The latest study by Roger Kram and co workers found the following:
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Methods
Ten experienced barefoot runners (mean + SD, age: 30.2 + 9.1 yrs) ran at 3.35 m/s with a mid-foot strike pattern on a Quinton 18-60 motorized treadmill modified to have a calibrated digital readout of speed. This classic treadmill has a rigid steel deck. All subjects gave written informed consent as per the Univ. of Colorado IRB. The inclusion criteria were: >18 years of age, mid-foot strike preference both barefoot and with shoes, run at least 25 km/week, including at least 8 km/week barefoot or in minimal running footwear (e.g. Vibram Five Fingers) for at least 3 months out of the last year, injury-free, self-reported ability to sustain 5 min/km (3.3 m/s) running pace for at least 60 minutes, and meeting the criteria of the ACSM
for minimal risk of exercise. To verify that subjects preferred a mid-foot strike pattern, they ran at their typical 10 km training pace across a 30m runway equipped with a force platform (AMTI, Watertown, MA) to which a sheet of paper was affixed. To orient foot placement with the force platform origin, we taped small pieces of marker pen felt to each subject’s right foot at 90, 70, and 33% of foot length (measured along the line between the heel and distal end of the second toe). We classified subjects as mid-foot strikers if the center of pressure at initial contact was between 33% and 70% of foot length. Subjects ran barefoot (BF) and in lightweight
cushioned running shoes (SH) (Nike Free 3.0; ~211 g/shoe). Subjects also ran barefoot on the same treadmill with 10 mm and 20 mm thick slabs of ethylene-vinyl acetate (EVA) foam affixed to the treadmill belt (Figure 2). The foam was identical to
that used in the running shoes. Prior to testing, subjects completed a 10 minute treadmill acclimation trial. The 4 conditions consisted of: shod, barefoot, barefoot on 10 mm foam, and barefoot on 20 mm foam, performed in random order. A 3-minute rest period separated each of the running trials. We calculated metabolic power
(W/kg) from rates of oxygen consumption and carbon dioxide production using the Brockway equation [5]. We calculated stride kinematics from high-speed digital video recordings (210 FPS, Casio EX-FH20).
Conclusions:
metabolic power requirements for running barefoot and in lightweight running shoes were not significantly different
metabolic cost for barefoot running was 1.91% cheaper on the 10 mm foam compared to the rigid surface
The reduction in metabolic cost on the 20mm thick surface was not statistically
significant
and finally
"Based on the “1% rule”, we would expect that running in 210g shoes to be 2.10% more expensive than barefoot running. However, according to our
data, it was essentially the same. 10 mm of foam cushioning (approximately the thickness of the forefoot shoe midsole) afforded a benefit of 1.91%.
Thus, it appears that the positive effects of shoe cushioning counteract the negative effects of added mass, resulting in a metabolic cost for shod running approximately equal to that of barefoot running.
http://www.asbweb.org/conferences/2012/abstracts/261.pdf
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Textured insoles use in normal gait and in neurology
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Vertical forces produce horizontal progression
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Textured insoles use in normal gait and in neurology
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Vertical forces produce horizontal progression
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