Purpose： The purpose of this study was to examine the effects of landing kinematics and electromyographic （EMG） activities of medial gastrocnemius on a combined inversion and plantarflexion surface on the ankle （M...Purpose： The purpose of this study was to examine the effects of landing kinematics and electromyographic （EMG） activities of medial gastrocnemius on a combined inversion and plantarflexion surface on the ankle （MG）, peroneus longus （PL）, and tibialis anterior （TA） muscles. Methods： Twelve recreational athletes performed five drop landings from an overhead bar of 30 cm height on to three surfaces： a flat surface, a 25° inversion surface, and a combined surface of 25° inversion and 25° plantarflexion. The kinematic variables and integrated EMG （IEMG） of the three muscles were assessed using a one-way repeated measures ANOVA and a 3 × 3 （surface × muscle） ANOVA, respectively （p 〈 0.05）. Results： The IEMG results showed a significant muscle by surface interaction. The flat surface induced higher TA activity than the two tilted surfaces. The inverted surface produced significantly higher inversion peak angle and velocity than the flat surface, but similar PL activity across the surfaces. The MG IEMG, ankle plantarflexion angle, and inversion range of motion were significantly higher for the combined surface compared to the inverted surface. Conclusion： These findings suggest that compared to the inversion surface, the combined plantarflexion and inversion surface seems to provide a more unstable surface condition for lateral ankle sprains during landing.展开更多
Background:Tibial stress fracture(TSF)is an overuse running injury with a long recovery period.While many running studies refer to biomechanical risk factors for TSF,only a few have compared biomechanics in runners wi...Background:Tibial stress fracture(TSF)is an overuse running injury with a long recovery period.While many running studies refer to biomechanical risk factors for TSF,only a few have compared biomechanics in runners with TSF to controls.The aim of this systematic review and meta-analysis was to evaluate biomechanics in runners with TSF compared to controls.Methods:Electronic databases PubMed,Web of Science,SPORTDiscus,Scopus,Cochrane,and CINAHL were searched.Risk of bias was assessed and meta-analysis conducted for variables reported in 3 or more studies.Results:The search retrieved 359 unique records,but only the 14 that compared runners with TSF to controls were included in the review.Most studies were retrospective,2 were prospective,and most had a small sample size(5-30 per group).Many variables were not significantly different between groups.Meta-analysis of peak impact,active,and braking ground reaction forces found no significant differences between groups.Individual studies found larger tibial peak anterior tensile stress,peak posterior compressive stress,peak axial acceleration,peak rearfoot eversion,and hip adduction in the TSF group.Conclusion:Meta-analysis indicated that discrete ground reaction force variables were not statistically significantly different in runners with TSF compared to controls.In individual included studies,many biomechanical variables were not statistically significantly different between groups.However,many were reported by only a single study,and sample sizes were small.We encourage additional studies with larger sample sizes of runners with TSF and controls and adequate statistical power to confirm or refute these findings.展开更多
Poor cardiorespiratory fitness may mediate vascular impairments at rest and following an acute bout of exercise in young healthy individuals.This study aimed to compare flow mediated dilation(FMD)and vascular augmenta...Poor cardiorespiratory fitness may mediate vascular impairments at rest and following an acute bout of exercise in young healthy individuals.This study aimed to compare flow mediated dilation(FMD)and vascular augmentation index(AIx75)between young adults with low,moderate,and high levels of cardiorespiratory fitness before and after an acute bout of aerobic exercise.Forty-three participants(22 men;21 women)between 18 and 29 years of age completed the study.Participants were classified into low,moderate,and high health-related cardiorespiratory fitness groups according to age-and sex-based relative maximal oxygen consumption(V_O2 max)percentile rankings.FMD was performed using Doppler ultrasound and AIx75 was performed using pulse wave analysis at baseline and 60-min after a 30-min bout of treadmill running at 70%V_O2 max.A significant interaction(p=0.047;ηp 2=0.142)was observed,with the moderate fitness group exhibiting a higher FMD post-exercise compared with baseline([6.7%3.1%]vs.[8.5%2.8%],p=0.028;d=0.598).We found a significant main effect of group for AIx75(p=0.023;ηp 2=0.168),with the high fitness group exhibiting lower AIx75 compared to low fitness group([10%10%]vs.[2%10%],respectively,p=0.019;g=1.07).This was eliminated after covarying for body fat percentage(p=0.489).Our findings suggest that resting FMD and AIx75 responses are not significantly influenced by cardiorespiratory fitness,but FMD recovery responses to exercise may be enhanced in individuals with moderate cardiorespiratory fitness levels.展开更多
Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear vers...Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear versus cytoplas- mic compartments. Changes in free intracellular Ca2+ were monitored with ratiometric Ca2+- fluorophores using confo- cal microscopy. On average, spontaneous oscillations developed in 79% of rat aortic smooth muscle cells that were synchronous between the cytoplasm and nucleus. Reduction of extracellular Ca2+ (< 1 μM) decreased the frequency and amplitude of the cytoplasmic oscillations with 48% of the oscillations asynchronous between the nuclear and cytoplasmic compartments. Similar results were obtained with the Ca2+ channel blockers, nimodipine and diltiazem. Arg-vasopressin (AVP) induced a rapid release of intracellular Ca2+ stores that was greater in the nuclear compartment (4.20 ± 0.23 ratio units, n = 56) than cytoplasm (2.54 ± 0.28) in cells that had spontaneously developed prior oscillations. Conversely, cells in the same conditions lacking oscillations had a greater AVP-induced Ca2+ transient in the cytoplasm (4.99 ± 0.66, n = 17) than in the nucleus (2.67 ± 0.29). Pre-treatment with Ca2+ channel blockers depressed the AVP responses in both compartments with the cytoplasmic Ca2+ most diminished. Depletion of internal Ca2+ stores prior to AVP exposure blunted the nuclear response, mimicking the response of cells that lacked prior oscillations. Spontaneous oscillating cells had a greater sarcoplasmic reticulum network than cells that did not oscillate. We propose that sponta- neous nuclear oscillations rely on perinuclear sarcoplasmic reticulum stores, while the cytoplasmic oscillations rely on Ca2+ influx.展开更多
The systemic health benefits of regular skeletal muscle activity are well documented.Increased skeletal muscle activity is associated with an improved systemic metabolic state,reduced incidence of diabetes and obesity...The systemic health benefits of regular skeletal muscle activity are well documented.Increased skeletal muscle activity is associated with an improved systemic metabolic state,reduced incidence of diabetes and obesity,and improved function with age.Despite these known systemic benefits,many healthy people do not meet the recommended daily dose of skeletal muscle activity（exercise）needed to prevent systemic metabolic disease,leading to an in-creased prevalence of obesity.展开更多
Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion....Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion.Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT’s relationship with traditional computerized neurocognitive testing(CNT)domains.Methods:We employed a cross-sectional study among 14 concussed(15.9±9.8 days post-concussion,mean±SD)individuals and 14 healthy controls matched for age,sex,and driving experience.Participants completed a driving simulator and CNT(CNS Vital Signs)assessment within 48 h of symptom resolution.A driving-RT composite(ms)was derived from 3 simulated driving scenarios:stoplight(green to yellow),evasion(avoiding approaching vehicle),and pedestrian(person running in front of vehicle).The CNT domains included verbal and visual memory;CNT-RT(simple-,complex-,Stroop-RT individually);simple and complex attention;motor,psychomotor,and processing speed;executive function;and cognitive flexibility.Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups,Pearson correlations(r)examined driving RT and CNT domain relationships among cohorts separately,and p values were controlled for false discovery rate via Benjamini-Hochberg procedures(a=0.05).Results:Concussed participants demonstrated slower driving-RT composite scores than controls(mean difference=292.86 ms;95%confidence interval(95%CI):70.18515.54;p=0.023;d=0.992).Evasion-RT(p=0.054;d=0.806),pedestrian-RT(p=0.258;d=0.312),and stoplight-RT(p=0.292;d=0.585)outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits.Among concussed individuals,driving-RT outcomes did not significantly correlate with CNT domains(r-range:0.51 to 0.55;p>0.05).No correlations existed between driving-RT outcomes and CNT domains among control participants either(r-range:0.52 to 0.72;p>0.05).Conclusion:Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns.Driving-RT and CNT-RT measures correlated moderately but not statistically,which indicates that CNT-RT is not an optimal surrogate for driving RT.展开更多
Whole-brain irradiation（WBI）,usually delivered in 25–30fractions to accumulate a total dose of 55–60 Gy,is commonly used for the treatment of primary tumors in the central nervous system（CNS）and brain metastases...Whole-brain irradiation（WBI）,usually delivered in 25–30fractions to accumulate a total dose of 55–60 Gy,is commonly used for the treatment of primary tumors in the central nervous system（CNS）and brain metastases.With improved treatment techniques patients have prolonged overall survival,but are more likely to experience late adverse effects.展开更多
Purpose–The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training(BST)for stroke survivors affected by hemiparesis.Design/methodology/approach–Other studies have investi...Purpose–The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training(BST)for stroke survivors affected by hemiparesis.Design/methodology/approach–Other studies have investigated symmetric physiotherapy.A key difficulty in previous work is in maintaining mirror-imaged trajectories between the affected and less-affected limbs.This obstacle was overcome in this work by using a two-armed robotic exoskeleton to enforce symmetry.In total,15 subjects,W6 months post stroke were,randomly assigned to bilateral symmetric robotic training,unilateral robotic training,and standard physical therapy.Findings–After 12 training sessions(90 minutes/session),the bilateral training group had the greatest intensity of movement training.They also had the greatest improvement in range of motion at the shoulder.The unilateral training group showed the greatest reduction in spasticity.Research limitations/implications–The rationale for symmetric physiotherapy is that it might promote connections from the undamaged brain hemisphere.The robot generated copious amounts of detailed kinematic data.Even though these data provided insights into the human to machine interface using different training modalities,it proved difficult to draw neurological conclusions.It is recommended that future research along these lines should include measures of neurophysiological change and/or changes in neurological activity.Practical implications–This research suggests that the advantage of bilateral symmetric movement over other modalities is slight,and that robotic training has comparable results with standard care.If BSTis used,care is potentially needed toavoid exacerbation of spasticity.Finally,this research includes a novel quantitative approach for evaluating robotic training.Originality/value–This study is of value to therapeutic researchers interested in new physiotherapy techniques,roboticists interested in developing rehabilitation devices,or for rehabilitation game designers interested in using virtual reality.展开更多
Participation in ultramarathon events has grown substantially in the past decade.However,poor understanding of the physiological outcomes associated with participation in this sport prevents athletes and clinicians fr...Participation in ultramarathon events has grown substantially in the past decade.However,poor understanding of the physiological outcomes associated with participation in this sport prevents athletes and clinicians from adequately addressing performance and recovery tactics.The purpose of this review was to summarize developments in the literature in the last 10 years regarding acute and chronic responses to ultramarathon running with a focus on the peripheral vascular system,neuromuscular outcomes,and running mechanics.Evidence suggests that there are acute impairments in large artery compliance especially following the longer ultramarathon distances.However,most literature indicates that chronic vascular impairments are not evident in ultramarathon runners.Both central and peripheral fatigue mechanisms contribute to declines in muscle force production that may last up to several weeks in some muscles following an ultramarathon.Alterations in gait kinematics and skeletal muscle oxidative capacity increase the metabolic cost of running over prolonged running distances(>4 h).Several factors such as elevation changes and nutritional practices make interpretation of findings challenging.Future studies are needed to better understand the interplay among systems and how external factors contribute to these outcomes to optimize performance and inform recovery strategies in this increasingly popular sport.展开更多
A provocative and overly reductive mantra is that"the back of the eye is the front of the brain".Retinal imaging techniques that take advantage of this"window"to the central nervous system can prov...A provocative and overly reductive mantra is that"the back of the eye is the front of the brain".Retinal imaging techniques that take advantage of this"window"to the central nervous system can provide valuable information regarding injury to the nervous system with relative ease and with a limited burden to patients.The retina develops embryonically as part of the neuroectoderm,is made up principally of neurons and their supporting cells,and is synaptically tied to the central nervous system(CNS).This has led to significant interest in using retinal health as a biomarker for brain health-given the relatively limited accessibility of brain tissue in chronic neurodegenerative diseases that progress over decades.The retina is not truly part of the CNS,and as with much of brain imaging-the grounds for asserting the pathological specificity of retinal imaging is limited.Biophotonics-based methods such as optical coherence tomography indirectly provide an opportunity to evaluate retinal neurodegeneration,while autopsy studies,histology and immunohistochemistry predominate as the methods that collect direct pathological data.Our understanding of pathological retinal lesions characteristic of demyelinating diseases,specifically diseases showing anterior visual pathway involvement,has grown significantly in recent years.However,much of the underlying pathobiology of injury remain unexplored.This review aims to highlight the major pathological features of the retina in multiple sclerosis,and its most used animal models(experimental autoimmune encephalomyelitis and cuprizone),with a particular focus on n the role of inflammation.展开更多
文摘Purpose： The purpose of this study was to examine the effects of landing kinematics and electromyographic （EMG） activities of medial gastrocnemius on a combined inversion and plantarflexion surface on the ankle （MG）, peroneus longus （PL）, and tibialis anterior （TA） muscles. Methods： Twelve recreational athletes performed five drop landings from an overhead bar of 30 cm height on to three surfaces： a flat surface, a 25° inversion surface, and a combined surface of 25° inversion and 25° plantarflexion. The kinematic variables and integrated EMG （IEMG） of the three muscles were assessed using a one-way repeated measures ANOVA and a 3 × 3 （surface × muscle） ANOVA, respectively （p 〈 0.05）. Results： The IEMG results showed a significant muscle by surface interaction. The flat surface induced higher TA activity than the two tilted surfaces. The inverted surface produced significantly higher inversion peak angle and velocity than the flat surface, but similar PL activity across the surfaces. The MG IEMG, ankle plantarflexion angle, and inversion range of motion were significantly higher for the combined surface compared to the inverted surface. Conclusion： These findings suggest that compared to the inversion surface, the combined plantarflexion and inversion surface seems to provide a more unstable surface condition for lateral ankle sprains during landing.
文摘Background:Tibial stress fracture(TSF)is an overuse running injury with a long recovery period.While many running studies refer to biomechanical risk factors for TSF,only a few have compared biomechanics in runners with TSF to controls.The aim of this systematic review and meta-analysis was to evaluate biomechanics in runners with TSF compared to controls.Methods:Electronic databases PubMed,Web of Science,SPORTDiscus,Scopus,Cochrane,and CINAHL were searched.Risk of bias was assessed and meta-analysis conducted for variables reported in 3 or more studies.Results:The search retrieved 359 unique records,but only the 14 that compared runners with TSF to controls were included in the review.Most studies were retrospective,2 were prospective,and most had a small sample size(5-30 per group).Many variables were not significantly different between groups.Meta-analysis of peak impact,active,and braking ground reaction forces found no significant differences between groups.Individual studies found larger tibial peak anterior tensile stress,peak posterior compressive stress,peak axial acceleration,peak rearfoot eversion,and hip adduction in the TSF group.Conclusion:Meta-analysis indicated that discrete ground reaction force variables were not statistically significantly different in runners with TSF compared to controls.In individual included studies,many biomechanical variables were not statistically significantly different between groups.However,many were reported by only a single study,and sample sizes were small.We encourage additional studies with larger sample sizes of runners with TSF and controls and adequate statistical power to confirm or refute these findings.
基金approved by the Towson University Institutional Review Board(IRB#1810041426)study was registed on Clinical Trials.gov public website(NCT06163456).
文摘Poor cardiorespiratory fitness may mediate vascular impairments at rest and following an acute bout of exercise in young healthy individuals.This study aimed to compare flow mediated dilation(FMD)and vascular augmentation index(AIx75)between young adults with low,moderate,and high levels of cardiorespiratory fitness before and after an acute bout of aerobic exercise.Forty-three participants(22 men;21 women)between 18 and 29 years of age completed the study.Participants were classified into low,moderate,and high health-related cardiorespiratory fitness groups according to age-and sex-based relative maximal oxygen consumption(V_O2 max)percentile rankings.FMD was performed using Doppler ultrasound and AIx75 was performed using pulse wave analysis at baseline and 60-min after a 30-min bout of treadmill running at 70%V_O2 max.A significant interaction(p=0.047;ηp 2=0.142)was observed,with the moderate fitness group exhibiting a higher FMD post-exercise compared with baseline([6.7%3.1%]vs.[8.5%2.8%],p=0.028;d=0.598).We found a significant main effect of group for AIx75(p=0.023;ηp 2=0.168),with the high fitness group exhibiting lower AIx75 compared to low fitness group([10%10%]vs.[2%10%],respectively,p=0.019;g=1.07).This was eliminated after covarying for body fat percentage(p=0.489).Our findings suggest that resting FMD and AIx75 responses are not significantly influenced by cardiorespiratory fitness,but FMD recovery responses to exercise may be enhanced in individuals with moderate cardiorespiratory fitness levels.
文摘Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear versus cytoplas- mic compartments. Changes in free intracellular Ca2+ were monitored with ratiometric Ca2+- fluorophores using confo- cal microscopy. On average, spontaneous oscillations developed in 79% of rat aortic smooth muscle cells that were synchronous between the cytoplasm and nucleus. Reduction of extracellular Ca2+ (< 1 μM) decreased the frequency and amplitude of the cytoplasmic oscillations with 48% of the oscillations asynchronous between the nuclear and cytoplasmic compartments. Similar results were obtained with the Ca2+ channel blockers, nimodipine and diltiazem. Arg-vasopressin (AVP) induced a rapid release of intracellular Ca2+ stores that was greater in the nuclear compartment (4.20 ± 0.23 ratio units, n = 56) than cytoplasm (2.54 ± 0.28) in cells that had spontaneously developed prior oscillations. Conversely, cells in the same conditions lacking oscillations had a greater AVP-induced Ca2+ transient in the cytoplasm (4.99 ± 0.66, n = 17) than in the nucleus (2.67 ± 0.29). Pre-treatment with Ca2+ channel blockers depressed the AVP responses in both compartments with the cytoplasmic Ca2+ most diminished. Depletion of internal Ca2+ stores prior to AVP exposure blunted the nuclear response, mimicking the response of cells that lacked prior oscillations. Spontaneous oscillating cells had a greater sarcoplasmic reticulum network than cells that did not oscillate. We propose that sponta- neous nuclear oscillations rely on perinuclear sarcoplasmic reticulum stores, while the cytoplasmic oscillations rely on Ca2+ influx.
基金supported in part by awards from the National Institutes of Health–National Center for Medical Rehabilitation Research(R01HD084645R01HD082109)
文摘The systemic health benefits of regular skeletal muscle activity are well documented.Increased skeletal muscle activity is associated with an improved systemic metabolic state,reduced incidence of diabetes and obesity,and improved function with age.Despite these known systemic benefits,many healthy people do not meet the recommended daily dose of skeletal muscle activity（exercise）needed to prevent systemic metabolic disease,leading to an in-creased prevalence of obesity.
基金the Office of the Vice President of Research at the University of Georgia.
文摘Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion.Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT’s relationship with traditional computerized neurocognitive testing(CNT)domains.Methods:We employed a cross-sectional study among 14 concussed(15.9±9.8 days post-concussion,mean±SD)individuals and 14 healthy controls matched for age,sex,and driving experience.Participants completed a driving simulator and CNT(CNS Vital Signs)assessment within 48 h of symptom resolution.A driving-RT composite(ms)was derived from 3 simulated driving scenarios:stoplight(green to yellow),evasion(avoiding approaching vehicle),and pedestrian(person running in front of vehicle).The CNT domains included verbal and visual memory;CNT-RT(simple-,complex-,Stroop-RT individually);simple and complex attention;motor,psychomotor,and processing speed;executive function;and cognitive flexibility.Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups,Pearson correlations(r)examined driving RT and CNT domain relationships among cohorts separately,and p values were controlled for false discovery rate via Benjamini-Hochberg procedures(a=0.05).Results:Concussed participants demonstrated slower driving-RT composite scores than controls(mean difference=292.86 ms;95%confidence interval(95%CI):70.18515.54;p=0.023;d=0.992).Evasion-RT(p=0.054;d=0.806),pedestrian-RT(p=0.258;d=0.312),and stoplight-RT(p=0.292;d=0.585)outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits.Among concussed individuals,driving-RT outcomes did not significantly correlate with CNT domains(r-range:0.51 to 0.55;p>0.05).No correlations existed between driving-RT outcomes and CNT domains among control participants either(r-range:0.52 to 0.72;p>0.05).Conclusion:Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns.Driving-RT and CNT-RT measures correlated moderately but not statistically,which indicates that CNT-RT is not an optimal surrogate for driving RT.
基金supported by National Institutes of Health(NIH),grants:R01CA213441,R01CA133216the Pediatric Brain Tumor Foundation Institute Grant
文摘Whole-brain irradiation（WBI）,usually delivered in 25–30fractions to accumulate a total dose of 55–60 Gy,is commonly used for the treatment of primary tumors in the central nervous system（CNS）and brain metastases.With improved treatment techniques patients have prolonged overall survival,but are more likely to experience late adverse effects.
基金This work was supported by a seed funding award from CITRIS in 2010,SFP#66,“Paradigm Shift of Neurorehabilitation of Stroke Patients using Wearable Robotics.”。
文摘Purpose–The purpose of this paper is to evaluate the physiotherapeutic benefits of bilateral symmetric training(BST)for stroke survivors affected by hemiparesis.Design/methodology/approach–Other studies have investigated symmetric physiotherapy.A key difficulty in previous work is in maintaining mirror-imaged trajectories between the affected and less-affected limbs.This obstacle was overcome in this work by using a two-armed robotic exoskeleton to enforce symmetry.In total,15 subjects,W6 months post stroke were,randomly assigned to bilateral symmetric robotic training,unilateral robotic training,and standard physical therapy.Findings–After 12 training sessions(90 minutes/session),the bilateral training group had the greatest intensity of movement training.They also had the greatest improvement in range of motion at the shoulder.The unilateral training group showed the greatest reduction in spasticity.Research limitations/implications–The rationale for symmetric physiotherapy is that it might promote connections from the undamaged brain hemisphere.The robot generated copious amounts of detailed kinematic data.Even though these data provided insights into the human to machine interface using different training modalities,it proved difficult to draw neurological conclusions.It is recommended that future research along these lines should include measures of neurophysiological change and/or changes in neurological activity.Practical implications–This research suggests that the advantage of bilateral symmetric movement over other modalities is slight,and that robotic training has comparable results with standard care.If BSTis used,care is potentially needed toavoid exacerbation of spasticity.Finally,this research includes a novel quantitative approach for evaluating robotic training.Originality/value–This study is of value to therapeutic researchers interested in new physiotherapy techniques,roboticists interested in developing rehabilitation devices,or for rehabilitation game designers interested in using virtual reality.
文摘Participation in ultramarathon events has grown substantially in the past decade.However,poor understanding of the physiological outcomes associated with participation in this sport prevents athletes and clinicians from adequately addressing performance and recovery tactics.The purpose of this review was to summarize developments in the literature in the last 10 years regarding acute and chronic responses to ultramarathon running with a focus on the peripheral vascular system,neuromuscular outcomes,and running mechanics.Evidence suggests that there are acute impairments in large artery compliance especially following the longer ultramarathon distances.However,most literature indicates that chronic vascular impairments are not evident in ultramarathon runners.Both central and peripheral fatigue mechanisms contribute to declines in muscle force production that may last up to several weeks in some muscles following an ultramarathon.Alterations in gait kinematics and skeletal muscle oxidative capacity increase the metabolic cost of running over prolonged running distances(>4 h).Several factors such as elevation changes and nutritional practices make interpretation of findings challenging.Future studies are needed to better understand the interplay among systems and how external factors contribute to these outcomes to optimize performance and inform recovery strategies in this increasingly popular sport.
文摘A provocative and overly reductive mantra is that"the back of the eye is the front of the brain".Retinal imaging techniques that take advantage of this"window"to the central nervous system can provide valuable information regarding injury to the nervous system with relative ease and with a limited burden to patients.The retina develops embryonically as part of the neuroectoderm,is made up principally of neurons and their supporting cells,and is synaptically tied to the central nervous system(CNS).This has led to significant interest in using retinal health as a biomarker for brain health-given the relatively limited accessibility of brain tissue in chronic neurodegenerative diseases that progress over decades.The retina is not truly part of the CNS,and as with much of brain imaging-the grounds for asserting the pathological specificity of retinal imaging is limited.Biophotonics-based methods such as optical coherence tomography indirectly provide an opportunity to evaluate retinal neurodegeneration,while autopsy studies,histology and immunohistochemistry predominate as the methods that collect direct pathological data.Our understanding of pathological retinal lesions characteristic of demyelinating diseases,specifically diseases showing anterior visual pathway involvement,has grown significantly in recent years.However,much of the underlying pathobiology of injury remain unexplored.This review aims to highlight the major pathological features of the retina in multiple sclerosis,and its most used animal models(experimental autoimmune encephalomyelitis and cuprizone),with a particular focus on n the role of inflammation.
