Rpms on the bike

Triathlon Forum
1

Lower rpms are more “efficient” as far as power produced per calorie burned. This is pretty obvious since human muscle is SO inefficient…so much energy is wasted on each contraction, it makes sense that decreasing the number of wasteful contractions each minute is more “efficient”.

But, the trick is to find where “efficiency” and available muscle glycogen consumption rates best meet the criteria of the individual’s physiology and the race distance/speed at hand. If you can store glycogen and spare your glycogen by having a lower burn rate/kg better than I, it seems to me that you could race at a lower rpm than I. Or, if your muscles were better vascularized, thereby sparing glycogen by being able to utilize blood glucose better than I, you could race at a lower rpm. Or, if you are lighter, going uphill you could race at lower rpms than I, because I have to burn more glycogen/kg to haul my heavy rear up that hill. If I “muscle up” and crank over that hill to keep up with you, my glycogen burn rate just sent me into a burn rate that I cannot continue for long…that’s OK if the finish is at the top of the hill…but, if we have 50 miles to go, I’d better conserve glycogen so I can have something left later.

Then, we have to work out muscle perfusion availablility due to cardiac output, size of the muscle perfused, and tension in the muscle to determine the “best” rpm for an individual. Shorter TT’ers tend to have lower rpms, because they can afford to burn their glycogen…the race isn’t going to be long, so they aren’t worried about whether it is calorically efficient or not. On the other hand, RAAM riders tend to have lower rpms, too…it’s more calorically efficient, but they apply much lower force per pedal revolution than the short TT’er, so they aren’t depleting available glycogen very fast and/or they aren’t exceeding the rate of blood glucose delivery.

Somewhere in the middle is what most of the rest of us are doing, and it makes sense that the rpms would be somewhat higher for an individual in the middle distances. One person’s range might be circa 70 in the middle distances, mine might be circa 80, someone else’s in the 90’s. If any of us were to do a shorter race, or a much longer race, our “ideal rpms” might change to a lower rpm.

Does this seem to make sense? If it does, it would behoove people to stop chasing real high rpms (because Lance Armstrong turned 120 on a mountainclimb), or to stop avoiding lower rpms (because low rpms are what beginners do), and to experiment to find what’s best at different distances/speeds.

Surely one rpm isn’t best under all circumstances for any one individual…whaddayathink?

2

I like to sit at around 80-90 most of the time. My pedaling style doesn’t suit real high cadence (I like to drop my heel at the bottom of each stroke), but this is the minimum for not getting cramps on the run.

The only time I would differ is on slight downhills (damn gear-locking), in which case I might go to 110+, or against headwinds (which I like to over-power, so lower cadence it is).

It’s good to do high-cadence drills though, because it trains your neuromuscles and makes you more effecient. Same for low low cadence (but this will work on strength too - just don’t get too bulky).

3

Here’s what I noticed with me, in the past few weeks

In training I have had difficulty getting my heart rate up to LT for extended periods, my leg muscles seem likt they cannot push the higher gear that would raise my HR to LT, but on the other hand I do not feel comfortable spinnnig above 85 RPM either

So yesterday in training, after 2 laps of a 10 mile TT at 5 beats below my LT, I gave it my all and held my HR at LT for the last 5 miles, and push an 80 RPM cadence.

What I found is that my legs recovered, but it really hurt pushing the bigger gears. I did however drop 45 seconds off the same 10 mile TT from last weekend (went 23:20 without any aero stuff - 25.71 MPH).

So I think it is possible to keep the same 80-85 RPM cadence but push a bigger gear and still remain efficient, even though same say that spinning a faster cadence would be more efficient. I find this especially true with the Rotors as I tend to not get “stuck” on top of the bigger gears.

4

Weren’t you doing a 40K this weekend?

5

Surely one rpm isn’t best under all circumstances for any one individual…whaddayathink?

Absolutely. “Efficiency” is but one ingredient to endurance performance. You can be highly efficient (ie, burn less calories) yet put out crappy power. You still lose, even if you are the most efficient athlete on the course.

As for what it means for rpms, it comes down to this: Cadence is a self-selected variable. A smart athlete pays close attention to power output, fatigue, PE, and most importantly – results in races and race-simulation rides.

Once I got fluent in the use of my power meter and turned off my cadence display, I found that my long-time cadence of 95 on the flats was not optimal. 85-88 was more powerful and staved off fatigue better. Climbing, I have the best balance of power and fatigue resistance at 78-80 rpms.

Before all that testing, I had assumed that the same cadence would be optimal on flats and hills – but it’s not. The gearing differences affect muscle firing in different ways, and it turns out I am better off slowing my cadence when in low gears.

I’m not suggesting higher or lower is better for anyone; I’m only saying that you really don’t know what’s best if you set your cadence meter on some number you read in a magazine article. We all have to get out there and ride and discover our preferred cadences.

6

I agree although I don’t think it is quite so simple as best gearing or cadence for a particular distance in a particular individual. For instance, the best cadence for any particlar individual and any particular distance may change based upon how ell trained they are or how well recovered they are. Further, pedaling style plays a big role. Assuming your analysis is correct (there are a couple of possible glitches in it I think), someone who pedals in the PC style can pedal at a slower cadence than someone who doesn’t because for the same power they are putting less force on the pedal, so they can go to a more efficient cadence and not burn hurt power output.

So, inother words, for people to know what is best for them they need to train and test various modes. It would be very tedous and most don’t have the inclination to do so, so we get guesses and rationalizations and what “feels” right.

7

nope, 2 weeks out, CBR California State TT Championships, (40k)

www.californiatt.com
.

8

Your power meter results coincide with my rough estimate of my “better” rpm’s too. It’s such findings in real-world racing that convinced me to go to the lower-mid 80’s, especially for shorter TT’s. I think this range it better for me in TT’s up to maybe 20 miles. I’m not sure about 40K or 1/2 ironman or full ironman distances…my GUESS is that I might do better with a slightly higher cadence, OR simply less force (and, of course, less speed) on the pedal so that I have glycogen in reserve for the run.

When you climb, you drop your cadence. Do you also scoot back on the saddle? It seems to me that if you do scoot back the lower cadence may coincide with pulling up more…easier to do when the head of your femur is farther from the bottom bracket; which is one thing scooting back does for you. If so, you may be taking some of the load off of your extensors and applying your flexors more to assist in making the pedal go around.

If you were a steep rider and stayed steep on the uphills, I’d guess you might keep your same rpm most all of the time. How about steep riders? Do you maintain the same rpm most always, or do you slide back going uphill and drop your rpms?

9

Gary, when I push too big a gear, my perceived exertion goes up, and some time thereafter, I slow down. My HR slows, too. What I do is to spin slightly higher rpms (which coincides with a higher HR) until my legs recover, then drop to a bigger gear and see if I can hold the speed, if I can, I drop to the next bigger gear. Somewhere in there, my HR begins to drop, but, my perceived exertion has risen, and my legs begin to tire. It’s walking this tightrope line of too much perceived exertion (too low an rpm), and too high a HR (too high an rpm) that I try to balance. If I am having trouble getting my HR up to a level that is “supposedly” my LT, I drop to a lower gear, or the run is going to be a dog.

It’s interesting that you find you can stay “on top of” the bigger gear easier with Rotors…I notice the same thing. But, I also notice I tend to run slightly higher rpms with the Rotors…upper 80’s. Maybe this is because I haven’t adjusted fully, because the slowest point of the pedal speed (about 4:00?) at an rpm of 88 may “feel” like the low 80’s to my legs…which would coincide with what I normally turn over. I thought I had adapted really quickly because they felt so “normal” but, in hindsight, I think I have a way to go in my adaptation.

10

This does make some sense to me, and is a more viable explanation for the phenomenon that each person does seem to develop their own “best” or most efficient cadence.

This is very insightful. Thank you.

11

I think you are right…what is best one day may not be best the next for any individual.

I also think the PC style is a good strategy for the reason you said…you can decrease the force required by the extensors by using the flexors and maintain the same speed as you had before decreasing the extensor force. Decreasing this extensor force has to conserve glycogen in the extensors compared to NOT decreasing extensor force. OR, maintain the same extensor force and simply fully unweight the rising leg with the flexors so that extensor force isn’t used to do that task, and the speed must rise. And, this can be done at lower rpms, because less force is needed by the extensors if the flexors are assisting.

If the HR rises because of using more muscle (the flexors), it doesn’t matter, because local glycogen reserves are what is most important in maintaining sub-max VO2 efforts. However, if by using more muscle, you can also use a lower rpm, the HR may not be higher at all, because of the efficiency gained by riding at the lower rpm.

Whatever it is that is “best”, it is an interesting balance of glycogen management.

12

I was were you are at in the adaptation process about 7 mos. ago

I was pushing a bigger gear at my normal cadence of 85-90 following 3 months on the Rotors

It seems that you have pretty much reached full Rotor adapation from what you describe

Now, with more dedicated training, at the same cadence and gear, my heart rate is 5 beats lower in training TT’s

So I am working to push an even bigger gear, trying to stay ay 85 RPM, and raise my HR up to LT

Later this year I plan to train with wattage instead of just HR (on the TT bike) so that I can pace myself better while racing, I hope to anyhow …

13

I’m convinced Power is a better way to train than HR. Not that HR isn’t important, I just think Power is MORE important. I guess Julian would agree? He’s become well versed in Power!

14

I’d have to consider myself a steep rider (my TT bike must be at least 80 degrees, with the nose of the saddle in front of the BB). I climb better out of the saddle than in the saddle, perhaps because it opens up my hip angle more.

It’s been pointed out that high cadence is less oxygen-efficient (i.e., it uses more oxygen per Watt produced?). I happen to get muscle fatigue far earlier than I get “winded” (which only happens to me when sprinting at the end of a running race). I have a pretty high hematocrit (>46), so I suspect that I can deliver a bunch of oxygen to the muscles. I wouldn’t be surprised if Armstrong is very able to deliver so much oxygen to his muscles that he doesn’t care if he creates a whole bunch of lactate by spinning, especially if it’s the final climb.

I TT at ~100 (102 two weeks ago in a 40K), and climb at around 70-75 if it isn’t really, really steep.

15

klehner wrote: It’s been pointed out that high cadence is less oxygen-efficient (i.e., it uses more oxygen per Watt produced?). I happen to get muscle fatigue far earlier than I get “winded” (which only happens to me when sprinting at the end of a running race).

This type of athlete that has this particular way of adapting seems to me to be a better candidate for higher rpms…because rpms around 100 tend to delay muscle fatigue compared to rpms at 80, although 100 rpm “costs” more in heartrate. He has more heartrate to spare compared to his strength. I think that what I’m trying to get to, is that people should find their weaknesses and strengths, and train/race accordingly.

It’s interesting to me that you spin along at 100 and are steep, but drop to the 70’s when you climb. The fact that you like to stand when climbing, and the other info you gave makes me think you are fairly light weight, too. Is this so?

I also find it interesting that you don’t get “winded”…a sign of a high HR, except during sprints at the end of a run. Put this all together, and it seems like your cardiovascular system is better adapted for your exercises of choice than your muscular system. Do you think you’d do better if you worked on strength more? I’m not talking about lifting weights, I’m talking about big gears on the bike, uphill running/bounding, etc. With your tendency to muscular fatigue prior to cardiovascular fatigue, it seems you might have some unused potential there. Agree? Disagree? Full of beans?

16

if i can push say 400kgs or so on a legpress should i be pedalling at a lower cadence. my legs tend to get tired pushing a big gear pretty quick

17

Nah, I seriously doubt that leg press and cadence are directly related. You don’t push very hard at all on a bike pedal…at least, not for long…certainly not long enough to do a simple 10 mile Time Trial…you can push really hard for a couple of minutes at the most. I might leg press more than Francois by at least double, if we’re talking about one rep. But, he’d kill me on a bike, and his cadence is much lower than mine.

Anaerobic feats probably have nothing to do with sub-VO2 max efforts over a race distance.

19

If you consider 77-78 kg to be light, then I’m light. I think my predilection for standing comes from my running background.

As for my HR, it has never been particularly high (highest I’ve ever seen was 191), and the last two-three years I can’t raise it much above 170 (max in the 40K was 170, average was 162). I must have a decent stroke volume.

Almost all of my running is hills these days, due to the geography where I work; most of my riding is hills, too. Short (~.5mi) but steep. I’ve never been able/willing to push big gears; my 40K was mostly in the 53/16-17 range. Whenever I’ve wanted to go faster, my body says “SPIN!”.

At age 46, I doubt I have any potential, much less unused potential…

21

Francois wrote: you would probably bench press 5 times what I do :wink:

Nah, I haven’t lifted in years. However, I did a fit assesment at a local University last week and benched 300. Surprised myself. Turns out I can’t do double what you do on the leg press, I can do half a ton, but that’s not double 600!

Those are some really big gears you’re pushing…no knee pain I assume?

23

No, 77-78kg isn’t what I would say is “light”. Maybe it is your running background that drives up your cadence. Maybe I’m barking up a tree that the oppossum has already fled! Hill running and standing while climbing do seem to go together, though! Still don’t think you could do better with some on-the-bike strength work? I’m not saying you can, I’m just trying to figure out patterns: if they are there, and if so…are they meaningful?