Background:Bone stress injuries(BSIs)are common in female runners,and recurrent BSI rates are high.Previous work suggests an association between higher impact loading during running and tibial BSI.However,it is unknow...Background:Bone stress injuries(BSIs)are common in female runners,and recurrent BSI rates are high.Previous work suggests an association between higher impact loading during running and tibial BSI.However,it is unknown whether impact loading and fatigue-related loading changes discriminate women with a history of multiple BSIs.This study compared impact variables at the beginning of a treadmill run to exertion andthe changes in those variables with exertion among female runners with no history of BSI as well as among those with a history of single or multiple BSIs.Methods:We enrolled 45 female runners(aged 18-40 years)for this cross-sectional study:having no history of diagnosed lower extremity BSI(N-BSI,n=14);a history of 1 lower extremity BSI(1-BSI,n=16);and diagnosed by imaging,or a history of multiple(>3)lower extremity BSIs(M-BSI,n=15).Participants completed a 5-km race speed run on an instrumented treadmill while wearing an Inertial Measurement Unit.The vertical average loading rate(VALR),vertical instantaneous loading rate(VILR),vertical stiffness during impact via instrumented treadmill,and tibial shock determined as the peak po sitive tibial acceleration via Inertial Measurement Unit were measured at the beginning and the end of the run.Results:There were no differences between groups in VALR,VILR,vertical stiffness,or tibial shock in a fresh or exerted condition.However,compared to N-BSI,women with M-BSI had greater increase with exertion in VALR(-1.8%vs.6.1%,p=0.01)and VILR(1.5%vs.4.8%,p=0.03).Similarly,compared to N-BSI,vertical stiffness increased more with exertion among women with M-BSI(-0.9%vs.7.3%,p=0.006)and 1-BSI(-0.9%vs.1.8%,p=0.05).Finally,compared to N-BSI,the increase in tibial shock from fresh to exerted condition was greater among women with M-BSI(0.9%vs.5.5%,p=0.03)and 1-BSI(0.9%vs.11.2%,p=0.02).Conclusion:Women with 1-BSI or M-BSIs experience greater exertion-related increases in impact loading than women with N-BSI.These observations imply that exertion-related changes in gait biomechanics may contribute to risk of BSI.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: Excessive vertical impacts at landing are associated with common running injuries. Two primary gait-retraining interventions aimed at reducing impact forces are transition to forefoot strike and increasing...Background: Excessive vertical impacts at landing are associated with common running injuries. Two primary gait-retraining interventions aimed at reducing impact forces are transition to forefoot strike and increasing cadence. The objective of this study was to compare the shortand long-term effects of 2 gait-retraining interventions aimed at reducing landing impacts.Methods: A total of 39 healthy recreational runners using a rearfoot strike and a cadence of 170 steps/min were randomized into cadence(CAD) or forefoot strike(FFS) groups. All participants performed 4 weeks of strengthening followed by 8 sessions of gait-retraining using auditory feedback. Vertical average load rates(VALR) and vertical instantaneous load rates(VILR) were calculated from the vertical ground reaction force curve. Both cadence and foot strike angle were measured using 3D motion analysis and an instrumented treadmill at baseline and at 1 week,1 month, and 6 months post retraining.Results: ANOVA revealed that the FFS group had significant reductions in VALR(49.7%) and VILR(41.7%), and changes were maintained long term. Foot strike angle in the FFS group changed from 14.2° dorsiflexion at baseline to 3.4° plantarflexion, with changes maintained long term. The CAD group exhibited significant reduction only in VALR(16%) and only at 6 months. Both groups had significant and similar increases in cadence at all follow-ups(CAD, +7.2% to 173 steps/min;and FFS, +6.1% to 172 steps/min).Conclusion: Forefoot strike gait-retraining resulted in significantly greater reductions in VALR and similar increases in cadence compared to cadence gait-retraining in the short and long term. Cadence gait-retraining resulted in small reductions in VALR at only the 6-month follow-up.展开更多
Barefoot running has been around for millions of years,and it is safe to presume that for most of that time,the practice occasioned little interest.Our ancestors ran barefoot because they had no shoes.When footwear wa...Barefoot running has been around for millions of years,and it is safe to presume that for most of that time,the practice occasioned little interest.Our ancestors ran barefoot because they had no shoes.When footwear was first invented during the last 40,000 years (no doubt at different times and in different places),shoes were by necessity minimal-essentially sandals and moccasins-designed to protect the sole of the foot but lacking any of the sophisticated features and materials present in modem running shoes such as elevated cushioned heels,arch supports,and toe springs.Most of these features were invented in the 1970s,and they quickly became more popular and sophisticated as running underwent a worldwide boom.Today,the vast majority of runners think it is normal to wear cushioned running shoes,and would never dream of running without them.展开更多
基金supported in part by appointments to the Department of Defense Research Participation Program at the U.S.Army Research Institute of Environmental Medicine administered by the Oak Ridge Institute for Science and Educationsupport from the U.S.Department of Defense+2 种基金Defense Health ProgramJoint Program Committee(W81XWH-16-1-0652)the National Institutes of Health shared instrumentation grant(S10 RR023405)。
文摘Background:Bone stress injuries(BSIs)are common in female runners,and recurrent BSI rates are high.Previous work suggests an association between higher impact loading during running and tibial BSI.However,it is unknown whether impact loading and fatigue-related loading changes discriminate women with a history of multiple BSIs.This study compared impact variables at the beginning of a treadmill run to exertion andthe changes in those variables with exertion among female runners with no history of BSI as well as among those with a history of single or multiple BSIs.Methods:We enrolled 45 female runners(aged 18-40 years)for this cross-sectional study:having no history of diagnosed lower extremity BSI(N-BSI,n=14);a history of 1 lower extremity BSI(1-BSI,n=16);and diagnosed by imaging,or a history of multiple(>3)lower extremity BSIs(M-BSI,n=15).Participants completed a 5-km race speed run on an instrumented treadmill while wearing an Inertial Measurement Unit.The vertical average loading rate(VALR),vertical instantaneous loading rate(VILR),vertical stiffness during impact via instrumented treadmill,and tibial shock determined as the peak po sitive tibial acceleration via Inertial Measurement Unit were measured at the beginning and the end of the run.Results:There were no differences between groups in VALR,VILR,vertical stiffness,or tibial shock in a fresh or exerted condition.However,compared to N-BSI,women with M-BSI had greater increase with exertion in VALR(-1.8%vs.6.1%,p=0.01)and VILR(1.5%vs.4.8%,p=0.03).Similarly,compared to N-BSI,vertical stiffness increased more with exertion among women with M-BSI(-0.9%vs.7.3%,p=0.006)and 1-BSI(-0.9%vs.1.8%,p=0.05).Finally,compared to N-BSI,the increase in tibial shock from fresh to exerted condition was greater among women with M-BSI(0.9%vs.5.5%,p=0.03)and 1-BSI(0.9%vs.11.2%,p=0.02).Conclusion:Women with 1-BSI or M-BSIs experience greater exertion-related increases in impact loading than women with N-BSI.These observations imply that exertion-related changes in gait biomechanics may contribute to risk of BSI.
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.
基金funded by a student scholarship from the Force and Motion Foundation(501(c)(3))。
文摘Background: Excessive vertical impacts at landing are associated with common running injuries. Two primary gait-retraining interventions aimed at reducing impact forces are transition to forefoot strike and increasing cadence. The objective of this study was to compare the shortand long-term effects of 2 gait-retraining interventions aimed at reducing landing impacts.Methods: A total of 39 healthy recreational runners using a rearfoot strike and a cadence of 170 steps/min were randomized into cadence(CAD) or forefoot strike(FFS) groups. All participants performed 4 weeks of strengthening followed by 8 sessions of gait-retraining using auditory feedback. Vertical average load rates(VALR) and vertical instantaneous load rates(VILR) were calculated from the vertical ground reaction force curve. Both cadence and foot strike angle were measured using 3D motion analysis and an instrumented treadmill at baseline and at 1 week,1 month, and 6 months post retraining.Results: ANOVA revealed that the FFS group had significant reductions in VALR(49.7%) and VILR(41.7%), and changes were maintained long term. Foot strike angle in the FFS group changed from 14.2° dorsiflexion at baseline to 3.4° plantarflexion, with changes maintained long term. The CAD group exhibited significant reduction only in VALR(16%) and only at 6 months. Both groups had significant and similar increases in cadence at all follow-ups(CAD, +7.2% to 173 steps/min;and FFS, +6.1% to 172 steps/min).Conclusion: Forefoot strike gait-retraining resulted in significantly greater reductions in VALR and similar increases in cadence compared to cadence gait-retraining in the short and long term. Cadence gait-retraining resulted in small reductions in VALR at only the 6-month follow-up.
文摘Barefoot running has been around for millions of years,and it is safe to presume that for most of that time,the practice occasioned little interest.Our ancestors ran barefoot because they had no shoes.When footwear was first invented during the last 40,000 years (no doubt at different times and in different places),shoes were by necessity minimal-essentially sandals and moccasins-designed to protect the sole of the foot but lacking any of the sophisticated features and materials present in modem running shoes such as elevated cushioned heels,arch supports,and toe springs.Most of these features were invented in the 1970s,and they quickly became more popular and sophisticated as running underwent a worldwide boom.Today,the vast majority of runners think it is normal to wear cushioned running shoes,and would never dream of running without them.
