Why Does My Coach Keep Harping On Cadence?? It’s Science!
As an athlete myself, there always seems to be one thing or another that my coach harps on me to improve…. Nutrition… Sleep… Consistency… Mobility…. Core…. The list goes on!! But as a coach, I find that one of the things I am probably driving my athletes crazy over is CADENCE!
Here’s why… It has been shown in numerous studies that a moderately-high cadence--somewhere between 85-95 revolutions per minute (RPM) on the bike and approximately 180 steps per minute (SPM) on the run--is the most efficient. Of course, there are absolutely exceptions to this rule - especially with respect to the run - but for the vast majority of athletes, this will hold true.
Let’s talk about why…. First, for the bike, it decreases the stress on the cardiovascular system. Pedaling faster, achieved by shifting into a light(ish) gear that allows you to actually hold that cadence, uses our slow-twitch muscle fibers. These fibers are more efficient at utilizing fat for energy, are more resilient to fatigue, and recover more rapidly compared to fast-twitch muscle fibers. In short, we can use slow-twitch fibers for longer periods of time than fast ones - that’s a good thing when it comes to endurance sports (and, no matter the distance, ALL triathlons are endurance events).
In comparison, our bodies rely on fast-twitch muscle fibers when we need to generate a lot of force, like lifting heavy things, climbing big hills, or mashing huge gears. While it’s great to have these as an option when you need them, unfortunately, they are not as metabolically efficient as their slow-twitch brothers and sisters, and, thus, require a lot of glycogen. Unfortunately, our muscle cells can only store so much glycogen; but the human body has a nearly endless supply of fat (yes, even in very lean athletes!) from which the slow-twitch fibers can pull energy.
Some studies have also shown that a higher cycling cadence also results in more blood flow to the working muscles. More blood flow means more oxygen, which also means more endurance.
So, that pretty much covers the bike… Now let’s look at why cadence matters so much on the run.
Really it’s just physics. A quicker cadence is usually the result of a shorter stride length. A shorter stride length means the runner is likely landing under their center of gravity. A runner with a slower cadence is likely overstriding (longer stride = slower cadence).
Overstriding is - almost unequivocally - not good. When we overstride, our foot is usually landing far out in front of our center of gravity, which means we are likely striking the ground with our heel and landing with a straight leg. This is essentially slamming the brakes on all the forward momentum that we just had/generated!
The force of our heel striking the ground gets reverberated all the way up through the joints of the outstretched leg and into the lower back. Conversely, when you land with your foot more under your center of gravity (using a shorter stride length, with a higher cadence), your ankle, knee, and hip are all able to do their jobs as shock absorbers.
Not only does a longer stride length send shock waves through your entire body with every footfall, but it also requires far more muscle recruitment because you basically have to regenerate all that momentum that the force of your heel hitting the ground just threw away. When it comes to exercise, more muscle recruitment is often a good thing, but in this case, it’s just wasted energy and momentum.
All that being said, when it comes to the run, cadence is a bit more variable/controversial than the ideal bike cadence. Previously, the “golden rule” said we should all aim for approximately 180 steps per minute for an efficient running stride. While that is still generally the accepted number, one recent study of Ultramarathoners actually indicated that running cadence might be a bit more personal.
In this study, the average cadence of the runners did turn out to be the “magical” 182spm but the overall range went all the way from 155 to 203spm. What’s more, those two runners (the guy who ran with 155spm cadence and the guy who ran with 203spm cadence) finished within minutes of each other!
Though 180spm does still stick out as a good number for the average runner to aim for, there are definitely other factors to take into consideration. One obvious factor you might remember from high-school physics: the length of the lever - in this case, the athlete’s leg. Runners with longer legs tend to have a slightly lower efficient cadence and athletes with shorter legs usually run with a quicker cadence.
Now all of us triathletes can circle back and see a final reason why cycling cadence is even more important for us…. Maintaining that higher cadence on the bike, essentially “sets” your metronome for your run!
So, the next time your coach harps on you to get your cadence up on the bike or the run, you’ll remember why your cadence matters and that your coach is just trying to help you be the most efficient and fastest endurance athlete you can be!