Happy New Year readers! With 2016 finally upon us, it’s time to start laying down base training for a successful year of racing. During this early phase of your year, it’s a good time to think about and train things that you really don’t have time for during the race season. One of these components: our running biomechanics.
I want to preface this article by saying that I think one has to be careful when consciously making an effort to significantly alter form. Firstly, researchers have shown that when you try to significantly alter your gait (i.e. during the barefoot running craze, trying to change to a forefoot strike from a rearfoot strike), not only did many runners become more injury prone, but their running economy went down (at least for a while) when battling their natural biomechanics.
Secondly, as most hobby runners increase mileage (and the variety of running that mileage contains), running economy and form improves without specifically trying to alter it. This point is important to me because many of us are strapped for time. If you only have 4 hours in a week to run, and your goal is to get faster, then you better spend them actually running.
That being said, while the normal range of what is acceptable for an economical stride is quite broad, there are some key elements that can and should be addressed with our form. One simple and easy to understand example is excessive arm motion; if you swing you arms a lot, it will increase oxygen consumption without making you go faster. So swing your arms just enough, but not too much.
Things get more complicated when we start looking from the waste down and measures such as stride length, stride frequency, flight time and contact time. That’s what I want to take a closer look at with this article.
Running up hill: Elites vs. Amateurs
I recently came across this study from 2012 published in the Journal of Strength and Conditioning Research, which looked at the above variables (stride length, flight time etc.) in elites vs. amateur runners. What I like about this study is that they kept things very simple: take the two groups of runners and make them run at a bunch of different speeds and a few different inclines. Then, measure the variables and see if there are any differences in how they move.
Results
Overall, much of what the study found is predictable. For instance, as speed went up stride length, stride frequency, flight time (time with no ground contact) increased, while contact time (time spent touching the ground) went down. This was seen in both the elites and the amateurs.
However, one of the most interesting results to me came when they compared the elite and amateur runners when the slope started to increase. These two groups of runners adapted to this change in different ways:
AMATEURS: When they ran on a 2% slope, their contact time INCREASED.
ELITES: When they ran on a 2% slope, their contact time (at the same slope and speed as the amateurs) stayed the SAME.
So how did these runners run at the same speed, at the same incline, while the amateurs kept their feet on the ground longer? The answer is simple: the elites decreased their stride length and increased their stride frequency.
As the authors state:
“A significant change was found in (stride length) and (stride frequency) when increasing the gradient up to 2% at all speeds in (elite runners). Amateur runners did not significantly change stride length and stride frequency…”
So in other words, once the slope was kicked up to 2%, the elites took short quick strides, tapping the ground quickly with each step. The amateurs, by contrast, struggled to keep their same stride length and frequency, and hammered more energy into each stride, keeping their foot planted on the ground longer.
So which is better? I think a good way to visualize the difference is to picture the epic battles between Lance Armstrong and Jun Ullrich in the Tour de France. Lance was known for his fast cadence, dancing on his pedals, and spinning his crank at a high RPM. Ullrich was on the other end of the spectrum. He stayed seated, mashed a massive gear, and kept his RPM low. Lance’s style relied more on the cardiovascular system (heart, lungs, blood), while Ullrich relied more on his powerful quads. Their physical appearance supported each style too: Lance was slightly thinner and lighter, while Ullrich had more meat on his legs to push that low cadence.
Now I’m not saying that because Lance beat Ullirch (doping questions aside), that his style was better. It’s simply a good way to visualize the physiological impact of each style. The elite runners, without a doubt, will tax their large muscle groups (i.e. gluts/quads) less with a shorter, quicker, less powerful stride. They rely on their heart and lungs to chip away at hills rather than trying to launch themselves up. As endurance athletes, this makes sense as a sustainable strategy to use over long distances, and elites use it naturally.
Practical Applications
We run a lot of hills with our club, Health and Performance. 1x/week our speed sessions are on hills, and almost all of our long runs are on hills. Both from a biomechanical and cardiovascular stimulus standpoint, I definitely recommend building them into your schedule in a variety of ways on a regular basis.
Specifically, this study is a great reminder of one way your running biomechanics could change if you significantly ramp up your training this year.
It is important to note the conclusions I am discussing are a simplified version of the truth. Take a look at the full text of the article to see what I mean. At slower speeds and steeper slopes (7%), the difference between elites and amateurs wasn’t quite as obvious in this study. So it’s not as simple as saying everybody should increase their turnover up every hill, and another reminder of why it’s important not to over think and manipulate your running form.
That being said, after a period of ramping up mileage if you find as you run up inclines that your stride length is shortening and your cadence is increasing, don’t fight it! If things feel comfortable, stick with it, and accept that your body is naturally learning to run more efficiently.
Dr. Sean Delanghe, BSc. (Hons), DC is a chiropractor, coach, and a regular contributor to the RunWaterloo blog.
