Justin,

I’d put money down that my contact phase is shorter and cadence higher in XC flats, Vibrams, and barefoot. Shouldn’t be too hard to put some numbers on that from the raw videos. I hope to get some of my students on film next semester to boost the sample a bit as an exploratory pilot study, and then I have an XC runner that may take this on as a full-blown project next year.

Pete

Jason

Thanks for the response Ian. You make an excellent point about
allowing time for adaptation to occur. People all too often want
change to happen instantly, but it takes time. Too many people push
too hard and wind up getting hurt. It needs to be thought of as a long
term processs of relearning – it doesn’t happen overnight.
Incidentally, this is a big flaw in many academic studies that compare
metabolic efficiency between gaits. You can’t just ask a heel striker
to run forefoot on the spot and make a comparison – I wouldn’t expect
anything other than that they would be less efficient.

Pete

On Wednesday, January 26, 2011, Disqus

Katie,

Thanks for the comment – I run almost exclusively in lightweight trainers or
flats, and am glad I made the switch. The Vibrams are nice – I use them
about once a week, but they are pricey for what they are. A more runner
specific model called the Fivefingers Bikila is coming out next year.
Regarding barefooting on the treadmill, the friction can do a number on your
feet, so I’d recommend at least a pair of socks.

Pete

Ian,

Thanks for the comment – this kind of feedback is invaluable to a newcomer
to the field like me. Regarding the points you made:

1. I’ll be the first to agree that treadmills are very different than
overground running – I actually hate running on a treadmill in most cases.
We started out shooting outside, mostly just playing around, and I hope to
get back to it in the Spring or next Fall. The bungee idea is an
interesting one.

2. Contact time is one thing I definitely plan to look at – I have the
strong sense that I’m in contact during stance for a shorter period of time
when barefoot or in Vibrams, but haven’t put any numbers on it yet.
Regarding vertical force, how would you measure strain in the videos? I can
definitely see the treadmill bed drop at foot contact – is this what you’re
referring to? I’d like to get force plates or pressure mats, but don’t have
the funds yet.

3. I definitely see the correlation between heel to forefoot drop and
footstrike – I’m landing much more flat-footed as the drop decreases.

4. Regarding footstrike, I’m using midfoot as equivalent to flat foot. No
matter what we do, it seems we are trying to create categories for what may
essentially be a continuous spectrum of strike positions from hard heel to
pure forefoot. Even among heel strikers, I’ve seen a huge degree of
variability in slow motion videos we shot at the Manchester Marathon. Some
are striking way at the back of the heel with the toes pointing way up, and
others have a more mild heel strike like my own. The distinct forefoot
strikes I’ve watched almost always seem to land way up on the lateral
forefoot – very interesting and very different.

5. I’m in total agreement that the heel-lift plays a major role in forcing a
heel-strike. My question is how good/abundant are the data showing that a
heel-strike is a bad thing? I think that’s a question that people would
like to see answered in a conclusive way. Based on what I’ve seen and read,
I’d probably agree right now that a heel strike is not the way we naturally
run, but is more a result of conditioning or being forced by our footwear.
For example, my kids land almost pure flat-footed when I filmed them running
barefoot (3 and 5 at the time I filmed them). Are there papers correlating
footstrike patterns with injury likelihood? I’ve been reading mostly
straight biomechanics literature so far, haven’t gotten much into the injury
data.

Pete

I look forward to reading about larger studies you do with your students.

Pete, looks like the following comments have surpassed my basic view of the issue ;) My view of the ‘correct’ form is mostly from reading all the various articles regarding running, shoes and walking form:

http://www.popularmechanics.co…
http://www.kk.org/cooltools/ar…
http://www.dailymail.co.uk/hom…
http://blog.wired.com/wiredsci…
http://nymag.com/health/featur…
http://www.popularmechanics.co…

as well as personal experience. I’m fairly new to running. I’ve had a pair of Brooks trail shoes for a while but only started to ‘really’ run this year. I’d alway felt running to be a ‘jarring’ experience, mostly as I was running heel-toe (landing on heel, launching from toes) and was pretty uncomfortable with it. I started reading the above articles, found vibram shoes then started running more and more, as Vibrams, and their necessary barefoot-style running form, allowed me a more comfortable run (less jarring on bones and joints.) The way I see it, the foot is a really good spring-loaded lever. By landing on the front half of the foot (including the mid-foot), it seems you allow that spring-loaded lever to function as it shoud, as opposed to landing on the pivot point (ankle), bypassing the ‘spring’ (achilles/calf.) I didn’t mean to imply that your videos above didn’t show fore or mid-foot landing, it just seemed to me not as obvious as I’d thought it would. I’ve not seen myself in such a manner, so I could probably be landing just the same. It just feels a bit more pronounced when I’m actually running.

1. Treadmills tend to pull your foot back on the belt since wind resistance and inertia are absent. A good way to simulate an outdoor gait is to use a bungee system pulling back from about the center of gravity of the runner. This allows your limbs to be propulsive.
2. Contact time (as pointed out below) and vertical force are a good measure of the effect of footwear geometry. This can be measured from the videos knowing the strain (deflection) of the treadmill.
3. Geometry is very important in where and how you load your leg during the gait cycle. If you cut open the shoes, you will see the following heel to forefoot drop (center of heel to ball of foot): Barefoot 0 mm, Sock 0 mm, Vibram 0 mm, Sir Isaac 5 mm, Kilkenny 8 mm, Launch 12 mm, Adrenaline 13 mm, Crocs 12 mm?, Nike Free 12 mm.
4. Foot strike definition is not well defined. Newton Running regards a midfoot/forefoot strike as under the metatarsals heads, basically the ball of the foot. Strict forefoot is more like Pose running (closer to a sprinters gait). Midfoot is often described like Chi Running, landing flat.
5. A heel lift inevitably causes your leg to load early in the gait cycle, before your leg is properly (and protectively) flexed. Anyone using running shoes since the early 1970s most likely has been conditioning themselves to heel strike. Guaranteed you didn’t as a kid running barefoot.

Disclaimer: I’m director of product development and education at Newton Running Company, and like Peter am a University lecturer, lifelong runner (former professional endurance athlete) and worked with the likes of Nike and Salomon for many years.

I’m also curious as to how the different footwear affects the amount of time that one’s foot remains on the ground, since that is also a measure of efficiency. It’s hard to tell with the naked eye, and a treadmill affects that too, but I think I can see some differences as to where you pick up your feet as well as how/where you put them down.

Did you feel any of the differences while you were running or was it mostly noticeable when you checked the video?

This is great initial research. Since I don’t have access to a lab and funding I will have to live vicariously through your research.

I have a couple recommendations for future research.
-Use individuals not aware of the test purposes. They may consciously modify their running technique if they understand the test purposes.
-Do study participants exhibit a measurable change in foot strike over a set time period when switching from Stability to Barefoot shoes?
-Is there an increase in injury rates when consciously switching to forefoot strike? I have heard many coaches, including Joe Friel state that switching to a forefoot strike will increase injury levels. I wonder if this proves true and if so under what conditions.

As always, there are a lot more questions then answers, so I don’t expect everything to be answered.

I can’t speak for others, but mine doesn’t change from treadmill to road or to rough trail. Leg angle might change a bit, but foot landing is almost always the same (for me): I almost always tend to land on the outside edge of mid-foot, with a rolling motion towards the big toe. In appearance, it probably looks much closer to a flat-footed landing, but it really isn’t.