brick94513-GoGoGo Mentor Group - Closed For Now! (Page 28)

Taken from the Science of Sport, Ross Tucker, Phd.

Heel vs. Midfoot vs. Forefoot: How do elite runners land?

I've finally gotten around to this post, which is probably two weeks in the making, and it follows on from our recent series on running shoes. That series began by looking at whether shoes are in fact as much a cause of injury as a cure, and then evolved into a discussion of how the running market is evolving. Twenty years ago, it was all about motion-control shoes preventing overpronation to prevent injury. Today, it's all about running "barefoot in your shoes", as companies try to go back to "natural" without selling you "the Emperor's clothes", in effect! (It's quite a long post, my apologies, but a lot of important information to get through...)

The next logical question is to ask how is the foot supposed to land during running? This question evolves out of the discussion of shoes. vs barefoot running, and is often at the heart of discussions on running technique. Very often, debates of "technique" tend to start from the feet, jump to the knees ("lift your knees") and then skip to the arms, and that's about it! We won't go into too much detail on technique today, focusing instead on only one of many aspects - the landing of the foot, and particularly, whether the elite runners tend to land on the heel, the midfoot, or the forefoot.

Elite runners footstrike patterns

Perhaps surprisingly, there are very few studies looking at elite runners and footstrike patterns during actual races. Despite this, until recently, the overwhelming majority of coaches and experts were advocating that heel-striking was the most effective technique, simply because most athletes did it. That claim will come up again, but the perception that it was most effective has, over the last few years, been changing. And with the advent of Pose and other running techniques, as well as the observation that not all elite runners are landing on the heel first, people have now begun to advocate that forefoot landing is better! So we have this 180 degree shift, often in the absence of any substantial data to support the claim.

I am sure that many will have seen this kind of assertion (this one is from Wikipedia):

Leaning forward places a runner's centre of mass on the front part of the foot, which avoids landing on the heel and facilitates the use of the spring mechanism of the foot. In other words, landing on the heel is bad, to be avoided...

Or there is this, from Gordon Pirie (admittedly somewhat older):

"Running equals springing through the air, landing elastically on the forefoot with a flexed knee..."

But what is "better"? Where science has yet to catch up with opinion

It's important at this point to ask the very pertinent, but infrequently asked question: "What does 'better' mean?". In other words, when people are advocating that it's 'better' to land on the forefoot, what do they mean? Is it faster? More efficient? Less injury-prone? The fact is, the word "better" is used without studies specifically looking at any single one of these aspects. And the 'prudence concept', as applied to science, says that you cannot say something is "better" unless it's been studied and compared to the alternatives. Unfortunately, the science lags behind in this regard.

So for example, above you have the quote that you are supposed to land elastically on the forefoot. That implies performance and efficiency, which might be true for short exercise, lasting a minute or two. But in an event like the marathon, are we sure it remains the "better" option? If you went out and ran 2 hours today, landing on your forefoot instead of landing as you've always done, what would be the likely outcome? Chances are, you'd be hurting for a few days, with calf muscles that you had perhaps forgotten you had! Worst case scenario, you'd be injured for months with an Achilles tendon injury. That is certainly not a desirable outcome. So there are problems with making sweeping statements about landing patterns.

But more than this, these kinds of statements are never grounded in proof. So for example, when it's written that you land "elastically", has anyone ever done the study of elastic energy return in different types of running? They haven't, but there is theory about it, and that's where these recommendations come from. So the approach in the discussion that follows is for me to adopt the role of "questioner", playing Devil's Advocate, with the humble admission that science simply does not know the right answer, only the possibilities...

Looking at one particular study - elite 21 km runners

So in the current climate where real evidence is scarce and opinions hold sway, let's take a look at one study that has examined footstrike patterns during running events. It was done in 2004 in Japan, and published in 2007 in the Journal of Strength of Conditioning (not sure of the reason for the delay - it happens sometimes in science!). The full reference, for those interested, is Hasegawa et al., J Strength & Cond., 2007, (21), 888-893

It was performed at the 2004 Sapporro International Half Marathon in Japan. The scientists set up a high speed camera (very important for accurate collection of information - beats YouTube science any day!) at the 15km mark of the race, and captured most of the runners coming through. In total, they were able to observe the foot strike of 248 men and 35 women, and characterize them as either heel-strikers, mid-foot or forefoot strikers. They also measured Ground Contact Time at the 15km point.

The finding - what do you expect?

Before giving their main finding away, take a moment to guess what they would have found...If you are anything like me, and have read the substantial amount on the internet and in books about how it's "better" (there's that word again) to land on your forefoot, then of course, your expectation might be that they found:

• The majority of runners land on the forefoot
• Those that DO NOT land on the forefoot are the runners who finish towards the back of the field

Well, if that's what you thought, you'd be completely incorrect...! Because the finding is the following:

• The vast majority (75%) of the elite runners land on the heel
• About 1 in four (24%) runners landed on the mid-foot
• Only 4 out of 283 runners landed on the forefoot

Those runners that landed on the forefoot did not finish in the first four positions, so the common argument (a flawed one) that the best athletes are forefoot strikers is not supported by this finding.

Possible conclusions - how you read the study is influenced by what you wish to prove...

So, given this, one is tempted to say that the landing of the foot makes no difference to overall performance. Of course, this is not necessarily true. As I wrote above, science is often taken out of context, and this is one such example. You cannot, for example, rule out the possibility that these heel-strikers might be a few seconds or minutes faster if they just learned to land on their forefoot! Personally, I think that's highly unlikely, and what is more likely is that they'll end up in rehab for Achilles injuries, but even that is a "bald assertion", based only on opinion!

Now, however, here is where it gets interesting, and this is where the forefoot advocates got quite excited. When the researchers divided the finishers into groups of 50, they started to see something of a change in mid-foot landing as you moved further down the list. In otherwords, there was a higher percentage of midfoot strikers in the first 50 runners than in the second, and then third, and so on. The graph below shows this for heel-strikers and mid-foot strikers (I haven't shown forefoot, because it's so tiny and insignificant by comparison):

At first glance, the conclusion from this graph is that if you want to be a faster runner, finishing higher up in the overall order, then you should be a midfoot striker, not a heel-striker. That's how many people interpreted the finding. And this may well be true. Unfortunately, there is another possible reason it looks like it does - perhaps it's simply a function of running faster.

Speed and footstrike

In otherwords, you naturally shift your contact point with the ground further forward when you run faster. The average speed, incidentally, of the first 50 runners was 3 minutes 3 seconds per kilometer. The second group of 50 runners averaged 3 minutes 10 seconds per kilometer. Hardly a big difference, but given the range (the 50th runner is at least a minute behind the 1st runner), is it possible that groups of 50 is too big, and that all this "finding" represents is a speed effect on footstrike?

The point is, this study does not allow you to differentiate between three possibilities:

1. Faster runners are midfoot strikers (could be co-incidence or some other cause); or
2. Midfoot strikers are faster runners (and therefore we should all change our running style and land on the front part of the foot more); or
3. All runners would eventually be midfoot strikers, if they just ran fast enough!

This is another classic example of how a scientific result can be taken out of context and applied to give advice that may not be 100% correct.

Personal opinion and implications of this study

My personal reaction to this research, when it came out, was that it disproved the popular theory that all runners should be aiming to become midfoot or forefoot strikers. Most of us (well, I'm in this group, apologies if you are not) are nowhere near the elite level, and we're often told by experts and coaches that the elite are landing on the ball of the foot or the midfoot, and so we should too.

But the next time you think of running like Gebrselassie and trying to land mid or forefoot, consider this: if you go out and sprint 100m, you're likely to run on your toes the whole way - because you're running faster, you land more on the mid-foot, or even the forefoot.

Sprinting as you are, you'll probably cover 100m in 14 seconds, which puts you only 1 second ahead of a Bekele or a Gebrselassie in a 5000m race, so is it any wonder they are midfoot strikers on the track - they're running as fast as most of us sprint? The point I'm trying to make is, if you ran the speed they did, you'd be a mid-foot striker too! But just as I suspect they change as they slow down, we all do. So why, and on what basis, should you try to run with the same foot strike when you are running perhaps 3 minutes per kilometer SLOWER than them? Again, these are relatively bald assertions, but hopefully you recognize the implication of speed on foot strike.

So when you go out and run a 3 hour, or a 4 hour marathon, that's another story altogether. And what the Pose running study at UCT showed me a few years ago is that if you change the landing of the foot, you predispose the athlete to injury - that study took a group of runners and within two weeks had them all running on the midfoot (please don't write in to say that Pose doesn't mean midfoot, because Romanov was the coach and he was happy with their technique!). Two weeks later, they all broke down with Achilles tendon injuries!

Why? Because sitting where you are right now, if I was to walk into your office or your home and take you outside and ask you to please run landing on your forefoot or midfoot, I can pretty much guarantee that the way you would achieve this is to point your toe down...you're probably doing this as you read this - contract the calf, and point your toe away from your body, like in ballet. Now imagine your body weight landing on that contracted calf muscle 85 times a minute for 4 hours. That, simply put, is a recipe for disaster.

However, if you can gradually change your landing, then I do believe that you can shift your footstrike. But it's a gradual process. And more important, what is the point? There is no evidence that heel-strikers are injured more, no evidence that mid-foot runners are faster and perform better than heel-strikers, and so the ultimate question is:

Why would you want to change your foot landing to begin with? Science has little to offer you in support of this. And so my advice, having read this far (well done!), is to forget about the possibility that you're landing "wrongly", and just let your feet land where, and how they land, and worry about all the other things you can when you run!

If there is one thing you change in your running, don't focus on your footstrike, but rather on WHERE your feet land relative to your body. Because if you are over-reaching and throwing your foot out in front of you, that's a problem, but what happens when the rubber meets the road is less relevant!

I'm sure there's more to this topic, based on your questions and comments. As usual, fire away! And remember the humble admission from earlier - science, believe it or not, does not know the answer definitively! (just as we can't tell you why Bekele is so dominant in World X-Country!)

Ross

Thanks for all the input on my QOTD last night... all good stuff.

So here's what happened today: I woke up at 0500 all jacked up for my week prior to my first Sprint.  I was thinking I'd do a OWS but at 0900 I changed that to a Masters Swim session at the Gym.  I had a break from work at 1000 so I did a "Transition Visualization" (as learned in my Clinic over the weekend) and got spooked… so I changed my training plan to my normal Monday [T1, Bike, T2, and Run] on the Spring Sprint race course.  So 1/4 mile into the bike I realized I had absolutely nothing in my legs (most likely fatigue from my coast ride yesterday).  The head winds around the Island were brutal and my legs were totally burning.  After turning T2 and getting on the run course I wussed out and only did a 1/4 mile.  It was a legit brick but I just didn’t have the gas...  Training Log posted.

The rest of my week looks as follows... Tuesday= OWS; Wednesday= light run and complete bike PMCS; Thursday= OWS and light bike ride; Friday= 100% Tri-gear shakedown inspection and maintenance, light bike/short run (just to stay frosty). Saturday= Sleep in... then get ready to hit the clubs with my boyz and hammer beer and shots all night till Sunday morning when Transition opens and get my race on!

Yeah... How many of you actually believed that last bit of nonsense.  HA-HA!  Hope I can sleep well this week(?).

David,

Condolences and prayers on your family's loss.


Best- 

Clan Woody

Trying to get prepared for my race on Saturday.  I think I got the last of my items taken care of today.

When I was at the Sea Otter, this guy hears me talking to my wife about lights while our kids were playing.  He starts talking to me about lights and then proceeds to start pulling out all of these prototypes for new lighting systems out of his backpack.  Just so happens, the guy ends up being the proprietor of JetLites in Reno, NV.

So, I gave him a call today and he hooked me up with one of his lights at a great price.  Plus, I found out he will be at my race providing battery support for their product.

Here's the one I bought:

http://www.jetlites.com/blast-hid-1000

Article from BT archives:

Physics

The work required to move a bike down the road is measured in watts. To define it very simply, Watts = Force x Cadence, or how hard you press on the pedals multiplied by the number of times per minute you apply this force.  Two cyclists, Bob and Bill, weigh the same, have identical bikes, identical aerodynamics and are riding next to each other at the same speed on a flat road. Because they are riding the same speed and we’ve controlled all the other variables, they are performing the same work, ie, riding at the same watts. However, Bob is mashing at 70rpm while Bill spins at 110 rpms. Bob’s pedaling style dictates that he press hard on the pedals with each stroke. But he does so less frequently than Bill, who is pushing lightly on the pedals but much more frequently.

Physiology

Low cadence cycling requires us to push harder on the pedals, but what does this mean at the level of our leg muscles? To generate that higher force contraction, your leg muscles must recruit more fast-twitch muscle fibers vs slow-twitch fibers.

Slow-twitch fibers:

• Primarily burn fat for fuel, an almost limitless supply of fuel for even the leanest athlete.
• Are very resistant to fatigue: they are built to go and go, all day.
• Recover quickly when allowed to rest.

Fast-twitch fibers:

• Burn glycogen for fuel. This glycogen is stored within the muscles and is in relative short supply, about 2000 calories for a well-trained, well-fueled athlete.
• Fatigue quickly, are NOT built to go all day.
• Take a long time to recover before they can be used again.

Matches

CyclingPeaksSoftware.com developed this analogy. I think it’s a good one, but I like to elaborate a bit. Imagine your legs are a book of slow and fast burning matches. The purpose of training is to increase the size, number and flavor (ratio of slow and fast) of your matches, depending on the demands of the race. Sports requiring short bursts of speed favor athletes with lots of fast matches. Endurance events favor slow matches. You can use either match to do the work of racing but the total number of matches in the book is finite. And once you burn a match, it’s gone - you can’t get it back.

Now, back to our discussion of cadence. You are riding on a flat road, approaching a hill that will take you about a minute to climb. You will likely do one of four things:

1. Shift to a gear that feels comfortable and/or powerful for you. You feel good when you climb at 60-70rpm so you do that, shifting to the middle of the cassette.
2. Climb at 60rpm since you showed up to the ride with a 21-11 rear cassette.
3. Say “The hill will only take me a minute to climb. I don’t want to lose any speed so I’ll hop out of the saddle, stand up and hammer up the hill. I’ll recover on the decent.”
4. Shift into your 25 cog and spin up the hill at 85-90rpm.

Option #1: Low cadence = high force = high fast twitch recruitment = burning matches that you may need towards the end of the run. Forget “feels” powerful. Power is watts to the wheel, period. If you can climb a hill at the same speed (equal watts) at 60rpm or 90rpm, choose 90rpm. Conserve your fast twitch fibers so you can recruit them later in the run.

Option #2: See Option #1 and always bring enough gears to the race. In my experience, the only people who attach sexual competency issues to the gearing on their bike are folks who don’t climb. I have (no lie) six cassettes hanging in my garage that I swap on and off my bikes according to the terrain of the ride. I have everything from a 27-12 to a 19-11. You can flatten any hill if you have enough gears on your bike J.

Option #3: Standing = power spike = high fast twitch recruitment = you know the drill. From riding with a powermeter for many years I can tell you that if you don’t have a meter it is VERY difficult to stand in the saddle and not toss out huge watts for a brief amount of time. It might “feel” ok, but chances are very high that you just burned a few matches with your little burst.

Option #4: Bingo! Spin up the hill, burn slow, not fast matches so you can use those matches on the run, burning the last one as you cross the finish line.

What is the optimal cadence?

Ok, so I’ve sold you on the value of high cadence vs low cadence. But what is the optimal cadence? In my experience, most athletes should ride at a cadence of 88-95+ rpm. A few notes here:

• Notice that this cadence is right in line with an optimal running cadence. I believe it is hard to run off the bike at 90+ rpm if you’ve been cycling for hours at 80rpm. You’re asking your legs to make a huge adjustment, in addition to the difficulty of transitioning from cycling to running.
• More experienced and stronger cyclists will be comfortable within a wide range of cadences. When I began cycling, anything under 88rpm felt like mashing, while 95+ felt too fast. I was always searching for that right gear. Now, after many, many miles, I can ride equally comfortably at 78-82 or 100-105. My tool kit is much larger (see below).

Cadence and Training

Some coaches prescribe low cadence intervals as a method to train your body to push harder on the pedals. However, consider the importance of specificity: if you want to run longer, run longer; if you want to swim faster, swim faster; if you want to ride the bike farther, ride the bike farther. If you want to ride the bike faster at 92rpm, then ride the bike fast (high watts, ie greater work output) at 92rpm. 

Having said that, both low and high cadence work are useful for increasing your “cadence comfort,” or your comfort within a wide range of cadences. By this I mean you have strong, resilient, well-adapted legs that can handle a broad range of cadences, including that high force/high wattage contraction that may happen if you run out gears, decide to climb out of the saddle, etc. You have a large tool kit to handle a broad range of conditions.

The most common tool is a period of low cadence intervals fitted into the early season. My guidance:

• Beginner: useful tool early season for developing sport-specific strength and “cadence comfort” quickly in their cycling careers.
• Intermediate: useful early season, see above. However, after 4-6 weeks of low cadence intervals, transition to lactate threshold intervals at normal, time trial cadence. Reserve low cadence for fartlek-style training - grind up a hill at random to build or retain this cadence comfort.
• Advanced: high watts at race specific cadence is more useful. These athletes have already developed cadence comfort and a period of low cadence intervals is, I believe, often an unnecessary step. I reserve low cadence work for:
  1. Fartlek, see above.
  2. The last hour of long rides, to force recruitment of fast twitch fibers when they are already on the edge.

• Athletes training with power: the ability to measure watts while cycling at very low cadences creates possible exceptions to this guidance. The power-training athlete can truly turn his bike into a piece of gym equipment and is, I believe, more justified in adding low cadence intervals to his training routine.

In summary:

• Focus your training to develop speed (wattage) at your race-specific cadence - the cadence you plan to race at. My suggestion is 88-92+ rpm, with weaker, less experienced cyclists targeting the high end of this range.
• Supplement this race-specific training with informal low cadence/out of the saddle work to build this resiliency above and expand your range of comfortable cadences. See my guidance above for how to build low cadence intervals into your particular training season.
• Bring the proper gearing to the race! And when in doubt, bring more gears! I think a compact crank is an excellent tool for all cyclists to consider.
• Bring these fast, strong, resilient legs to the race. Put them on a bike with the proper gearing. Exercise smart, disciplined pacing and climbing skills to limit the number of matches you burn on the bike course, burning that last match at the finish line!