What pedal cadence should a triathlete strive to hold?

Road cyclists tend to have a higher cadence than triathletes. Why is this? Is it bad?

Member Question from bvanhouts

"I have a question about the cadence while riding a time trial bike: that is, how many RPMs is appropriate? As a fanatical road bike rider, I have seen a shift from riding with relative low RPM's (like Jan Ullrich) to having a high cadence (like Armstrong). Therefore when I ride my road bike I like to ride with a cadence of at least 90-95. Now I'm focusing more on triathlons and the thing I noticed is that triathletes seem to ride with incredible low cadence compared to road bikers. My question is: is this on purpose, i.e. is there some kind of benefit for a triathlete to have a lower cadence because of the upcoming run? If so, then should I train more at a lower cadence? I don't know why, but I thought the difference was quite surprising."

Answer by Dean Phillips
FitWerx

There was nothing like watching the difference in cadence and riding styles during all those Lance Armstrong vs. Jan Ulrich battles. Lance had the entire cycling world chasing a higher and higher cadence as he seemed to spin his way to win seven consecutive Tours. A higher cadence can be beneficial for many riders, but higher is not always better and when taken to the extreme will have a negative impact on power.

Before we get into what changes in our bodies at high and low cadences, there are some tactical reasons why you may see a bike racer spinning along at 100rpms, while a triathlete may pass you grinding things out at 85rpm. The bike racer has to be ready at all times to chase an attack or handle the quicker pace changes that are typical in bike races. A higher cadence will allow for that fast burst of power to chase down a wheel. A triathlete is trying to maintain a steady pace and ignore other riders, which typically results in a continuous effort at the most effective cadence, which oftentimes is lower. It’s important to note that triathletes also ride at a wide range of cadences, and some of the most successful triathletes in the world ride at cadences from the low 70s to the high 90s, so we can’t simply group them all in the lower cadence group.

Benefits of high cadence

Let’s look at the benefits to riding at higher cadences. A higher cadence requires less force per pedal stroke and places less stress on your joints and muscles, which reduces the risk for overuse injuries. There is however a point at which too high a cadence starts becoming less effective. The best cadence is individual and depends on a host of factors including type of event, duration, and intensity. Most riders will have a range of cadences that are all equally effective.

The definition of power is helpful when talking about what happens at different cadences. The amount of power a cyclist produces on a bike is the product of the force applied to the pedals, multiplied by cadence.

[Force x Cadence = Power]

When cadence increases, the amount of force needed on the pedals goes down, and vice versa. It’s easy to visualize how a higher cadence requires less force per pedal stroke.

Lets take a closer look at what actually happens when cadence changes and why that may or may not be beneficial to a particular rider. To produce force on the pedals, muscles in the legs must contract or, more specifically, shorten. The amount of force needed will dictate how many muscle fibers are used during that part of the pedal stroke. A general rule is that the fewer muscle fibers needed, the easier or less fatiguing it is to maintain a given power level. I’m sure there are some physiology and biomechanics majors that will wince at such a generalized statement, but for the purpose of this answer, it’ll do. Since a higher cadence will require less force per pedal stroke, it’s easy to conclude that fewer muscle fibers will be needed at the higher cadence and over time it will be more beneficial to the rider. Now don’t go jumping on your bikes chasing Lance’s super-high cadence just yet; there’s a downside we need to consider.

Downside of too high cadence

Muscle shortening speed is another factor in selecting cadence. As cadence gets higher, the muscles have to fire faster to keep up. Muscles are strongest at slower shortening speeds, so higher cadences will eventually require more muscle fibers to produce the force necessary to maintain that power output. It’s a bit counterintuitive, but just like too low a cadence will require extra muscle fibers, too high a cadence will also require recruitment of extra muscle fibers.

Optimal cadence

The optimal cadence range occurs when your body balances the best combination of muscle force and muscle speed. Too low a cadence and too many muscle fibers get recruited, while too high a cadence also results in too many muscle fibers getting recruited. There’s also trainability and adaptation factors that need to be taken into consideration when selecting the best cadence range, but there will generally be a downside when cadence gets too high or too low.

I’ll often recommend a triathlete ride at the highest cadence they’re comfortable riding at without giving up any power. A good range I often recommend is 85-100rpm. To say one end of that range is better than the other is to overthink the matter. As long as power is maintained, there’s little downside to riding at a brisk high cadence, and your joints and muscles will thank you in the long run.

 

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Dean Phillips is a co-owner of Fit Werx² in Peabody, MA.  Dean frequently writes tech articles for BeginnerTriathlete.com and is humble enough that he would likely never tell you (so we'll tell you for him) just how fast he is on a bike.  Dean holds multiple TT course records in New England, having broken records previously held by some of America's best pro cyclists, and he set these while being a father of three young children and owning his own business.  Dean knows speed and how to get the most out of his training time.