Pedal stroke analysis with Powertap advanced metrics

[ed72]

Which really makes sense both anecdotally and from perfusion POV, doesn't it?

Possible. No data and no tools to measure. I believe my limitation in the reclined/bent position is O2 delivery (lung) and possibly really due to insufficient CO2 for transport since CO2 is what is monitoring in the hypothalmus and drives heart rate. I have proven to myself that the time constant of this feedback system is much slower on a bent than on an upright. and other things. Anyway. I need to met a recumbent riding Anesthesiologist but only if he or she is an average athlete from the east coast USA, like me.

https://academic.oup.com/bjaed/article/5/6/207/331369

 

[bladderhead]

I have COPD and I have two recumbent bikes, so all this talk of perfusion and metabolic efficiency does nothing to lift my mood. Unscientific, I know, and on that pedalling efficiency test I would obviously be an outlier, but scraping feels more metabolically efficient to me.

 

[ed72]

I have COPD and I have two recumbent bikes, so all this talk of perfusion and metabolic efficiency does nothing to lift my mood. Unscientific, I know, and on that pedalling efficiency test I would obviously be an outlier, but scraping feels more metabolically efficient to me.

I have asthma. I hideous attack on a 300K recently. I also have a messed up cervical spine with occipital neuralgia.....the double vision and throwing up is lovely.

 

[Balor]

And I am precluded from operating heavy machinery . And huge numb feet with high BB problem.
Anyway, for some unfanthoamble reason my gluts and quads always feel underutilized on a bent, while hamstrings always feel over-utilised. Maybe they are just tight? But I can touch my toes...

Only thing that somewhat changes that that is 'reverse pedalling (though mostly about quads), but that is entire can of worms entirely. I feel I should go with 'upright seat/low bb/reverse pedalling/partial fairing', just need to get me a seat that does not cause recumbutt with upright angle.

 

[ed72]

My glutes and quads take make most of the power. Hamstrings not all that much comparatively.

My hamstrings would get really, really sore when I was following the BROL scraping and pulling circles because we all know bent pedaling is so different and uses different muscles. I still have the same muscles. I put it on my Santa list but got coal. I figure I gave it around 9,000 miles before putting my thinking cap on.

I decided that the recruitment pattern had to be a little different and also recognized getting over the top of the pedal stroke with a back fixed to a seat (bent) adds a degree of complexity. So, I figured that the body would naturally self select the proper firing patterns if I just punished it enough. And I did. Tabatha intervals at 500 watts several times per week. Pulling hard from say 4 o'clock overstressed the hamstrings for sure. Once I got that fixed, there was localized soreness at a certain point in my quads. Moving the body position a little away from the crank a little (not quite overextended) helped but the real help for me was the rotor crank. I am pretty sure shorter cranks with oval rings would have done the same thing (making the knee angle less acute at the top). I do sense a little less glute engagement on the bent compared to the upright, which is one reason I am hoping to get that railgun seat. The glutes should be a huge driver when doing TT type efforts and I do "feel" that the glutes are putting too much burden onto the quads and to me it is because the body is fixed in 2D on a bent whereas the motion is 3D on an upright. I am also hoping that the numb feet will go away (new seat) with better blood flow (external iliac artery, iliopsoas, and inguinal ligamen tolerance stack-up so to speak) due to less hip constrainment.....pulling back hard only makes this worse. I also never used to be able to ride much more than an hour on a bent without numb feet while never having this problem on an upright. I still get it when riding hard especially hilly. My feet were ok aft 200k and 300k two weekends ago. Still working on it. Increased cadence a bit helped, too. Definitely a works in progress.

 

[bladderhead]

the double vision and throwing up is lovely.

I am not drunk. Honest.

 

[bladderhead]

I am glad you liked that post. After I posted it I thought you might be offended. My misplaced irony will be my downfall. Your condition sounds bloody awful. Does it come on suddenly, without warning?

 

[Balor]

My hamstrings would get really, really sore when I was following the BROL scraping and pulling circles because we all know bent pedaling is so different and uses different muscles.

I should note that it might be 'fault' of MBB bents that I have because only way to cruise with minimum arm requirement is 'scraping pedalling' method (for me, at least, I'm inept at leg-steering).
*however*, it was true also on on my RWD... (plus numb feet).

I will pull bars and push hard when climbing/sprinting, but otherwise I mostly scrape.
I presume that is a separate problem related to my 'bracing woes'. For some reason, only people I know (you too) that output similar wattages on bent and df bikes are ridiculously thin.

 

[ed72]

I am glad you liked that post. After I posted it I thought you might be offended. My misplaced irony will be my downfall. Your condition sounds bloody awful. Does it come on suddenly, without warning?

No offense, I thought it was funny.

Usually wakes me up and then I have a rocky period of time. Three days out of seven wasted this week. Visual issues have no rhyme or reason other than associated with general symptoms-I just don't ride or do much other than sit on the couch under those conditions. Kills my training. This partly explains why I spend so much time researching fitness related topics such as how to pedal better or how to eliminate numb feet. Just dreaming of better days so to speak.

 

[ed72]

I should note that it might be 'fault' of MBB bents that I have because only way to cruise with minimum arm requirement is 'scraping pedalling' method (for me, at least, I'm inept at leg-steering).
*however*, it was true also on on my RWD... (plus numb feet).

I will pull bars and push hard when climbing/sprinting, but otherwise I mostly scrape.
I presume that is a separate problem related to my 'bracing woes'. For some reason, only people I know (you too) that output similar wattages on bent and df bikes are ridiculously thin.

I don't for sure have the answers but the seat to rider interface in conjunction with pedaling technique and crank length seem to get short shrift. Bilateral foot numbness is fairly common with recumbent bikes. A randonneuring buddy just converted to recumbents and he gets severe bilateral foot numbness despite never having foot numbness on uprights and this is a fellow who would ride 300-400 miles nonstop. I believe the problem is vascular. Specifically, hard pulling and scraping from 3:30 or 4 o'clock ish and downwards thru and around the deadspot. The Psoas is supporting part of the body weight when pedaling thusly and I suspect this affects blood flow of the external iliac artery. It is not a natural motion. I only pull, scrap, and bridge if I need a lot of power on hills or when a pitbull in Florida is chasing me.
I have other theories, too.

Quote from link

• reducing psoas hypertrophy by not pulling up on the pedals

http://www.medicineofcycling.com/blog/research-review-endofibrosis-of-the-iliac-arteries/

 

[Balor]

Nae, that's unlikely related to pedal-pulling (much), more due to extreme hip/trunk angle (closed position). We bentriders surely have THAT covered!

 

[ed72]

Balor, you could be right. I know in my case that it has nothing to do with pedals or tight shoes. The foot numbness riding a bent is a completely different feel than the Morton's Neuroma associated with ill fitting shoes. I used to get so-called hot foot on very long rides especially if I overhydrated. I went to wider and bigger shoes and midsole cleat. Problem solved. I have tried to duplicate bent numb feet by sitting with legs elevated but not been able to duplicate; thus, my thinking compression of vascular structures either in sacrum or hip area. Why else would railgun customers report higher power figures when lowering the seat, I assume/hope it is due to better blood flow to the legs.

You could also be wrong. Bridging the sacrum and hips anterior while pulling the psoas muscle (scaping) could compress the exterior iliac artery in some people. Constant use of the psoas would make it larger, which would put force anteriorly onto the iliac artery.

I don't scrap.

 

[Balor]

Numb feet is compound problem. It is blood pressure first and foremost, but other things can exacerbate it and cause it to be better or worse.
For instance, did you apply enough pressure to your feet to emulate pressure from your soles (due to pedalling) in your experiment?
I sometimes get numb HANDS when I do hard intervals and pull on the bars, for instance.

Given that in my case blood pressure in legs is nearly 100 mmhg higher when sitting compared to supine, it makes sense that equal pressure on your nerves/vessels in your feet when would preclude proper circulation in supine position but not when sitting down.
So, it makes sense why midfoot and looser shoes would help too.
Midfoot, by greatly reducing passive calf load, might help in more ways than one too.

 

[ed72]

Pressure to the soles of my feet do not cause Morton's Neuroma aka hot foot ever since I went midsole cleat and upsized my shoes to an extra wide carbon sole BUT...I do not have hot foot on a bent. Separate problem. I did have hot foot once in a while as an upright rider. After the shoe change, I was able to climb out of the saddle for many hours in a day in all sort of temperatures. So-called hot foot is due to pinching of the nerve in the metatarsal area. As an aside, swollen feet can cause hot foot due to excessive....never mind. I am a connoisseur of neurological pain, a sort of "amateur". Hot foot due to tight shoes is not what I now feel. Bent feet numbness feels quite different to me. However, I do agree with you that it is blood pressure related and the ischemia effects the nerves more broadly throuout the feet and the sensation is not the same as hot foot. It is more of a pins and needles feeling over the entire foot rather than an intense burning sensation that is more localized.

I have spent countless hours reading and trying to find a solution and all the usual advice is thrown out but the OP never comes back and says, "yep, them sandals or those pedals or those new shoes got ride of the problem" and to be frank, I don't remember anyone ever saying that they found a concrete solution to numb feet on a bent.

A better test would probably be to torture myself on the trainer for hours. Raise the front end 10-12 inches. Lower the front end 10-12 inches.

Like I said, my numbness has gotten much better but certainly not perfect. I can live with it. I don't know whether I can do a 600k or 1200K nonstop but I hope to find out. Not too long ago, I would have to stop sooner than 2 hours on the bike before I changed my pedaling technique (not to forget the RS4X crank) and I am certain scraping is pure hogwash in addition to the likelihood of being the proximal cause of my formerly more concerning foot problems.

 

[Balor]

Hmm. I indeed got severe 'hot foot' on DF on 400+ km brevets, but I also have varus and very flat feet.

I found a concrete solution that works for ME - BB not higher than 7 cm above seat (and even than I got mild spells of foot numbness when lots of climbing were involved).
20+ cm? Numb foot onset in about an hour. Nearly 30? Half hour (even on pancake flat ground).

12cm? 2-3 hours, relieved when you take a break for a while, so does not bother than much, but still annoying. Again, worse when climbing.

And in my case it it is 'somewhat' combined with 'hot-foot'-like symptoms, but helped (a bit) by cleat wedges and moving cleats as far back as possible (which is quite far on shimano autumn/winter boots). And yea, none of this is really needed on DF, though I don't ride it much and far anymore... maybe things got worse since than, because even walking is harder now.

 

[paco1961]

Never experienced a second of foot numbness or hot foot over years of DF riding. When I started on the CB I noticed some foot tingling or numbness. Moved cleats back as far as possible (Shimano 2-bolt Standard SPD set up) which solved 98% of the problem.

As for scraping ... and any other pedaling technique, I’ve learned a few valuable things over the years. One is that one’s natural position/motion is usually close to best for your particular anatomy. After much experimentation on DF, determined that no amount of ankeling or any other pedaling shenanigan resulted in anything other than reduced efficiency. The only improvement was to bump up my cadence by about 10%. On the CB I found scraping to be a bad option. We are all different in anatomy so one size definitely doesn’t fit all.

 

[telephd]

Possible. No data and no tools to measure. I believe my limitation in the reclined/bent position is O2 delivery (lung) and possibly really due to insufficient CO2 for transport since CO2 is what is monitoring in the hypothalmus and drives heart rate. I have proven to myself that the time constant of this feedback system is much slower on a bent than on an upright. and other things. Anyway. I need to met a recumbent riding Anesthesiologist but only if he or she is an average athlete from the east coast USA, like me.

https://academic.oup.com/bjaed/article/5/6/207/331369

Ed, I carefully read the article in the link you posted to see where you got your thoughts on respiratory physiology. I found the authors mentioned nothing about your O2/CO2 transport ideas. I really don't want to contribute more to the thread drift but I thought Id add my $0.02 since I see it so often misrepresented on this and other forums. The hypothalamus is only very minimally involved in regulating respiration and then (minimally) under the influence of the sympathetic nervous system. Respiration is predominantly controlled in the brain stem via the respiratory control areas of the Pons and the Medulla Oblongata. The Medulla is also responsible for regulating ( increasing or decreasing) heart rate and blood pressure too. CO2 concentration, not O2 concentration, plays the major role in governing respiratory rate through the chemistry that involves changes in pH, detected by receptors in the aorta and carotid arteries, that are the result of the reactions outlined in the paper you linked. If you have further interest this link explains respiratory control in greater detail:

https://courses.lumenlearning.com/boundless-ap/chapter/respiration-control/

 

[ed72]

Ed, I carefully read the article in the link you posted to see where you got your thoughts on respiratory physiology. I found the authors mentioned nothing about your O2/CO2 transport ideas. I really don't want to contribute more to the thread drift but I thought Id add my $0.02 since I see it so often misrepresented on this and other forums. The hypothalamus is only very minimally involved in regulating respiration and then (minimally) under the influence of the sympathetic nervous system. Respiration is predominantly controlled in the brain stem via the respiratory control areas of the Pons and the Medulla Oblongata. The Medulla is also responsible for regulating ( increasing or decreasing) heart rate and blood pressure too. CO2 concentration, not O2 concentration, plays the major role in governing respiratory rate through the chemistry that involves changes in pH, detected by receptors in the aorta and carotid arteries, that are the result of the reactions outlined in the paper you linked. If you have further interest this link explains respiratory control in greater detail:

https://courses.lumenlearning.com/boundless-ap/chapter/respiration-control/

Thanks, I am trying to learn how to best pedal on a recumbent while maximizing comfort and power.

It has not been easy and indeed, there is a lot of misinformation out there. . My point was not precise but it was simply that HR is controlled centrally monitoring CO2, which we are both saying. I have observed a number of differences between DF and recumbent cycling that has helped. For instance, the warm on a bent takes longer before a truly hard effort can be made and this perplexed me for a very long time-it is explained in the attached paper. I don't recall ever reading this from a fellow bent rider. Not just a warm up, by easing into a hard effort compared to an upright. The O2 delivery dynamics are different.....somehow. It isn't entirely clear to me whether delivery of O2 is my limitation compared to DF or uptake into the working muscles due to pressure differentials from supine to upright or due to exchange differentials within the lungs....or the seat itself. I do know that more conscious control of breathing helps and to not hyperventilate,which seems very much more easy to do on a bent. Pedaling technique and cadence are the only easy variables to control. I do not understand why but it also appears that higher cadence (compared to my naturally selected cadence) helps in terms of raising aerobic and possibly reduction of foot numbness but not 100% on the numbness. Helps venous return? I have noticed from youtube videos that the more powerful bent riders seem to have an unusually high cadence compared to similar output DF rider but then again, they pedal shorter cranks.

You indicated that you do not wish to contribute further to the thread drift, but to be honest, what contribution did you make other than to indicate CO2 monitoring in the brain stem and HR regulation is more complex than my simple sentence about it.

The OP got the single best advice from Larry. His knee is too acutely bent at the top. Shorter cranks, slight boom adjustment maybe, QXL rings, etc. could help. He didn't even say what problem he was trying to solve other than applying power earlier and "any thoughts". However, I am quite certain his quest to perfect circles is misguided. I did not post what percentage of power that I gained by getting it over the top easier but it was significant. A shorter crank with QXL rings might do it for OP. I used the Rotor RS4X. On a training climb that I do, my previous best was around 12 minutes and with just the crank, I was down about 90 seconds and my power across the entire PD curve was up very significantly. Thus, I would encourage the OP to follow Larry's advice and there is not much more to say to him on the topic of static pedal positions. OTOH, there is a lot to discuss on the dynamics of pedaling and sorry you consider that off topic.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827567/

 

[ed72]

Hmm. I indeed got severe 'hot foot' on DF on 400+ km brevets, but I also have varus and very flat feet.

I found a concrete solution that works for ME - BB not higher than 7 cm above seat (and even than I got mild spells of foot numbness when lots of climbing were involved).
20+ cm? Numb foot onset in about an hour. Nearly 30? Half hour (even on pancake flat ground).

12cm? 2-3 hours, relieved when you take a break for a while, so does not bother than much, but still annoying. Again, worse when climbing.

And in my case it it is 'somewhat' combined with 'hot-foot'-like symptoms, but helped (a bit) by cleat wedges and moving cleats as far back as possible (which is quite far on shimano autumn/winter boots). And yea, none of this is really needed on DF, though I don't ride it much and far anymore... maybe things got worse since than, because even walking is harder now.

Have you tried increased cadence?

I have been playing around there increasing it. Not sure if it is helping or not but I have been consciously increasing mine. I read a few things indicating it might help but internal efficiency is inversely related to cadence so there might be a tradeoff there.

My buddy is about to give up riding due to the numbness. He is young and healthy. I wonder how prevalent foot numbness is on bents. If it really is just the height of the feet above the seat (not angle....height drop), why don't the seats have an easy way to raise or lower (not angle....height differential to the feet).

https://www.ncbi.nlm.nih.gov/pubmed/8775571

 

[Balor]

I read a few things indicating it might help but internal efficiency is inversely related to cadence so there might be a tradeoff there.

Not unlike scraping and pulling
Still, if it does not work for you - than it does not to be sure. But every biomechanical model is a complex system of tradeoffs.

But a drastic change in model like going recument might shift the balance one way or an other. It would take a highly trained sports scientist (with a battery of tests performed on you) to predict what goes where on first princeples, so for us lesser mortals it bodes well just to keep an open mind and adhere to strict scientific standards when analysing evidence.