[nnc-list] Cadence

[Donald Mitchell]

http://www.beginnertriathlete.com/cms/article-detail.asp?articleid=433

Cycling Cadence
The physics and physiology of high and low cadence cycling. Both low and 
high cadence work are useful for increasing your “cadence comfort,” or your 
comfort within a wide range of cadences.

Physics

The work required to move a bike down the road is measured in watts. To 
define it very simply, Watts = Force x Cadence, or how hard you press on the 
pedals multiplied by the number of times per minute you apply this force.  
Two cyclists, Bob and Bill, weigh the same, have identical bikes, identical 
aerodynamics and are riding next to each other at the same speed on a flat 
road. Because they are riding the same speed and we’ve controlled all the 
other variables, they are performing the same work, ie, riding at the same 
watts. However, Bob is mashing at 70rpm while Bill spins at 110 rpms. Bob’s 
pedaling style dictates that he press hard on the pedals with each stroke. 
But he does so less frequently than Bill, who is pushing lightly on the 
pedals but much more frequently.

Physiology

Low cadence cycling requires us to push harder on the pedals, but what does 
this mean at the level of our leg muscles? To generate that higher force 
contraction, your leg muscles must recruit more fast-twitch muscle fibers vs 
slow-twitch fibers.

Slow-twitch fibers:

    * Primarily burn fat for fuel, an almost limitless supply of fuel for 
even the leanest athlete.
    * Are very resistant to fatigue: they are built to go and go, all day.
    * Recover quickly when allowed to rest.

Fast-twitch fibers:

    * Burn glycogen for fuel. This glycogen is stored within the muscles and 
is in relative short supply, about 2000 calories for a well-trained, 
well-fueled athlete.
    * Fatigue quickly, are NOT built to go all day.
    * Take a long time to recover before they can be used again.

Matches

CyclingPeaksSoftware.com developed this analogy. I think it’s a good one, 
but I like to elaborate a bit. Imagine your legs are a book of slow and fast 
burning matches. The purpose of training is to increase the size, number and 
flavor (ratio of slow and fast) of your matches, depending on the demands of 
the race. Sports requiring short bursts of speed favor athletes with lots of 
fast matches. Endurance events favor slow matches. You can use either match 
to do the work of racing but the total number of matches in the book is 
finite. And once you burn a match, it’s gone - you can’t get it back.



Now, back to our discussion of cadence. You are riding on a flat road, 
approaching a hill that will take you about a minute to climb. You will 
likely do one of four things:

   1. Shift to a gear that feels comfortable and/or powerful for you. You 
feel good when you climb at 60-70rpm so you do that, shifting to the middle 
of the cassette.

   2. Climb at 60rpm since you showed up to the ride with a 21-11 rear 
cassette.

   3. Say “The hill will only take me a minute to climb. I don’t want to 
lose any speed so I’ll hop out of the saddle, stand up and hammer up the 
hill. I’ll recover on the decent.”

   4. Shift into your 25 cog and spin up the hill at 85-90rpm.

Option #1: Low cadence = high force = high fast twitch recruitment = burning 
matches that you may need towards the end of the run. Forget “feels” 
powerful. Power is watts to the wheel, period. If you can climb a hill at 
the same speed (equal watts) at 60rpm or 90rpm, choose 90rpm. Conserve your 
fast twitch fibers so you can recruit them later in the run.

Option #2: See Option #1 and always bring enough gears to the race. In my 
experience, the only people who attach sexual competency issues to the 
gearing on their bike are folks who don’t climb. I have (no lie) six 
cassettes hanging in my garage that I swap on and off my bikes according to 
the terrain of the ride. I have everything from a 27-12 to a 19-11. You can 
flatten any hill if you have enough gears on your bike J.

Option #3: Standing = power spike = high fast twitch recruitment = you know 
the drill. From riding with a powermeter for many years I can tell you that 
if you don’t have a meter it is VERY difficult to stand in the saddle and 
not toss out huge watts for a brief amount of time. It might “feel” ok, but 
chances are very high that you just burned a few matches with your little 
burst.

Option #4: Bingo! Spin up the hill, burn slow, not fast matches so you can 
use those matches on the run, burning the last one as you cross the finish 
line.

What is the optimal cadence?

Ok, so I’ve sold you on the value of high cadence vs low cadence. But what 
is the optimal cadence? In my experience, most athletes should ride at a 
cadence of 88-95+ rpm. A few notes here:

    * Notice that this cadence is right in line with an optimal running 
cadence. I believe it is hard to run off the bike at 90+ rpm if you’ve been 
cycling for hours at 80rpm. You’re asking your legs to make a huge 
adjustment, in addition to the difficulty of transitioning from cycling to 
running.

    * More experienced and stronger cyclists will be comfortable within a 
wide range of cadences. When I began cycling, anything under 88rpm felt like 
mashing, while 95+ felt too fast. I was always searching for that right 
gear. Now, after many, many miles, I can ride equally comfortably at 78-82 
or 100-105. My tool kit is much larger (see below).

Cadence and Training

Some coaches prescribe low cadence intervals as a method to train your body 
to push harder on the pedals. However, consider the importance of 
specificity: if you want to run longer, run longer; if you want to swim 
faster, swim faster; if you want to ride the bike farther, ride the bike 
farther. If you want to ride the bike faster at 92rpm, then ride the bike 
fast (high watts, ie greater work output) at 92rpm.

Having said that, both low and high cadence work are useful for increasing 
your “cadence comfort,” or your comfort within a wide range of cadences. By 
this I mean you have strong, resilient, well-adapted legs that can handle a 
broad range of cadences, including that high force/high wattage contraction 
that may happen if you run out gears, decide to climb out of the saddle, 
etc. You have a large tool kit to handle a broad range of conditions.

The most common tool is a period of low cadence intervals fitted into the 
early season. My guidance:

    * Beginner: useful tool early season for developing sport-specific 
strength and “cadence comfort” quickly in their cycling careers.

    * Intermediate: useful early season, see above. However, after 4-6 weeks 
of low cadence intervals, transition to lactate threshold intervals at 
normal, time trial cadence. Reserve low cadence for fartlek-style training - 
grind up a hill at random to build or retain this cadence comfort.

    * Advanced: high watts at race specific cadence is more useful. These 
athletes have already developed cadence comfort and a period of low cadence 
intervals is, I believe, often an unnecessary step. I reserve low cadence 
work for:

         1. Fartlek, see above.

         2. The last hour of long rides, to force recruitment of fast twitch 
fibers when they are already on the edge.

    * Athletes training with power: the ability to measure watts while 
cycling at very low cadences creates possible exceptions to this guidance. 
The power-training athlete can truly turn his bike into a piece of gym 
equipment and is, I believe, more justified in adding low cadence intervals 
to his training routine.

In summary:

    * Focus your training to develop speed (wattage) at your race-specific 
cadence - the cadence you plan to race at. My suggestion is 88-92+ rpm, with 
weaker, less experienced cyclists targeting the high end of this range.

    * Supplement this race-specific training with informal low cadence/out 
of the saddle work to build this resiliency above and expand your range of 
comfortable cadences. See my guidance above for how to build low cadence 
intervals into your particular training season.

    * Bring the proper gearing to the race! And when in doubt, bring more 
gears! I think a compact crank is an excellent tool for all cyclists to 
consider.

    * Bring these fast, strong, resilient legs to the race. Put them on a 
bike with the proper gearing. Exercise smart, disciplined pacing and 
climbing skills to limit the number of matches you burn on the bike course, 
burning that last match at the finish line!

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