Simple within-stride changes in treadmill speed can drive selective changes in human gait symmetry.

Millions of people walk with asymmetric gait patterns, highlighting a need for customizable rehabilitation approaches that can flexibly target different aspects of gait asymmetry. Here, we studied how simple within-stride changes in treadmill speed could drive selective changes in gait symmetry. In Experiment 1, healthy adults (n = 10) walked on an instrumented treadmill with and without a closed-loop controller engaged. This controller changed the treadmill speed to 1.50 or 0.75 m/s depending on whether the right or left leg generated propulsive ground reaction forces, respectively. Participants walked asymmetrically when the controller was engaged: the leg that accelerated during propulsion (right) showed smaller leading limb angles, larger trailing limb angles, and smaller propulsive forces than the leg that decelerated (left). In Experiment 2, healthy adults (n = 10) walked on the treadmill with and without an open-loop controller engaged. This controller changed the treadmill speed to 1.50 or 0.75 m/s at a prescribed time interval while a metronome guided participants to step at different time points relative to the speed change. Different patterns of gait asymmetry emerged depending on the timing of the speed change: step times, leading limb angles, and peak propulsion were asymmetric when the speed changed early in stance while step lengths, step times, and propulsion impulses were asymmetric when the speed changed later in stance. In sum, we show that simple manipulations of treadmill speed can drive selective changes in gait symmetry. Future work will explore the potential for this technique to restore gait symmetry in clinical populations.

Perceptions of Pediatric Endocrinologists and Neurologists on the Drivers of Telehealth Use.

OBJECTIVE: To assess the extent and drivers of telehealth use variation across clinicians within the same pediatric subspecialties. METHODS: In this mixed methods study, 8 pediatric medical groups in California shared data for eleven subspecialties. We calculated the proportion of total visits delivered via telehealth by medical group for each subspecialty and identified the 8 most common International Classification of Diseases 10 diagnoses for telehealth and in-person visits in endocrinology and neurology. We conducted semi-structured interviews with 32 pediatric endocrinologists and neurologists and applied a positive deviance approach comparing high versus low utilizers to identify factors that influenced their level of telehealth use. RESULTS: In 2019, medical groups that submitted quantitative data conducted 1.8 million visits with 549,306 unique pediatric patients. For 3 subspecialties, there was relatively little variation in telehealth use across medical groups: urology (mean: 16.5%, range: 9%-23%), orthopedics (mean: 7.2%, range: 2%-14%), and cardiology (mean: 11.2%, range: 2%-24%). The remaining subspecialties, including neurology (mean: 58.6%, range: 8%-93%) and endocrinology (mean: 49.5%, range: 24%-92%), exhibited higher levels of variation. For both neurology and endocrinology, the top diagnoses treated in-person were similar to those treated via telehealth. There was limited consensus on which clinical conditions were appropriate for telehealth. High telehealth utilizers were more comfortable conducting telehealth visits for new patients and often worked in practices with innovations to support telehealth. CONCLUSIONS: Clinicians perceive that telehealth may be appropriate for a range of clinical conditions when the right supports are available.

The Older Persons' Index of Multiple Deprivation: Measuring the deprivation circumstances of older populations in Aotearoa New Zealand.

Existing indices of multiple deprivation exclude indicators specifically relevant to the population aged ≥65 years. In this study we create a whole-of-population cohort of people aged ≥65 years living in private dwellings and who completed the 2013 New Zealand Census of Populations and Dwellings to create an Older Persons' Index of Multiple Deprivation (OPIMD). We combined 22 indicators representing 6 domains of deprivation (Income, Housing, Health, Assets, Connectedness and Geographic access) to establish this individual-level measure of deprivation. We used smoking data from the census to validate the OPIMD and describe the geography of the OPIMD by District Health Board, contrasting these patterns with a conventional area deprivation index. The OPIMD has the potential to inform policies concerning resource allocation for the older population. An accompanying website with an interactive atlas and an online OPIMD calculator is available for wider use of the data. Further research is required to explore associations between the OPIMD and other major health and social outcomes affecting this population.

Use of Telehealth Across Pediatric Subspecialties Before and During the COVID-19 Pandemic.

Importance: The identification of variation in health care is important for quality improvement. Little is known about how different pediatric subspecialties are using telehealth and what is driving variation. Objective: To characterize trends in telehealth use before and during the COVID-19 pandemic across pediatric subspecialties and the association of delivery change with no-show rates and access disparities. Design, Setting, and Participants: In this cohort study, 8 large pediatric medical groups in California collaborated to share aggregate data on telehealth use for 11 pediatric subspecialties from January 1, 2019, to December 31, 2021. Main Outcomes and Measures: Monthly in-person and telehealth visits for 11 subspecialties, characteristics of patients participating in in-person and telehealth visits, and no-show rates. Monthly use rates per 1000 unique patients were calculated. To assess changes in no-show rates, a series of linear regression models that included fixed effects for medical groups and calendar month were used. The demographic characteristics of patients served in person during the prepandemic period were compared with those of patients who received in-person and telehealth care during the pandemic period. Results: In 2019, participating medical groups conducted 1.8 million visits with 549 306 unique patients younger than 18 years (228 120 [41.5%] White and 277 167 [50.5%] not Hispanic). A total of 72 928 patients (13.3%) preferred a language other than English, and 250 329 (45.6%) had Medicaid. In specialties with lower telehealth use (cardiology, orthopedics, urology, nephrology, and dermatology), telehealth visits ranged from 6% to 29% of total visits from May 1, 2020, to April 30, 2021. In specialties with higher telehealth use (genetics, behavioral health, pulmonology, endocrinology, gastroenterology, and neurology), telehealth constituted 38.8% to 73.0% of total visits. From the prepandemic to the pandemic periods, no-show rates slightly increased for lower-telehealth-use subspecialties (9.2% to 9.4%) and higher-telehealth-use subspecialties (13.0% to 15.3%), but adjusted differences (comparing lower-use and higher-use subspecialties) in changes were not statistically significant (difference, 2.5 percentage points; 95% CI, -1.2 to 6.3 percentage points; P = .15). Patients who preferred a language other than English constituted 6140 in-person visits (22.2%) vs 2707 telehealth visits (11.4%) in neurology (P < .001). Conclusions and Relevance: There was high variability in adoption of telehealth across subspecialties and in patterns of use over time. The documentation of variation in telehealth adoption can inform evolving telehealth policy for pediatric patients, including the appropriateness of telehealth for different patient needs and areas where additional tools are needed to promote appropriate use.

Mobilizing the U.S. Military's TRICARE Program for Value-Based Care: A Report From the Defense Health Board.

The U.S. Military Health System spends about $50 billion annually to provide care to 9.6 million active duty service members, retirees, and their families through its TRICARE health plans. TRICARE follows the predominant payment model in the USA-fee-for-service-although the Department of Defense (DoD) and Congress encourage and mandate a move toward alternative payment models-mainly, fee-for-value. For the next TRICARE contracts which will begin in 2023, the DoD asked its health-focused federal advisory committee, the Defense Health Board (DHB), to recommend how best to assess and prioritize leading value-based healthcare initiatives identified from private, public, and employer-based health plans. The November 2020 report, 'Modernization of the TRICARE Benefit', specifies a rubric to evaluate these value-based care initiatives not only in traditional measures of effectiveness but also in terms of the Defense Health Agency's Quadruple Aim with its focus on readiness. The goal of TRICARE's move toward value-based care is to leverage its size and focus on prevention of disease and injury to maintain the readiness of the U.S. Armed Forces in addition to delivering great outcomes and value to the DoD's nearly 10 million beneficiaries. The DHB emphasizes that TRICARE's size and focus on providing quality care at lower cost will incentivize providers to participate in the shift toward value-based care despite the potential challenges in transitioning to this system. This shift also aims to motivate other large government and private payors to accelerate the adoption of value-based care through TRICARE's example.

The human preference for symmetric walking often disappears when one leg is constrained.

KEY POINTS: We hypothesized that minimization of metabolic power could drive people to walk asymmetrically when one leg is constrained We studied healthy young adults and independently constrained one or both step lengths to be markedly shorter or longer than preferred using visual feedback When one leg was constrained to take a shorter or longer step than preferred, asymmetric walking patterns were less metabolically costly than symmetric walking patterns When one leg was constrained to take a shorter or longer step than preferred and the other leg was allowed to move freely, most participants naturally adopted an asymmetric gait People may prefer to walk asymmetrically to minimize metabolic power when the function of one leg is constrained during fixed-speed treadmill walking ABSTRACT: The bilateral symmetry inherent in healthy human walking is often disrupted in clinical conditions that primarily affect one leg (e.g. stroke). This seems intuitive: with one leg constrained, gait becomes asymmetric. However, the emergence of asymmetry is not inevitable. Consider that symmetric walking could be preserved by matching the movement of the unconstrained leg to that of the constrained leg. While this is theoretically possible, it is rarely observed in clinical populations. Here, we hypothesized that minimization of metabolic power could drive people to walk asymmetrically when one leg is constrained, even when symmetric walking remains possible. We tested this hypothesis by performing two experiments in healthy adults. In Experiment 1, we constrained one step to be markedly shorter or longer than preferred. We observed that participants could significantly reduce metabolic power by adopting an asymmetric gait (one short/long step, one preferred step) rather than maintaining a symmetric gait (bilateral short/long steps). Indeed, when allowed to walk freely in this situation, participants naturally adopted a less effortful asymmetric gait. In Experiment 2, we applied a milder constraint that more closely approximated magnitudes of step length asymmetry that are observed in clinical populations. Responses in this experiment were more heterogeneous, though most participants adopted an asymmetric gait. These findings support two central conclusions: (1) symmetry is not necessarily energetically optimal in constrained human walking, and (2) people may prefer to walk asymmetrically to minimize metabolic power when one leg is constrained during fixed-speed treadmill walking, especially when the constraint is large.

Impact of a Family Medicine Minor Procedure Service on Cost of Care for a Health Plan.

BACKGROUND AND OBJECTIVES: Academic medical centers (AMC) are among some of the most expensive places to provide care. One way to cut costs is by decreasing unnecessary referrals to specialists for procedures that can be provided by well-trained primary care physicians. Our goal is to measure the financial impact of an office-based minor procedure service driven entirely by family physicians. METHODS: We examined claims data for procedures performed on patients insured under our AMC's home-grown accountable care organization-style health plan (Stanford Health Care Alliance [SHCA]). Descriptive statistics was used to compare the volume and cost of procedures performed by family medicine (FM) versus specialty care (SC). We preformed a subanalysis of SC procedures to explore the degree to which consultation and facility fees increased costs for SC. We used mathematical modeling to estimate the impact on cost of care if procedures were shifted from SC to FM and to calculate a return on investment (ROI). RESULTS: Our data set examined 6,974 outpatient procedures performed on SHCA patients from 2016-2018 at a cost of $5,263,720 to SHCA. FM performed 6% of procedures at an average cost of $236 per procedure, while SC performed 94% of procedures at an average cost of $787 per procedure. FM saved money for all 12 types of skin, musculoskeletal, and reproductive procedures assessed; the average saved per procedure was $551. This represents a 70% cost savings. ROI was 2.33; for every $1 spent on FM procedures, SHCA saved $2.33. CONCLUSION: A family medicine minor procedure service significantly lowered health spending at our AMC.

Mass spectrometry studies of the fragmentation patterns and mechanisms of protonated peptoids.

Peptoids belong to a class of sequence-controlled polymers comprising of N-alkylglycine. This study focuses on using tandem mass spectrometry techniques to characterize the fragmentation patterns of a set of singly and doubly protonated peptoids consisting of one basic residue placed at different positions. The singly protonated peptoids fragment by producing predominately high-abundant C-terminal ions called Y-ions and low-abundant N-terminal ions called B-ions. Computational studies suggest that the proton affinity (PA) of the C-terminal fragments is generally higher than that of the N-terminal fragments, and the PA of the former increases as the fragments are elongated. The B-ions are likely formed upon dissociating the proton-activated amide bonds via an oxazolone structure, and the Y-ions are produced subsequently by abstracting a proton from the newly formed B-ions, which is energetically favored. The doubly protonated peptoids prefer to fragment closest to either the N- or the C-terminus and produce corresponding B/Y-ion pairs. The basic residue seems to dictate the preferred fragmentation site, which may be the result of minimizing the repulsion between the two charges. Water and terminal neutral losses are a facile process accompanying the peptoid fragmentation in both charge states. The patterns appear to be highly influenced by the location of the basic residue.

Fast track patients' satisfaction, compliance and confidence with emergency department discharge planning.

BACKGROUND: Across Australia over one million patients are discharged from the emergency department. Discharge planning involves the communication of healthcare information to optimise patient safety, self-management and compliance with ongoing treatment. Little is known about the adequacy of discharge planning, therefore, the aim of this study was to explore the experience, confidence, satisfaction and perceptions of patients recently discharged from ED.. METHODS: The descriptive exploratory study was conducted in one district Tasmanian hospital. Data collection involved patient telephone interviews and a retrospective medical record audit. RESULTS: A convenience sample of 100 patients was used for the study. Overall, the majority (93%) of patients understood their treatment, were confident to be discharged home (88%), and satisfied (90%) with emergency care. The majority of patients' understood their discharge diagnosis (86%) and were provided with verbal (84%) discharge information. Discharge referral instructions were followed up by 60% of patients with 26% of patients re-presenting to emergency. CONCLUSIONS: The study highlighted that the majority of patients were satisfied with care, complied with discharge healthcare information and confident to be discharged. However, a number of patients failed to adhere to discharge follow up advice and re-presented to the emergency.

Ankle power biofeedback attenuates the distal-to-proximal redistribution in older adults.

BACKGROUND: Compared to young adults, older adults walk slower, with shorter strides, and with a characteristic decrease in ankle power output. Seemingly in response, older adults rely more than young on hip power output, a phenomenon known as a distal-to-proximal redistribution. Nevertheless, older adults can increase ankle power to walk faster or uphill, revealing a translationally important gap in our understanding. RESEARCH QUESTION: Our purpose was to implement a novel ankle power biofeedback paradigm to encourage favorable biomechanical adaptations (i.e. reverse the distal-redistribution) during habitual speed walking in older adults. METHODS: 10 healthy older adults walked at their preferred speeds while real-time visual biofeedback provided target increases and decreases of 10 and 20% different from preferred ankle power. We evaluated the effect of changes in ankle power on joint kinetics, kinematics, and propulsive ground reaction forces. Pre and post overground walking speed assessments evaluated the effect of increased ankle power recall on walking speed. RESULTS: Biofeedback systematically elicited changes in ankle power; increasing and decreasing ankle power by 14% and 17% when targeting ±20% different from preferred, respectively. We observed a significant negative correlation between ankle power and hip extensor work. Older adults relied more heavily on changes in ankle angular velocity than ankle moment to modulate ankle power. Lastly, older adults walked almost 11% faster when recalling increased ankle power overground. SIGNIFICANCE: Older adults are capable of increasing ankle power through targeted ankle power biofeedback - effects that are accompanied by diminished hip power output and attenuation of the distal-to-proximal redistribution. The associated increase in preferred walking speed during recall suggests a functional benefit to increased ankle power output via transfer to overground walking. Further, our mechanistic insights allude to translational success using ankle angular velocity as a surrogate to modulate ankle power through biofeedback.

Different domains of deprivation and their relationship with obesity in New Zealand 4-year-old children.

BACKGROUND: There is a relationship between childhood obesity and area-level deprivation. While the New Zealand Index of Deprivation (NZDep) has been used widely in research for the past 20 years, the Index of Multiple Deprivation (IMD) was released in 2017. This study aims to investigate the association between deprivation and childhood obesity in New Zealand and compare measures of deprivation. METHODS: Data from 316 794 4-year-olds in New Zealand undertaking the B4 School Check in 2010 to 2016, a national health and development screen, were analysed. Multilevel logistic regression models assessed the relationship between area-level deprivation and individual-level child obesity. Models were adjusted for age, sex, immigration status, ethnicity, and year. Deprivation was measured using the census-based NZDep2013 (deciles) and the administrative data-based IMD (deciles). The seven domains of the IMD were also considered. RESULTS: The relationship between deprivation and obesity was very similar for the IMD and NZDep2013, point estimates were near identical, and confidence intervals overlapped substantially. Higher levels of deprivation were associated with a higher prevalence of child obesity. The relationship between deprivation and child obesity varied considerably across IMD domains. The education domain had the strongest association with child obesity and had an association with child obesity independent of the other domains of deprivation. CONCLUSION: Overall, there was little difference between the NZDep and IMD. However, the IMD's domains and IMD-1 approach reveal more nuanced understandings of the deprivation-obesity gradient, including the importance of area-level education deprivation for predicting child obesity rates.

Biomechanical effects of augmented ankle power output during human walking.

The plantarflexor muscles are critical for forward propulsion and leg swing initiation during the push-off phase of walking, serving to modulate step length and walking speed. However, reduced ankle power output is common in aging and gait pathology, and is considered a root biomechanical cause of compensatory increases in hip power generation and increased metabolic energy cost. There is a critical need for mechanistic insight into the precise influence of ankle power output on patterns of mechanical power generation at the individual joint and limb levels during walking. We also posit that rehabilitative approaches to improve locomotor patterns should consider more direct means to elicit favorable changes in ankle power output. Thus, here we used real-time inverse dynamics in a visual biofeedback paradigm to test young adults' ability to modulate ankle power output during preferred speed treadmill walking, and the effects thereof on gait kinematics and kinetics. Subjects successfully modulated peak ankle power in response to biofeedback targets designed to elicit up to ±20% of normal walking values. Increasing ankle power output alleviated mechanical power demands at the hip and increased trailing limb positive work, propulsive ground reaction forces and step lengths. Decreasing ankle power had the opposite effects. We conclude that ankle power generation systematically influences the workload placed on more proximal leg muscles, trailing leg mechanical output and step length. Our findings also provide a promising benchmark for the application of biofeedback to restore ankle power in individuals with deficits thereof due to aging and gait pathology.

More push from your push-off: Joint-level modifications to modulate propulsive forces in old age.

INTRODUCTION: Compared to young adults, older adults walk with smaller propulsive forces and a redistribution to more proximal leg muscles for power generation during push-off. Despite this deficit in propulsive function, older adults can increase push-off intensity when encouraged to via real-time biofeedback. However, the specific joint-level modifications used by older adults to enhance propulsive force generation has yet to be elucidated. The purpose of this study was to identify the joint-level modifications used by young and older adults to modulate propulsive forces when walking at their preferred speed. METHODS: 9 young and 16 older adults walked at their preferred speed while visual biofeedback prompted them to modulate their propulsive forces using targets prescribed at ±10% and ±20% of their preferred value. Older adults were then divided into groups exhibiting relatively larger or smaller baseline redistribution to more proximal leg muscles for power generation. RESULTS: Neither young nor either older adult cohort modulated propulsive forces by altering their peak ankle power generation. Instead, subjects increased trailing limb extension and attenuated mechanical power demands at the hip during push-off. Older adults that had a larger baseline redistribution exhibited larger responses to enhanced push-off intensity than their peers-for example, walking with 11% less hip flexor power and 10% more trailing limb extension during push-off when exerting larger than preferred propulsive forces. CONCLUSION: Propulsive force biofeedback that elicits larger than preferred propulsive forces also increases trailing limb extension and attenuates mechanical power demands at the hip in older adults most exhibiting a distal-to-proximal redistribution. Our results suggest that considering baseline redistribution may be important in the personalized prescription of interventions aimed at enhancing walking performance by improving push-off intensity.

Synthesis and Mass Spectrometry Analysis of Oligo-peptoids.

Peptoids are sequence-controlled peptide-mimicking oligomers consisting of N-alkylated glycine units. Among many potential applications, peptoids have been thought of as a type of molecular information storage. Mass spectrometry analysis has been considered the method of choice for sequencing peptoids. Peptoids can be synthesized via solid phase chemistry using a repeating two-step reaction cycle. Here we present a method to manually synthesize oligo-peptoids and to analyze the sequence of the peptoids using tandem mass spectrometry (MS/MS) techniques. The sample peptoid is a nonamer consisting of alternating N-(2-methyloxyethyl)glycine (Nme) and N-(2-phenylethyl)glycine (Npe), as well as an N-(2-aminoethyl)glycine (Nae) at the N-terminus. The sequence formula of the peptoid is Ac-Nae-(Npe-Nme)4-NH2, where Ac is the acetyl group. The synthesis takes place in a commercially available solid-phase reaction vessel. The rink amide resin is used as the solid support to yield the peptoid with an amide group at the C-terminus. The resulting peptoid product is subjected to sequence analysis using a triple-quadrupole mass spectrometer coupled to an electrospray ionization source. The MS/MS measurement produces a spectrum of fragment ions resulting from the dissociation of charged peptoid. The fragment ions are sorted out based on the values of their mass-to-charge ratio (m/z). The m/z values of the fragment ions are compared against the nominal masses of theoretically predicted fragment ions, according to the scheme of peptoid fragmentation. The analysis generates a fragmentation pattern of the charged peptoid. The fragmentation pattern is correlated to the monomer sequence of the neutral peptoid. In this regard, MS analysis reads out the sequence information of the peptoids.

Fungible parameter estimates in structural equation modeling.

Extending work by Waller (2008) on fungible regression coefficients, we propose a method for computation of fungible parameter estimates in structural equation modeling. Such estimates are defined as distinct alternative solutions for parameter estimates, where all fungible solutions yield identical model fit that is only slightly worse than the fit provided by optimal estimates. When such alternative estimates are found to be highly discrepant from optimal estimates, then substantive interpretation based on optimal estimates is called into question. We present a computational method and 3 illustrations showing the potential impact of this approach in applied research, and we discuss implications and issues for further research. (PsycINFO Database Record

Modified Distribution-Free Goodness-of-Fit Test Statistic.

Covariance structure analysis and its structural equation modeling extensions have become one of the most widely used methodologies in social sciences such as psychology, education, and economics. An important issue in such analysis is to assess the goodness of fit of a model under analysis. One of the most popular test statistics used in covariance structure analysis is the asymptotically distribution-free (ADF) test statistic introduced by Browne (Br J Math Stat Psychol 37:62-83, 1984). The ADF statistic can be used to test models without any specific distribution assumption (e.g., multivariate normal distribution) of the observed data. Despite its advantage, it has been shown in various empirical studies that unless sample sizes are extremely large, this ADF statistic could perform very poorly in practice. In this paper, we provide a theoretical explanation for this phenomenon and further propose a modified test statistic that improves the performance in samples of realistic size. The proposed statistic deals with the possible ill-conditioning of the involved large-scale covariance matrices.

Instilling a culture of cleaning: Effectiveness of decontamination practices on non-disposable sphygmomanometer cuffs.

Background: Sphygmomanometers and their cuffs are non-critical items that can act as a fomite for transmission of pathogens which may cause healthcare-associated infection (HAI), leading to an argument that disposable equipment improves patient safety. Aim: The aim of this study was to demonstrate that decontamination decreased in microbial contamination of non-disposable sphygmomanometer cuffs, providing evidence to negate the need to purchase, and dispose of, single-patient-use cuffs, reducing cost and environmental impact. Methods: A pre-post intervention study of available sphygmomanometer cuffs and associated bedside patient monitors was conducted using a series of microbiological samples in a rural emergency department. A Wilcoxon signed-rank test analysed the effect of the decontamination intervention. To further examine the effect of the decontamination intervention, Mann-Whitney U-tests were conducted for each aspect. Findings: Contamination was significantly higher before decontamination than afterwards (Z = -5.14, U = 55.0, P < 0.001, η2 = 0.61 inner; Z = -5.05, U = 53.5, P < 0.001, η2 = 0.59 outer). Discussion: Decontamination of non-disposable sphygmomanometer cuffs decreases microbial load and risk of HAI, providing evidence to negate arguments for disposable cuffs while being environmentally sensitive and supportive of a culture of patient safety and infection control.

The New Zealand Indices of Multiple Deprivation (IMD): A new suite of indicators for social and health research in Aotearoa, New Zealand.

For the past 20 years, the New Zealand Deprivation Index (NZDep) has been the universal measure of area-based social circumstances for New Zealand (NZ) and often the key social determinant used in population health and social research. This paper presents the first theoretical and methodological shift in the measurement of area deprivation in New Zealand since the 1990s and describes the development of the New Zealand Index of Multiple Deprivation (IMD). We briefly describe the development of Data Zones, an intermediary geographical scale, before outlining the development of the New Zealand Index of Multiple Deprivation (IMD), which uses routine datasets and methods comparable to current international deprivation indices. We identified 28 indicators of deprivation from national health, social development, taxation, education, police databases, geospatial data providers and the 2013 Census, all of which represented seven Domains of deprivation: Employment; Income; Crime; Housing; Health; Education; and Geographical Access. The IMD is the combination of these seven Domains. The Domains may be used individually or in combination, to explore the geography of deprivation and its association with a given health or social outcome. Geographic variations in the distribution of the IMD and its Domains were found among the District Health Boards in NZ, suggesting that factors underpinning overall deprivation are inconsistent across the country. With the exception of the Access Domain, the IMD and its Domains were statistically and moderately-to-strongly associated with both smoking rates and household poverty. The IMD provides a more nuanced view of area deprivation circumstances in Aotearoa NZ. Our vision is for the IMD and the Data Zones to be widely used to inform research, policy and resource allocation projects, providing a better measurement of area deprivation in NZ, improved outcomes for Maori, and a more consistent approach to reporting and monitoring the social climate of NZ.

The independent effects of speed and propulsive force on joint power generation in walking.

Walking speed is modulated using propulsive forces (FP) during push-off and both preferred speed and FP decrease with aging. However, even prior to walking slower, reduced FP may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time FP measurements to decouple and investigate the interaction between joint-level coordination, whole-body FP, and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9-1.3m/s). We immediately calculated the average FP from each speed. Subjects then walked at 1.3m/s while completing a series of biofeedback trials with instructions to match their instantaneous FP to their averaged FP from slower speeds. Walking slower decreased FP and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced FP, not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body FP, and walking speed in our aging population.

Does dynamic stability govern propulsive force generation in human walking?

Before succumbing to slower speeds, older adults may walk with a diminished push-off to prioritize stability over mobility. However, direct evidence for trade-offs between push-off intensity and balance control in human walking, independent of changes in speed, has remained elusive. As a critical first step, we conducted two experiments to investigate: (i) the independent effects of walking speed and propulsive force (FP) generation on dynamic stability in young adults, and (ii) the extent to which young adults prioritize dynamic stability in selecting their preferred combination of walking speed and FP generation. Subjects walked on a force-measuring treadmill across a range of speeds as well as at constant speeds while modulating their FP according to a visual biofeedback paradigm based on real-time force measurements. In contrast to improvements when walking slower, walking with a diminished push-off worsened dynamic stability by up to 32%. Rather, we find that young adults adopt an FP at their preferred walking speed that maximizes dynamic stability. One implication of these findings is that the onset of a diminished push-off in old age may independently contribute to poorer balance control and precipitate slower walking speeds.