill. I went hard up the first steep pitch at around 400W and my HR climbed from 165-192 (my max) over 0.5 km. At that point I backed off a little to around 350W (I wasn't watching my HR, it was just instinctive) and my HR came back down to 175. Then I pushed again at 400W and my HR went back up, but this time peaked at 185 before I felt the need to back off again. My HR then went back down to 175. Then on the last steep section I went again, but this time I was struggling to hold 300W while my HR again hit 192 and then I had to back right off for a few seconds before one last push over the crest at 400W which left me gasping for breath on the limiter.

I realise it is the power level driving my increase in HR, but it's my HR that I feel sets my power limit (in terms of duration at a given power) in these situations. At least while I am not overly fatigued. When I am very fatigued my HR response becomes much less dynamic and my available power range shrinks!

Ric Stern

I understand what you're saying, it feels like that for everyone (including me). As i approach some sort of max (in this case it sounds like you're just above VO2max or MAP) you can feel the blood pulsating through your ears and it may feel like your heart's about to pop out of your chest, etc. And, yes, you're right it's likely that once you try sustaining efforts above FTP (this is called FRC or W') your HR is likely going to ramp up at a faster rate. As you ease off your HR will decrease (unless there's something wrong your heart). The fatigue you (everyone) feels is multifactorial, some of which haven't been fully elucidated, but vary from increases in H+ ions to psychological issues of how much pain we can tolerate (e.g. for me, in a virtual event i'm not that bothered about hurting myself so will ease up sooner, in a real world road race i'm giving it everything until my legs blow off) to fuelling, pre-existing fatigue, etc.

if you're wanting to have more power at MAP, there's a variety of training you can do to increase it. whether you want to be doing lots of it now may depend on when your main events are (as specifically hitting MAP training hard can't be done for too long, too extensively).

Alan K

For some reason, the above sci-hub link does not load on my iPad… just so you know, but it’s not very important.

terrymorse 

Thanks. I tried it on my iPad. The page opens fine, but the PDF won't scroll. Works ok in MacOS Safari.

PeteHski

Yes, I was above MAP on that particular climb so I knew I couldn’t sustain it for very long. I did a much longer simulated climb at the weekend (Alpe du Zwift) and was riding steady at around sweet spot and FTP for the steepest ramps, so my HR was relatively stable. In that case I felt more limited by leg muscle fatigue than cardio. Toward the end of the climb I was starting to feel it a bit in the legs, while my HR was holding steady.

it is interesting what you said about psychological factors. I too will generally tolerate a lot more suffering during an outdoor event, especially if it’s a key target event.

The only specific MAP training I have done is focused intervals (mostly when using Sufferfest/SYSTM plans). But I haven’t done those for a while and only in the lead up to key events. At the moment I’m just doing a variety of Zwift rides and events of various intensity and duration. Nothing structured. But I do track my overall TSS.

Ric Stern

if you're 'old' (e.g. >40) then you probably should be doing year round MAP efforts...

PeteHski

I’m 56, so definitely in the “old” category. I do MAP efforts on a weekly basis, but this winter I have moved away from structured workouts. So I’m relying on hard Zwift rides/races for my MAP efforts and everything else actually!

So I might do a couple of hard Zwift rides with some decent MAP efforts (I find the Surrey Hills climbs are good for that) along with other less intense rides and at least one longer endurance ride. Only around 5-8 hours total per week at the moment.

My fitness is pretty consistent on this more casual regime, but I’m a fair way off my peak when I’ve followed a more structured plan for several months.

Carbonfiberboy 

IME, well countless hours experimenting with decreasing leg fatigue on long rides, I've found that the diagram at the top of that link is totally wrong.

1) Pushing down at the bottom of the pedal stroke is a complete waste of energy and causes bouncing in the saddle at high rpms. Your pedal force should always be tangent to the pedal circle. No wasted energy. It should be possible for one to pedal at 150 rpm without bouncing. A good test of this is to pedal for say 45' on a trainer at 120 rpm, in a very small gear while staying in HR zone 2. I could do this in my late 50s and early 60s. It's a great frustration that I can't anymore. The trick is to pedal while staying in contract with the shoe uppers. This is where those who put in some time riding fixed or SS acquire some good skills.

2) Leaving weight on the pedal during the backstroke means you have to push harder on the downstroke. Any time one has to use more force to propel the bike than is absolutely necessary causes more fatigue than is absolutely necessary. That said, one's hip flexors are much smaller than one's leg muscles and will stay that way no matter how hard one trains them. Asking them to lift the weight of one's leg is definitely their limit for long rides. One hears about long distance riders getting exhausted and starting to pedal squares. This is simply a lack of training discipline, i.e. thinking it doesn't matter how one pedals.

3) Weight training works because the cyclist then uses a smaller percentage of total available muscle force which in turn means that one gets to use a higher percentage of endurance fibers. Putting as little force as possible through as much of the pedal circle as possible, consistent with creating the desired power, also uses a smaller percentage of available fibers and thus increases endurance.

4} One only need implement #3 to the extent that one attains one's desired level of endurance.

5) The reason that low cadence, high effort seated intervals work is not because they increase measurable muscle strength. That's the usual red herring. Rather it's because doing them teaches one's nervous system how to keep pedal force tangent to the circle. One tries to pedal with no upper body motion whatsoever, no prying on the bars, legs only, 3-4 X 10', 50-55 cadence, Z3, though some pros did them in Z4.

6) Pedaling as above for endurance increases the number of muscles involved in said pedaling. That decreases the percentage of fiber used in each muscle.

PeteHski

That diagram that you say is totally wrong is from a very well regarded source (Dr. Jeff Broker, who tested over a hundred elite and pro cyclists and developed the power, force model it represents. Subsequent studies and countless data from power meter pedals etc have supported his model and therefore it is still often cited today as a reference.

The light negative force on the upstroke due to leg weight appears to be inevitable when pedalling at a normal cadence under significant power. I think studies have shown that pro cyclists tend to be slightly better at minimising this negative force on the upstroke, but none of them pull up or pedal “circles”.

Here is another article that includes this diagram and has links to other similar studies and data.

Note: In reference to your statement that “your pedal force should always be tangential to the pedal circle” I would suggest you take a reality check at the actual pedal force vectors, which are far from tangential except for around the 3 o’clock position.

https://bythlon-pedal.myshopify.com/...the-upstroke-2

Carbonfiberboy 

Simple inspection contradicts the usefulness of the vectors shown in the diagram in your link. Really?? At 180° one's radial force should be almost as great as one's tangential force at 90°? Again, really? There's no way anyone can pedal like that and not bounce in their saddle even at moderate cadences.

I didn't acquire my pedaling technique by reading. I experimented over the years with various force application schemes, using toe clips as a teen and clipless as an adult. There's no way one can do as I suggest using flat pedals. In considering what I'm advocating, this is strictly to increase endurance while seated. It's not for developing maximum short term power or riding OOS. I have found that in hill sprints at max power a relatively low cadence, say 75, and max effort on the downstroke and upstroke combined will produce the most power, though in conventional flat sprinting, the downstroke is everything, and one will be producing at lot of radial force at the bottom. It's not my purpose here to discuss those instances or anything beyond endurance cycling.

As I said, I didn't get my technique from books or websites but rather through paying close attention on the road and on my rollers. I still remember the sensation when I first pedaled three consecutive smooth and effortless pedal strokes. Simply googling this string: "force tangent to the pedal circle feedback" produced the following links which I believe make my case for me:

https://pubmed.ncbi.nlm.nih.gov/21507064/
https://ojs.ub.uni-konstanz.de/cpa/article/view/966/880
https://www.garmin.com/en-US/blog/fi...-train-for-it/
https://join.cc/cycling-tips/what-is...-you-train-it/
https://www.roadbikerider.com/efficient-pedal-stroke/
https://www.frontiersin.org/articles...22.958827/full
https://core.ac.uk/download/pdf/41530915.pdf

and there are many more in this vein. I suppose it's possible that being a competitive Alpine and Nordic skier developed my hamstrings and hip flexors to such an extent that I could easily employ the techniques of pedaling tangent to the circle and saw the potential the first time I got on a bike with rat traps and toe clips. Suddenly I was turbine-powered and felt like I could almost do power wheelies.

Note that I never said one should pull up on the upstroke during endurance cycling, only unweight the pedal. During hill sprints however, one should pull up so hard that one is on the edge of the rear wheel losing traction.

IME a proficient endurance cyclist should be able to pedal one legged on the trainer for 2 minutes with each leg at an 80 cadence while keeping the chain tight and also pedal seated at a 120 cadence for 45' without bouncing. Those two drills prove that one can unweight the upstroke pedal and pedal tangent to the circle. Those drills are not that hard but they do take practice and they do improve my performance on long climbs. I used to do them every year starting about Jan. 1 on alternate Tuesdays and continuing to April 1, when I'd start doing low cadence hill repeats once a week.

PeteHski

Have a read of this paper discussing the relationship between tangential and radial pedal forces:-

https://journals.physiology.org/doi/...iol.00733.2021

It's quite technical, but the highlights are Figures 4 and 5 showing what happens when you restrict radial forces in an effort to improve efficiency.

Conclusion

"Using an optimal control model of a cyclist, we showed and explained that the radial pedal forces that occur during cycling are unavoidable when maximizing average mechanical power output during a full cycle. It is true that the “ineffective” radial pedal forces do not contribute to the power delivered by the cyclist to the crank. However, the idea that avoiding these radial pedal forces will lead to more efficient pedaling is incorrect. In fact, the opposite is true: avoiding radial pedal forces causes ineffective use of muscles that not only leads to a decrease in maximal AMPO in sprint cycling, but also to a decrease in pedaling efficiency."


Here are typical examples of actual vector force plots from a power meter

Cyclo-Sphere ? Analytical Cyclist
https://edsasslercoaching.com/thoughts/actual-testing/


"I learned a long time ago that what your body is telling you isn’t what’s really happening, so I started actually testing."

PeteHski

Another earlier study with the same conclusion regarding tangential and radial forces related to power and efficiency.

https://www.researchgate.net/figure/...fig4_245480810

They all show the same thing i.e. that tangential pedal forces are not very large away from the 90 degree position and that significant radial forces are an integral part of the pedal stroke and attempting to reduce them is not a good idea - even if it sounds intuitive.

PeteHski

Shimano's force vector plot:-

https://bike.shimano.com/en-EU/techn.../function.html

They all look just like the original Broker vector force diagram, which has never really been in dispute.

PeteHski

To quote Andrew Coggan from this forum exchange (from 2007)

https://forum.slowtwitch.com/forum/S...ling_P1169680/


"If pedaling style is so important, why has no one ever been able to show it? That is, no study has ever shown a correlation between the pattern of force application and efficiency, nor has any study ever demonstrated that, as group, more efficient cyclists pedal differently than less efficient cyclists. OTOH, numerous studies have demonstrated a correlation between fiber type and efficiency, despite the significant variability involved in quantifying the former. "

Carbonfiberboy 

Yes, testing is good. One doesn't need any equipment to test. Just pedal 150. I already said that hard efforts will unavoidably create radial forces. One of the first things one learns when starting to ride brevets is that one does not get out of the saddle and hammer up the little risers like one usually does. Instead, one gears down and spins up. Just let those other folks go, you'll see them again later. As they say in the long distance forum, a century is not a long ride. That said, one will always profit even on a 60 mile ride by reducing radial forces as much as is convenient. One TTs any longish ride by riding moderate on the flats and hard on the hills. The ability to reduce radial forces is just a tool, and a very good tool to have in one's toolbox. I do stiff-legged deadlifts and a back machine to strengthen my hamstrings, the Roman chair for my hip flexors.

What makes it interesting is that humans are built to exploit ground reaction forces during locomotion. We have millions of years of evolution and decades of daily experience with that built into us. But bicycles are a whole 'nother story. A bicycle is a machine for extracting the maximum amount of energy possible from the human body. It's not natural. Riding efficiently requires a lot of synapse retraining, and not everyone wants to bother with that. Note the many threads about foot retention vs. flats. But if one wants to improve their endurance, trying to reduce radial forces is a good start and strength training will help with that.