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* '''Running shoes reduce pronation'''. Motion control shoes (the highest level of anti-pronation) only reduce pronation by about 21.5% when compared with a simple cushioned shoe. It seems unlikely that this is enough to produce any real -world affecteffect.

* '''Barefoot running.''' The reduced impact seen with barefoot running late in 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, and they there is a growing body of evidence to suggest that the transition to barefoot running is associated with a high injury risk.

There is good evidence to support the widely held belief that injury rates among runners are quite high, with estimates of injury rates varying between 20% and 80% of runners<ref name="van Gent-2007"/>. It is widely assumed that excessive impact forces, and excessive pronation cause running injuries , and that running shoes are therefore designed to mitigate alleviate these problems<ref name="Nigg-2001"/><ref name="HintermannNigg1998"/><ref name="McKenzie-1985"/><ref name="Johnston-2003"/><ref name="Heil1992"/><ref name="Yamashita-2005"/>. This leads to the common recommendation that different types of shoes should be recommended based on a runners arch height. In fact, REI<ref name="www.rei.com"/>, Zappos<ref name="www.zappos.com"/>, Runners' World<ref name="www.runnersworld.com"/>, and Road Runner Sports<ref name="roadrunnersports.com"/> all include this advice.

The relationship between impact and injury is less clear than one might suppose. It has been suggested that while excessive impact can result in injury, lower levels of impact result in positive adaptation are the stimulus for improved strength and remodelingperformance<ref name="Hreljac-2004"/> and these impacts may be an important part of training<ref name="Nigg-1997"/>(See [[Supercompensation]]. ) There is evidence that the impact seen in running does not result in injury:

[[File:ImpactAndInjuryBahlsen1988.jpg|rightnone|thumb|300px| A graph of peak vertical impact force and the frequency of running-related injuries<ref name="Bahlsen1988"/>.]]

There is good evidence that increased cushioning does not reduce impact<ref name="Robbins-1990"/><ref name="WrightNeptune1998"/><ref name="ClarkeFrederick2008"/><ref name="NiggBahlsen1987"/>. However, runners who are normally run in shoes have greater impact forces when running barefoot, but this is reversed with barefoot experience<ref name="Robbins-1990"/><ref name="Divert-2005"/><ref name="Robbins-1987"/>.

The evidence indicates that even Motion Control shoes can only reduce pronation by around 1.5%, which is unlikely to be enough to make any real-world difference. * A meta-analysis of 5 studies showed that motion control shoes can reduce pronation when compared with barefoot or simple cushioned shoes, but only by about 2%<ref name="Cheung-2011"/>. * A study compared a Motion Control shoe (MC) with a Cushioned shoe (CT) with 20 high arched (HA) and 20 low arched (LA) runners<ref name="Butler-2006"/>. The motion control shoe was the New Balance 1122 and the cushioned shoe was the New Balance 1022. The change in pronation (in degrees) is shown below. {| class="wikitable"! ! CT! MC! Change|-| LA| 7.9| 6.3| 1.6|-| HA| 8.0| 7.4| 0.6|}* A study of 10 male runners compared "normal" running shoes with and without a 10 degree orthotic wedge showed the orthotic reduced pronation by 6.7 degrees<ref name="PerryLafortune1995"/>. * A study of 25 inexperienced, over-pronating female runners looked at differences in pronation in motion control and cushioned shoes, before and after a 1.5 Km (~1 mile) run<ref name="CheungNg2008"/>. These runners only averaged 2.1 Km (1.3 miles) per week and had pronation of more than 6 degrees. The Motion Control shoes reduced pronation by 3.3 degrees before the run, but after just this short run the Motion Control shoes made no difference. The motion control shoes were Adidas Supernova Control and the cushioned shoes were Adidas Supernova Cushion. The results are shown below:{| class="wikitable"! ! CT! MC! Change|-| Before 1.5 Km run| 13.9| 10.6| 3.3|-| After 1.5 Km run| 17.7| 17.7| 0|}* A study of 10 experienced rear foot runners were tested with shoes of varying heel flare<ref name="Clarke-1983"/>. This seems unlikely 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 significanttwice as large as the pronation when measured on the shoe<ref name="Stacoff-2001"/>.

* 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"/>.

* Three studies compared assigning evaluated the idea that shoe type should be determined by arch height<ref name="KnapikTrone2014"/>. Runners were put into two groups, with one group assigned shoes based on the shape of the arch with , and the other group just assigning assigned a single stability shoe type to runners regardless of their arch<ref name="KnapikTrone2014"/>. These studies found no difference in injury rates. The studies were done by the US Army (2168 men, 951 women), Air Force (1955 men, 718 women), and Marine Corps (840 men, 571 women).

** The neutral runners had higher levels of pain in the neutral shoe than the stability shoe, and the pronated . 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.)

* Instances There are some instances of Metatarsal Stress fractures in runners who had changed to minimalist shoes, with no other changes in their training habits<ref name="GiulianiMasini2011"/>.* A study of 99 runners who were randomly assigned a traditional cushioned shoe (Nike Pegasus), partial-minimalist shoes (Nike Free 3.0 V.2) or minimalist shoes (Vibram 5-Finger Bikila)<ref name="RyanElashi2013"/>. The runners had a minimum of 5 years' experience and had no injuries in the previous 6 months. The runners took part in a 12 week training program in which they gradually adopted their assigned footwear . They increased their time in the assigned footware from 10 min (19%) in week 1 to 115 min (58%) in week 12. The Runners in the two minimalist shoes had a greater rate of injury compared with runners in the traditional shoes, . Runners with the partly minimal shoes (Nike Free) having had the highest overall injury rate and . Runners in the minimalist shoes (5 Fingers) having had the greatest shin and calf pain. * A study looked at bone marrow edema in 36 experienced runners transitioning to Vibram FiveFingers (VFF) shoes<ref name="RidgeJohnson2013"/>. 36 experienced The runners were randomly assigned VFF or their normal running shoes, with the VFF runners gradually transitioning based on the recommendations of the Vibram at that time. Only 1 of the 17 runners in the control group showed signs of a bone marrow edema, compared with 9 of the 19 VFF runners. =See Also=* [[Shoes| Running Shoes]]* [[The Journey to Minimalist Running]]* [[Toughening Feet]]* [[Modified Nike Free]]In 2014, Vibram settled a lawsuit that they made false and unsubstantiated claims that their FiveFingers shoes could reduce injury rates.