I am not a run coach
I am a slightly OCD research and reader. There is always so much more to learn, so honestly I feel like what I know amounts to a drop of water in all of the oceans of the world. However, being a numbers nerd, a computer geek, and an obsessive personality in general, sometimes it comes across like I know more than I do. Not too long ago, I got into a conversation on the topic of running metrics. In typical fashion, I probably came across like I know a lot more than I think I do. Keep that in mind as you read the rest of this. I am just a runner that has done a little research and is trying to apply what I have come to understand.
So, there are a lot of things about running and running performance that are pretty difficult to quantify and monitor on a day to day basis, things like VO2MAX, dietary efficiency, hydration efficiency, lactate thresholds, and more just aren’t things you can slap a chest strap on and quantify (perhaps yet, perhaps never). On the other hand, there are metrics that we can track, and they can provide a huge insight into what we are doing when we are running, and perhaps how we can improve. Most runners that have been training for any length of time have at least heard of training by herat rate and heart rate zones, even if they aren’t doing it yet. When you talk to runners, and other endurance sports athletes, the heart rate monitor is often where they start, and at least for running, it is as far as they get. However, when athletes get to a point where they make the concsious choice to “get better” they start looking at other factors.
That is where things get so interesting, complex, and far less ‘common knowledge’. With some of the modern heart rate straps and watches, we have access to some other metrics that make up the running stride that we can use to get better, if we understand how to use them. Before we can really get into how to use them, we have to start by understanding what they are.
Math & Mechanics
On the other hand, cadence is something that we hear about a lot, but a surprising number of people do not truly understand the numbers presented, and how they apply to running. Basically, your cadence is the number of times one of your feet touches the ground in a minute. We know that the best in the world run at high cadence, some of them as high as 210 strides per minute. Meanwhile most mere mortals struggle to reach 180 strides per minute without introduce form issues.
The stride length is a far more difficult thing though. With a little math, we can pretty quickly find what kind of stride length is required to hit a pace. Let us take a pace that would Boston Qualify for a man in the 40-44 age group, 3:30 minutes. In order to get there, a runner would need to run at an average of 7.5 minute miles. Using a cadence oc 180 strides per minute we find that each mile requires 1350 strides, or 135 strides per tenth of a mile. Multiply that by 26.2 and you will have to take 35370 strides. But, if that is the case, how long does each stride have to cover to make that happen? Well, a mile is 5280 feet and we need 1350 steps to cover that. Again let’s just cut that to a tenth of a mile so the numbers aren’t so overwhelming. so 528 / 135 gives us 3.91 feet. Which it turns out is 1.19 meters. We convert that to metric, because that is how most of our devices will monitor it.
What this means is that with the the knowledge that the distance to travel is unchanging, we can increase the cadence and reduce the length required to maintain the same speed, or we can increase the stride length and reduce the cadence. Increasing both goes faster, decreasing both goes slower.
In simplest terms, stride length and cadence dictate speed. Every other measurable metric we talk about when it comes to running, is either a result or contributing factor to these two metrics.
Heart rate is such a common metric, and so many people run by heart rate zones that many runners think of a heart rate zone as resulting in a pace. In reality, the exact opposite is true. The heart rate is a result of many factors, but how fast a runner is moving is not one of them. It is however a result of temperature, body temperature, body hydration, nutrition in addition to how much energy is being expended per stride in order to overcome gravity and inertia for each continuing stride.
In many ways, monitoring heart rate is easy, but it is largely a metric that lags behind energy expenses, and as such too much focus on it can lead to making decisions based upon erroneous assumptions because there are too many other contributing, and unquantifiable factors.
Ground Contact Time
This should make sense to most. It is a measure of how long the foot is on the ground for each stride. It can be used for a metric, but like heart rate it is a result. The faster your stride, and the longer the stride length, the shorter the ground contact time.
Quantifiable Contributing Factors
While there remain a slew of factors that we can only control to a marginal degree as recreational athletes, there are plenty of things we can, and we can use these things to make us better.
This does not need all that much explanation. The heavier you are, the more energy it requires to launch your body into the air and to move forward. It also means that the heavier you are, the harder it is to slow down and turn thanks to the laws motion. Momentum is hard to overcome, and the more mass that is moving, the harder it is to slow down.
Measured in either centimeters, the vertical oscillation is the amount of upward motion that is generated with each stride. Too much and there is wasted energy that should be used to move forward. Too little and the forward carry is not enough to sustain the stride length required. Unfortunately, even this number can have some be a little deceptive, since there can be some masking of vertical oscillation by the fluid and soft launch / land of a highly efficient stride. Given that, if the oscillation numbers are low enough that this is a factor, then it really is not an issue. For Garmin users, they now report this as a % of efficency. In either case, the lower the number the better. How low? for a Garmin user, the target is to get below 8.6.
Ground Contact Balance
While being a the result of a result, monitoring the balance, or mesure of the ground contact time difference between the left and right foot stride will quickly identify where there are issues like favoring one side or the other due to a form or injury issue and even something as subtle as an imbalance in the strength of each side of the body.
There is also a trend towards monitoring ‘watts’ like a power meter from the bike world. This is also a useful number, but keep in mind that it is a value that is extrapolated by looking at Vertical Oscillation, Weight and Stride Length to determine the amount of power is output to reach those values. While there sales pitch is that is an effective tool for analysis, it is just another way of presenting the same data. as the run dynamics data coming off of a Garmin Run strap, or a Wahoo Tickr.
Before running out the door to start applying all of this though, there is the other side of the equation. In order to be able to reach these numbers, the body needs to be taught to move in a manner that makes these things attainable. Unfortunately, many runners are their own worst enemy. Key parts of the running motion are simply getting in the way.
Over the years, runners have been told that heel striking is bad. The reasons, are often things like knee, ankle and hip injuries. Sometimes the story is that more padding protects these injuries. Other times it is about less padding. Shoes can cure it. The dirty little secret. Heel striking is not the problem. More or less padding is not going to solve the problem. The problem is over striding.
Or more specifically, landing with the foot in front of the hip, while stilll moving forward, or at a speed lower than the speed of the body’s iniertia. That is a mouthful, and a lot to wrapt he head around. Simplifying it, think about a a fence. It is starting to lean forward, in order to straighten it up, a brace is place in front of it, at an angle to push teh fence backwards towards vertical. When a runner over strides, the foot becomes that brace pushing backwards. While heel striking is often a symptom of over striding, heel strike under the hip does not generate force counter to the forward momentum. Watching runners out amd about, there are many that run with a midfoot strike while still over striding. Remember the goal here is to move forward with the least effort. Something that costs slows that momentum is a net energy loss, that results in a slower run that cannot be sustained as long.
Of course the counter to over striding is the other problem. As runners work to keep that landing under the hip, the entire stride shortens due to a lack of hip rotation that prevents getting enough push from behind or a lack of strength in the foot to push off with enough force to maintain the stride length. All too often this leads runners to stand too vertical, perhaps even rolling the shoulders forward to get that head forward position that we have all seen on the elite runners. That posture leads to rolled shoulders and in all likelihood, wasted energy o. tense shoulders neck and hands.
Yes, posture kills. The head is a lot of weight. If it is forward and out of line woth the body, there is a bunch of weight being supported by soft tissue. Think about holding a 1 lb dumbbell. at your side it is easy. hood out in fornt of you at arms length and it gets hard fast. if your posture gets that head forward, the supporting muscles have to work harder. Getting your body in line, with a strong core, lets everything else relax, which in turn saves energy.
Uphill & Downhill
Just because the terrain changes, the goals don’t change. remeber the math equation earlier? Going up a hill, the stride length shortens so the cadence goes up. Downhill, the length extends, so the cadence goes down. What does not change though, is form. The foot still stays under the hip. The upper body stays relaxed and in line.
That is a lot of information to absorb. The quick takeaway, is that becoming a better runner is not about any one thing. Improving any one aspect without understanding all of the factors can work short term, but may mask other issues. The reality is that the quest to become a better or faster runner is not about either of those goals. The quest for better and faster is really a quest to be a more efficient runner by removing the things that are costing energy and speed.
In order to do that, most runners need work not on faster, but on slower, smoother and getting the stride form to a point where muscle memory allows them to adjust the mechanics of cadence and length without sacrificing form.
This is all a great start, but the next question and answer is, how can a runner use the tools like a Garmin to improve, and how can equipment like shoes help or hurt in this quest. Those answers are in the section.