Background:This prospective study explored the effects of endurance running(ER) in minimal versus standard running shoes on the foot’s superficial layer intrinsic muscles and the function of the longitudinal arch.Our...Background:This prospective study explored the effects of endurance running(ER) in minimal versus standard running shoes on the foot’s superficial layer intrinsic muscles and the function of the longitudinal arch.Our hypothesis was that running in minimal shoes would cause hypertrophy in these muscles and lead to higher,stronger,stiffer arches.Methods:The hypothesis was tested using a sample of 33 healthy runners randomized into two groups,a control group shod in traditional running footwear and an experimental group shod in minimal support footwear,whose feet were scanned in an MRI before and after a 12-week training regime.Running kinematics as well as arch stiffness and height were also assessed before and after the treatment period.Results:Analysis of anatomical cross-sectional areas and muscle volumes indicate that the flexor digitomm brevis muscle became larger in both groups by 11%and 21%,respectively,but only the minimally shod runners had significant areal and volumetric increases of the abductor digiti minimi of 18%and 22%,respectively,and significantly increased longitudinal arch stiffness(60%).Conclusion:These results suggest that endurance running in minimal support footwear with 4 mm offset or less makes greater use of the springlike function of the longitudinal arch,thus leading to greater demands on the intrinsic muscles that support the arch,thereby strengthening the foot.展开更多
Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using...Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using kinematic data only.Methods： Fourteen male recreational runners（age 23.4 4.4 years, height 177.5 5.2 cm, and body mass 69.5 5.3 kg） were tested on 2separate days within 1 week. At each session, subjects ran seven 5-min trials on a treadmill at 10 km/h, interspersed with 5 min of sitting passive recovery. Each trial was performed on a different slope gradient, ranging from 8%（downhill） to t8%（uphill）, assigned in a random order.Furthermore, each subject ran one 5-min trial wearing minimal shoes（MS） and the subsequent trial wearing traditional shoes（TS） in a counterbalanced randomized order ensuring that each slope was ran once in MS and once in TS. Kinematic data were collected using a photocell measuring system and high-speed video camera, with kvertand klegstiffness being calculated from these data.Results： Leg compression, contact times, and vertical displacement of the center of mass during running were significantly smaller in MS compared to TS across all slopes. In the two footwear conditions, step frequency significantly increased with a（positive） increase in slope.Kinematic analyses indicated that klegwas greater when running in MS than TS and this between-footwear difference remained similar across slopes. On the contrary, kvertdid not change on the basis of footwear, but increased with positive increases in slope.Conclusion： This study showed that kvertand klegduring running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.展开更多
It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of ou...It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of our body form. As our bodies have adapted to run, it seems unusual that up to 79% of modern day runners are injured annually. The etiology of these injuries is clearly multifactorial. However, 1 aspect of running that has significantly changed over the past 50 years is the footwear we use. Modern running shoes have become increasingly cushioned and supportive, and have changed the way we run. In particular, they have altered our footstrike pattern from a predominantly forefoot strike(FFS) landing to a predominantly rearfoot strike(RFS) landing. This change alters the way in which the body is loaded and may be contributing to the high rate of injuries runners experience while engaged in an activity for which they were adapted. In this paper, we will examine the benefits of barefoot running(typically an FFS pattern),and compare the lower extremity mechanics between FFS and RFS. The implications of these mechanical differences, in terms of injury, will be discussed. We will then provide evidence to support our contention that FFS provides an optimal mechanical environment for specific foot and ankle structures, such as the heel pad, the plantar fascia, and the Achilles tendon. The importance of footwear will then be addressed, highlighting its interaction with strike pattern on mechanics. This analysis will underscore why footwear matters when assessing mechanics. Finally, proper preparation and safe transition to an FFS pattern in minimal shoes will be emphasized. Through the discussion of the current literature, we will develop a justification for returning to running in the way for which we were adapted to reduce running-related injuries.展开更多
Background： The majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditi...Background： The majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditions and their relationship with injury severity have not been performed. The purpose of this study was to investigate the effects of wearing athletic shoes on muscular strength and its relationship to lower extremity injuries, specifically female basketball players due to the high incidence of ankle injuries in this population. Methods： During pre-season, 11 female collegiate basketball players underwent inversion and eversion muscle strength testing using an iso- kinetic dynamometer in both a barefoot and shod conditions. The difference between conditions was calculated for inversion and eversion peak torque, time to peak torque as well as eversion-to-inversion peak torque percent strength ratio for both conditions. Lower extremity injuries were documented and ranked in severity. The ranked difference between barefoot and shod conditions for peak torque and time to peak torque as well as percent strength ratio was correlated with injury ranking using a Spearman rho correlation （p） with an a level of 0.05. Results： The ranked differences in barefoot and shod for peak eversion and inversion torque at 120°/s were correlated with their injury ranking. Ranking of the athletes based on the severity of injuries that were sustained during the season was found to have a strong, positive relationship with the difference in peak eversion torque between barefoot and shod （p = 0.78; p = 0.02）. Conclusion： It is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Nar- rowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.展开更多
Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure...Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure,mechanical characteristics and transmission routes of deck loads.The simplified calculation models were brought out for the stud design of the longitudinal girders and transverse girders in the composite floor system of Nanjing Dashengguan Yangtze River Bridge (NDB).Studs were designed and arranged by taking the middle panel of 336 m main span for example.The results show that under deck loads,the longitudinal girders in the composite floor system of through steel bridges are in tension-bending state,longitudinal shear force on the interface is caused by both longitudinal force of "The first mechanical system" and vertical bending of "The second mechanical system",and studs can be arranged with equal space in terms of the shear force in range of 0.2d (where d is the panel length) on the top ends.Transverse girders in steel longitudinal and transverse girders-concrete slab composite deck are in compound-bending state,and out-of-plane bending has to be taken into account in the stud design.In orthotropic integral steel deck-concrete slab composite deck,out-of-plane bending of transverse girders is very small so that it can be neglected,and studs on the orthotropic integral steel deck can be arranged according to the structural requirements.The above design methods and simplified calculation models have been applied in the stud design of NDB.展开更多
A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the derm...A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.展开更多
Background:Numerous studies about the interaction between footwear(and barefoot) and kinematic and kinetic outcomes have been published over the last few years.Recent studies however lead to the conclusion that the as...Background:Numerous studies about the interaction between footwear(and barefoot) and kinematic and kinetic outcomes have been published over the last few years.Recent studies however lead to the conclusion that the assumed interactions depend mainly on the subjects" experience of barefoot(BF) walking/running,the preferred running strike pattern,the speed,the hardness of the surface,the thickness of the midsole material,and the runners’ level of ability.The aim of the present study was to investigate lower leg kinematics o\’ BF running and running in minimal running shoes(MRS) to assess comparability of BF kinematics in both conditions.To systematically compare both conditions we monitored the influencing variables described above in our measurement setup.We hypothesized that running in MRS does not alter lower leg kinematics compared to BF running.Methods:Thirty-seven subjects,injury-free and active in sports,ran BF on an EVA foam runway,and also ran shod wearing Nike Free 3.0 on a tartan indoor track.Lower-leg 3D kinematics was measured to quantify rearfoot and ankle movements.Skin markers were used in both shod and BF running.Results:All runners revealed rearfoot strike pattern when running barefoot.Differences between BF and MRS running occurred particularly during the initial stance phase of running,both in the sagittal and the frontal planes.BF running revealed a flatter foot placement,a more plantar flexed ankle joint and less inverted rearfoot at touchdown compared to MRS running.Conclusion:BF running does not change the landing automatically to forefoot running,especially after a systematic exclusion of surface and other influencing factors.The Nike Free 3.0 mimics some BF features.Nevertheless,changes in design of the Nike Free should be considered in order to mimic BF movement even more closely.展开更多
Background:Previous studies of foot strike patterns of distance runners in road races have typically found that the overwhelming majority of shod runners initially contact the ground on the rearfoot.However,none of th...Background:Previous studies of foot strike patterns of distance runners in road races have typically found that the overwhelming majority of shod runners initially contact the ground on the rearfoot.However,none of these studies has attempted to quantify foot strike patterns of barefoot or minimally shod runners.This study classifies foot strike patterns of barefoot and minimally shod runners in a recreational road race.Methods:High-speed video footage was obtained of 169 barefoot and 42 minimally shod distance runners at the 2011 New York City Barefoot Run.Foot strike patterns were classified for each runner,and frequencies of forefoot,midfoot,and rearfoot striking were compared between the barefoot and minimally shod groups.Results:A total of 59.2%of barefoot runners were forefoot strikers,20.1%were midfoot strikers,and 20.7%were rearfoot strikers.For minimally shod runners,33.3%were forefoot strikers,19.1%were midfoot strikers,and 47.6%were rearfoot strikers.Foot strike distributions for barefoot and minimally shod runners were significantly different both from one another and from previously reported foot strike distributions of shod road racers.Conclusion:Foot strike patterns differ between barefoot and minimally shod runners,with forefoot striking being more common,and rearfoot striking less common in the barefoot group.展开更多
Purpose:This study examined variation in foot strike types,lower extremity kinematics,and arch height and stiffness among Tarahumara Indians from the Sierra Tarahumara.Mexico.Methods:High speed video was used to study...Purpose:This study examined variation in foot strike types,lower extremity kinematics,and arch height and stiffness among Tarahumara Indians from the Sierra Tarahumara.Mexico.Methods:High speed video was used to study the kinematics of 23 individuals.13 who habitually wear traditional minimal running sandals(huaraches).and 10 who habitually wear modern,conventional running shoes with elevated,cushioned heels and arch support.Measurements of foot shape and arch stiffness were taken on these individuals plus an additional sample of 12 individuals.Results:Minimally shod Tarahumara exhibit much variation with 40%primarily using midfoot strikes,30%primarily using forefoot strikes,and30%primarily using rearfoot strikes.In contrast,75%of the conventionally shod Tarahumara primarily used rearfoot strikes,and 25%primarily used midfoot strikes.Individuals who used forefoot or midfoot strikes landed with significantly more plantarflexed ankles,flexed knees,and flexed hips than runners who used rearfoot strikes.Foot measurements indicate that conventionally shod Tarahumara also have significantly less stiff arches than those wearing minimal shoes.Conclusion:These data reinforce earlier studies that there is variation among foot strike patterns among minimally shod runners,but also support the hypothesis that foot stiffness and important aspects of running form,including foot strike,differ between runners who grow up using minimal versus modem,conventional footwear.展开更多
In recent years, the computer drawing technology that deals with three-dimensional (3D) design of footwear has become hot topics. Rhino is a kind of common and practical 3D design software with strong drawing and rend...In recent years, the computer drawing technology that deals with three-dimensional (3D) design of footwear has become hot topics. Rhino is a kind of common and practical 3D design software with strong drawing and rendering graphics function, which is widely used to design industrial products. In this paper, through decomposition and modeling, modeling and drawing methods were analyzed in various parts of footwear by Rhino, as well as the smooth technology and adjustments to its profile curve by an example of lady's high boots. Finally, through a series introductions of rendering effects for footwear in color, light perception, grain characteristic, and 3D graphics, the main technical essential is achieved and difficulties in design of overall footwear styles are solved.展开更多
基金supported by the Charles Phelps Taft Research Center at the University of Cincinnati
文摘Background:This prospective study explored the effects of endurance running(ER) in minimal versus standard running shoes on the foot’s superficial layer intrinsic muscles and the function of the longitudinal arch.Our hypothesis was that running in minimal shoes would cause hypertrophy in these muscles and lead to higher,stronger,stiffer arches.Methods:The hypothesis was tested using a sample of 33 healthy runners randomized into two groups,a control group shod in traditional running footwear and an experimental group shod in minimal support footwear,whose feet were scanned in an MRI before and after a 12-week training regime.Running kinematics as well as arch stiffness and height were also assessed before and after the treatment period.Results:Analysis of anatomical cross-sectional areas and muscle volumes indicate that the flexor digitomm brevis muscle became larger in both groups by 11%and 21%,respectively,but only the minimally shod runners had significant areal and volumetric increases of the abductor digiti minimi of 18%and 22%,respectively,and significantly increased longitudinal arch stiffness(60%).Conclusion:These results suggest that endurance running in minimal support footwear with 4 mm offset or less makes greater use of the springlike function of the longitudinal arch,thus leading to greater demands on the intrinsic muscles that support the arch,thereby strengthening the foot.
基金supported by the University of Franche Comte' (France) and the Exercise, Performance, Health, and Innovation platform of Besancon
文摘Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using kinematic data only.Methods： Fourteen male recreational runners（age 23.4 4.4 years, height 177.5 5.2 cm, and body mass 69.5 5.3 kg） were tested on 2separate days within 1 week. At each session, subjects ran seven 5-min trials on a treadmill at 10 km/h, interspersed with 5 min of sitting passive recovery. Each trial was performed on a different slope gradient, ranging from 8%（downhill） to t8%（uphill）, assigned in a random order.Furthermore, each subject ran one 5-min trial wearing minimal shoes（MS） and the subsequent trial wearing traditional shoes（TS） in a counterbalanced randomized order ensuring that each slope was ran once in MS and once in TS. Kinematic data were collected using a photocell measuring system and high-speed video camera, with kvertand klegstiffness being calculated from these data.Results： Leg compression, contact times, and vertical displacement of the center of mass during running were significantly smaller in MS compared to TS across all slopes. In the two footwear conditions, step frequency significantly increased with a（positive） increase in slope.Kinematic analyses indicated that klegwas greater when running in MS than TS and this between-footwear difference remained similar across slopes. On the contrary, kvertdid not change on the basis of footwear, but increased with positive increases in slope.Conclusion： This study showed that kvertand klegduring running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.
文摘It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of our body form. As our bodies have adapted to run, it seems unusual that up to 79% of modern day runners are injured annually. The etiology of these injuries is clearly multifactorial. However, 1 aspect of running that has significantly changed over the past 50 years is the footwear we use. Modern running shoes have become increasingly cushioned and supportive, and have changed the way we run. In particular, they have altered our footstrike pattern from a predominantly forefoot strike(FFS) landing to a predominantly rearfoot strike(RFS) landing. This change alters the way in which the body is loaded and may be contributing to the high rate of injuries runners experience while engaged in an activity for which they were adapted. In this paper, we will examine the benefits of barefoot running(typically an FFS pattern),and compare the lower extremity mechanics between FFS and RFS. The implications of these mechanical differences, in terms of injury, will be discussed. We will then provide evidence to support our contention that FFS provides an optimal mechanical environment for specific foot and ankle structures, such as the heel pad, the plantar fascia, and the Achilles tendon. The importance of footwear will then be addressed, highlighting its interaction with strike pattern on mechanics. This analysis will underscore why footwear matters when assessing mechanics. Finally, proper preparation and safe transition to an FFS pattern in minimal shoes will be emphasized. Through the discussion of the current literature, we will develop a justification for returning to running in the way for which we were adapted to reduce running-related injuries.
文摘Background： The majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditions and their relationship with injury severity have not been performed. The purpose of this study was to investigate the effects of wearing athletic shoes on muscular strength and its relationship to lower extremity injuries, specifically female basketball players due to the high incidence of ankle injuries in this population. Methods： During pre-season, 11 female collegiate basketball players underwent inversion and eversion muscle strength testing using an iso- kinetic dynamometer in both a barefoot and shod conditions. The difference between conditions was calculated for inversion and eversion peak torque, time to peak torque as well as eversion-to-inversion peak torque percent strength ratio for both conditions. Lower extremity injuries were documented and ranked in severity. The ranked difference between barefoot and shod conditions for peak torque and time to peak torque as well as percent strength ratio was correlated with injury ranking using a Spearman rho correlation （p） with an a level of 0.05. Results： The ranked differences in barefoot and shod for peak eversion and inversion torque at 120°/s were correlated with their injury ranking. Ranking of the athletes based on the severity of injuries that were sustained during the season was found to have a strong, positive relationship with the difference in peak eversion torque between barefoot and shod （p = 0.78; p = 0.02）. Conclusion： It is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Nar- rowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.
基金Project(2004G016-B) supported by the Science and Technology Development Program of Railways Department,China
文摘Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure,mechanical characteristics and transmission routes of deck loads.The simplified calculation models were brought out for the stud design of the longitudinal girders and transverse girders in the composite floor system of Nanjing Dashengguan Yangtze River Bridge (NDB).Studs were designed and arranged by taking the middle panel of 336 m main span for example.The results show that under deck loads,the longitudinal girders in the composite floor system of through steel bridges are in tension-bending state,longitudinal shear force on the interface is caused by both longitudinal force of "The first mechanical system" and vertical bending of "The second mechanical system",and studs can be arranged with equal space in terms of the shear force in range of 0.2d (where d is the panel length) on the top ends.Transverse girders in steel longitudinal and transverse girders-concrete slab composite deck are in compound-bending state,and out-of-plane bending has to be taken into account in the stud design.In orthotropic integral steel deck-concrete slab composite deck,out-of-plane bending of transverse girders is very small so that it can be neglected,and studs on the orthotropic integral steel deck can be arranged according to the structural requirements.The above design methods and simplified calculation models have been applied in the stud design of NDB.
文摘A promising direction in the tanning industry is the use of natural minerals as environmentally friendly technologically efficient materials that are able to adjust and regulate the efficiency of formation of the dermis structure and the properties of finished leather. The use of finely-dispersed minerals promotes alignment of topographic areas in thickness, increases the yield of leather on the area by avoiding bonding structural elements of the dermis. Changes in the microstructure of the dermis, as a result of mineral filling, contribute to improvement of performance and hygienic properties of finished leather. And the study of the properties of the specified skins should be consistent with the features of operations on their cutting, shoe molding and shoe upper fixing preparations. The most important properties of leather materials, which largely determine the quality of basic technological operations of shoe manufacturing are the deformation properties. Lack of information about relaxation and deformation properties of the leather produced by the new technologies do not allow to predict their ability to form shapes and save it--indicates the relevance of this study. This paper analyzes relaxation and deformation characteristics of natural leather for shoe uppers, filled with natural minerals montmorillonite and zeolite, and the ability to predict their formation and preservation of shape in service. Features of deformation of the skin with mineral content were assessed by determining single-cycle characteristics when attaching to a complete test cycle ＂loading-unloading-rest＂ sample. Correlations of elastic and plastic （permanent） deformation have been established, kinetics of changes in linear characteristics of the samples after removal of the load has been investigated. Introduction of dispersions of mineral to the structure of the dermis contributes to the strength of semi-finished leather, increase of the uniformity of mechanical properties in the longitudinal and transverse directions and rise of shape stability index. It is shown that the direction of this study allows us to offer new competitive ecologically friendly materials to produce shoes.
文摘Background:Numerous studies about the interaction between footwear(and barefoot) and kinematic and kinetic outcomes have been published over the last few years.Recent studies however lead to the conclusion that the assumed interactions depend mainly on the subjects" experience of barefoot(BF) walking/running,the preferred running strike pattern,the speed,the hardness of the surface,the thickness of the midsole material,and the runners’ level of ability.The aim of the present study was to investigate lower leg kinematics o\’ BF running and running in minimal running shoes(MRS) to assess comparability of BF kinematics in both conditions.To systematically compare both conditions we monitored the influencing variables described above in our measurement setup.We hypothesized that running in MRS does not alter lower leg kinematics compared to BF running.Methods:Thirty-seven subjects,injury-free and active in sports,ran BF on an EVA foam runway,and also ran shod wearing Nike Free 3.0 on a tartan indoor track.Lower-leg 3D kinematics was measured to quantify rearfoot and ankle movements.Skin markers were used in both shod and BF running.Results:All runners revealed rearfoot strike pattern when running barefoot.Differences between BF and MRS running occurred particularly during the initial stance phase of running,both in the sagittal and the frontal planes.BF running revealed a flatter foot placement,a more plantar flexed ankle joint and less inverted rearfoot at touchdown compared to MRS running.Conclusion:BF running does not change the landing automatically to forefoot running,especially after a systematic exclusion of surface and other influencing factors.The Nike Free 3.0 mimics some BF features.Nevertheless,changes in design of the Nike Free should be considered in order to mimic BF movement even more closely.
文摘Background:Previous studies of foot strike patterns of distance runners in road races have typically found that the overwhelming majority of shod runners initially contact the ground on the rearfoot.However,none of these studies has attempted to quantify foot strike patterns of barefoot or minimally shod runners.This study classifies foot strike patterns of barefoot and minimally shod runners in a recreational road race.Methods:High-speed video footage was obtained of 169 barefoot and 42 minimally shod distance runners at the 2011 New York City Barefoot Run.Foot strike patterns were classified for each runner,and frequencies of forefoot,midfoot,and rearfoot striking were compared between the barefoot and minimally shod groups.Results:A total of 59.2%of barefoot runners were forefoot strikers,20.1%were midfoot strikers,and 20.7%were rearfoot strikers.For minimally shod runners,33.3%were forefoot strikers,19.1%were midfoot strikers,and 47.6%were rearfoot strikers.Foot strike distributions for barefoot and minimally shod runners were significantly different both from one another and from previously reported foot strike distributions of shod road racers.Conclusion:Foot strike patterns differ between barefoot and minimally shod runners,with forefoot striking being more common,and rearfoot striking less common in the barefoot group.
基金a grant from the American School of Prehistoric Research (Harvard University)
文摘Purpose:This study examined variation in foot strike types,lower extremity kinematics,and arch height and stiffness among Tarahumara Indians from the Sierra Tarahumara.Mexico.Methods:High speed video was used to study the kinematics of 23 individuals.13 who habitually wear traditional minimal running sandals(huaraches).and 10 who habitually wear modern,conventional running shoes with elevated,cushioned heels and arch support.Measurements of foot shape and arch stiffness were taken on these individuals plus an additional sample of 12 individuals.Results:Minimally shod Tarahumara exhibit much variation with 40%primarily using midfoot strikes,30%primarily using forefoot strikes,and30%primarily using rearfoot strikes.In contrast,75%of the conventionally shod Tarahumara primarily used rearfoot strikes,and 25%primarily used midfoot strikes.Individuals who used forefoot or midfoot strikes landed with significantly more plantarflexed ankles,flexed knees,and flexed hips than runners who used rearfoot strikes.Foot measurements indicate that conventionally shod Tarahumara also have significantly less stiff arches than those wearing minimal shoes.Conclusion:These data reinforce earlier studies that there is variation among foot strike patterns among minimally shod runners,but also support the hypothesis that foot stiffness and important aspects of running form,including foot strike,differ between runners who grow up using minimal versus modem,conventional footwear.
文摘In recent years, the computer drawing technology that deals with three-dimensional (3D) design of footwear has become hot topics. Rhino is a kind of common and practical 3D design software with strong drawing and rendering graphics function, which is widely used to design industrial products. In this paper, through decomposition and modeling, modeling and drawing methods were analyzed in various parts of footwear by Rhino, as well as the smooth technology and adjustments to its profile curve by an example of lady's high boots. Finally, through a series introductions of rendering effects for footwear in color, light perception, grain characteristic, and 3D graphics, the main technical essential is achieved and difficulties in design of overall footwear styles are solved.
