Cadence, Stride Length, Gait and Pace: The Great Debate
So I provided a data set yesterday of my cadence, stride, and pace over time along with HR v Pace and Official race times over time to see what conclusions readers would draw from the data. See
here for the original post.
The question I came into this experiment was, do I need to change my cadence/stride/gait to be faster?
To start off, when I started creating training plans for others I provided the following instructions on foot strike:
"Foot strike - The general recommendation is to have about 180 steps per minute or more. To have these many steps per minute, it forces you to take smaller, shorter strides and quicker foot movements. You can measure this with a phone app metronome or have someone watch you run and count. This is most important during the SPEED/TEMPO sessions. Foot strike during the easy running (LR or EA) is still important for reducing injury risk by making sure it is light-footed."
This was provided to a reader on 11/28/15.
My last instructions were:
"Foot strike - The general recommendation is to have about 180 steps per minute or more. To have this many steps per minute, it forces you to take smaller, shorter strides and quicker foot movements. You can measure this with a phone app metronome or have someone watch you run and count. Your Garmin might measure this (dependent on which you have). This is most important during the STRENGTH sessions. Foot strike during the easy running (LR or EA) is still important for reducing injury risk by making sure it is light-footed. Don't force this too much. Gradually over time find your happy place for cadence with a nice quick stride. Having your foot fall underneath your torso is the most important part because overstriding tends to lead to injuries."
This was provided to a reader on 9/27/16.
This is provided to show that my opinion and instructions can and will change over time. More time = more data = new training philosophies.
So to start, where did the 180 steps per minute recommendation come from? Is it like many other running philosophies handed down over time with no basis in anything other than observation (like running 20 miles for marathon training)? Is it merely based on elites which may or may not be applicable in our training ideals (like running 20 miles for marathon training)?
In 1984, Coach Jack Daniels was evaluating the cadence of elite runners in the Olympics. He noted that 45/46 runners had a cadence of 180 or more. These elite athletes were Olympic quality and competing in the events from the 800m and up. These people are fast! Daniels also noted that none of his recreational runners had a cadence above 180 and that most were at 150-170. And thus, the idea was born that to run like an elite, we should all be running at 180 steps per minute or more. Sometimes this story was misquoted as it was passed around and became we should all run at 180 steps per minute.
So does it make sense? Should we be running 180 steps per minute like the elites? Well now that we have our handy dandy data we can see what it says...
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The relationship between pace vs (cadence x stride) is clear. In fact, it's downright science. Take the number of steps per minute and the distance they cover and use 1.0 miles as a marker and you get pace (min/mile). Simple math. Which means that cadence x stride is what determines pace. If I were to suggest a cadence of 180 steps per minute to a 7:30 min/mile runner, then the stride would be 1.19 meters. If I were to suggest a cadence of 180 steps per minute to a 15:00 min/mile runner, then the stride would be 0.59 meters.
I think you can see where this starts to break down. The key isn't 180 steps per minute as I wouldn't suggest a 15:00 min/mile keep their stride to 0.59 meters. Rather that person should worry about running a 15:00 min/mile comfortably and the cadence and stride will be what they are.
I think the real key in the suggestion of 180 steps per minute doesn't lie in the cadence itself. In lies, truly in the footfall location. It doesn't matter if you're heel, fore, or mid striker. What matters is if you're an over strider. If you find your foot falling outside the torso of your body. Think back to the days of physics. Every action has an equal reaction. So if you put 400 pounds of force into the ground, then the ground will put 400 pounds back into your foot (simply put, ignoring friction, heat, sound, etc.) Thus, how your foot "receives and distributes" that force is reliant on where your foot is in relation to the ground when it makes contact. The foot underneath your torso will distribute the force more evenly throughout your leg. Whereas, the force when the foot is outside the torso will not distribute evenly and will be more focused locally in the lower leg. Thus, this force leads to muscle and bone damage in the lower leg.
I also think the suggestion of increasing cadence to 180 doesn't lie in the 180 but in the concept in getting faster. You can see the relationship of cadence and stride are interrelated in creating pace. If you increase one and not the other, then you get faster. If you increase both, then you get even faster. If you decrease one and increase the other, you may very well find yourself at the same speed, slower, or faster. So in an ideal situation you increase both your cadence and your stride to run faster. But the caveat to increasing your stride length is you don't want to do it at the expense of over striding and increasing the risk for injury.
For example:
Cadence x Stride = Pace
2 x 2 = 4
Inc Cadence x Stride = Inc Pace
3 x 2 = 6
Cadence x Inc Stride = Inc Pace
2 x 3 = 6
Dec Cadence x Inc Stride = ??? Pace
1 x 3 = 3? or 1.5 x 3 = 4.5? or 0.5 x 5 = 2.5?
Inc Cadence x Inc Stride = Inc Pace
3 x 3 =9
So the idea of "recommending 180 steps per minute" should be really stated as "run with what feels like a natural cadence and with your foot always falling underneath your torso". This will make you faster and prevent injury at the same time. The number is irrelevant. As you get faster, your cadence and stride will either both increase or one will increase on its own.
So this is where I come back to my data set.
I have run really really really fast twice in my data collection life. Both of these instances came from end of the race sprints. During the Madison Mini HM in 2015, I had a sprint to the finish. From the brief data, I ran a 4:57 min/mile using 216 spm which equates to a stride length of 1.51 meters.
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During the Hot2Trot 10k in 2016, I had a sprint to the finish race for 3rd place. From the brief data collected, I ran a 5:18 min/mile using 211 spm which equates to a stride length of 1.44 meters.
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In both these cases, I ran fast. Like really fast. I ran a 4:57 min/mile or a 5:18 min/mile. While it was only for a brief moment, my body figured out how to do it. By doing a cadence of 211-216 and a stride length of 1.44-1.51 meters. So my form wasn't necessarily my limiting factor. Outside of a video, I don't know whether I was over striding to accomplish these paces, but what I do know is I did them. But if I could do them momentarily, why couldn't I continue to do them? Surely it wasn't my form holding me back?
So that brings me back to the data set I showed earlier. From Dec 15- Jan 15 (blue dots) my strategy was different. I had a longer stride and slower cadence. Now my strategy has changed to a faster cadence and a shorter stride. That's to say if you look at the data from Feb 2015 through Nov 2016 you don't see much of a difference. Maybe a hint, but nothing dramatic. Most of the red dots, green dots, and purple triangles are intermixed. However, compare the HR stats and the race time stats and there is a huge difference between Feb 2015 to Nov 2016.
In Feb 2015 my PRs were
5k - 23:36
10k - 49:49
HM - 1:53:18
M - 4:20:34
In Nov 2016 my PRs are
5k - 21:49 (est. 19:21)
10k - 44:23 (est. 40:29)
HM - 1:38:49 (est. 1:28:26)
M - 3:23:43 (est. 3:09:50)
And my HR stats based on different paces were
Pace - Feb vs Nov
10:00 - 148 vs 126
9:30 - 150 vs 127
9:00 - 154 vs 130
8:30 - 159 vs 136
8:00 - 164 vs 138
7:30 - 168 vs 146
So during the timeframe of Feb 2015 to Nov 2016, my cadence and stride length used to run certain paces didn't really change that much. But my HR relative to certain paces and my race times changed dramatically. This would suggest in of itself that cadence and stride length played a minimal to no role in my ability to race faster and have a lower HR at matching pace. Or said another way, there are a
multitude of other things you should try to improve outside of cadence and stride length that will likely improve your racing and HR far more than they will.
So, my suggestion is to improve cadence to the point at which you are no longer over striding. This will make you faster and reduce injury. But don't force to continue increasing cadence at paces that don't need it by shortening your stride length. If you run a 15:00 min/mile with a cadence of 150, that very well may be appropriate for that speed given the need for reducing over striding. As you continue to increase your cadence the faster you will get. By increasing your cadence you very likely are spending less time on the ground. Less time on the ground = more time in the air without any forces acting on you. This means more power focused into each step rather than in other directions other than forward. It's also why I am a big proponent of sound and foot strike. Sound is generated by force (equal forces thing again). That means if two forces both hit the same surface but one does so with less sound then it does so with less loss of energy. Less loss of energy means more energy return with each step and thus you run faster. So light quick feet are the best (as long as it doesn't cause much vertical bounce, because then you're just wasting energy in a new plane).
But don't try to manually increase stride length. By doing so you may actually just be over striding. Manually increasing stride length during a run is not the same as naturally increasing your stride length. I almost feel there are two "stride lengths". There's the distance in which you try to manually put your foot out to increase distance. And then there's the stride which occurs naturally, but that increase in length when you put more power underneath each step. So if you want to increase stride length, don't do it manually during a run. Instead work on exercises that will put more power into your steps. And where does power come from?
Well there is endurance power. The power to continue to run at fast paces. This is where I attribute nearly 100% of my ability to race faster and train with a lower HR. Again going back to the data shown earlier, I was capable of running a 6:30-7:00 min/mile back in early 2015 just for 0.1 miles. Now I can run that for several miles (did 7:11 for 9 last night). So that comes from endurance power. Nothing changed from my stride to enable that pace for duration. It was simply increasing your endurance. More specifically your powerhouse of the leg, the mitochondria. These little guys will enable you to run further faster. And how do you build mitochondria? With smart training built around concepts like relative easy paced training, periodization, and balance. By building the mitochondria and getting stronger and more endurance in the legs it takes less effort to run a certain pace. Less effort at a certain pace = lower HR = going further faster! None of which is directly tied with changing cadence or stride, but ancillary connected.
You can also consider running hills or sprints. Running hills doesn't manually change your stride, but what it does do is force your body to adapt to creating more power with each step. You have to sprint up a hill, then your body better darn well figure out how. So when you aren't running up a hill anymore but you still have the same available power per step, then your stride length will increase. It won't increase because you're reaching further out. It will increase because of the extra strength or power behind each step.
So in conclusion, only increase your cadence to the point that it reduces over striding. Don't worry about increasing your stride length manually during running, but focus on building endurance and power through actual exercises like endurance training and possibly hill work (although I'll say that outside of running hills on a regular basis I have not done any actual "hill training" to get from where I was to where I am)
Alright, that's all I got. Let's hear those opinions. How did I do? Did I get it right or did I miss the mark? Is there something I might be missing? Some role that I'm not evaluating correctly?
