Latest revision as of 19:41, 8 March 2017

The design of most running shoes does not match the available science, and understanding this will help you know What to Look for in Running Shoes. The commonly held beliefs follow this logic: Runners get injured due to impact and excessive Pronation, running shoes reduce impact and pronation, and therefore running shoes reduce injury. Unfortunately, every part of this rationale seems to be flawed. There are other aspects of shoe design, such as the raise heel or arch support that have even less evidence to support them.

• 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 impact. There is good evidence that increased cushioning does not reduce impact forces. Runners who normally run in shoes will have higher impact when initially running barefoot, but after adaptation the impact forces are actually lower without shoes.
• Running shoes reduce pronation. Motion control shoes (the highest level of anti-pronation) only reduce pronation by about 1.5% when compared with a simple cushioned shoe. It seems unlikely that this is enough to produce any real-world effect.
• 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.
• Arch support. Often running shoes have a raised area under the arch that is intended to provide support. I found no evidence to support this idea.
• 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.

1 The Myth of Running Shoe Types

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^[1]. It is widely assumed that impact forces and excessive pronation cause running injuries, and that running shoes are designed to alleviate these problems^{[2][3][4][5][6][7]}. This leads to the common recommendation that different types of shoes should be recommended based on a runners arch height. In fact, REI^[8], Zappos^[9], Runners' World^[10], and Road Runner Sports^[11] all include this advice.

This image probably originated with the "The Running Shoe Book"^[12].

2 Impact & Injury

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 are the stimulus for improved strength and performance^[13][14].

Footstrike impact metrics.

There are various ways of evaluating impact, and not all studies use the same metric or are not clear on which metric is used.

• Active Peak is the greatest force or acceleration detected during foot strike.
• Peak Impact is the greatest force seen during the initial landing.
• Loading Rate is how rapidly the forces build up and can either be averaged over parts of this section of the graph or an instantaneous peak can be used. (That would be peak rate of change of impact, not peak impact.)
• Where the impact is measured from may be important. Impact can be measured as force between the foot and the ground using a pressure plate, the acceleration of the foot/shoe, or the acceleration of the tibia.
• Impact is sometimes normalized to body weight, but not always.
• Not all studies have evaluated impact when the subjects have had time to adapt to a particular shoe (or lack of shoes). It seems reasonable to me that a runner's impact levels will be different in unfamiliar footwear.

There is evidence that the impact seen in running does not result in injury:

• Impact forces are not related to injury rates in epidemiologic studies^[14].
• A study of three runners found that impact forces at the heel are not related to the forces at common injury sites such as the ankle, Achilles, or knee^[15].
• A study of 131 runners showed that injury rates were highest in those with the lowest impact levels^[16].
• The impact forces of 210 notice runners were evaluated for the symmetry of their impact forces and their subsequent injury rates^[17]. The injured runners had greater symmetry than the uninjured, and there was no difference between the impact forces on the injured side compared with the uninjured side. (However, see the results on the companion study below).
• Another study of the 210 notice runners mentioned above found that Loading Rate was related to the injury rate of male (but not female) runners, though the female runners had a higher Loading Rate than the males^[18]. However, when time spend running was considered, the relationship between Loading Rate and injury disappeared.
• A review of the available research in 2007 found no relationship between impact and injury rates^[1].
• A review of the available research in 1992 found no evidence that injury rates were related to hard or soft surfaces^[19]. (Of course, you can't assume too much about the impact rates from the surface.)

However, there is also some evidence of a relationship between higher impact and stress fractures, but not other types of injury:

• A study that compared 20 runners who had never been injured with 20 runners that had prior injuries found that peak impact rates were higher in those that had been previously been injured^[20].
• A study of five female runners who had previously had a stress fracture showed higher peak impact forces than subjects without stress fractures^[21].
• A meta-analysis of 13 studies found that while there was no correlation between rates of stress fracture and impact, there was a relationship for the rate of loading^[22].
• A study of 20 female runners with a previous history of unilateral tibial stress fractures showed they had high rates of impact, but not greater peak impact than matched controls^[23]. Strangely the injured runners were no more asymmetric than the controls, with higher impact levels in both injured and uninjured legs.
• A comparison of runners with previous tibial stress fractures found that the injured runners had greater braking and impact forces than the controls^[24]. However, the injured runners

It seems possible that Loading Rate is related to stress fractures, but it seems unlikely that impact is related to other injury types. (It's estimated that stress fractures account for 0.7% to 20% of clinical injuries^[25].)

3 Pronation, Arch Height & Injury

The evidence for the correlation between pronation and injury is rather mixed. This is compounded by the use of arch height as a proxy for pronation.

• An analysis of 29 studies showed that high or low arched feet had slightly higher risk of injury than normally arched feet^[26].
• There is also evidence for the opposite conclusion, where high or low arched feet have a lower risk of injury^[27].
• One study found that while injury rates are the same for different arch heights, the location of the injuries varies with arch height^[28].
• Another study found that while injury rates are similar for different arch heights, those with low arches had more expensive injuries^[29]. (This was a study in the military, where such expenditure is more easily tracked.)
• A year-long study of 927 novice runners showed no correlation between arch height and injury rates^[30].
• A study of 1597 runners found that those with the lowest arches were 2.7x more likely to have knee (patellofemoral) pain than those with the highest arches^[31]. (Note that this study used navicular drop as an indicator of pronation, but other factors contribute significantly to navicular drop^[32].)
• A retrospective study found that arch height was not different between runners who had previously been injured and those that had never been injured^[20].

A graph of peak vertical impact force and the frequency of running-related injuries^[16].

4 Running Shoes & Impact

There is evidence that increased cushioning does not reduce impact, and may even increase it.

• A study of 14 runners using three different midsole harnesses (25, 35, 45 Shore) at three different speeds showed no difference in impact measured with a force plate for the different shoes^[33]. The impact did increase with increasing pace, and based on my shoe reviews the three shoes are relatively soft (most are ~45 Shore, with some Hoka shoes going as soft as 35 Shore).
• Comparing shoes with the same midsole hardness but fore/heel heights of 0mm/4mm, 8mm/12mm, 16mm/20mm, plus barefoot found there were no impact changes between the shod conditions^[34]. The runners only had 5-10 minutes to adapt to each condition, and it's unclear if any of the runners had barefoot experience. The impact for the barefoot condition was lower than shod, but the runners changed to a forefoot landing when barefoot.
• There was no difference found in impact forces between two shod conditions where one type of shoe provided 50% more cushioning than the control shoe^[35].
• A study of 93 runners that compared three hardness shoes (40, 52, & 65 Shore) showed that the softer shoes had the greatest impact peak^[36]. Based on my measurements of running shoes, the range of firmness in this test goes from somewhat soft to remarkably firm. The impact ranged from 1.70x Body Weight (BW) for the hardest shoe, to 1.64x BW for the medium and 1.54x BW for the hardest. The impact was measured using a force plate and used the impact peak, not the active peak (see diagram above) which is why the impact is much lower than other studies that report 2.0-2.4x BW. The study found that running increased their joint stiffness in the softer shoes, which may be the cause of the greater impact.
• Highly cushioned Minimax shoes and conventional shoes may result in more knee stress than minimalist shoes^[37]. The study looked at 20 male runners and measured impact with a pressure plate while filming the leg movement. The leg movement was then used to estimate knee stress based on a model that used knee movement and angle. The Minimax shoes were Hoka, the minimalist shoes were Vibram FiveFingers, but the conventional shoes were not specified. The runners were not familiar with the non-traditional shoes, and only had 5 minutes familiarization. The study also found greater contact forces in the non-minimalist shoes.
• Runners who normally run in shoes have greater impact forces when running barefoot, but this is reversed with as a runner becomes adapted to being barefoot^[38][39][40].
• In a study somewhat related to shoes and impact, a study looked at impact and running surface and found there were not impact differences between concrete, synthetic track, natural grass, and a treadmill^[41]. The study used a pressure sensor in the shoe's insole and an accelerometer attached to the Tibia, with the runners wearing non-cushioned, minimalist shoes.

As noted above, the interaction of impact and injury rates is unclear.

5 Running Shoes & Pronation Control

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%^[42].
• A study compared a Motion Control shoe (MC) with a Cushioned shoe (CT) with 20 high arched (HA) and 20 low arched (LA) runners^[43]. 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.

• 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^[44].
• 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^[45]. 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:

• A study of 10 experienced rear foot runners were tested with shoes of varying heel flare^[46]. 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^[47][48].
  
• A study of 7 people compared pronation when stepping down from a platform in shoes and when barefoot^[49]. The shoe was the Adidas Response Cushion and the platform was 4 inches/10 cm high. Pronation with shoes was less (17.9 degrees) than when barefoot (20.5 degrees). However, because the reduction was so small, the study concluded that it was impractical to alter pronation with this type of footwear.

6 Running Shoes & Achilles Strain

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^[50], but there is little evidence to support this:

• No studies have shown raised heels reduce Achilles (or other) injuries^[1].
• Shoes with the different levels of a drop do not change the range of motion of the ankle during running^[51].
• A study of five runners, each running in five different shoes with heel heights of 2.1-3.3cm (5.0 to 9.5 degrees) did not support the idea that heel height changes stress on the Achilles' tendon^[51].
• 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^[52]. 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^[53]. 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 study of 12 male runners looked at foot strike for shoes with 0mm, 4mm, and 8mm of drop, plus barefoot^[54]. The barefoot condition was midfoot strike rather than rear foot strike in the shoes. The different drop conditions were not significantly different, though there was a trend towards more rear foot strike with the 8mm drop than with 0mm and 4mm drops.
• A drop of 15mm or 7.5mm did not produce a significant reduction in Achilles tendon stress^[55].
• A study comparing the minimal Vibram FiveFingers with Hoka Minimax shoes suggests there may be more Achilles tendon stress in minimal shoes^[56]. However, the group size was small (n=12), and there's no indication that the runners had experience with either type of footwear.

7 Running Shoes & Injury Rates

Several studies have found there is no evidence to support the idea that running shoes can reduce injury rates^[57][1][19]. One 2015 study did show a reduced injury rate with motion control shoes.

• A study of 247 runners over 5 months showed no difference in injury rates between firm and softly cushioned shoes^[58].
• Three studies compared evaluated the idea that shoe type should be determined by arch height^[59]. Runners were put into two groups, with one group assigned shoes based on the shape of the arch, and the other group just assigned a stability shoe regardless of their arch. 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).
• A study of 81 women training for a half marathon were randomly assigned cushioned, stability and motion control shoes^[60]. The cushioned shoe was a Nike Pegasus, the stability was Nike Structure Triax, and the motion control was Nike Nucleus. The runners were then analyzed based on their arch height.
  • The study found that the motion control shoe was associated with the highest levels of pain while running for all foot types, though the difference was only significant for the neutral and pronated foot types.
  • All the highly pronated runners wearing the motion control shoe missed a training day due to pain, the highest proportion of any of the subgroups.
  • 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.
• A study of 372 recreational runners assigned them randomly either a neutral or motion controlled shoe and found that those in the neutral shoe had a higher injury rate^[61]. The study is unusual in that it blinded both the subjects and the testers to the type of shoe used. The shoe type is not identified in the study, other than to say they were commercially available and modified so the runner would not know the brand or type. Both types of shoe were a 10 mm drop, and the motion control shoes had a Medial Post made of both firmer foam and a plastic insert. The study found that those in the neutral shoe had nearly twice the injury rate of those in the motion control shoes. When the subjects were divided by their Pronation, the study found that the injury rates were only different in those runners with Pronation (~25% of both groups). The study also noted that the greatest predictor of injury is a history of prior injuries, and both groups had ~75% of previously injured runners.
• An intriguing study suggests of 264 runners preparing for a marathon found that runners who swapped between multiple shoes had lower injury rates than those who only used a single pair at a time^[62]. However, the data is self-reported and there were other differences between the groups, such as the multiple shoe runners having run more half-marathons than the single shoe group.

8 Shoes and Running Economy

Main article: The Science of Running Economy

Studies have consistently shown that heavier shoes reduce running economy^{[63][64][65][66]}. Each 100g/3.5oz added to the weight of each shoe reduces running economy by about 1%^{[67][66][68][69]}. Studies of cushioning and Running Economy have provided conflicting information. I believe this conflict is due to some studies using a cushioned treadmill to compare barefoot and shod conditions. Not surprisingly, if a study uses a cushioned treadmill, the cushioning provided by the shoe does not confer any additional advantage over the barefoot condition. Analyzing the research, I conclude that a well cushioned running shoe can improve Running Economy by an estimated 2-3.5% compared with a weight matched un-cushioned shoe^[67][66][70]. Note that running shoes provide less cushioning in colder temperatures^[71]. There are indications that a highly flexible shoe that is modified with a springy carbon fiber plate might be more efficient than a highly flexible shoe on its own^[72][73].

9 Heel Counters

The Heel Counter is intended to link the heel of the foot to the shoe,

• A study found that a rigid heel counter did not prevent slippage within the shoe any better than a flexible heel counter^[74].
• A source of confusion in biomechanical studies is that it is much easier to measure the movement of a heel counter than the foot within. Studies can assume that changes in the movement of the heel counter reflect the equivalent changes at the foot. One study found the pronation of the foot can be twice as large as the pronation when measured on the shoe^[48], and another found there were significant differences between the movement of the heel and the movement of the heel counter^[75].
• One study found that cutting the bottom of the heel counter away reduced Running Economy by 2.4%^[76], a relatively large change. Personally, I suspect this reduction in economy is due to the discomfort of the modified shoe, but the results are intriguing.
  
  

  The removed heel counter.
• Some runners are concerned that a rigid heel counter may irritate the Achilles tendon. I found no research to support or refute this concern, but personally I see it as relatively unlikely. I suspect that irritation of the Achilles tendon by a shoe is more likely to be due to the extreme rear of the upper coming up to high, or curving inwards to cup around the heel too far. Note that pain in this area could also be due to the irritation of the bursa, rather than the tendon (retrocalcaneal bursitis).

10 Minimalist & Barefoot Running

Most research looks at factors that might be related to injury risk, rather than injury rates directly. The one study so far that compared barefoot/minimalist running and injury rates found broadly similar injury rates. This suggests that minimalist or barefoot running neither increases nor reduces the risk of injury. However, there remains some compelling evidence that the transition to barefoot or minimalist footwear is correlated with higher injury rates, especially stress fractures in the foot.

• A study comparing 107 barefoot runners with 94 shod controls found similar injury rates^[77]. The barefoot runners had fewer injuries per runner, but ran less miles, so the injury rate (injuries per mile) was similar.
  • The barefoot runners ran 75% of their mileage barefoot and the remainder in minimal shoes, characterized by no arch support, no reinforced heel counter and no midsole. (That's a pretty good definition of a minimalist shoe.) The barefoot runners had been barefoot for an average of 1.7 years, and 63% began running barefoot 6–12 months before the study. That's a reasonably good adaptation period and should avoid any injuries related to the transition,
  • The study attempted to ensure the two groups were similar, but there are far more men in the barefoot group (88%) than the shod group (73%).
  • The runners' average mileage was 25 miles/week in the shod group and 15 miles in the barefoot group. (The study required a minimum of 10 miles/week.)
  • There were 346 running related injuries, just under half of them clinically diagnosed. There were significantly more injuries per runner for the shod runners, but when the injury rate is normalized by the mileage the barefoot runners have a non-significantly higher injury rate.
    
    

    Injury rates per runner and normalized to mileage.
  • The barefoot runners had more foot injuries, but fewer injures elsewhere, most noticeably in the hip.
    
    

    Location if injuries for both groups. It's important to note this is given as the number of injuries, not the percentage normalized which is a little misleading as there are more shod runners than barefoot.
  • The barefoot runners had far more injuries to the sole of the foot (plantar surface), mostly cuts.
  • Shod runners may have had far more plantar fasciitis. (This re-enforces my belief that arch supports contribute to plantar fasciitis.)
• A review of 23 studies found moderate evidence for higher Cadence and lower impact, but noted a lack of high quality evidence^[78]. Examples include:
  • Barefoot running can produce reduce impact forces compared with cushioned shoes^[39]
  • Shoes increase Ground Contact Time compared with barefoot^[79].
  • Compared with barefoot, running shoes reduced the ability to estimate surface angle, with a greater estimation error with thicker shoes^[80][81].
• There are some instances of Metatarsal Stress fractures in runners who had changed to minimalist shoes, with no other changes in their training habits^[82].
• A study of 99 runners 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)^[83]. 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 footwear from 10 min (19%) in week 1 to 115 min (58%) in week 12.
  • Runners in the traditional shoes had a lower incident of injury (#4/32 runners) than the partially minimalist (#12/32 runner) or minimalist (#7/35 runners).
  • The only statistically significant difference in pain scores for the shoe conditions was in shin and calf pain, with runners in the partially minimalist and minimalist shoes having greater pain scores than the traditional shoes. However, the underlying data is a little more complex. Below are shown the pain scores before and after the trial for each shoe type. As you can see, the pain goes up by the greatest percentage for the partially minimalist, but this rise is from a much lower initial level. The absolute level of pain is lowest for the partially minimalist condition, making this study tricky to interpret.

• A study looked at bone marrow edema in 36 experienced runners transitioning to Vibram FiveFingers (VFF) shoes^[84]. The runners were randomly assigned VFF or their normal running shoes, with the VFF runners gradually transitioning based on the recommendations of 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.
• In 2014, Vibram settled a lawsuit that they made false and unsubstantiated claims that their FiveFingers shoes could reduce injury rates.

11 Personal Observations

While this page is dedicated to the current scientific research, I do want to add a few personal observations as a counterpoint.

• My testing of Running Sensors has made me realize how many ways there are of measuring the impact forces of running. I believe that this warrants much deeper scientific research.
  • Impact can be measured as simple acceleration, or as "jerk" which is the rate of change of acceleration. In some situations, the human body can adapt to a continuous level of acceleration much better than it can to a rapidly changing level of acceleration. This can be observed when an aircraft takes off, and the initial buildup of acceleration seems quite dramatic, but after 10-20 seconds the steady acceleration is harder to notice.
  • The impact forces can be measured on the ground, on the shoe, on the tibia (lower leg), or on the torso. Each location is likely to have a different result.
• I've observed some potentially interesting patterns during my initial testing using TgForce, RunScribe, MilestonePod, Moov Now, and Wahoo TICKR Run.
  • When use a forefoot foot strike the impact measured on my shoe is typically a little higher than when I heel strike. However, the impact measured on my tibia is vastly lower. When heal striking, the impact on my shoe is typically in the 7-9g range, and 5-7g on my Tibia. When I land on my forefoot the impact on my shoe is 8-12g but the Tibial impact is 2-4g.
  • When comparing Maximalist shoes with minimally or cushioned shoes I'm typically finding that the impact measured on my shoe is a little higher with the more cushioned shoes, but the Tibial impact is virtually the same regardless of cushioning. (There is a very slight suggestion that more cushioned shoes have fractionally lower Tibial impact.)

12 References

<references> ^{[72] [57] [50] [51] [79] [55] [80] [81] [58] [30] [30] [19] [2] [15] [3] [4] [32] [31] [14] [16] [5] [6] [7] [1] [59] [28] [29] [20] [27] [26] [42] [60] [82] [39] [78] [83] [84] [51] [38] [39] [40] [35] [33] [8] [9] [10] [11] [12] [13] [21] [22] [52] [53] [43] [44] [45] [46] [47] [48] [74] [75] [49] [54] [70] [63] [64] [65] [66] [67] [69] [68] [71] [23] [19] [18] [17] [25] [76] [77] [24] [34] [36] [56] [62] [41] [37] [61] [73]}

1. ↑ ^{1.0 1.1 1.2 1.3 1.4} RN. van Gent, D. Siem, M. van Middelkoop, AG. van Os, SM. Bierma-Zeinstra, BW. Koes, Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review., Br J Sports Med, volume 41, issue 8, pages 469-80; discussion 480, Aug 2007, doi 10.1136/bjsm.2006.033548, PMID 17473005
2. ↑ ^{2.0 2.1} BM. Nigg, The role of impact forces and foot pronation: a new paradigm., Clin J Sport Med, volume 11, issue 1, pages 2-9, Jan 2001, PMID 11176139
3. ↑ ^{3.0 3.1} Beat Hintermann, Benno M. Nigg, Pronation in Runners, Sports Medicine, volume 26, issue 3, 1998, pages 169–176, ISSN 0112-1642, doi 10.2165/00007256-199826030-00003
4. ↑ ^{4.0 4.1} DC. McKenzie, DB. Clement, JE. Taunton, Running shoes, orthotics, and injuries., Sports Med, volume 2, issue 5, pages 334-47, PMID 3850616
5. ↑ ^{5.0 5.1} CA. Johnston, JE. Taunton, DR. Lloyd-Smith, DC. McKenzie, Preventing running injuries. Practical approach for family doctors., Can Fam Physician, volume 49, pages 1101-9, Sep 2003, PMID 14526862
6. ↑ ^{6.0 6.1} Barbara Heil, Running Shoe Design and Selection Related to Lower Limb Biomechanics, Physiotherapy, volume 78, issue 6, 1992, pages 406–412, ISSN 00319406, doi 10.1016/S0031-9406(10)61525-8
7. ↑ ^{7.0 7.1} MH. Yamashita, Evaluation and selection of shoe wear and orthoses for the runner., Phys Med Rehabil Clin N Am, volume 16, issue 3, pages 801-29, Aug 2005, doi 10.1016/j.pmr.2005.02.006, PMID 16005404
8. ↑ ^{8.0 8.1} Running Shoes: How to Choose, http://www.rei.com/learn/expert-advice/running-shoes.html, Accessed on 26 November 2014
9. ↑ ^{9.0 9.1} http://www.zappos.com/running-shoe-fit-guide, http://www.zappos.com/running-shoe-fit-guide, Accessed on 26 November 2014
10. ↑ ^{10.0 10.1} Take This Simple Test To Learn If You Have High or Low Arches, http://www.runnersworld.com/running-shoes/take-wet-test-learn-your-foot-type, Accessed on 26 November 2014
11. ↑ ^{11.0 11.1} http://www.roadrunnersports.com/rrs/content/choosing-running-shoes/, http://www.roadrunnersports.com/rrs/content/choosing-running-shoes/, Accessed on 26 November 2014
12. ↑ ^{12.0 12.1} Peter R. Cavanagh, The running shoe book, date 1980, publisher Anderson World, location Mountain View, CA, isbn 0890371822
13. ↑ ^{13.0 13.1} A. Hreljac, Impact and overuse injuries in runners., Med Sci Sports Exerc, volume 36, issue 5, pages 845-9, May 2004, PMID 15126720
14. ↑ ^{14.0 14.1 14.2} Nigg, Benno M. "Impact forces in running." Current Opinion in Orthopaedics 8.6 (1997): 43-47.
15. ↑ ^{15.0 15.1} SH. Scott, DA. Winter, Internal forces of chronic running injury sites., Med Sci Sports Exerc, volume 22, issue 3, pages 357-69, Jun 1990, PMID 2381304
16. ↑ ^{16.0 16.1 16.2} author Alexander Bahlsen, The Etiology of Running Injuries: A Longitudinal, Prospective Study, 1988
17. ↑ ^{17.0 17.1} SW. Bredeweg, I. Buist, B. Kluitenberg, Differences in kinetic asymmetry between injured and noninjured novice runners: a prospective cohort study., Gait Posture, volume 38, issue 4, pages 847-52, Sep 2013, doi 10.1016/j.gaitpost.2013.04.014, PMID 23673088
18. ↑ ^{18.0 18.1} SW. Bredeweg, B. Kluitenberg, B. Bessem, I. Buist, Differences in kinetic variables between injured and noninjured novice runners: a prospective cohort study., J Sci Med Sport, volume 16, issue 3, pages 205-10, May 2013, doi 10.1016/j.jsams.2012.08.002, PMID 22921763
19. ↑ ^{19.0 19.1 19.2 19.3} W. van Mechelen, Running injuries. A review of the epidemiological literature., Sports Med, volume 14, issue 5, pages 320-35, Nov 1992, PMID 1439399
20. ↑ ^{20.0 20.1 20.2} A. Hreljac, RN. Marshall, PA. Hume, Evaluation of lower extremity overuse injury potential in runners., Med Sci Sports Exerc, volume 32, issue 9, pages 1635-41, Sep 2000, PMID 10994917
21. ↑ ^{21.0 21.1} Susan K. Grimston, Benno M. Nigg, Veronica Fisher, Stanley V. Ajemian, External loads throughout a 45 minute run in stress fracture and non-stress fracture runners, Journal of Biomechanics, volume 27, issue 6, 1994, pages 668, ISSN 00219290, doi 10.1016/0021-9290(94)90983-0
22. ↑ ^{22.0 22.1} AA. Zadpoor, AA. Nikooyan, The relationship between lower-extremity stress fractures and the ground reaction force: a systematic review., Clin Biomech (Bristol, Avon), volume 26, issue 1, pages 23-8, Jan 2011, doi 10.1016/j.clinbiomech.2010.08.005, PMID 20846765
23. ↑ ^{23.0 23.1} CE. Milner, R. Ferber, CD. Pollard, J. Hamill, IS. Davis, Biomechanical factors associated with tibial stress fracture in female runners., Med Sci Sports Exerc, volume 38, issue 2, pages 323-8, Feb 2006, doi 10.1249/01.mss.0000183477.75808.92, PMID 16531902
24. ↑ ^{24.0 24.1} Rebecca Avrin Zifchock, Irene Davis, Joseph Hamill, Kinetic asymmetry in female runners with and without retrospective tibial stress fractures, Journal of Biomechanics, volume 39, issue 15, 2006, pages 2792–2797, ISSN 00219290, doi 10.1016/j.jbiomech.2005.10.003
25. ↑ ^{25.0 25.1} M. Fredericson, F. Jennings, C. Beaulieu, GO. Matheson, Stress fractures in athletes., Top Magn Reson Imaging, volume 17, issue 5, pages 309-25, Oct 2006, doi 10.1097/RMR.0b013e3180421c8c, PMID 17414993
26. ↑ ^{26.0 26.1} JW. Tong, PW. Kong, Association between foot type and lower extremity injuries: systematic literature review with meta-analysis., J Orthop Sports Phys Ther, volume 43, issue 10, pages 700-14, Oct 2013, doi 10.2519/jospt.2013.4225, PMID 23756327
27. ↑ ^{27.0 27.1} DN. Cowan, BH. Jones, JR. Robinson, Foot morphologic characteristics and risk of exercise-related injury., Arch Fam Med, volume 2, issue 7, pages 773-7, Jul 1993, PMID 7906597
28. ↑ ^{28.0 28.1} DS. Williams, IS. McClay, J. Hamill, Arch structure and injury patterns in runners., Clin Biomech (Bristol, Avon), volume 16, issue 4, pages 341-7, May 2001, PMID 11358622
29. ↑ ^{29.0 29.1} Teyhen, LTC Deydre S., et al. "Impact of Foot Type on Cost of Lower Extremity Injury."
30. ↑ ^{30.0 30.1 30.2} R. O. Nielsen, I. Buist, E. T. Parner, E. A. Nohr, H. Sorensen, M. Lind, S. Rasmussen, Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study, British Journal of Sports Medicine, volume 48, issue 6, 2013, pages 440–447, ISSN 0306-3674, doi 10.1136/bjsports-2013-092202
31. ↑ ^{31.0 31.1} MC. Boling, DA. Padua, SW. Marshall, K. Guskiewicz, S. Pyne, A. Beutler, A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort., Am J Sports Med, volume 37, issue 11, pages 2108-16, Nov 2009, doi 10.1177/0363546509337934, PMID 19797162
32. ↑ ^{32.0 32.1} MJ. Mueller, JV. Host, BJ. Norton, Navicular drop as a composite measure of excessive pronation., J Am Podiatr Med Assoc, volume 83, issue 4, pages 198-202, Apr 1993, doi 10.7547/87507315-83-4-198, PMID 8473991
33. ↑ ^{33.0 33.1} B.M. Nigg, H.A. Bahlsen, S.M. Luethi, S. Stokes, The influence of running velocity and midsole hardness on external impact forces in heel-toe running, Journal of Biomechanics, volume 20, issue 10, 1987, pages 951–959, ISSN 00219290, doi 10.1016/0021-9290(87)90324-1
34. ↑ ^{34.0 34.1} Joseph Hamill, Elizabeth M. Russell, Allison H. Gruber, Ross Miller, Impact characteristics in shod and barefoot running, Footwear Science, volume 3, issue 1, 2011, pages 33–40, ISSN 1942-4280, doi 10.1080/19424280.2010.542187
35. ↑ ^{35.0 35.1} T. Clarke, E. Frederick, L. Cooper, Effects of Shoe Cushioning Upon Ground Reaction Forces in Running, International Journal of Sports Medicine, volume 04, issue 04, 2008, pages 247–251, ISSN 0172-4622, doi 10.1055/s-2008-1026043
36. ↑ ^{36.0 36.1} Jose Manuel Garcia Aznar, Jennifer Baltich, Christian Maurer, Benno M. Nigg, Increased Vertical Impact Forces and Altered Running Mechanics with Softer Midsole Shoes, PLOS ONE, volume 10, issue 4, 2015, pages e0125196, ISSN 1932-6203, doi 10.1371/journal.pone.0125196
37. ↑ ^{37.0 37.1} J. Sinclair, J. Richards, J. Selfe, J. Fau-Goodwin, H. Shore, The Influence of Minimalist and Maximalist Footwear on Patellofemoral Kinetics During Running., J Appl Biomech, Mar 2016, doi 10.1123/jab.2015-0249, PMID 26959346
38. ↑ ^{38.0 38.1} SE. Robbins, GJ. Gouw, Athletic footwear and chronic overloading. A brief review., Sports Med, volume 9, issue 2, pages 76-85, Feb 1990, PMID 2180026
39. ↑ ^{39.0 39.1 39.2 39.3} C. Divert, G. Mornieux, H. Baur, F. Mayer, A. Belli, Mechanical comparison of barefoot and shod running., Int J Sports Med, volume 26, issue 7, pages 593-8, Sep 2005, doi 10.1055/s-2004-821327, PMID 16195994
40. ↑ ^{40.0 40.1} SE. Robbins, AM. Hanna, Running-related injury prevention through barefoot adaptations., Med Sci Sports Exerc, volume 19, issue 2, pages 148-56, Apr 1987, PMID 2883551
41. ↑ ^{41.0 41.1} Weijie Fu, Ying Fang, David Ming Shuo Liu, Lin Wang, Sicong Ren, Yu Liu, Surface effects on in-shoe plantar pressure and tibial impact during running, Journal of Sport and Health Science, volume 4, issue 4, 2015, pages 384–390, ISSN 20952546, doi 10.1016/j.jshs.2015.09.001
42. ↑ ^{42.0 42.1} RT. Cheung, MY. Wong, GY. Ng, Effects of motion control footwear on running: a systematic review., J Sports Sci, volume 29, issue 12, pages 1311-9, Sep 2011, doi 10.1080/02640414.2011.591420, PMID 21751855
43. ↑ ^{43.0 43.1} RJ. Butler, IS. Davis, J. Hamill, Interaction of arch type and footwear on running mechanics., Am J Sports Med, volume 34, issue 12, pages 1998-2005, Dec 2006, doi 10.1177/0363546506290401, PMID 16902231
44. ↑ ^{44.0 44.1} SD Perry, MA Lafortune, Influences of inversion/eversion of the foot upon impact loading during locomotion, Clinical Biomechanics, volume 10, issue 5, 1995, pages 253–257, ISSN 02680033, doi 10.1016/0268-0033(95)00006-7
45. ↑ ^{45.0 45.1} R. T. Cheung, G. Y. Ng, Influence of Different Footwear on Force of Landing During Running, Physical Therapy, volume 88, issue 5, 2008, pages 620–628, ISSN 0031-9023, doi 10.2522/ptj.20060323
46. ↑ ^{46.0 46.1} TE. Clarke, EC. Frederick, CL. Hamill, The effects of shoe design parameters on rearfoot control in running., Med Sci Sports Exerc, volume 15, issue 5, pages 376-81, 1983, PMID 6645865
47. ↑ ^{47.0 47.1} BM. Nigg, M. Morlock, The influence of lateral heel flare of running shoes on pronation and impact forces., Med Sci Sports Exerc, volume 19, issue 3, pages 294-302, Jun 1987, PMID 3600244
48. ↑ ^{48.0 48.1 48.2} 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 11224823
49. ↑ ^{49.0 49.1} Mako Fukano, Toru Fukubayashi, Changes in talocrural and subtalar joint kinematics of barefoot versus shod forefoot landing, Journal of Foot and Ankle Research, volume 7, issue 1, 2014, pages 42, ISSN 1757-1146, doi 10.1186/s13047-014-0042-9
50. ↑ ^{50.0 50.1} DB. Clement, JE. Taunton, A guide to the prevention of running injuries., Can Fam Physician, volume 26, pages 543-8, Apr 1980, PMID 21293616
51. ↑ ^{51.0 51.1 51.2 51.3} C. Reinschmidt, BM. Nigg, Influence of heel height on ankle joint moments in running., Med Sci Sports Exerc, volume 27, issue 3, pages 410-6, Mar 1995, PMID 7752869
52. ↑ ^{52.0 52.1} M. Giandolini, N. Horvais, Y. Farges, P. Samozino, JB. Morin, Impact reduction through long-term intervention in recreational runners: midfoot strike pattern versus low-drop/low-heel height footwear., Eur J Appl Physiol, volume 113, issue 8, pages 2077-90, Aug 2013, doi 10.1007/s00421-013-2634-7, PMID 23584279
53. ↑ ^{53.0 53.1} N. Horvais, P. Samozino, Effect of midsole geometry on foot-strike pattern and running kinematics, Footwear Science, volume 5, issue 2, 2013, pages 81–89, ISSN 1942-4280, doi 10.1080/19424280.2013.767863
54. ↑ ^{54.0 54.1} N. Chambon, N. Delattre, E. Berton, N. Guéguen, G. Rao, The effect of shoe drop on running pattern, Computer Methods in Biomechanics and Biomedical Engineering, volume 16, issue sup1, 2013, pages 97–98, ISSN 1025-5842, doi 10.1080/10255842.2013.815919
55. ↑ ^{55.0 55.1} Dixon, Sharon J., and David G. Kerwin. "The influence of heel lift manipulation on Achilles tendon loading in running." Journal of Applied Biomechanics 14 (1998): 374-389.
56. ↑ ^{56.0 56.1} J. Sinclair, J. Richards, H. Shore, Effects of minimalist and maximalist footwear on Achilles tendon load in recreational runners, Comparative Exercise Physiology, volume 11, issue 4, 2015, pages 239–244, ISSN 1755-2540, doi 10.3920/CEP150024
57. ↑ ^{57.0 57.1} C E Richards, P J Magin, R Callister, Is your prescription of distance running shoes evidence-based?, British Journal of Sports Medicine, volume 43, issue 3, 2009, pages 159–162, ISSN 0306-3674, doi 10.1136/bjsm.2008.046680
58. ↑ ^{58.0 58.1} D. Theisen, L. Malisoux, J. Genin, N. Delattre, R. Seil, A. Urhausen, Influence of midsole hardness of standard cushioned shoes on running-related injury risk, British Journal of Sports Medicine, volume 48, issue 5, 2013, pages 371–376, ISSN 0306-3674, doi 10.1136/bjsports-2013-092613
59. ↑ ^{59.0 59.1} Joseph J. Knapik, Daniel W. Trone, Juste Tchandja, Bruce H. Jones, Injury-Reduction Effectiveness of Prescribing Running Shoes on the Basis of Foot Arch Height: Summary of Military Investigations, Journal of Orthopaedic & Sports Physical Therapy, volume 44, issue 10, 2014, pages 805–812, ISSN 0190-6011, doi 10.2519/jospt.2014.5342
60. ↑ ^{60.0 60.1} M. B. Ryan, G. A. Valiant, K. McDonald, J. E. Taunton, The effect of three different levels of footwear stability on pain outcomes in women runners: a randomised control trial, British Journal of Sports Medicine, volume 45, issue 9, 2010, pages 715–721, ISSN 0306-3674, doi 10.1136/bjsm.2009.069849
61. ↑ ^{61.0 61.1} Laurent Malisoux, Nicolas Chambon, Nicolas Delattre, Nils Gueguen, Axel Urhausen, Daniel Theisen, Injury risk in runners using standard or motion control shoes: a randomised controlled trial with participant and assessor blinding, British Journal of Sports Medicine, volume 50, issue 8, 2016, pages 481–487, ISSN 0306-3674, doi 10.1136/bjsports-2015-095031
62. ↑ ^{62.0 62.1} L. Malisoux, J. Ramesh, R. Mann, R. Seil, A. Urhausen, D. Theisen, Can parallel use of different running shoes decrease running-related injury risk?, Scandinavian Journal of Medicine & Science in Sports, volume 25, issue 1, 2015, pages 110–115, ISSN 09057188, doi 10.1111/sms.12154
63. ↑ ^{63.0 63.1} T. Lussiana, N. Fabre, K. Hébert-Losier, L. Mourot, Effect of slope and footwear on running economy and kinematics, Scandinavian Journal of Medicine & Science in Sports, volume 23, issue 4, 2013, pages e246–e253, ISSN 09057188, doi 10.1111/sms.12057
64. ↑ ^{64.0 64.1} LN. Burkett, WM. Kohrt, R. Buchbinder, Effects of shoes and foot orthotics on VO2 and selected frontal plane knee kinematics., Med Sci Sports Exerc, volume 17, issue 1, pages 158-63, Feb 1985, PMID 3982270
65. ↑ ^{65.0 65.1} S. Sobhani, S. Bredeweg, R. Dekker, B. Kluitenberg, E. van den Heuvel, J. Hijmans, K. Postema, Rocker shoe, minimalist shoe, and standard running shoe: a comparison of running economy., J Sci Med Sport, volume 17, issue 3, pages 312-6, May 2014, doi 10.1016/j.jsams.2013.04.015, PMID 23711621
66. ↑ ^{66.0 66.1 66.2 66.3} The separate effects of shoe mass and cushioning on the energetic cost of barefoot vs. shod running. Wierzbinski, Corbyn. University of Colorado at Boulder. Departmental Honors Thesis. http://digitool.library.colostate.edu///exlibris/dtl/d3_1/apache_media/L2V4bGlicmlzL2R0bC9kM18xL2FwYWNoZV9tZWRpYS8xMTkyODM=.pdf
67. ↑ ^{67.0 67.1 67.2} JR. Franz, CM. Wierzbinski, R. Kram, Metabolic cost of running barefoot versus shod: is lighter better?, Med Sci Sports Exerc, volume 44, issue 8, pages 1519-25, Aug 2012, doi 10.1249/MSS.0b013e3182514a88, PMID 22367745
68. ↑ ^{68.0 68.1} Frederick , E. C. The energy cost of load carriage on the feet during running. In: Winter, D.A., R. W. Norman, R. P. Wells, K. C. Hayes, and A. E. Patla (Editors), Biomechanics IX-B Human Kinetics Publ., Champaign, IL, pp.295-300, 1985
69. ↑ ^{69.0 69.1} Frederick, E. C., Physiological and ergonomics factors in running shoe design. Applied Ergonomics 15(4): 281-287, 1984
70. ↑ ^{70.0 70.1} KD. Tung, JR. Franz, R. Kram, A test of the metabolic cost of cushioning hypothesis during unshod and shod running., Med Sci Sports Exerc, volume 46, issue 2, pages 324-9, Feb 2014, doi 10.1249/MSS.0b013e3182a63b81, PMID 24441213
71. ↑ ^{71.0 71.1} Mansour Y Dib, Jay Smith, Kathie A Bernhardt, Kenton R Kaufman, Kevin A Miles, Effect of Environmental Temperature on Shock Absorption Properties of Running Shoes, Clinical Journal of Sport Medicine, volume 15, issue 3, 2005, pages 172–176, ISSN 1050-642X, doi 10.1097/01.jsm.0000165348.32767.32
72. ↑ ^{72.0 72.1} Keonyoung Oh, Sukyung Park, The bending stiffness of shoes is beneficial to running energetics if it does not disturb the natural MTP joint flexion, Journal of Biomechanics, volume 53, 2017, pages 127–135, ISSN 00219290, doi 10.1016/j.jbiomech.2017.01.014
73. ↑ ^{73.0 73.1} JP. Roy, DJ. Stefanyshyn, Shoe midsole longitudinal bending stiffness and running economy, joint energy, and EMG., Med Sci Sports Exerc, volume 38, issue 3, pages 562-9, Mar 2006, doi 10.1249/01.mss.0000193562.22001.e8, PMID 16540846
74. ↑ ^{74.0 74.1} Van Gheluwe, Bart, Rudi Tielemans, and Philip Roosen. "The influence of heel counter rigidity on rearfoot motion during running." Sort 100 (1995): 250.
75. ↑ ^{75.0 75.1} A. Stacoff, C. Reinschmidt, E. Stüssi, The movement of the heel within a running shoe., Med Sci Sports Exerc, volume 24, issue 6, pages 695-701, Jun 1992, PMID 1602942
76. ↑ ^{76.0 76.1} U. Jorgensen, Body load in heel-strike running: The effect of a firm heel counter, The American Journal of Sports Medicine, volume 18, issue 2, 1990, pages 177–181, ISSN 0363-5465, doi 10.1177/036354659001800211
77. ↑ ^{77.0 77.1} AR. Altman, IS. Davis, Prospective comparison of running injuries between shod and barefoot runners., Br J Sports Med, volume 50, issue 8, pages 476-80, Apr 2016, doi 10.1136/bjsports-2014-094482, PMID 26130697
78. ↑ ^{78.0 78.1} K. P. Perkins, W. J. Hanney, C. E. Rothschild, The Risks and Benefits of Running Barefoot or in Minimalist Shoes: A Systematic Review, Sports Health: A Multidisciplinary Approach, volume 6, issue 6, 2014, pages 475–480, ISSN 1941-7381, doi 10.1177/1941738114546846
79. ↑ ^{79.0 79.1} B. Braunstein, A. Arampatzis, P. Eysel, GP. Brüggemann, Footwear affects the gearing at the ankle and knee joints during running., J Biomech, volume 43, issue 11, pages 2120-5, Aug 2010, doi 10.1016/j.jbiomech.2010.04.001, PMID 20462583
80. ↑ ^{80.0 80.1} K. Sekizawa, MA. Sandrey, CD. Ingersoll, ML. Cordova, Effects of shoe sole thickness on joint position sense., Gait Posture, volume 13, issue 3, pages 221-8, May 2001, PMID 11323228
81. ↑ ^{81.0 81.1} S. Robbins, E. Waked, J. McClaran, Proprioception and stability: foot position awareness as a function of age and footwear., Age Ageing, volume 24, issue 1, pages 67-72, Jan 1995, PMID 7762465
82. ↑ ^{82.0 82.1} Jeffrey Giuliani, Brendan Masini, Curtis Alitz, Brett D. Owens, Barefoot-simulating Footwear Associated With Metatarsal Stress Injury in 2 Runners, Orthopedics, 2011, ISSN 0147-7447, doi 10.3928/01477447-20110526-25
83. ↑ ^{83.0 83.1} M. Ryan, M. Elashi, R. Newsham-West, J. Taunton, Examining injury risk and pain perception in runners using minimalist footwear, British Journal of Sports Medicine, volume 48, issue 16, 2013, pages 1257–1262, ISSN 0306-3674, doi 10.1136/bjsports-2012-092061
84. ↑ ^{84.0 84.1} Sarah T. Ridge, A. Wayne Johnson, Ulrike H. Mitchell, Iain Hunter, Eric Robinson, Brent S. E. Rich, Stephen Douglas Brown, Foot Bone Marrow Edema after a 10-wk Transition to Minimalist Running Shoes, Medicine & Science in Sports & Exercise, volume 45, issue 7, 2013, pages 1363–1368, ISSN 0195-9131, doi 10.1249/MSS.0b013e3182874769