Changes In Walking Speed Research Articles

ASSOCIATIONS BETWEEN WALKING SPEED AND GUT MICROBIOME DIVERSITY IN OLDER MEN FROM THE MROS STUDY

Abstract While gut dysbiosis has been linked to frailty in aging, its association with early mobility impairments is unclear. Here, our primary goal was to determine the cross-sectional associations between walking speed and gut microbiome in 740 older men (84±4y) from MrOS with available stool samples and 400m walking speed measured in 2014–16. We also analyzed the retrospective longitudinal associations between changes in 6-meter walking speed (from 2005-06 to 2014-16) and gut microbiome composition among participants with available data (702/740). The gut microbiome composition was determined by 16S sequencing (DADA2 and SILVA). We examined diversity, taxa abundance (by ANCOM-BC), and performed network analysis (by NetCoMi) to uncover microbial communities interactions by walking speed levels. Higher walking speed (m/s) was associated with greater microbiome Shannon α-diversity (R=0.11; P=0.004). Decline in walking speed was associated with lower Shannon α-diversity (R=0.07; P=0.054). Faster walking speed and less decline in walking speed were associated with higher abundance of genus-level bacteria that produce short-chain fatty acids, and possess anti-inflammatory properties, including Paraprevotella, Fusicatenibacter, and Alistipes, adjusting for age, race, site, education, health, marital status, weight, height, physical activity, batch, medications, energy, and fiber intake (P< 0.05). The gut microbiome networks of participants in the first vs. last quartile of walking speed (≤0.9 vs. ≥1.2 m/s) exhibited distinct characteristics, including different cluster numbers, hubs, and centrality measures (P< 0.05). Faster walking speed and its less decline were associated with higher gut microbiome diversity, suggesting potential role of microbiome in preserving mobility in aging.

Task-oriented exercise effects on walking and corticospinal excitability in multiple sclerosis: protocol for a randomized controlled trial

BackgroundMultiple sclerosis (MS) is a degenerative disease of the central nervous system (CNS) that disrupts walking function and results in other debilitating symptoms. This study compares the effects of ‘task-oriented exercise’ against ‘generalized resistance and aerobic exercise’ and a ‘stretching control’ on walking and CNS function in people with MS (PwMS). We hypothesize that task-oriented exercise will enhance walking speed and related neural changes to a greater extent than other exercise approaches.MethodsThis study is a single-blinded, three-arm randomized controlled trial conducted in Saskatchewan, Canada. Eligible participants are those older than 18 years of age with a diagnosis of MS and an expanded Patient-Determined Disease Steps (PDDS) score between 3 (‘gait disability’) and 6 (‘bilateral support’). Exercise interventions are delivered for 12 weeks (3 × 60-min per week) in-person under the supervision of a qualified exercise professional. Interventions differ in exercise approach, such that task-oriented exercise involves weight-bearing, walking-specific activities, while generalized resistance and aerobic exercise uses seated machine-based resistance training of major upper and lower body muscle groups and recumbent cycling, and the stretching control exercise involves seated flexibility and relaxation activities. Participants are allocated to interventions using blocked randomization that stratifies by PDDS (mild: 3–4; moderate: 5–6). Assessments are conducted at baseline, post-intervention, and at a six-week retention time point. The primary and secondary outcome measures are the Timed 25-Foot Walk Test and corticospinal excitability for the tibialis anterior muscles determined using transcranial magnetic stimulation (TMS), respectively. Tertiary outcomes include assessments of balance, additional TMS measures, blood biomarkers of neural health and inflammation, and measures of cardiorespiratory and musculoskeletal fitness.DiscussionA paradigm shift in MS healthcare towards the use of “exercise as medicine” was recently proposed to improve outcomes and alleviate the economic burden of MS. Findings will support this shift by informing the development of specialized exercise programming that targets walking and changes in corticospinal excitability in PwMS.Trial registrationClinicalTrials.gov, NCT05496881, Registered August 11, 2022. https://classic.clinicaltrials.gov/ct2/show/NCT05496881. Protocol amendment number: 01; Issue date: August 1, 2023; Primary reason for amendment: Expand eligibility to include people with all forms of MS rather than progressive forms of MS only.

An adaptive gait event detection method based on stance point for walking assistive devices

This paper presents an adaptive and fuzzy logic-based gait event detection method for wearable assistive devices. A conventional and straightforward way to detect gait events is to utilize gyroscope measurements in the sagittal plane for time-series pattern recognition (positive peaks and negative peaks) based on a predefined threshold. This approach works well in the biomechanics analysis while it may have difficulties adapting to the changes in human walking speed for wearable robot applications. To tackle the above issue, first, we keep updating the detection threshold according to the last stride information. Second, we detect the stance point (zero-velocity point) as an indicator to distinguish between the heel strike and toe off events by combining the information about the foot angular velocity and acceleration. A method to construct a fuzzy membership function is also proposed via a series of moving intervals from foot acceleration data. Validation of the proposed gait event detection method using force plates showed that the method obtained high detection accuracy (F1-score = 0.99) for healthy subjects with and without the robotic support limb (RSL).

Effects of high-intensity gait training with and without soft robotic exosuits in people post-stroke: a development-of-concept pilot crossover trial

IntroductionHigh-intensity gait training is widely recognized as an effective rehabilitation approach after stroke. Soft robotic exosuits that enhance post-stroke gait mechanics have the potential to improve the rehabilitative outcomes achieved by high-intensity gait training. The objective of this development-of-concept pilot crossover study was to evaluate the outcomes achieved by high-intensity gait training with versus without soft robotic exosuits.MethodsIn this 2-arm pilot crossover study, four individuals post-stroke completed twelve visits of speed-based, high-intensity gait training: six consecutive visits of Robotic Exosuit Augmented Locomotion (REAL) gait training and six consecutive visits without the exosuit (CONTROL). The intervention arms were counterbalanced across study participants and separated by 6 + weeks of washout. Walking function was evaluated before and after each intervention using 6-minute walk test (6MWT) distance and 10-m walk test (10mWT) speed. Moreover, 10mWT speeds were evaluated before each training visit, with the time-course of change in walking speed computed for each intervention arm. For each participant, changes in each outcome were compared to minimal clinically-important difference (MCID) thresholds. Secondary analyses focused on changes in propulsion mechanics and associated biomechanical metrics.ResultsLarge between-group effects were observed for 6MWT distance (d = 1.41) and 10mWT speed (d = 1.14). REAL gait training resulted in an average pre-post change of 68 ± 27 m (p = 0.015) in 6MWT distance, compared to a pre-post change of 30 ± 16 m (p = 0.035) after CONTROL gait training. Similarly, REAL training resulted in a pre-post change of 0.08 ± 0.03 m/s (p = 0.012) in 10mWT speed, compared to a pre-post change of 0.01 ± 06 m/s (p = 0.76) after CONTROL. For both outcomes, 3 of 4 (75%) study participants surpassed MCIDs after REAL training, whereas 1 of 4 (25%) surpassed MCIDs after CONTROL training. Across the training visits, REAL training resulted in a 1.67 faster rate of improvement in walking speed. Similar patterns of improvement were observed for the secondary gait biomechanical outcomes, with REAL training resulting in significantly improved paretic propulsion for 3 of 4 study participants (p < 0.05) compared to 1 of 4 after CONTROL.ConclusionSoft robotic exosuits have the potential to enhance the rehabilitative outcomes produced by high-intensity gait training after stroke. Findings of this development-of-concept pilot crossover trial motivate continued development and study of the REAL gait training program.

Assessment of the efficacy and safety of fampridine

ObjectiveAssessment of the efficacy and safety of fampridine for walking improvement in adult patients with multiple sclerosis. MethodA descriptive retrospective study of all patients who initiated treatment with fampridine between March, 2014 and February, 2015. Efficacy was assessed through the 25-foot walk test and the 12-item walking scale for multiple sclerosis. It was reviewed whether patients had suffered any of the most frequent adverse effects described in the pivotal clinical trial. ResultsSix patients were included, with a 66.7% response rate. At 3-6 months, the mean change in walking speed (compared to baseline) was 39.32% and there was a mean improvement of 15 points in the walking scale. Only one patient presented adverse effects. ConclusionsThe results obtained are encouraging, particularly when fampridine is the only drug currently approved to control such a disabling symptom as instability while walking.

65 Neuroscience in the Everyday World: Lateralization of Brain Activity During Dual-Task Walking

Objective:Functional near-infrared spectroscopy (fNIRS) is a non-invasive functional neuroimaging method that takes advantage of the optical properties of hemoglobin to provide an indirect measure of brain activation via task-related relative changes in oxygenated hemoglobin (HbO). Its advantage over fMRI is that fNIRS is portable and can be used while walking and talking. In this study, we used fNIRS to measure brain activity in prefrontal and motor region of interests (ROIs) during single- and dual-task walking, with the goal of identifying neural correlates.Participants and Methods:Nineteen healthy young adults [mean age=25.4 (SD=4.6) years; 14 female] engaged in five tasks: standing single-task cognition (serial-3 subtraction); single-task walking at a self-selected comfortable speed on a 24.5m oval-shaped course (overground walking) and on a treadmill; and dual-task cognition+walking on the same overground course and treadmill (8 trials/condition: 20 seconds standing rest, 30 seconds task). Performance on the cognitive task was quantified as the number of correct subtractions, number of incorrect subtractions, number of self-corrected errors, and percent accuracy over the 8 trials. Walking speed (m/sec) was recorded for all walking conditions. fNIRS data were collected on a system consisting of 16 sources, 15 detectors, and 8 short-separation detectors in the following ROIs: right and left lateral frontal (RLF, LLF), right and left medial frontal (RMF, LMF), right and left medial superior frontal (RMSF, LMSF), and right and left motor (RM, LM). Lateral and medial refer to ROIs’ relative positions on lateral prefrontal cortex. fNIRS data were analyzed in Homer3 using a spline motion correction and the iterative weighted least squares method in the general linear model. Correlations between the cognitive/speed variables and ROI HbO data were applied using a Bonferroni adjustment for multiple comparisons.Results:Subjects with missing cognitive data were excluded from analyses, resulting in sample sizes of 18 for the single-task cognition, dual-task overground walking, and dual-task treadmill walking conditions. During dual-task overground walking, there was a significant positive correlation between walking speed and relative change in HbO in RMSF [r(18)=.51, p&lt;.05] and RM [r(18)=.53, p&lt;.05)]. There was a significant negative correlation between total number of correct subtractions and relative change in HbO in LMSF ([r(18)=-.75, p&lt;.05] and LM [r(18)=-.52, p&lt;.05] during dual-task overground walking. No other significant correlations were identified.Conclusions:These results indicate that there is lateralization of the cognitive and motor components of overground dual-task walking. The right hemisphere appears to be more active the faster people walk during the dual-task. By contrast, the left hemisphere appears to be less active when people are working faster on the cognitive task (i.e., serial-3 subtraction). The latter results suggest that automaticity of the cognitive task (i.e., more total correct subtractions) is related to decreased brain activity in the left hemisphere. Future research will investigate whether there is a change in cognitive automaticity over trials and if there are changes in lateralization patterns in neurodegenerative disorders that are known to differentially affect the hemispheres (e.g., Parkinson’s disease).

Analysis of muscle synergy and muscle functional network at different walking speeds based on surface electromyographic signal

An in-depth understanding of the mechanism of lower extremity muscle coordination during walking is the key to improving the efficacy of gait rehabilitation in patients with neuromuscular dysfunction. This paper investigates the effect of changes in walking speed on lower extremity muscle synergy patterns and muscle functional networks. Eight healthy subjects were recruited to perform walking tasks on a treadmill at three different speeds, and the surface electromyographic signals (sEMG) of eight muscles of the right lower limb were collected synchronously. The non-negative matrix factorization (NNMF) method was used to extract muscle synergy patterns, the mutual information (MI) method was used to construct the alpha frequency band (8-13 Hz), beta frequency band (14-30 Hz) and gamma frequency band (31-60 Hz) muscle functional network, and complex network analysis methods were introduced to quantify the differences between different networks. Muscle synergy analysis extracted 5 muscle synergy patterns, and changes in walking speed did not change the number of muscle synergy, but resulted in changes in muscle weights. Muscle network analysis found that at the same speed, high-frequency bands have lower global efficiency and clustering coefficients. As walking speed increased, the strength of connections between local muscles also increased. The results show that there are different muscle synergy patterns and muscle function networks in different walking speeds. This study provides a new perspective for exploring the mechanism of muscle coordination at different walking speeds, and is expected to provide theoretical support for the evaluation of gait function in patients with neuromuscular dysfunction.

Real-Time Visual Kinematic Feedback During Overground Walking Improves Gait Biomechanics in Individuals Post-Stroke.

Treadmill-based gait rehabilitation protocols have shown that real-time visual biofeedback can promote learning of improved gait biomechanics, but previous feedback work has largely involved treadmill walking and not overground gait. The objective of this study was to determine the short-term response to hip extension visual biofeedback, with individuals post-stroke, during unconstrained overground walking. Individuals post-stroke typically have a decreased paretic propulsion and walking speed, but increasing hip extension angle may enable the paretic leg to better translate force anteriorly during push-off. Fourteen individuals post-stroke completed overground walking, one 6-min control bout without feedback, and three 6-min training bouts with real-time feedback. Data were recorded before and after the control bout, before and after the first training bout, and after the third training bout to assess the effects of training. Visual biofeedback consisted of a display attached to eyeglasses that showed one horizontal bar indicating the user's current hip angle and another symbolizing the target hip extension to be reached during training. On average, paretic hip extension angle (p = 0.014), trailing limb angle (p = 0.025), and propulsion (p = 0.011) were significantly higher after training. Walking speed increased but was not significantly higher after training (p = 0.089). Individuals demonstrated a greater increase in their hip extension angle (p = 0.035) and propulsion (p = 0.030) after the walking bout with feedback compared to the control bout, but changes in walking speed did not significantly differ (p = 0.583) between a control walking bout and a feedback bout. Our results show the feasibility of overground visual gait feedback and suggest that feedback regarding paretic hip extension angle enabled many individuals post-stroke to improve parameters important for their walking function.

Age-associated changes in lower limb weight-bearing strategy during walking

BackgroundAs people age there is a proximal shift of joint moment generation from ankle plantarflexion and knee extension toward hip extension and flexion moments. This age-related redistribution has been documented in the context of propulsive force generation during the push-off phase with less evidence in the context of weight bearing. Additionally, these sagittal plane joint moments have been a primary focus of studies though the hip frontal plane moment also contributes to vertical support but has received less attention. Furthermore, how aging affects the relationships between changes in sagittal and frontal joint moments and changes in vertical support force as a function of walking speed remains unclear Research questionHow does aging affect the contributions of sagittal and frontal plane joint moments to weight-bearing across different walking speeds? MethodsGait analysis was performed on 24 young and 17 healthy older subjects walked on the treadmill at their preferred and 30 % faster speeds. Stepwise linear regression analysis was performed to determine the joint moments that predict the peak amplitudes of the vertical ground reaction force (VGRF) across different walking speeds. ResultsHip abduction and knee extension moments were the primary contributors to leading limb weight-bearing in young, whereas hip extension moment was the primary contributor in older adults. Ankle plantarflexion moment was the main contributor to trailing limb weight-bearing in young and hip flexion moment was the main contributor in older adults. From preferred to faster walking speed changes in knee extension moment were the primary contributor to changes in the trailing limb weight-bearing in young whereas changes in hip extension moment were the primary contributor in olderadults. SignificanceThese findings suggested that older and younger adults used different joint moment contributions to produce leading limb and trailing limb vertical support forces across different walking speeds.

Concurrent validity of walking speed measured by a wearable sensor and a stopwatch during the 10-meter walk test in individuals with stroke

BackgroundWalking speed is often measured with a stopwatch throughout stroke recovery. Wearable sensors also have been used recently to measure walking speed and provide information about spatiotemporal characteristics of walking.Research Question:Do walking speeds measured with stopwatch and APDM wearable sensors have concurrent validity? MethodsIndividuals with chronic stroke (n = 62) performed the 10-meter walk test at comfortable and maximal speeds. Walking speeds were measured with a stopwatch and APDM Opal wireless wearable sensors (3-unit). Tests of concurrent validity between stopwatch and APDM (Bland-Altman plots, systematic and proportional bias, and intraclass correlations) and test-retest reliability between trials (intraclass correlations, standard error of measurement, and minimal detectable change) were performed. ResultsWalking speeds measured with APDM were ∼0.07 m/s slower than those measured with stopwatch (systematic bias; t ≥ 13.1, p < 0.001). Intraclass correlations ranged from poor to excellent. There were greater differences in walking speeds between APDM and stopwatch for individuals with faster walking speeds (proportional bias). Test-retest reliability was excellent for both APDM and stopwatch (intraclass correlation≥0.94). Standard error of measurement ranged from 0.04 to 0.07 m/s and minimal detectable change ranged from 0.10 to 0.19 m/s.Significance:It may be inappropriate to use walking speed measurements from APDM sensors and stopwatch interchangeably in individuals with chronic stroke. Differences in walking speeds may reflect stopwatch error or the derivation of walking speed from wearable sensors. Test-retest reliability was excellent for both stopwatch and APDM, but minimal detectable change values were large. Large changes in walking speed may be required to be confident that the change is a true and clinically meaningful change and not measurement error. The validity and reliability of measuring walking speed with wearable sensors in individuals with chronic stroke has important implications for determining community ambulation, assessing improvements after rehabilitation, and developing exercise prescriptions.

A new driving strategy for Lower limb-assisted exoskeleton robot

In this work, a control strategy is developed for a lower limb-assisted exoskeleton. To determine the current motion gait of the human body, the hip and knee joint angles, and plantar pressure values are sensed and analyzed, which are then used to actuate the exoskeleton to provide support for the hip and knee joints. The dual motion systems-the exoskeleton drive system and the human lower limb motion system-are established in this control approach. Without the need to first learn the user's gait, the assistance of the exoskeleton is provided by the motions of the human movement system and is sufficiently flexible to account for changes in step length and walking speed as the user moves through the gait cycle. Throughout this process, the exoskeleton system avoids providing power, providing the freedom to walk and stop in the course of our daily lives.

Accurate Stride-Length Estimation Based on LT-StrideNet for Pedestrian Dead Reckoning Using a Shank-Mounted Sensor.

Pedestrian dead reckoning (PDR) is a self-contained positioning technology and has been a significant research topic in recent years. Pedestrian-stride-length estimation is the core part of the PDR system and directly affects the performance of the PDR. The current stride-length-estimation method is difficult to adapt to changes in pedestrian walking speed, which leads to a rapid increase in the error of the PDR. In this paper, a new deep-learning model based on long short-term memory (LSTM) and Transformer, LT-StrideNet, is proposed to estimate pedestrian-stride length. Next, a shank-mounted PDR framework is built based on the proposed stride-length-estimation method. In the PDR framework, the detection of pedestrian stride is achieved by peak detection with a dynamic threshold. An extended Kalman filter (EKF) model is adopted to fuse the gyroscope, accelerometer, and magnetometer. The experimental results show that the proposed stride-length-estimation method can effectively adapt to changes in pedestrian walking speed, and our PDR framework has excellent positioning performance.

Spatial-Temporal Analysis of Gait in Amyotrophic Lateral Sclerosis Using Foot-Worn Inertial Sensors: An Observational Study

Introduction: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that alters gait and increases the risk of falls. The current model of care involves in-person multidisciplinary clinic visits to, in part, assess alterations in gait, evaluate safety, and make recommendations for management. Clinic visits, however, are relatively infrequent, and multidisciplinary evaluations can be physically demanding for patients. To better understand how gait changes over time in those with ALS and enable healthcare providers to properly respond to these changes, remote monitoring of functional mobility would be advantageous. Methods: The objective of this study was to remotely track long-term changes in walking speed using wearable inertial measurement units (IMUs). Nine ALS patients and 6 healthy controls submitted twice-weekly home walking recordings for 24 and 4 weeks, respectively. An IMU data processing method was developed and validated against laboratory-measured walking speed. Results: For both ALS patients and healthy controls, home walking speed was less than clinic walking speed by an average of 0.19 m/s (p = 0.0024). Over 24 weeks, home walking speed significantly decreased for 5 of 9 ALS patients at an average of −0.021 m/s/months (p = 0.005). Those who eventually transitioned to using assistive device (AD) while on the study demonstrated a greater decrease in walking speed than those who did not. Conclusions: Remote longitudinal gait monitoring of ALS patients is feasible with the use of an IMU. Decreases in walking speed were detected in the majority of patients, most strongly in those who eventually transitioned to an AD. Home walking speed may more accurately represent the walking abilities of ALS patients in their real-life environments, a finding which further supports the case for remote monitoring in ALS.

Decrease in maximum paced walking speed predicts hospitalization in community-dwelling older people with disabilities.

Walking speed is a useful predictor of hospitalization for community-dwelling older people. However, whether it is an effective predictor for disabled older people has not been clarified. This study aimed to investigate the association of walking speed with unexpected hospitalizations in community-dwelling, disabled, older people. The participants were ambulatory, community-dwelling older adults aged ≥ 65years with disabilities. Comfortable and maximum walking speeds were measured at two timepoints, baseline and 3months later. Furthermore, the change over time at 3months in walking speed was also calculated. If the change in walking speed decreased more than 0.1m/s, it was defined as walking speed decreased. The primary outcome was unexpected hospitalization during 4-year follow-up. The associations among baseline walking speed, walking speed decline, and hospitalization were analyzed using Cox regression analysis adjusted for potential confounding factors. A total of 93 people (age 81.8 ± 7.0years, 64 female) were included, and unexpected hospitalization occurred in 47 people during 4-year follow-up. On Cox regression analysis adjusted for potential confounding factors, only the maximum walking speed decrease was significantly associated with hospitalization (hazard ratio = 2.53, 95% confidence interval: 1.23-5.21), not baseline walking speed and comfortable walking speed decrease. As for the assessment of walking speed for the prediction of unexpected hospitalization in disabled people, measurement at a single timepoint is not useful, whereas change over time is. Monitoring of change over time in maximum walking speed appears to be one of the indicators for the health management of disabled people.

Investigating the efficacy of a tactile feedback system to increase the gait speed of older adults

The objective of this study was to determine (1) if a novel haptic feedback system could increase the walking speed of older adults while it is being employed during overground walking and (2) whether the frequency at which this feedback was presented would have a differential impact on the ability of users to change walking speed while it was present. Given that peak thigh extension has been found to be a biomechanical surrogate for stride length, and consequently gait speed, vibrotactile haptic feedback was provided to the participants' thighs as a cue to increase peak thigh extension while the effect on gait speed was monitored. Ten healthy community-dwelling older adults (68.4 ± 4.1 years) participated. Participants' peak thigh extension, cadence, normalized stride length and velocity, along with their coefficients of variation (COV) were compared across baseline normal and fast walking (with no feedback) and three different frequency of feedback conditions. The findings indicated that, compared to self-selected normal and fast walking speeds, peak thigh extension was significantly increased when feedback was present and after it was withdrawn in a post-test. An increase in thigh extension led to an increase in stride length and, consequently, an increase in stride velocity compared to normal speed. There were no significant differences in the gait parameters as a function of feedback frequency during its application. In conclusion, while present, the haptic feedback system increased thigh extension and walking speed in older adults regardless of the feedback frequency and when the feedback was withdrawn, participants could maintain an increase in those parameters.

Dual-task walking on real-world surfaces: Adaptive changes in walking speed, step width and step height in young and older adults

ObjectivesAge-related changes in dual-task walking are well established, but research in this topic is based on evidence from laboratory rather than real-world studies. We investigated how dual-task walking on real-world surfaces affects young and older adults' gait characteristics and cognitive resource allocation. MethodSixteen young (aged 19–35, 12 female) and fifteen older adults (aged 70–85, 7 female) with no major neurological or musculoskeletal disorders walked at a self-selected speed on forty-metre outdoor paths that had asphalt or grass surface. They walked with or without a cognitive task (counting backwards). Cognitive task difficulty was individually adjusted at 80 % accuracy. Participants performed the three tasks in Single Task (ST Asphalt, ST Grass, ST Cognitive) and Dual Task context (DT Asphalt-Cognitive, DT Grass-Cognitive). ResultsThe two groups showed similar dual task effects in cognition and walking speed, both of which were slower when dual-task walking. Older adults' steps were wider overall but only young adults widened their step width when dual-task walking on grass compared to asphalt. Similarly, young adults' step height increased from single to dual-task walking when on grass, where older adults' did not. DiscussionThe lack of adaptation of step width and height when dual-task walking may leave older adults vulnerable to tripping or falling in common real-world conditions, such as while walking on grass, gravel, or uneven city sidewalks. Considering this, the built environment should be made more accessible to facilitate older adults' safe walking.

Effects of Walking Speed and Added Mass on Hip Joint Quasi-Stiffness in Healthy Young and Middle-Aged Adults.

Joint quasi-stiffness has been often used to inform exoskeleton design. Further understanding of hip quasi-stiffness is needed to design hip exoskeletons. Of interest are wearer responses to walking speed changes with added mass of the exoskeleton. This study analyzed hip quasi-stiffness at 3 walking speed levels and 9 added mass distributions among 13 young and 16 middle-aged adults during mid-stance hip extension and late-stance hip flexion. Compared to young adults, middle-aged adults maintained a higher quasi-stiffness with a smaller range. For a faster walking speed, both age groups increased extension and flexion quasi-stiffness. With mass evenly distributed on the pelvis and thighs or biased to the pelvis, both groups maintained or increased extension quasi-stiffness. With mass biased to the thighs, middle-aged adults maintained or decreased extension quasi-stiffness while young adults increased it. Young adults decreased flexion quasi-stiffness with added mass but not in any generalizable pattern with mass amounts or distributions. Conversely, middle-aged adults maintained or decreased flexion quasi-stiffness with even distribution on the pelvis and thighs or biased to the pelvis, while no change occurred if biased to the thighs. In conclusion, these results can guide the design of a hip exoskeleton's size and mass distribution according to the intended user's age.

Carrying children, groceries, and water across varying terrain: Changes in gait and comfortable walking speed

BackgroundCarrying items of substantial weight and value in one’s arms while traversing challenging terrain is a common task that requires considerable care. Carrying valuable (e.g., child) or variable (e.g., water) items, compared to stable ones (e.g., groceries) demands increased coordination, and is likely to lead to slower comfortable walking speed (CWS) and altered gait mechanics, especially on difficult terrain. Research questionHow are gait parameters altered by carrying items of substantial weight and varying value and dynamics across more and less demanding terrain? MethodsIn two experiments, participants carried their child, an equally weighted sack of groceries, or an open bucket of water in the same manner across level floor and across uneven stairs of varying heights with gaps between them. Kinematics were assessed for both terrains; kinetics were measured for one step up and one step down on stairs. ResultsMixed models ANOVAs with repeated measures revealed that CWS on uneven stairs was approximately 65 % of CWS for level floor, regardless of the item carried. Step-to-step coefficients of variation for step length and CWS were also greater. Water was carried most slowly, with shorter steps on level floor and reduced accelerations on uneven stairs. CWS with children and groceries did not differ. SignificanceCarrying items of weight and worth with varying dynamics across more and less challenging terrain illustrates the ecological complexity of walking. Terrain requiring greater flexibility, strength, and coordination reduced CWS substantially, a complexity-speed tradeoff. More variable, difficult to control items altered CWS and other gait patterns regardless of terrain difficulty, suggesting terrain and item dynamics contributed independently to gait adjustments. More valuable items were not carried more slowly than less valuable ones. Carrying tasks deserve greater attention in research and clinical assessment.

Urinary Phthalate Metabolites and Slow Walking Speed in the Korean Elderly Environmental Panel II Study.

Previous epidemiological studies have suggested that phthalate exposure may contribute to neurocognitive and neurobehavioral disorders and decreased muscle strength and bone mass, all of which may be associated with reduced physical performance. Walking speed is a reliable assessment tool for measuring physical performance in adults age 60 y and older. We investigated associations between urinary phthalate metabolites and slowness of walking speed in community-dwelling adults ages 60-98 y. We analyzed 1,190 older adults [range, 60-98 y of age; , ] from the Korean Elderly Environmental Panel II study and measured repeatedly up to three times between 2012 and 2014. Phthalate exposure was estimated using the following phthalate metabolites in urine samples: mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-n-butyl phthalate (MnBP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and mono-benzyl phthalate (MBzP). Slowness was defined as a walking speed of . We used logistic and linear regression models to evaluate the association between each urinary phthalate metabolite and slowness or walking-speed change. We also used Bayesian kernel machine regression (BKMR) to examine overall mixture effects on walking speed. At enrollment, MBzP levels were associated with an increased odds of slowness [odds ratio (OR) per doubling increase: 1.15, 95% confidence interval (CI): 1.02, 1.30; OR for the highest vs. lowest quartile: 2.20 (95% CI: 1.12, 4.35) with p-trend across ]. In longitudinal analyses, MEHHP levels showed an increased risk of slowness [OR per doubling increase: 1.15 (95% CI: 1.02, 1.29), OR for the highest vs. lowest quartile: 1.47 (95% CI: 1.04, 2.06), ]; whereas those with higher MnBP showed a reduced risk of slowness [OR per doubling increase: 0.84 (95% CI: 0.74, 0.96), OR in the highest (vs. lowest) quartile: 0.64 (95% CI: 0.47, 0.87), ]. For linear regression models, MBzP quartiles were associated with slower walking speed () at enrollment, whereas MEHHP quartiles were associated with slower walking speed, and MnBP quartiles were associated with faster walking speed in longitudinal analysis ( and , respectively). Further, the BKMR analysis revealed negative overall trends between the phthalate metabolite mixtures and walking speed and DEHP group (MEHHP, MEOHP, and MECPP) had the main effect of the overall mixture. Urinary concentrations of prevalent phthalates exhibited significant associations with slow walking speed in adults ages 60-98 y. https://doi.org/10.1289/EHP10549.

The step in time study: A feasibility study of a mobile app for measuring walking ability after massage treatment in patients with osteoarthritis

BackgroundMassage therapy is a popular intervention for those suffering osteoarthritis, however, there is a paucity of evidence to support its effectiveness in osteoarthritis. A simple measure that could potentially assess the benefits of massage treatment is walking speed which is a predictor of mobility and survival length, particularly in ageing populations. The primary aim of the study was to assess the feasibility of using a phone app to measure walking ability in people with osteoarthritis.MethodsThis feasibility study used a prospective, observational design to collect data from massage practitioners and their clients over a 5-week period. Feasibility outcomes included practitioner and client recruitment and protocol compliance. The app MapMyWalk was used to record average speed for each walk. Pre-study surveys and post-study focus groups were conducted. Clients received massage therapy in a massage clinic and were instructed to walk in their own local community for 10 min every other day. Focus group data were analysed thematically. Qualitative data from clients’ pain and mobility diaries were reported descriptively. Average walking speeds were graphed for each participant in relation to massage treatments.ResultsFifty-three practitioners expressed interest in the study, 13 completed the training, with 11 successfully recruiting 26 clients, 22 of whom completed the study. 90% of practitioners collected all required data. A strong motivation for participating practitioners was to contribute to evidence for massage therapy. Client compliance with using the app was high, but low for completing pain and mobility diaries. Average speed remained unchanged for 15 (68%) clients and decreased for seven (32%). Maximum speed increased for 11 (50%) clients, decreased for nine (41%) and remained unchanged for two (9%). However, data retrieved from the app were unreliable for walking speed.ConclusionsThis study demonstrated that it is feasible to recruit massage practitioners and their clients for a study involving mobile/wearable technology to measure changes in walking speed following massage therapy. The results support the development of a larger randomised clinical trial using purpose-built mobile/wearable technology to measure the medium and long-term effects of massage therapy on people with osteoarthritis.