Changes

* '''Injuries due to impact. '''There is surprisingly little evidence that impact forces cause injuries, and there is even some evidence that lower impact forces are associated with higher injury rates. It's been suggested that excessive impact can result in injury, while more moderate impact can produce important adaptations that are necessary for improved performance.

* '''Injuries due to over pronation. '''The science around [[Pronation]] and injury rates is quite mixed. Part of the problem is science does not generally look at pronation directly, but uses arch height with the assumption that low arches pronate more. There is some evidence that high or low arches have slightly higher injury rates, or that different arch heights have different patterns of injury.

* '''Running shoes reduce injury'''. There is no evidence that running shoes reduce injury rates. Assigning shoes based on arch height does not change injury rate, nor is there any indication that more cushioned shoes have a lower injury rates. There is some evidence that motion control shoes cause greater leg pain and more training days lost, and this applies to all arch types.

* '''Raised heel. '''Another common feature of running shoes is a raised heel, which is intended to reduce the strain on the Achilles tendon. However there is little evidence that the raised heel actually reduces the strain on the Achilles tendon, and no evidence that the raised heel actually reduces Achilles tendon injuries.

* '''Barefoot running.''' The reduced impact seen with barefoot running led many people (myself included) to believe that this would in turn result in lower injury rates. However, there is no evidence that barefoot runners have a lower injury rates. More importantly, there is a growing body of evidence to suggest that the transition to barefoot running is associated with a high injury risk.

=The Myth of Running Shoe Types=

* A study of 10 experienced rear foot runners were tested with shoes of varying heel flare<ref name="Clarke-1983"/>. This heel flare is how much wider the heel is at the bottom than the top, and the flared heels reduced pronation from 12.6 to 11.1 degrees (1.5 degree decrease) when compared with any heel without any flare. In practice, it's rare for a shoe to be this narrow at its base, and other studies have not shown this effect<ref name="Nigg-1987"/><ref name="Stacoff-2001"/>. [[File:Clarke-1983-Heel-Flare.jpg|none|thumb|200px]]

* The heel counter is intended to link the heel of the foot to the shoe, but a study found that a rigid heel counter did not prevent slippage within the shoe any better than a flexible heel counter<ref name="Gheluwe-1995"/>. Also, the pronation of the foot can be twice as large as the pronation when measured on the shoe<ref name="Stacoff-2001"/>.

A common feature in running shoes is for the heel to be thicker than the forefoot, something that is commonly called "drop". In the 1980's a drop of 12-15mm was recommended to prevent Achilles tendon and calf injuries<ref name="Clement-1980"/>, but there is little evidence to support this:

* No studies have shown raised heels reduce Achilles (or other) injuries<ref name="van Gent-2007"/>.

* A study looked at 30 runners that were either assigned a minimal drop shoe (4mm) or were trained to adopt a midfoot strike (MFS) pattern<ref name="Giandolini-2013"/>. The minimal drop shoe reduced heel impact, but the MFS training had no effect.

* A study looked at 12 Rear Foot Strike runners using 16 combinations of midsole thickness and drop<ref name="HorvaisSamozino2013"/>. The lower drop shoes had a more midfoot strike pattern, but the thickness had no impact. (Ground contact time was greater with lower drop shoes.)

* A drop of 15mm or 7.5mm did not produce a significant reduction in Achilles tendon stress<ref name="Dixon-1998"/>.

=Injury Rates & Shoes=

** The neutral runners had higher levels of pain in the neutral shoe than the stability shoe. The pronating runners had higher levels of pain in the stability shoe than the neutral shoe. This is the opposite of most recommendations for shoe and foot type.

** Note that while the overall sample size was reasonable (81), each individual subgroup was quite small (5 to 18 runners) and variation within subgroup of results was large. The subgroups also varied significantly in weight, BMI, age, and years of running experience.

=Minimalist & Barefoot Running=

Most research looks at factors that might be related to injury risk, rather than injury rates directly. I found no studies that evaluated barefoot or minimalist running and injury rates. So while barefoot and minimalist running tends to have lower impact, it's unclear if this will have any bearing on injury rates. Of greater concern is some compelling evidence that the transition to barefoot or minimalist footwear is correlated with higher injury rates, especially stress fractures in the foot.

<ref name="Stacoff-2001">A. Stacoff, C. Reinschmidt, BM. Nigg, AJ. Van Den Bogert, A. Lundberg, J. Denoth, E. Stüssi, Effects of shoe sole construction on skeletal motion during running., Med Sci Sports Exerc, volume 33, issue 2, pages 311-9, Feb 2001, PMID [http://www.ncbi.nlm.nih.gov/pubmed/11224823 11224823]</ref>

<ref name="Gheluwe-1995">Van Gheluwe, Bart, Rudi Tielemans, and Philip Roosen. "The influence of heel counter rigidity on rearfoot motion during running." Sort 100 (1995): 250.</ref>

<references/>

[[Category:Science]]

[[Category:Injury]]