Your Optimal Cadence & HR

[RojoRacing]

After an hour spinning at 200w watching youtube I thought I'd do a little test. So I'd be averaging about 126HR for the first hour after it got warmed up and stable, my cadence was 80 for that portion which is my natural endurance cadence without looking. From there I dropped it to 70rpm for 3 mins and each 3 mins I would add 5 rpm till I got to 107 which was more like a sloppy 110 which is as fast as I can and still be smooth on 170mm cranks. Each person is going to have different results and each different crank length with produce an average window of results for people with shorter cranks with a window in the higher range.

After I got up to 107 I dropped back to whatever felt natural which ended up being 83, I little higher than earlier because I just got done with such a high cadence. Each step up in cadence brings with it an elevated HR step as well and after returning to a natural cadence it took 50 seconds to recover to a stable 135bpm, and then an avg of 133 for the next 3 minutes. I should mention 70 in erg gives the pedals a heavy feel with it being obvious where the power stroke of the rotation was. 75 was a quite a bit smoother, 80 smoother yet and 85 feeling like the best balance of a light pedal and balanced leg momentum. Getting up to 90 the pedals start feeling very light and I start to notice the weight of my legs, 95 less pedal weight and more leg weight, 100 even more so and at 110 I barely feel the pedals and it almost all leg control. 110 is just my max sustainable, I can spin up to 140 if I'm ramping up.

The first picture shows all the ramps as well as the 4 minutes of recovery at the end. What does this teach me? Well, not a whole lot I didn't already know from past experience but at a certain power you're going to have an optimal cadence for the lowest load on your HR which I'd think is good for endurance. That optimal cadence with change with crank length, rider, and effort and in % of FTP.

 

[RojoRacing]

It would be interesting to run the same test but in reverse and then with different crank lengths with the same rider, I'll leave that up to larry. Larry would have to do the test at about 175w to compare.

 

[xtalbike]

This is super interesting. Would you be willing to repeat the experiment on a DF? I'm wondering if some of the power loss that most recumbent riders experience relative to their power on an upright is due to the cost of raising and lowering the weight of their lower legs against the lever of having that weight out in front instead of directly underneath the power generating muscles. I've read that you don't experience this loss but maybe that's partly because your preferred cadence is on the low side so the effect is smaller. Fewer raising and lowering cycles per second, cadence, has less cost in terms of joules per second, watts. Prediction would be that increasing cadence on the DF at constant power has less effect on heart rate.

 

[RojoRacing]

I can’t perform such a test because I don’t lose power on a bent vs DF. Plus I’m too lazy to swap my trainers axel to accommodate my DF bike. Also my cadence isn’t on the low side, it’s a perfectly average cadence compared to just about every DF rider out there. It only seem low in the bent world because everyone keeps tossing on shorts cranks and then wondering why they loose leverage/power compared too their old DF bike with normal cranks.

there’s plenty of seat support on my V20 to support 1000+ watts sprints so having my body weight directly above the cranks isn’t going to matter. In fact the DF bike requires me to hold my body down into the cranks via the handlebars which is not in line with my crank and hips so it requires extra core muscle usage and could be considered a disadvantage although IMO an irrelevant one.

 

[xtalbike]

The test I was proposing doesn't address whether you lose power or not. It asks whether there's a difference in the relationship between heart rate and cadence on a DF vs a bent. I agree it's a pain to switch out bikes on the trainer when your bent is a Cruzbike. Since I have a RWD bent that I don't ride outside (because I always end up on the Cruzbikes) I might try this comparison myself.

 

[RojoRacing]

Ah then I miss understood your question. I don’t see that being the case since leg orientation doesn’t effect anything it seems.

 

[3bs]

this is interesting to me because the numbers are so close to where i pedal and my heart rate out on the bike, not a on trainer.

my natural comfort cadence is 82-84 which drives an average HR around 133-136 this is zone 2 for me.
i have been paying with lowering the cadence to a 75-80 range, for the same speed (click up a gear) but the pedals feel sluggish to me as well, but my HR also seems to actually click up closer to 140. i am not in great shape, and i have some lung issues, but i am not in horrible shape.

i ride a lot with a guy who is about 10 years younger than me and in great shape, and his numbers are all within a few ticks of mine.

and these are within a few ticks except the most important number wattage. for the same heart rate and cadence i am averaging around 160 watts.

 

[Andrew Wilson]

I found this very interesting also and that very day I went out and tried to hold 200w on flat roads just to see where my 61 y/o HR would be.
My comfortable cadence is around 75 -80. and 200w puts me around 135 -140 BPM.
And I run 170 cranks