Elite Males in Slow-Motion at the 2010 Boston Marathon: Cheruiyot, Merga, Kebede, Kigen, Goumri, Keflezighi, Hall

Saturday, May 8, 2010

Elite Males in Slow-Motion at the 2010 Boston Marathon: Cheruiyot, Merga, Kebede, Kigen, Goumri, Keflezighi, Hall

A few weeks ago I posted a slow-motion video of Ryan Hall from the 2010 Boston Marathon that was taken by a pair of my undergraduate students (thanks Erin and Daniella!). They headed down to Newton on Marathon Monday to watch and film portions the race, and as it turns out, they managed to capture some amazing slow-motion video of approximately the first 1000 runners to pass by near the 17 mile marker of the marathon. Below is a clip showing slow-motion video of the first six men to pass by the point where they were stationed. The video was filmed at 300 frames-per-second with a Casio Exilim EX-F1 digital camera (you can read my overview of the Casio EX-F1 here if you're interested in the technology), so this is true high-speed video.

Elite Male Runners in Slow Motion - 2010 Boston Marathon from Runblogger on Vimeo.
Video clip of elite males running near mile 17 of the 2010 Boston Marathon. Video courtesy of http://www.runblogger.com.

The runners in the clip are (in order)

1. Cheruiyot, Robert Kiprono (KEN, finishing time = 2:05:52, finish = 1st)
2. Merga, Deriba (ETH, finishing time = 2:08:39, finish = 3rd)
3. Kebede, Tekeste (ETH, finishing time = 2:07:23, finish = 2nd)
4. Kigen Kipkosgei, Moses (KEN, red/green shirt, finishing time: 2:12:04, finish = 8th)
5. Goumri, Abderrahim (Morocco, purple shirt closer to carmera, DNF)
6. Keflezighi, Mebrahtom (USA, finishing time = 2:09:26, finish = 5th)

And here's a version that is slowed down even further:

Elite Men in the 2010 Boston Marathon - Super Slow Motion from Runblogger on Vimeo.
Video clip of elite males running near mile 17 of the 2010 Boston Marathon. Video courtesy of http://www.runblogger.com.

And here below again is the clip of Ryan Hall (USA, finish time = 2:08:41, finish = 4th).

Ryan Hall - Boston Marathon 2010 from Runblogger on Vimeo.
Video clip of Ryan Hall running near mile 17 in the 2010 Boston Marathon. Video courtesy of http://www.runblogger.com.

Now, I make no claims of being an expert on running biomechanics, however, I have spent countless hours over the past few months analyzing slow-motion video of footstrikes (over 1500 of them!) for a project I have been working on with some of my undergraduate students. As you can see with these videos, even at 300fps it can be hard at times to classify very borderline cases, and doing so with a regular camera at 30fps would be near impossible - this is why I'm hesitant to trust many of the videos of elites that I see posted on sites like YouTube. At 30fps, the gaps between image frames of a fast moving subject are so great that the accurate classification of a split-second event like where the foot meets the ground is extremely difficult. Furthermore, this video is a snapshot from only a single spot in a single race, and I have seen footstrike to vary even within a person due to factors like fatigue, suspected injury, etc. That being said, I think we can glean at least a small amount of insight from these Boston videos, and since the discussion of which type footstrike is most efficient and least likely to cause injury is all the rage right now, here is my footstrike analysis of these six runners based on this video clip:

1. Cheruiyot: left = midfoot, right = midfoot
2. Merga: left = midfoot, right = obscured
3. Kebede: left = heel, right = midfoot
4. Kigen: left = mifoot, right = midfoot
5. Goumri: left = heel, right = heel
6. Keflezighi: left = heel, right = heel
7. Hall: left = midfoot, right = midfoot

Rather than write up my thoughts in paragraph form, I thought instead I would just share a few random musings that have entered my head upon watching this, and let you comment and provide additional insight as you see fit - I consider my comments section to be an open forum, but let's not let this devolve into a petty argument over barefoot/shod running as seems to so often happen when the topic of footstrike comes up these days.

1. Most of the elites shown here (and these are some of the absolute best in the world right now) are midfoot strikers, but this pattern is not universal. Both the 2009 (Merga) and 2010 (Cheruiyot) Boston winners are midfoot strikers here, but the 2009 NYC Marathon winner (Meb) is a clear heel striker. Furthermore, Goumri, who entered the 2010 Boston Marathon with the fastest marathon time of any of these guys (2:05:30 in the London Marathon in 2008), is also a clear heel striker. So it would seem, at least based upon this small sample (and I have a lot more video to look at in the coming months), that you can run really fast for a really long distance with either a midfoot or a heel strike.

2. These guys are running very, very fast. All of them are likely running at a sub 5-minute mile pace in this clip. For frame of reference, Cheruiyot's average pace was 4:48 min/mile for the full 26.2 - to me this is hard to even comprehend! Thus, it's hard to know for sure whether the footstrike patterns observed here are more a function of speed than anything else, but the presence of two heel strikers seems to go against this argument. Regardless, it would be interesting to get another video of each of these elite marathoners running at a more pedestrian 8:00 or 9:00 per mile pace. Maybe I'll film myself running at a 4:48 pace and see what I look like (and believe me, that will take some serious effort on my part, and it won't be nearly as pretty as what you see here!).

3. Both Cheruiyot and Meb appear to be wearing the same shoe - looks like the Nike Zoom Streak 3, It's interesting to see how strikingly different (no pun intended!) their landing patterns are despite the similar speed and shoe type.

4. It would be easy for some to suggest that Meb or Goumri could be faster if they altered their stride to land on the midfoot, but it is equally possible that this would throw them off their naturally most efficient gait and make them slower. It is these types of questions that science needs to begin to address.

5. As far as what makes these men such impressively fast marathoners, my suspicion is that footstrike is probably fairly insignificant. I'm sure they all have VO2max values that are through the roof, they can sustain paces a at a percentage of VO2max that is far higher than the average person, they have amazingly high lactate thresholds, a preponderence of slow-twitch fibers in their relevant running muscles, and are amazingly economical in their running biomechanics (i.e., outstanding running economy). In other words, all of these men are physiologically gifted in ways that most of us could only dream about, and that, moreso than what their feet are doing when they contact the ground, is what makes them so fast. We have a tendency as humans to focus on what we can easily observe, measure, and control, and footstrike is one of those things. However, the relative importance of footstrike when compared to these other factors is in my opinion questionable.

6. I have a lot more video to analyze in the coming months, and I just wrapped up analysis on a big project from another marathon - I'm hoping to get this published soon, so stay tuned for that. There's still a lot of science on running that needs to be done, and there are a lot of questions waiting to be answered, so my hope is that videos like this will stimulate discussion and testable hypotheses. If you have anything you'd like to add to the discussion, feel free to leave a comment and/or share this video on your own blog - my only request would be that you link back here if you do.

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Runblogger is edited and authored by Peter Larson. Pete is an anatomy professor, writer, and a fanatical runner with a bit of a shoe obsession. He is co-author of the book Tread Lightly. Follow Pete on Twitter, Facebook, Google+, and via email.