Manufacturing issues are an issue for sure, but in my experience measuring shoes with C-calipers most hit pretty close to the advertised offset. With time, midsole compression will likely vary due to the reasons you suggest as well as things like the weight of the runner, and probably foot strike type. But, if you assume heterogeneity is a problem in all shoes, it should fall out as variation about a mean. So a 12mm offset may range a bit about that number, and a 8mm will do the same.
Slope is an excellent point. If you maintain the same height differential Adidas ZX 750 Femme
between heel and forefoot, slope will be more severe in a smaller shoe. Drop would be the same, but the slope would change. This is my problem with a lot of kid’s shoes – they are essentially mini versions of adult shoes and have a crazy downward slope from heel to toe. Scaling by size would be ideal, but I suspect that would increase manufacturing costs, would it not? That might make the logical choice unlikely to happen. In a perfect world, we’d all have custom shoes! The nice thing about zero drop shoes is you don’t have to worry about this – slope will always bee the same.The American Council on Exercise (ACE) has Nike Air Max 2017 Femme
been taking the shoe industry to task recently. Several months ago they put toning shoes to the test, finding that claims of increased muscle usage and calorie burn are not substantiated when tested in the Nike M2k Tekno Heren
laboratory. Here’s an excerpt from the ACE toning shoe study:“Across the board, none of the toning shoes showed statistically significant increases in either exercise response or muscle activation during any of the treadmill trials. There is simply no evidence to support the claims that these shoes will help wearers exercise more intensely, burn more calories or improve muscle strength and tone…”In other words, they put the marketing claims by the shoe manufacturers to the test, and they don’t stack up to the science.Yesterday, ACE released findings of a study of another red hot footwear trend. Specifically, they published results Nike Air Max Classic BW Hombre
of a study that examined how running in the barefoot-style Vibram Fivefingers shoes compares to actually running barefoot, and to running in a typical cushioned running shoe.Focusing first on kinematics, the Nike Air Max 97 Donne
results of the study indicated that all 16 individuals were heel strikers in the New Balance shoes. However, when barefoot or in the Vibram shoes, about half of the individuals switched to a forefoot strike landing pattern with greater plantar flexion of the ankle at the moment of ground contact. Additionally, regardless of foot strike type, the subjects exhibited less total knee flexion during stance when running barefoot or in Vibrams than when they were wearing the NB shoes (so form did change in some ways, even if foot strike pattern did not). When compared to both shod conditions, barefoot runners exhibited less pronation Nike Air Max 270 Womens
(I love this little nugget of data!).With regard to kinetics, the researchers honed in on vertical loading rates – loading rate refers to how fast the foot impacts the ground (for more on this, read this post Nike Air Max 270 Mujer
on loading rates). There is some debate about whether loading rate is a good predictor of the likelihood of suffering a running injury, but there exists evidence for at least an association between vertical loading rate and risk of certain types of stress fractures. Results of the ACE study indicated that forefoot strikers exhibited lower mean loading rates than heel strikers (see graph below). Among forefoot strikers, loading rates were significantly lower when the runners were barefoot or in Vibrams than they were when they were wearing the neutral cushioned shoes. The opposite pattern held for heel strikers – loading Nike Air Span 2 Mujer
rates were significantly higher when barefoot or in Vibrams. Another way of saying this is that the cushioned shoes produced the lowest loading rates of the three conditions for heel strikers, but the highest loading rates for forefoot strikers.The design of the ACE study was simple and straightforward. Researchers at the University of Wisconsin La Crosse recruited 16 healthy female runners to participate, and they provided each subject with a pair of Vibram Fivefingers Bikila running shoes. The subjects were allowed two weeks to acclimate to the shoes, and were instructed to run in them 3 times each week for up to 20 minutes on each occasion (or until discomfort occurred – I personally would advocate for an much slower ramp-up than this). After the two week acclimation period, the subjects were brought into the laboratory and Nike Air Max 90 Homme
they ran across a force platform under three footwear conditions (7 times in each condition): 1) barefoot, 2) in Vibram Bikilas, and 3) in neutral cushioned shoes (New Balance 625). Both kinematic (e.g., joint angles) and kinetic (force) measurements were made for each running trial.