Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running

Background:Foot kinematics,such as excessive eversion and malalignment of the hindfoot,are believed to be associated with running-related injuries.The maj ority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics.However,technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns(RFS and FFS,respectively).This study uses a high-speed dual fluoroscopic imaging system(DFIS)to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics.Methods:Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models.A high-speed DFIS(100 Hz)was used to collect 6 degrees of freedom kinematics for participants’tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition.Results:Compared with RFS,FFS exhibited greater internal rotation at 0%-20%of the stance phase in the tibiotalar joint.The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS(p<0.001,Cohen’s d=0.92).RFS showed more dorsiflexion at 0%-20%of the stance phase in the tibiotalar joint than FFS.RFS also presented a larger anterior translation(p<0.001,Cohen’s d=1.28)in the subtalar joint at i nitial contact than FFS.Conclusion:Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance.The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RF S and FFS during running.

Physical activity and health in the presence of China's economic growth:Meeting the public health challenges of the aging population

Three decades of rapid economic development in China have not only benefited millions of Chinese by improving their living standards but have also dramatically increased the number of people who are part of the country's aging population. However, economic growth has not been accompanied by sufficient attention given to important public health issues, including an increase in the incidence of chronic diseases and a decline in physical activity(PA) that comes with an aging population. The rapid growth in China's older population will soon exert an impact on the nation's economy, population health status, and health behaviors, and will increase stress on its healthcare system. This review article provides a broad perspective on the impact of rapid economic development, industrialization, and urbanization on health-related behaviors, with a specific focus on PA among older adults. Specifically, the article offers an overview of the demographic context, significant public health challenges,evidence on PA and exercise interventions, and knowledge gaps and future directions for research.

Recruitment of older adults into randomized controlled trials:Issues and lessons learned from two community-based exercise interventions in Shanghai

Background: With the increasing need for high-quality exercise interventions in China, relatively little is known about issues and challenges related to recruitment of older Chinese adults into exercise-based disease prevention interventions. This study aims to describe the recruitment process and outcomes of 2 exercise interventions conducted in Shanghai, China.Methods: Recruitment information was ascertained from 2 community-based randomized controlled trials for 2 exercise interventions, the first designed to improve health outcomes for older women with knee osteoarthritis and the second to study changes in cognitive function in adults with mild cognitive impairment. Results were summarized in terms of recruitment sources, number screened, screening-to-enrollment ratios, and costs.Results: Recruitment was primarily achieved through working with local residential divisions(i.e., neighborhood associations and residential committees). Both studies achieved their planned target number of older adults(45 and 46, respectively) within a 1-year time frame, with a screening-to-randomized ratio of 5:1 and demonstrated excellent retention rates(range 87%–93%) at 6 months. The recruitment cost for the 2studies averaged RMB 189(about USD 30) per initial recruit and RMB 738(about USD 119) per participant randomized. Some major issues encountered during the recruitment process included(1) the use of community neighborhoods to support the conduct of the projects,(2) access to participants, and(3) feasibility.Conclusion: Analysis of the 2 randomized controlled trials has provided valuable insights into the recruitment process and identified resources that can help better planning and recruitment for future interventions. Recommendations aimed at increasing the success of future recruitment efforts are provided.

Physical activity, aging, and health in China: Addressing public health needs in the presence of continued economic growth and urbanization

The significant increase in the number of older adults in China,coupled with continuing industrialization and urbanization,has profound social and economic ramifications,including the evolution of major challenges to public health,elder care services,policy-making,and the nation’s healthcare system.While the unprecedented changes in political and economic structures have obviously increased China’s productivity and revenues,what is less well understood is how they

Effects of Tai Ji Quan training on gait kinematics in older Chinese women with knee osteoarthritis: A randomized controlled trial

Background: Although Tai Ji Quan has been shown to relieve pain and improve functional mobility in people with knee osteoarthritis(OA), little is known about its potential benefits on gait characteristics among older Chinese women who have a high prevalence of both radiographic and symptomatic knee OA. This study aims to assess the efficacy of a tailored Tai Ji Quan intervention on gait kinematics for older Chinese women with knee OA.Methods: A randomized controlled trial involving 46 older women in Shanghai, China, with clinically diagnosed knee OA. Randomized(1:1)participants received either a 60 min Tai Ji Quan session(n = 23) 3 times weekly or a 60 min bi-weekly educational session(n = 23) for 24 weeks.Primary outcomes were changes in gait kinematic measures from baseline to 24 weeks. Secondary outcomes included changes in scores on the Western Ontario and Mc Master University Osteoarthritis Index(WOMAC) and Short Physical Performance Battery(SPPB).Results: After 24 weeks the Tai Ji Quan group demonstrated better performance in gait velocity(mean difference, 8.40 cm/s, p = 0.01), step length(mean difference, 3.52 cm, p = 0.004), initial contact angle(mean difference, 2.19°, p = 0.01), and maximal angle(mean difference, 2.61°,p = 0.003) of flexed knees during stance phase compared to the control group. In addition, the Tai Ji Quan group showed significant improvement in WOMAC scores(p < 0.01)(mean difference,-4.22 points in pain, p = 0.002;-2.41 points in stiffness, p < 0.001;-11.04 points in physical function, p = 0.006) and SPPB scores(mean difference, 1.22 points, p < 0.001).Conclusion: Among older Chinese women with knee OA, a tailored Tai Ji Quan intervention improved gait outcomes. The intervention also improved overall function as indexed by the WOMAC and SPPB. These results support the use of Tai Ji Quan for older Chinese adults with knee OA to both improve their functional mobility and reduce pain symptomatology.

Effects of exergaming on motor skill competence,perceived competence,and physical activity in preschool children

Background: Few school settings offer opportunities for preschool children to engage in structured physical activity, and only a few studies have been conducted examining exergaming's effectiveness on health outcomes in this age group. This study's purpose, therefore, was to examine a school-based exergaming intervention's effect on preschool children's perceived competence(PC), motor skill competence(MSC), and physical activity versus usual care(recess), as well as to examine gender differences for these outcomes.Methods: A total of 65 preschool children from 2 underserved urban schools were assigned to 1 of 2 conditions, with the school as the experimental unit:(1) usual care recess group(8 weeks of 100 min of recess/week(5 days ￡ 20 min)) and(2) exergaming intervention group(8 weeks of100 min of exergaming/week(5 days ￡ 20 min) at school). All children underwent identical assessments of PC, MSC, and moderate-to-vigorous physical activity(MVPA) at baseline and at the end of the 8 th week.Results: A significant Group ￡ Time effect was observed for MVPA, F(1, 52) = 4.37, p = 0.04, h2 p= 0.04, but not for PC, F(1, 52) = 0.83, p = 0.37,h2 p= 0.02, or MSC, F(1, 52) = 0.02, p = 0.88, h2 p= 0.00. Specifically, the intervention children displayed significantly greater increased MVPA after8 weeks than the comparison children. Additionally, there was a significant time effect for MSC, F(1, 52) = 15.61, p < 0.01, h2 p= 0.23, and gender effect for MVPA, F(1, 52) = 5.06, p = 0.02, h2 p= 0.09. Although all preschoolers' MSC improved across time, boys demonstrated greater MVPA than girls at both time points.Conclusion: Exergaming showed a positive effect in promoting preschool children's MVPA at school and has the potential to enhance PC and MSC. More research with larger sample sizes and longer study durations are warranted.

Beijing 2022 Winter Olympic Games:Commitments to science and public health

The Beijing 24th 2022 Winter Olympic Games present a unique opportunity to promote the spirit and values of the Olympic Games in relation to their impact on physical activity and global health,sports medicine,and sports performance.The 2022 Winter Olympic Games mark the 98th year since the first Winter Games were held in Chamonix,France,in 1924.The inaugural Winter Olympic Games sponsored 16 events,and 250 athletes from 16 nations participated.1 In contrast,the Beijing 2022 Winter Olympic Games will sponsor 109 events.

Relationship of proprioception,cutaneous sensitivity,and muscle strength with the balance control among older adults

Background:Balance impairment is one of the strongest risk factors for falls.Proprioception,cutaneous sensitivity,and muscle strength are 3 important contributors to balance control in older adults.The relationship that dynamic and static balance control has to proprioception,cutaneous sensitivity,and muscle strength is still unclear.This study was performed to investigate the relationship these contributors have to dynamic and static balance control.Methods:A total of 164 older adults(female=89,left dominant=15,age:73.5±7.8 years,height:161.6±7.1 cm,weight:63.7±8.9 kg,mean±SD)participated in this study.It tested the proprioception of their knee flexion/extension and ankle dorsi/plantarflexion,along with cutaneous sensitivity at the great toe,first and fifth metatarsals,arch,and heel,and the muscle strength of their ankle dorsi/plantarflexion and hip abduction.The Berg Balance Scale(BBS)and the root mean square(RMS)of the center of pressure(CoP)were collected as indications of dynamic and static balance control.A partial correlation was used to determine the relationship between the measured outcomes variables(BBS and CoPRMS)and the proprioception,cutaneous sensitivity,and muscle strength variables.Results:Proprioception of ankle plantarflexion(r=-0.306,p=0.002)and dorsiflexion(r=-0.217,p=0.030),and muscle strength of ankle plantarflexion(r=0.275,p=0.004),dorsiflexion(r=0.369,p<0.001),and hip abduction(r=0.342,p<0.001)were weakly to moderately correlated with BBS.Proprioception of ankle dorsiflexion(r=0.218,p=0.020)and cutaneous sensitivity at the great toe(r=0.231,p=0.041)and arch(r=0.285,p=0.002)were weakly correlated with CoP-RMS in the anteroposterior direction.Proprioception of ankle dorsiflexion(r=0.220,p=0.035),knee flexion(r=0.308,p=0.001)and extension(r=0.193,p=0.040),and cutaneous sensitivity at the arch(r=0.206,p=0.028)were weakly to moderately correlated with CoP-RMS in the mediolateral direction.Conclusion:There is a weak-to-moderate relationship between proprioception and dynamic and static balance control,a weak relationship between cutaneous sensitivity and static balance control,and a weak-to-moderate relationship between muscle strength and dynamic balance control.

The late swing and early stance of sprinting are most hazardous for hamstring injuries

Hamstring strain injury is one of most prevalent noncontact injuries in sports that involve high-speed running,such as sprinting,soccer,and rugby.~1In order to optimize prevention strategies and injury rehabilitation,studies have been conducted to understand hamstring function during sprinting.^(2–4)However,differences have long existed in the literature as to the cause of hamstring strain injuries.One of the most

Physical activity and prevention of Alzheimer's disease

Alzheimer’s disease（AD）is an irreversible,progressive brain disorder that affects about 48 million people worldwide and is the cause of 60%–70%of dementia,particularly in people over 65 years old.Without prevention or treatment,the disease slowly destroys memory and thinking skills and,

A 6-week diet and exercise intervention alters metabolic syndrome risk factors in obese Chinese children aged 11-13 years

Purpose:A randomized,controlled trial was conducted to determine whether a 6-week low calorie diet and aerobic exercise intervention could alter metabolic syndrome(MetS) risk factors in pre-pubescent obese Chinese children.Methods:The subjects were randomized into diet and exercise(DE) and control(C) groups.The DE group ingested 1600-2000 kcal/day adjusted to each participant’s basal metabolic rate,and engaged in high-volume aerobic exercise(6 days/week,twice daily,for 3 h per session) for 6 weeks.A total of 215 obese children between the ages of 11 and 13 years were recruited into the study,with 167 subjects(DE,n=95;C,n=72) completing all phases.Pre-and post-study measures included body weight,body mass index,waist circumference,body fat percentage,blood pressure and other MetS-related markers from fasting blood samples(serum cholesterol,triglycerides,insulin,and glucose).Results:Compared to controls,the DE subjects experienced significantly reduced levels for all outcome markers(p 【 0.05),except for fasting blood glucose in boys(p=0.09).Conclusion:An intensive,6-week diet and exercise intervention had favorable effects in altering MetS risk factors in obese Chinese children aged 11 to 13.

Physical activity and cognitive function among older adults in China:A systematic review

Background: Physical activity(PA) has been shown to benefit cognitive function in older adults. However, the cognitive benefits of exercising for older Chinese adults have not been systematically documented. This study was to conduct a systematic review on evidence that PA is beneficial for cognitive functioning in older Chinese adults.Methods: Major databases, including Pub Med, EMBASE, Cochrane Library, Wan Fang, CNKI, and VIP, were searched for studies published in English or Chinese between January 2000 and December 2015. Randomized and non-randomized controlled trials(RCTs and non-RCTs), cohort,case-control and cross-sectional studies that evaluated PA and cognitive function among older Chinese adults were included in this review.Results: Of 53 studies included and reviewed, 33 were observational(22 cross-sectional, 7 case-control, and 4 cohort) and 20 were experimental(15 RCTs, 5 non-RCTs). Observational studies showed an association of reduced risk of cognitive-related diseases(i.e., mild cognitive impairment, Alzheimer's disease, and dementia) through PA, whereas experimental studies reported exercise-induced improvement in multiple domains of cognitive function(i.e., global cognitive function, memory, executive function, attention, language, and processing recourse).Conclusion: This systematic review provides initial evidence that PA may benefit cognition in older Chinese adults. Further studies of individuals with cognitive impairments and prospective and RCT studies having high scientific rigor are needed to corroborate the findings reported in this review.

Comments to “Mechanism of hamstring muscle strain injury in sprinting”by Yu et al.

We have carefully read Dr.Yu and his colleagues'~1review on the mechanism of hamstring muscle strain injury in sprinting.There is no doubt that they have done a lot work in this field.Their views are based on 3 pieces of evidence.First,observations from in situ animal models suggest that muscle strain injuries are highly associated with eccentric contractions.Second,the magnitude of muscle strain,rather than the force。

Surface effects on in-shoe plantar pressure and tibial impact during running

Purpose： This study aims to explore the effects of running on different surfaces on the characteristics of in-shoe plantar pressure and tibial acceleration. Methods： Thirteen male recreational runners were required to run at 12 km/h velocity on concrete, synthetic track, natural grass, a normal treadmill, and a treadmill equipped with an ethylene vinyl acetate （EVA） cushioning underlay （treadmill_EVA）, respectively. An in-shoe plantar pressure system and an accelerometer attached to the tibial tuberosity were used to record and analyze the characteristics of plantar pressure and tibial impact during running. Results： The results showed that there were no significant differences in the 1 st and 2nd peak plantar pressures （time of occurrence）, pressure-time integral, and peak pressure distribution for the concrete, synthetic, grass, and normal treadmill surfaces. No significant differences in peak positive acceleration were observed among the five tested surface conditions. Compared to the concrete surface, however, running on treadmillEVA showed a significant decrease in the 1st peak plantar pressure and the pressure time integral for the impact phase （p 〈 0.05）. These can be further ascribed to a reduced peak pressure observed at heel region （p 〈 0.05）. Conclusion： There may not be an inevitable relationship between the surface and the lower-limb impact in runners. It is, however, still noteworthy that the effects of different treadmill surfaces should be considered in the interpretation of plantar pressure performance and translation of such results to overground running.

Assessing proprioception:A critical review of methods

To control movement,the brain has to integrate proprioceptive information from a variety of mechanoreceptors.The role of proprioception in daily activities,exercise,and sports has been extensively investigated,using different techniques,yet the proprioceptive mechanisms underlying human movement control are still unclear.In the current work we have reviewed understanding of proprioception and the three testing methods:threshold to detection of passive motion,joint position reproduction,and active movement extent discrimination,all of which have been used for assessing proprioception.The origin of the methods,the different testing apparatus,and the procedures and protocols used in each approach are compared and discussed.Recommendations are made for choosing an appropriate technique when assessing proprioceptive mechanisms in different contexts.

Performance and safety in elite skiing sports:A big challenge on specificity,individuality,and complexity

Winter sports, including those with a focus on gliding with skis on snow, have become extremely complex in the last few decades. During the Olympic Games held in Pyeongchang, Republic of Korea, in 2018, a greater number of different skiing competitions took place： alpine skiing with giant slalom, downhill, slalom, and super-G and alpine combined; biathlon with 10-km sprint, 12.5-km pursuit, 15-km mass start, 20-km individual, and a 4×7.5-km relay; cross-country skiing with 6 different kinds of races including short, medium and long distances, classical and skating techniques, and individual and mass start; free-style skiing with aerials, moguls, ski cross, ski halfpipe, and ski slopestyle; Nordic skiing combined with ski jumping on large and normal hills, followed by cross-country skiing over 10 km; and snowboard with big air, half pipe, parallel giant slalom, slope style, and snowboard cross.

Effect of Taijiquan practice versus wellness education on knee pro-prioception in patients with knee osteoarthritis:a randomized con-trolled trial

OBJECTIVE: To determine the effects of Taijiquan practice on knee proprioception in patients with knee osteoarthritis(OA).METHODS: We conducted a randomized controlled trial comparing Taijiquan with a control condition(wellness education) in patients with knee OA. The patients participated in either a 60-min Taijiquan session three times weekly or a 60-min weekly educational session, for 24 consecutive weeks. The primary outcomes were changes in knee proprioception. Secondary outcomes were changes in the Western Ontario and Mc Master University Osteoarthritis Index(WOMAC).RESULTS: After 24 weeks, compared with the control group, the Taijiquan group demonstrated better improvements in the joint position sense in knee flexion(left:-2.12°; right:-2.02°), and knee extension(left:-2.22°; right:-1.54°). In addition,the Taijiquan group showed significantly greater improvements in the WOMAC scores(P < 0.05) for knee pain(left:-3.17 points; right:-3.74 points),stiffness(left:-2.43 points; right:-2.13 points),and physical function(left:-10.99 points; right:-8.00 points), compared with the control group.CONCLUSION: A 24-week Taijiquan practice resulted in a significant improvement in knee proprioception in patients with knee OA. The present findings add increasing evidence regarding the clinical benefits of Taijiquan as a therapeutic modality for patients to improve the reflex protection of knee joints against potentially harmful forces.

A Musculoskeletal Modeling of Hand-foot Crawling with Different Heights

As a bionic therapy,hand-foot crawling has been reported to be used for the rehabilitation of low back pain.However,there have been few relevant biomechanical studies about this type of exercise.The purpose of this study was to calculate muscle activation and lumbar spinal load based on the examined limb kinematics and kinetics,which associated with hand-foot crawling at the different Centre of Mass(CoM)heights.A total of 14 men performed hand-foot crawling at three CoM heights.The kinematics and kinetics data were collected.One-way repeated measure analysis of variance was used to analyze the efFect of the CoM height on crawling parameters.The crawling data from one subject at the three heights were used to calculate the muscle activation and compressive lumbar load with an OpenSim musculoskeletal model.The CoM heights had no significant effect on kinematics,kinetics or muscle activation.The spinal load was larger at higher heights.Hand-foot crawling was associated with lower trunk muscle activity.This study helps us to understand hand-foot crawling from the perspective of biomechanics.The findings from this study may help physical therapists choose hand-foot crawling as an appropriate exercise for patients with low back pain during early rehabilitation.

Recent studies of atomic-resolution structures of tau protein and structure-based inhibitors

Background:Alzheimer’s disease(AD)is one of the most popular tauopathies.Neurofibrillary tangles and senile plaques are-widely recognized as the pathological hallmarks of AD,which are mainly composed of tau andβ-amyloid(Aβ)respectively.Recent failures of drugs targeting Aβhave led scientists to scrutinize the crucial impact of tau in neurodegenerative diseases.Mutated or abnormal phosphorylated tau protein loses affinity with microtubules and assembles into pathological accumulations.The aggregation process closely correlates to two amyloidogenic core of PHF6(^(306)VQIVYK^(311))and PHF6*(^(275)VQILNK^(280))fragments.Moreover,tau accumulations display diverse morphological characteristics in different diseases,which increases the difficulty of providing a unifying neuropathological criterion for early diagnosis.Results:This review mainly summarizes atomic-resolution structures of tau protein in the monomeric,oligomeric and fibrillar states,as well as the promising inhibitors designed to prevent tau aggregation or disaggregate tau accumulations,recently revealed by experimental and computational studies.We also systematically sort tau functions,their relationship with tau structures and the potential pathological processes of tau protein.Conclusion:The current progress on tau structures at atomic level of detail expands our understanding of tau aggregation and related pathology.We discuss the difficulties in determining the source of neurotoxicity and screening effective inhibitors.We hope this review will inspire new clues for designing medicines against tau aggregation and shed light on AD diagnosis and therapies.

Assessing proprioception:What do you really want to know?——Response to Krewer et al.

Dear editor,In their comment,Krewer et al.1argue that before selecting a specific method for assessing proprioception,it is essential to consider which component of proprioception is to be assessed.They also note that there is no single method for assessing all aspects of the various proprioceptive senses,