Also see:
High Heeled Shoes: A Real Pain
The Effects Of Shoes On Foot Strike, Performance
Why Shoes Make “Normal” Gait Impossible
Kit Laughlin – Foot Sequence
Nature. 2010 Jan 28;463(7280):531-5. doi: 10.1038/nature08723.
Foot strike patterns and collision forces in habitually barefoot versus shod runners
Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, Mang’eni RO, Pitsiladis Y.
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
FEBRUARY 2001 PODIATRY MANAGEMENT p. 129-38
Footwear: The Primary Cause of Foot Disorders A continuation of the scientific review of the failings of modern shoes.
By William A. Rossi, D.P.M.
Why Shoes Make “Normal” Gait Impossible: How flaws in footwear affect this complex human function.
William A. Rossi, D.P.M.
J Biomech. 1995 Jul;28(7):817-27.
Influence of shoes and heel strike on the loading of the hip joint.
Bergmann G, Kniggendorf H, Graichen F, Rohlmann A.
The forces and moments acting at the hip joint influence the long-term stability of the fixation of endoprostheses and the course of coxarthrosis. These loads may depend on the kind of footwear and the walking or running style. These factors were investigated in a patient with instrumented hip implants. He wore different sports shoes, normal leather shoes, hiking boots and clogs and walked barefoot with soft, normal and hard heel strikes. The loads were lowest while walking and jogging without shoes. All shoes increased the joint force and the bending moment at the implant slightly but the torsional moment rose by up to 50%. No relation was found between the different type of shoes and the load increase, only shoes with very hard soles were clearly disadvantageous. Soft heels, soles or insoles did not offer advantages. Gait stability seems to play the most important role in increasing the joint loading and should be the criterion for the choice of footwear. Smooth gait patterns with soft heel strikes are the only means to reduce joint loading during slow jogging.
Footwear Science Volume 1, Issue 2, 2009 pages 81-94
The effects of habitual footwear use: foot shape and function in native barefoot walkers
K. D’Aout, T.C. Pataky, D. De Clercq & P. Aertsad
The human foot was anatomically modern long before footwear was invented, and is adapted to barefoot walking on natural substrates. Understanding the biomechanics of habitually barefoot walkers can provide novel insights both for anthropologist and for applied scientists, yet the necessary data is virtually non-existent. To start assessing morphological and functional effects of the habitual use of footwear, we have studied a population of habitually barefoot walkers from India (n = 70), and compared them with a habitually shod Indian control group (n = 137) and a Western population (n = 48). We focused on foot metrics and on the analysis of plantar pressure data, which was performed using a novel, pixel based method (Pataky and Goulermas 2008, Journal of Biomechanics, 41, 2136). Habitually shod Indians wore less often, and less constricting shoes than Western people. Yet, we found significant differences with their habitually barefoot peers, both in foot shape and in pressure distribution. Barefoot walkers had wider feet and more equally distributed peak pressures, i.e. the entire load carrying surface was contributing more uniformly than in habitually shod subjects, where regions of very high or very low peak pressures were more apparent. Western subjects differed strongly from both Indian populations (and most from barefoot Indians), by having relatively short and, especially, slender feet, with more focal and higher peak pressures at the heel, metatarsals and hallux. The evolutionary history of humans shows that barefoot walking is the biologically natural situation. The use of footwear remains necessary, especially on unnatural substrates, in athletics, and in some pathologies, but current data suggests that footwear that fails to respect natural foot shape and function will ultimately alter the morphology and the biomechanical behaviour of the foot.
J Biomech. 2000 Mar;33(3):269-78.
Biomechanical analysis of the stance phase during barefoot and shod running.
De Wit B, De Clercq D, Aerts P.
This study investigated spatio-temporal variables, ground reaction forces and sagittal and frontal plane kinematics during the stance phase of nine trained subjects running barefoot and shod at three different velocities (3.5, 4.5, 5.5 m s(-1)). Differences between conditions were detected with the general linear method (factorial model). Barefoot running is characterized by a significantly larger external loading rate than the shod condition. The flatter foot placement at touchdown is prepared in free flight, implying an actively induced adaptation strategy. In the barefoot condition, plantar pressure measurements reveal a flatter foot placement to correlate with lower peak heel pressures. Therefore, it is assumed that runners adopt this different touchdown geometry in barefoot running in an attempt to limit the local pressure underneath the heel. A significantly higher leg stiffness during the stance phase was found for the barefoot condition. The sagittal kinematic adaptations between conditions were found in the same way for all subjects and at the three running velocities. However, large individual variations were observed between the runners for the rearfoot kinematics.
Bone Joint Surg Br. 1992 Jul;74(4):525-7.
The influence of footwear on the prevalence of flat foot. A survey of 2300 children.
Rao UB, Joseph B.
We analysed static footprints of 2300 children between the ages of four and 13 years to establish the influence of footwear on the prevalence of flat foot. The incidence among children who used footwear was 8.6% compared with 2.8% in those who did not (p less than 0.001). Significant differences between the predominance in shod and unshod children were noted in all age groups, most marked in those with generalised ligament laxity. Flat foot was most common in children who wore closed-toe shoes, less common in those who wore sandals or slippers, and least in the unshod. Our findings suggest that shoe-wearing in early childhood is detrimental to the development of a normal longitudinal arch.
Med Sci Sports Exerc. 1987 Apr;19(2):148-56.
Running-related injury prevention through barefoot adaptations.
Robbins SE, Hanna AM.
A number of reports indicate an extremely low running-related injury frequency in barefoot populations in contrast to reports about shod populations. It is hypothesized that the adaptations which produce shock absorption, an inherent consequence of barefoot activity and a mechanism responsible for the low injury frequency in unshod populations, are related to deflection of the medial longitudinal arch of the foot on loading. It is also hypothesized that the known inability of this arch of the shod foot to deflect without failure (foot rigidity) is responsible for the high injury frequency in shod populations. To evaluate these hypotheses, 17 recreational runners were analyzed to study the adaptive pattern of the medial longitudinal arch of the foot due to increased barefoot weight-bearing activity. Changes occurred in the medial longitudinal arch which allowed deflection of this arch on loading which substantiated the hypotheses. Other evidence suggests that sensory feedback largely from the glabrous epithelium of the foot is the element of barefoot activity which induced these adaptations. The sensory insulation inherent in the modern running shoe appears responsible for the high injury frequency associated with running. The injuries are considered “pseudo-neuropathic” in nature.
Med Sci Sports Exerc. 1989 Apr;21(2):130-9.
Running-related injury prevention through innate impact-moderating behavior.
Robbins SE, Gouw GJ, Hanna AM.
The purpose of these experiments was to test the Robbins and Hanna hypothesis, which relates differences in discomfort from localized deformation at certain positions on the plantar surface to protective behavior (intrinsic foot shock absorption). A penetrometer was used to quantify the relations between localized load and pain and between load and depth of deformation. The magnitude of load required to elicit pain varied significantly (P less than 0.005) in relation to position on the plantar surface. With a load of 9 kg and a 10 mm spherical end on the penetrometer, 6% of the sample reported pain at the heelpad, 32% at the distal first digit, and 66% at the first metatarsal-phalangeal joint. This pattern was predicted by the Robbins and Hanna thesis. Two deformation patterns were observed which were best explained by deformation constraint by tight trabecular tethering of the epithelial membrane at the heelpad and distal first digit and unrestricted deformation due to loose trabecular tethering of the epithelial membrane at the first metatarsal-phalangeal joint. These data provide insight into how, when barefoot, the plantar surface resists perforation yet provides protection to local bony structures. These data further support the notion that plantar sensory feedback plays a central role in safe and effective locomotion.
J Sports Med Phys Fitness. 2009 Mar;49(1):6-13.
Biomechanical and physiological comparison of barefoot and two shod conditions in experienced barefoot runners.
Squadrone R, Gallozzi C.
AIM:
The first aim of this study was to assess how changes in the mechanical characteristics of the foot/shoe-ground interface affect spatio-temporal variables, ground pressure distribution, sagittal plane kinematics, and running economy in 8 experienced barefoot runners. The second aim was to assess if a special lightweight shoe (Vibram Fivefingers) was effective in mimic the experience of barefoot running.
METHODS:
By using an instrumented treadmill, barefoot running, running with the Fivefingers, and running with standard running shoe were compared, analyzing a large numbers of consecutive steps. Foot/shoe-ground interface pressure distribution, lower limb kinematics, V.O(2) and heart rate data were simultaneously collected.
RESULTS:
Compared to the standard shod condition when running barefoot the athletes landed in more plantarflexion at the ankle. This caused reduced impact forces and changes in stride kinematics. In particular, significantly shorter stride length and contact times and higher stride frequency were observed (P<0.05). Compared to standard shod condition, V.O(2) and peak impact forces were significantly lower with Fivefingers (P<0.05) and much closer to barefoot running. Lower limb kinematics with Fivefingers was similar to barefoot running with a foot position which was significantly more plantarflexed than in control shoe (P<0.05).
CONCLUSIONS:
The data of this study support the assumption that changes in the foot-ground interface led to changes in running pattern in a group of experienced barefoot runners. The Fivefingers model seems to be effective in imitating the barefoot conditions while providing a small amount of protection.
J Biomech. 2003 Aug;36(8):1169-76.
Changes in EMG signals for the muscle tibialis anterior while running barefoot or with shoes resolved by non-linearly scaled wavelets.
von Tscharner V, Goepfert B, Nigg BM.
The purpose of this project was to study the EMG pattern of the tibialis anterior muscle in heel-toe running. Specifically, EMG changes in time, intensity and frequency shortly before and after heel-strike were addressed using an EMG-specific non-linearly scaled wavelets analysis. This method allowed extracting the time, intensity and frequency information inherent in the EMG signal at any time. The EMG signals of 40 male subjects were recorded for running barefoot and with shoes. The results confirmed that the pre-heel-strike EMG activities were typically seen at higher EMG frequencies (60-270Hz) while the post-heel-strike EMG activities resulted in lower frequency signals (10-90Hz). The timing of the pre-heel-strike EMG activities was not influenced by the used shoe conditions. The timing of the post-heel-strike EMG activities was significantly delayed when wearing shoes. The intensity of the pre-heel-strike muscle activity increased compared to the post-heel-strike one when wearing shoes. One can conclude that the activity of the tibialis anterior adjusts specifically to exterior conditions. The frequency shift between pre- and post heel-strike muscle activity were discussed with respect to activation of different motor units.
Curr Sports Med Rep. 2009 Sep-Oct;8(5):262-6. doi: 10.1249/JSR.0b013e3181b9e3be.
Foot and ankle injuries in the barefoot sports.
Vormittag K, Calonje R, Briner WW.
Playing sports barefoot has been contested since the very beginnings of athletic competition. Even today, some data suggest that shoes may limit the adaptive pronation that occurs after footstrike during running gait. This pronation likely protects runners from injury. Boardsport participants who perform their sports barefoot on the water seem to be at risk for foot and ankle injuries. The high-impact forces in gymnastics place participants at risk for foot and ankle injuries, as well. Swimming and diving have a low rate of foot and ankle injuries. The risk of ankle sprain in beach volleyball, which is played barefoot, seems to be lower than that for indoor volleyball, played wearing shoes. Martial arts place competitors at risk for injuries to the foot and ankle from torsional and impact mechanisms. Athletes who hope to return to barefoot competition after injury should perform their rehabilitation in their bare feet.
Med Sci Sports Exerc. 2007 Feb;39(2):330-9.
Gait-related risk factors for exercise-related lower-leg pain during shod running.
Willems TM, Witvrouw E, De Cock A, De Clercq D.
PURPOSE:
Exercise-related lower-leg pain (ERLLP) is a common chronic sports injury. In clinical practice, deviant gait biomechanics are frequently considered to play a role in the development of ERLLP, although there is scarce scientific evidence that gait-related variables predispose athletes to this injury. The purpose of this study was to examine prospectively the gait-related risk factors for ERLLP during shod running in a young, physically active population.
METHODS:
The gait pattern during shod running of 400 physical education students was evaluated at the beginning of their academic study. This was accomplished by means of plantar pressure measurements and 3D gait kinematics. After this evaluation, the same sports physician registered all sports injuries during this study.
RESULTS:
During the follow-up period, 46 subjects developed ERLLP, of whom 29 subjects had bilateral complaints. Thus, 75 symptomatic lower legs (35 left and 40 right) were classified into the ERLLP group. Bilateral feet of 167 subjects who sustained no injuries at the lower extremities served as the referent group. Cox regression analysis revealed that subjects who will develop ERLLP have an altered running pattern compared with the referent subjects. More specifically, these subjects showed a significantly increased pronation excursion, accompanied by more pressure underneath the medial side of the foot, a delayed maximal eversion, and an accelerated reinversion.
CONCLUSION:
The findings of this study suggest that altered gait biomechanics during shod running play a role in the genesis of ERLLP and, thus, should be considered in prevention and rehabilitation of this pathology.
The Foot Volume 17, Issue 4 , Pages 205-213, December 2007
Shod versus unshod: The emergence of forefoot pathology in modern humans?
B. Zipfel, L.R. Berger
Background
Pathologies of the metatarsal bones in contemporary humans are common yet it remains unclear from an evolutionary perspective to what extent, if any, footwear and other environmental factors such as modern substrates have contributed to the emergence of common metatarsal pathological changes.
Objectives
To investigate the frequency of metatarsal bone pathologies in contemporary and habitually unshod pre-historic people in order to ascertain whether these frequencies are affected by variation in habitual behaviour, the wearing of footwear and/or exposure to modern substrates.
Method
The metatarsal elements from four human groups were examined for pathological variation. Three of these skeletal samples were from recent rural and urban shod populations (Sotho, Zulu and European) and one from habitually unshod pre-pastoral Holocene people who practiced a subsistence hunter gatherer lifestyle.
Results
The trends in the dominance of pathological lesions between the five metatarsal bones were broadly similar in all four samples. In all groups the first metatarsal presented with the greatest number of pathological lesions; more specifically, at the first metatarsal head. The Sotho and European groups presented with notably greater frequencies of pathological changes followed by the Zulu group and then the pre-pastoral.
Conclusions
The pathological lesions found in the metatarsals of the three recent human groups generally appeared to be more severe than those found in the pre-pastoral group. This result may support the hypothesis that pathological variation in the metatarsus was affected by habitual behaviour including the wearing of footwear and exposure to modern substrates.
Clin J Sport Med. 2001 Jan;11(1):2-9.
The role of impact forces and foot pronation: a new paradigm.
Nigg BM.
OBJECTIVE:
This article discusses the possible association between impact forces and foot pronation and the development of running-related injuries, and proposes a new paradigm for impact forces and foot pronation.
DATA SOURCES:
The article is based on a critical analysis of the literature on heel-toe running addressing kinematics, kinetics, resultant joint movements and forces, muscle activity, subject and material characteristics, epidemiology, and biologic reactions. However, this paper is not a review of the literature but rather an attempt to replace the established concepts of impact forces and movement control with a new paradigm that would allow explaining some of the current contradictions in this topic of research.
STUDY SELECTION:
The analysis included all papers published on this topic over the last 25 years. For the last few years, it concentrated on papers expressing critical concerns on the established concepts of impact and movement control.
DATA EXTRACTION:
An attempt was made to find indications in the various publications to support or reject the current concept of impact forces and movement control. Furthermore, the results of the available studies were searched for indications expanding the current understanding of impact forces and movement control in running.
DATA SYNTHESIS:
Data were synthesized revealing contradictions in the experimental results and the established concepts. Based on the contradictions in the existing research publications, a new paradigm was proposed.
CONCLUSION:
Theoretical, experimental, and epidemiological evidence on impact forces showed that one cannot conclude that impact forces are important factors in the development of chronic and/or acute running-related injuries. A new paradigm for impact forces during running proposes that impact forces are input signals that produce muscle tuning shortly before the next contact with the ground to minimize soft tissue vibration and/or reduce joint and tendon loading. Muscle tuning might affect fatigue, comfort, work, and performance. Experimental evidence suggests that the concept of “aligning the skeleton” with shoes, inserts, and orthotics should be reconsidered. They produce only small, not systematic. and subject-specific changes of foot and leg movement. A new paradigm for movement control for the lower extremities proposes that forces acting on the foot during the stance phase act as an input signal producing a muscle reaction. The cost function used in this adaptation process is to maintain a preferred joint movement path for a given movement task. If an intervention counteracts the preferred movement path, muscle activity must be increased. An optimal shoe, insert, or orthotic reduces muscle activity. Thus, shoes, inserts, and orthotics affect general muscle activity and, therefore, fatigue, comfort, work, and performance. The two proposed paradigms suggest that the locomotor system use a similar strategy for “impact” and “movement control.” In both cases the locomotor system keeps the general kinematic and kinetic situations similar for a given task. The proposed muscle tuning reaction to impact loading affects the muscle activation before ground contact. The proposed muscle adaptation to provide a constant joint movement pattern affects the muscle activation during ground contact. However, further experimental and theoretical studies are needed to support or reject the proposed paradigms.
J South Orthop Assoc. 1994 Winter;3(4):268-72.
The shod foot and its implications for American women.
Rudicel SA.
Throughout history, members of human societies have gone barefoot, and those societies seemingly had a low incidence of foot deformities and pain. Only one study has addressed the problem of infection through injury to the bare foot; otherwise, the unshod foot seems to have had minimal problems. Initially shoes were made in the shape of the foot and were sandals. Over time, shoes became decorative items and symbols of status and vanity. As the shape of shoes changed, they became deforming forces on the foot and the source of pain. Recent studies by the Council on Women’s Footwear of the American Orthopaedic Foot and Ankle Society have tried to document the problems caused by shoes on the feet of American women. Attempts should continue to educate women on appropriate shoes and proper fit.
J Strength Cond Res. 2013 Mar;27(3):733-7. doi: 10.1519/JSC.0b013e318280c9ce.
Effects of different footwear on vertical jump and landing parameters.
Laporta JW, Brown LE, Coburn JW, Galpin AJ, Tufano JJ, Cazas VL, Tan JG.
Little is known about the effects of different footwear on anaerobic performance variables. The purpose of this study was to investigate the effect of different footwear on vertical jumping and landing parameters. Ten men and 10 women participated. After a dynamic warm-up, subjects performed a vertical jump (VJ), depth drop (DD), and Bosco test on a force plate in 3 different conditions, on 3 separate days: bare feet (BF), minimalist footwear (MF), and tennis shoes (TS). Bare feet had greater relative peak power (relPP) in the VJ (men: BF, 59.87 ± 5.09 W⋅kg; MF, 58.39 ± 5.69 W·kg; TS, 57.70 ± 6.54 W·kg; women: BF, 45.26 ± 4.10 W·kg; MF, 45.06 ± 3.53 W·kg; TS, 44.77 ± 4.55 W·kg), while for men, jump height (JH) was also greater in BF and MF (BF, 44.5 ± 4.46 cm; MF, 43.47 ± 5.5 cm; TS, 41.47 ± 14.45 cm). Results of the Bosco test revealed average relPP was greatest in BF compared with MF and TS (men: BF, 19.70 ± 3.01 W·kg; MF, 19.28 ± 3.00 W·kg; TS, 18.93 ± 3.33 W·kg; women: BF, 14.68 ± 1.41 W·kg; MF, 13.97 ± 1.56 W·kg; TS 13.62 ± 1.67 W·kg), while for JH, BF and MF were greater than TS (men: BF, 28.62 ± 5.0 cm; MF, 27.78 ± 5.09 cm; TS, 26.54 ± 5.1 cm; women: BF, 18.60 ± 1.97 cm; MF, 17.86 ± 6.35 cm; TS, 17.35 ± 2.47 cm). No differences in relative impact force were seen during the DD between conditions. Therefore, athletes and coaches interested in enhancing single and multiple VJs might consider either BF or minimalist shoes.
