In case you doubt the impact of running shoes . . .

What do Orthotics and shoes actually do? Looking at data from a professional runner (click here if you can't read this post)

Posted by Steve Magness

Often times in research we focus on norms.  We look at the average effect of different

interventions and then apply them to everybody.  In this way, as a whole we get what 

the effects are for most people.  By doing this, sometimes we miss the individual effects.  

So in today’s first blog of 2013, I want to share with you some data on the effects 

of running shoes on data with one  individual athlete, Jackie Areson, who runs 

professionally for Nike.

In this data, what we did was stick her on a treadmill running at the same speed 

for every trial and set up my poor man’s high speed video analysis system 

(Casio Exilim + free motion analysis software), and took side and back views 

of her running.  What I was looking at was a comparison of shoes impacts on 

her mechanics.  Using barefoot as the “normal” and comparing from there.  We

 looked at all sorts of different Nike shoes (because that’s her sponsor), 

her old shoes she trained in in college (Brooks Ravena) and then just for the 

heck of it, each shoe with custom orthotics and without custom orthotics

 (she does NOT wear them) to see the effects orthotics had on her mechanics.

 So what you'll find below is a chart comparing I’ve included pictures below 

for you guys to take a look at that give a good indicator of things and includes

a few other shoes not included in the chart (because remember, this data is 

analyzed the old fashioned way so it takes a while to analyze it all!).

		Pronation	Pronation	Footstrike
	Orthotics?	change	Change (deg)	Degree	Ground Contact	Flight Time	Footstrike	Heel-toe drop
Lunar Fly	NO	7	10	93.6	0.214	0.114	whole	10mm
Lunar Fly	YES	7	9					10mm
Katanas	No	9	10	92	0.195	0.128	midfoot	4mm
Lunar Racers	No	9	13	93.4	0.2	0.123	whole	7mm
Lunar Racers	YES	9	11	98	0.209	0.119	Heel	7mm
Pegasus	No	8	10	100.7	0.214	0.104	Heel	12mm
Pegasus	yes	9	11	101.6	0.214	0.109	Heel	12mm
Vomeros	Yes	10	12	96.5	0.204	0.114	heel	11mm
Barefoot	No			93.8	0.195	0.119	forefoot	0mm

 Footstrike degree- 90deg= knee and ankle of foot are at 90deg angle. So 

greater the degree, means further out ankle is in front of knee at footstrike.

(Heel toe drop is using data from outside sources, not measured)

Pictures of shoes at footstrike- NO Orthotic on left.  Orthotic on right  

(except for Nike free, Katana, and streak XC- NO Orthotics on those)

What did we find with Jackie. 

 1. Orthotics almost always switch to a more pronounced heel 

strike (probably for a few reasons- They add weight, bulk, and increase 

the heel to toe drop.

2. Orthotics don't decrease pronation really, and don't have a uniform 

effect across shoes.  They tend to change things in different degress.

3. Footstrike is greatly influenced by shoe type.  It's hard to pick out 

definite trends, but the less heel-toe drop the more likely she lands forefoot 

or mid/whole foot.  Additionally, the lighter the shoe the more so.  Interestingly 

(and the data isn't up there) but for some reason she lands more whole foot with 

the Brooks Ravena then with comparable shoes in terms of heel/toe drop and 

weight.  My guess is because of the high toe spring changes her loading/landing 

pattern (because at this period of time, she protected her past foot injuries by not 

"pushing off" her big toe.) Also, the contrast between flats and shoes is remarkable.

4.  Using the simple measure of ground contact time tells you how minimal a 

shoe is.  It's a kind of "duh, that's obvious" conclusion, but a simple measure of 

comparing barefoot ground contact time versus shoe GC might be a useful measure.  

The difference (at the same speed) could give an indicator of how much the shoe 

"interferes".  So maybe a simple yet effective measure might be change in GC with 

each shoe?  (Just hypothesizing but how cool would it be to go to a shoe store and 

run barefoot, get a GC, then compare shoes effects on it, instead of doing pronation junk?)

5. Pronation- It varies.  And having junk in your shoe to stop it really didn't do much 

at all for Jackie. (and yes, pronation is natural, I just included in this analyse because 

it's easy to measure, everyone measures it, and I wanted to show the effects shoes 

had on it...)

Hopefully this data makes you think a little bit and gets you to see the individual 

differences that shoes create.

Thoughts, comments????  Mr. Magness always has good stuff to share 

. . . great job Steve!

Harry