Energy expenditure during typical household and community activities of daily living in persons with lower limb amputation: A pilot study

INTRODUCTION

Knowledge about the energy expenditure of typical activities of daily living (ADL) in persons with lower limb amputation (LLA) is lacking. This study investigated the following: (1) oxygen consumption per unit distance (V̇O 2 ; mL·kg -1 ·min -1 ), (2) proportion utilization of peak oxygen consumption (%V̇O 2 peak), (3) oxygen cost (energy cost; mL·kg -1 ·m -1 ), and (4) perceived exertion (rating of perceived exertion) of ADL in persons with LLA and able-bodied controls.

METHODS

Participants (21 with LLA/12 controls) performed 2 household ADL experiments: in-house walking and vacuuming and 3 community ADL experiments: marked shopping, fast walking, and stair negotiation. V̇O 2 peak was assessed with arm crank ergometry, and ambulatory activity was monitored for 7 days with a StepWatch.

RESULTS

Participants with LLA performed in-house walking, marked shopping, vacuuming, and stair negotiation at a similar V̇O 2 as controls, while their self-selected walking speed (WS) was significantly lower. Participants with LLA had significantly higher %V̇O 2 peak than controls during in-house walking and reported a significantly higher rating of perceived exertion for vacuuming and marked shopping. The highest possible WS of participants with LLA during fast walking was significantly lower than that of controls, but V̇O 2 was also significantly lower, indicating a limited capacity to walk at higher WS. Participants with LLA had a significantly lower daily step count, significantly lower-proportion high-intensity ambulation, but significantly higher-proportion low-intensity ambulation than controls, indicating that persons with LLA also walked at lower WS in daily life.

CONCLUSIONS

The results indicate that persons with LLA have increased physical and perceived effort during performance of ADL compared with persons without amputation, which has consequences for community participation, and hence independence and quality of life.

The Effect of Computerized Cognitive Training, with and without Exercise, on Cortical Volume and Thickness and Its Association with Gait Speed in Older Adults: A Secondary Analysis of a Randomized Controlled Trial

Background

Slower walking is associated with changes in cortical volume and thickness. Computerized cognitive training (CCT) and exercise improve cortical volume and thickness and thus, may promote gait speed. Slowing of gait is predictive of Alzheimer's disease.

Objective

To examine: 1) the effect of CCT, with or without physical exercise, on cortical volume and thickness and; 2) the association of changes in cortical volume and thickness with changes in gait speed.

Methods

A subset of 124 adults (n = 53), aged 65-85 years, enrolled in an 8-week randomized controlled trial and completed T1-weighted MRI and 4-meter walk at baseline and 8 weeks. Participants were randomized to: 1) active control (BAT; n = 19); 2) CCT (n = 17); or 3) CCT preceded by exercise (Ex-CCT; n = 17). Change in cortical volume and thickness were assessed and compared across all groups using Freesurfer.

RESULTS

BAT versus CCT increased left rostral middle frontal gyrus volume (p  = 0.027) and superior temporal gyrus thickness (p = 0.039). Ex-CCT versus CCT increased left cuneus thickness (p < 0.001) and right post central gyrus thickness (p = 0.005), and volume (p < 0.001). Ex-CCT versus BAT increased left (p = 0.001) and right (p = 0.020) superior parietal gyri thickness. There were no significant between-group differences in gait speed (p > 0.175). Increased left superior parietal volume (p = 0.036, r = 0.340) and thickness (p = 0.002, r = 0.348), right post central volume (p = .017, r = 0.341) and thickness (p = 0.001, r = 0.348), left banks of superior temporal sulcus thickness (p = 0.002, r = 0.356), and left precuneus thickness (p < 0.001, r = 0.346) were associated with increased gait speed.

CONCLUSIONS

CCT with physical exercise, but not CCT alone, improves cortical volume and thickness in older adults. These changes may contribute to the maintenance of gait speed in aging.

Prediction of walking speed one year following hip fracture based on pre-fracture assessments of mobility and physical activity

BACKGROUND

Older people with hip fracture are often medically frail, and many do not regain their walking ability and level of physical activity. The aim of this study was to examine the relationship between pre-fracture recalled mobility, fear of falling, physical activity, walking habits and walking speed one year after hip fracture.

METHODS

The study had a longitudinal design. Measurements were performed 3-5 days postoperatively (baseline) and at one year after the hip fracture. The measurements at baseline were all subjective outcome measures recalled from pre-fracture: The New Mobility Scale (NMS), the 'Walking Habits' questionnaire, The University of California, Los Angeles (UCLA) Activity Scale, Fear of Falling International (FES-I) and demographic variables. At one year 4-meter walking speed, which was a part of the Short Physical Performance Battery (SPPB) was assessed.

RESULTS

At baseline 207 participants were included and 151 were assessed after one year. Their age was mean (SD) 82.7 (8.3) years (range 65-99 years). Those with the fastest walking speed at one year had a pre-fracture habit of regular walks with a duration of ≥ 30 min and/or a frequency of regular walks of 5-7 days a week. Age (p =.020), number of comorbidities (p <.001), recalled NMS (p <.001), and recalled UCLA Activity Scale (p =.007) were identified as predictors of walking speed at one year. The total model explained 54% of the variance in walking speed.

CONCLUSIONS

Duration and frequency of regular walks before the hip fracture play a role in walking speed recovery one year following the fracture. Subjective outcome measures of mobility and physical activity, recalled from pre-fracture can predict walking speed at one year. They are gentle on the old and medically frail patients in the acute phase after hip fracture, as well as clinically less time consuming.

Slowing of Movements in Healthy Aging as a Rational Economic Response to an Elevated Effort Landscape

Why do we move slower as we grow older? The reward circuits of the brain, which tend to invigorate movements, decline with aging, raising the possibility that reduced vigor is due to the diminishing value that our brain assigns to movements. However, as we grow older, it also becomes more effortful to make movements. Is age-related slowing principally a consequence of increased effort costs from the muscles, or reduced valuation of reward by the brain? Here, we first quantified the cost of reaching via metabolic energy expenditure in human participants (male and female), and found that older adults consumed more energy than the young at a given speed. Thus, movements are objectively more costly for older adults. Next, we observed that when reward increased, older adults, like the young, responded by initiating their movements earlier. Yet, unlike the young, they were unwilling to increase their movement speed. Was their reluctance to reach quicker for rewards due to the increased effort costs, or because they ascribed less value to the movement? Motivated by a mathematical model, we next made the young experience a component of aging by making their movements more effortful. Now the young responded to reward by reacting faster but chose not to increase their movement speed. This suggests that slower movements in older adults are partly driven by an adaptive response to an elevated effort landscape. Moving slower may be a rational economic response the brain is making to mitigate the elevated effort costs that accompany aging.

A Scoping Review of Personal, Financial, and Environmental Determinants of Mobility Among Older Adults

OBJECTIVE

To synthesize available evidence of factors comprising the personal, financial, and environmental mobility determinants and their association with older adults' self-reported and performance-based mobility outcomes.

DATA SOURCES

PubMed, EMBASE, PsychINFO, Web of Science, AgeLine, Sociological Abstract, Allied and Complementary Medicine Database, and Cumulative Index to Nursing and Allied Health Literature databases search for articles published from January 2000 to December 2021.

STUDY SECTION

Using predefined inclusion and exclusion criteria, multiple reviewers independently screened 27,293 retrieved citations from databases, of which 422 articles underwent full-text screening, and 300 articles were extracted.

DATA EXTRACTION

The 300 articles' information, including study design, sample characteristics including sample size, mean age and sex, factors within each determinant, and their associations with mobility outcomes, were extracted.

DATA SYNTHESIS

Because of the heterogeneity of the reported associations, we followed Barnett et al's study protocol and reported associations between factors and mobility outcomes by analyses rather than by article to account for multiple associations generated in 1 article. Qualitative data were synthesized using content analysis. A total of 300 articles were included with 269 quantitative, 22 qualitative, and 9 mixed-method articles representing personal (n=80), and financial (n=1), environmental (n=98), more than 1 factor (n=121). The 278 quantitative and mixed-method articles reported 1270 analyses; 596 (46.9%) were positively and 220 (17.3%) were negatively associated with mobility outcomes among older adults. Personal (65.2%), financial (64.6%), and environmental factors (62.9%) were associated with mobility outcomes, mainly in the expected direction with few exceptions in environmental factors.

CONCLUSIONS

Gaps exist in understanding the effect of some environmental factors (eg, number and type of street connections) and the role of gender on older adults' walking outcomes. We have provided a comprehensive list of factors with each determinant, allowing the creation of core outcome set for a specific context, population, or other forms of mobility, for example, driving.

Effort cost of reaching prompts vigor reduction in older adults

As people age, they move slower. Is age-related reduction in vigor a reflection of a reduced valuation of reward by the brain, or a consequence of increased effort costs by the muscles? Here, we quantified cost of movements objectively via the metabolic energy that young and old participants consumed during reaching and found that in order reach at a given speed, older adults expended more energy than the young. We next quantified how reward modulated movements in the same populations and found that like the young, older adults responded to increased reward by initiating their movements earlier. Yet, their movements were less sensitive to increased reward, resulting in little or no modulation of reach speed. Lastly, we quantified the effect of increased effort on how reward modulated movements in young adults. Like the effects of aging, when faced with increased effort the young adults responded to reward primarily by reacting faster, with little change in movement speed. Therefore, reaching required greater energetic expenditure in the elderly, suggesting that the slower movements and reactions exhibited in aging are partly driven by an adaptive response to an elevation in the energetic landscape of effort. That is, moving slower appears to be a rational economic consequence of aging.

Significance statement

Healthy aging coincides with a reduction in speed, or vigor, of walking, reaching, and eye movements. Here we focused on disentangling two opposing sources of aging-related movement slowing: reduced reward sensitivity due to loss of dopaminergic tone, or increased energy expenditure movements related to mitochondrial or muscular inefficiencies. Through a series of three experiments and construction of a computational model, here we demonstrate that transient changes in reaction time and movement speed together offer a quantifiable metric to differentiate between reward- and effort-based alterations in movement vigor. Further, we suggest that objective increases in the metabolic cost of moving, not reductions in reward valuation, are driving much of the movement slowing occurring alongside healthy aging.

Mitochondrial Energetics in Skeletal Muscle Are Associated With Leg Power and Cardiorespiratory Fitness in the Study of Muscle, Mobility and Aging

BACKGROUND

Mitochondrial energetics are an important property of aging muscle, as generation of energy is pivotal to the execution of muscle contraction. However, its association with functional outcomes, including leg power and cardiorespiratory fitness, is largely understudied.

METHODS

In the Study of Muscle, Mobility, and Aging, we collected vastus lateralis biopsies from older adults (n = 879, 70-94 years, 59.2% women). Maximal State 3 respiration (Max OXPHOS) was assessed in permeabilized fiber bundles by high-resolution respirometry. Capacity for maximal adenosine triphosphate production (ATPmax) was measured in vivo by 31P magnetic resonance spectroscopy. Leg extension power was measured with a Keiser press system, and VO2 peak was determined using a standardized cardiopulmonary exercise test. Gender-stratified multivariate linear regression models were adjusted for age, race, technician/site, adiposity, and physical activity with beta coefficients expressed per 1-SD increment in the independent variable.

RESULTS

Max OXPHOS was associated with leg power for both women (β = 0.12 Watts/kg, p < .001) and men (β = 0.11 Watts/kg, p < .050). ATPmax was associated with leg power for men (β = 0.09 Watts/kg, p < .05) but was not significant for women (β = 0.03 Watts/kg, p = .11). Max OXPHOS and ATPmax were associated with VO2 peak in women and men (Max OXPHOS, β women = 1.03 mL/kg/min, β men = 1.32 mL/kg/min; ATPmax β women = 0.87 mL/kg/min, β men = 1.50 mL/kg/min; all p < .001).

CONCLUSIONS

Higher muscle mitochondrial energetics measures were associated with both better cardiorespiratory fitness and greater leg power in older adults. Muscle mitochondrial energetics explained a greater degree of variance in VO2 peak compared to leg power.

Quasi-passive lower limbs exosuit: an in-depth assessment of fatigue, kinematic and muscular patterns while comparing assistive strategies on an expert subject's gait analysis

Wearable robots are becoming a valuable solution that helps injured, and elderly people regain mobility and improve clinical outcomes by speeding up the rehabilitation process. The XoSoft exosuit identified several benefits, including improvement of assistance, usability, and acceptance with a soft, modular, bio-mimetic, and quasi-passive exoskeleton. This study compares two assistive configurations: (i) a bilateral hip flexion (HA, hips-assistance) and (ii) a bilateral hip flexion combined with ankle plantarflexion (HAA, hips-ankles-assistance) with the main goal of evaluating compensatory actions and synergetic effects generated by the human- exoskeleton interaction. A complete description of this complex interaction scenario with this actuated exosuit is evaluated during a treadmill walking task, using several indices to quantify the human-robot interaction in terms of muscular activation and fatigue, metabolic expenditure, and kinematic motion patterns. Evidence shows that the HAA biomimetic controller is synergetic with the musculature and performs better concerning the other control strategy. The experimentation demonstrated a metabolic expenditure reduction of 8% of Metabolic Equivalent of Task (MET), effective assistance of the muscular activation of 12.5%, a decrease of the muscular fatigue of 0.6% of the mean frequency, and a significant reduction of the compensatory actions, as discussed in this work. Compensatory effects are present in both assistive configurations, but the HAA modality provides a 47% reduction of compensatory effects when considering muscle activation.

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

BACKGROUND

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.

OBJECTIVE

We investigated associations between urinary phthalate metabolites and slowness of walking speed in community-dwelling adults ages 60-98 y.

METHODS

We analyzed 1,190 older adults [range, 60-98 y of age; mean±standard deviation (SD) , 74.81±5.99] 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 <1.0meter/second. 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.

RESULTS

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 quartiles=0.031]. 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), p- trend=0.035]; 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), p-trend=0.006]. For linear regression models, MBzP quartiles were associated with slower walking speed (p-trend=0.048) at enrollment, whereas MEHHP quartiles were associated with slower walking speed, and MnBP quartiles were associated with faster walking speed in longitudinal analysis (p-trend=0.026 and <0.001, 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.

DISCUSSION

Urinary concentrations of prevalent phthalates exhibited significant associations with slow walking speed in adults ages 60-98 y. https://doi.org/10.1289/EHP10549.

Effectiveness of a Single Prolonged Aerobic Exercise Session on Executive Function Task Performance in Physically Active Adults (21-70 Years of Age)

We sought to examine the effectiveness of an acute prolonged exercise session on post-exercise executive function in physically active adults and to assess if age or pre-exercise cognitive performance was predictive of the magnitude of change in executive task performance. Self-registered cyclists were recruited prior to participating in a 161-km mass-participation cycling event. Cyclists were excluded if they had not previously participated in a similar endurance event, were young (<18 y), or were cognitively impaired (Mini CogTM < 3 units). Immediately after completing the exercise session, the time taken to complete Trail Making Test Part A and Part B (TMT A + B) was assessed. A faster time to complete the TMT A + B was observed after exercise (+8.5%; p = 0.0003; n = 62; age range = 21-70 y). The magnitude of change in TMT A + B performance (pre vs. post) was influenced by pre-exercise TMT A + B performance (r2 = 0.23, p < 0.0001), not age (r2 =0.002; p = 0.75). Prolonged exercise had a small-to-moderate effect on post-exercise compared to pre-exercise executive function task performance (Cohen's d = 0.38-0.49). These results support the effectiveness of a single prolonged exercise bout to augment executive function in physically active adults, irrespective of age.

Cross-Sectional and Longitudinal Associations of Creatinine-to-Cystatin C Ratio with Sarcopenia Parameters in Older Adults

OBJECTIVES

Accumulating evidence from cross-sectional studies suggests that the serum creatinine-to-cystatin C ratio (CCR) may be a useful biomarker for sarcopenia. This study aimed to assess the cross-sectional and longitudinal associations of CCR with sarcopenia and its parameters in community-dwelling older adults.

DESIGN

Cross-sectional and longitudinal study.

SETTING AND PARTICIPANTS

This 6-year prospective cohort study included the repeated measurement data from 1,253 Japanese residents (662 males and 591 females) aged ≥65 years who underwent medical checkups in Kusatsu and Hatoyama, Japan. A total of 4,421 observations were collected.

MEASUREMENTS

The CCR was grouped into quartiles by sex (Q1-Q4) using Q4 as the reference category. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 algorithm. Skeletal muscle mass index (SMI) measured using segmental multifrequency bioelectrical impedance analysis, handgrip strength (HGS), usual gait speed (UGS), and maximal gait speed (MGS) were measured repeatedly as sarcopenia parameters. The association of the CCR with changes in sarcopenia, SMI, HGS, UGS, and MGS during the 6-year period were analyzed using a generalized linear mixed-effects model.

RESULTS

The prevalence of sarcopenia at baseline was 13.1% (11.9% in males and 14.5% in females). In a cross-sectional analysis, the CCR quartile was inversely associated with sarcopenia and was positively associated with SMI, HGS, and MGS (P for trend < 0.001). In a longitudinal analysis during the 6 years, a significant increase in sarcopenia in Q2 (B = 1.1% point/year; P = 0.026 for group-by-time interaction) and significant declines in SMI (B = -0.01 kg/m2/year; P = 0.044 for group-by-time interaction) and MGS (B = -0.008 m/sec/year; P = 0.041 for group-by-time interaction) in Q1 were observed compared with Q4. However, the dose-response relationship was significant only for MGS (P = 0.033 for trend). No significant group-by-time interaction was observed for HGS. CCR was not significantly associated with UGS either cross-sectionally or longitudinally.

CONCLUSIONS

CCR is a useful biomarker regarding the status of sarcopenia. It may be used for sarcopenia screening even in older adults whose physical function is difficult to assess. However, further longitudinal studies are needed to determine whether CCR can be a predictor of future sarcopenia.

Predictive Validity of Different Walking Measures to Identify the Incident Long-Term Care Needs in Older Adults

OBJECTIVES

A comfortable walking speed is a suitable measurement of functional status in older adults. In addition to assessing their comfortable walking speed, two complex walking tests were administered to a cohort of older people, assuming that these tests would be a more sensitive predictor of the incident long-term care needs than comfortable walking speed.

DESIGN

A prospective observational study was conducted to collect data.

SETTING AND PARTICIPANTS

Among the initial 5,563 community-dwelling independent older adults (aged ≥ 65 years), 935 were excluded and the data of 4,628 (mean age, 73.9 ± 5.5 years, 65-94 years; 2,052 men, 2,576 women) older adults were finally analyzed.

METHODS

Three walking tasks were administered: comfortable, complicated balance, and Go-stop walking. Complicated balance walking was measured under comfortable walking conditions, with participants having to walk with their hands crossed at the shoulder joint at 90°. For the Go-stop walking test, the time taken to walk 2 meters was measured using a stopwatch. For two years following baseline assessments, participants received monthly follow-ups for incident certification of the need for care under the long-term care insurance (LTCI) system.

RESULTS

Low performance in comfortable, complicated balance, and Go-stop walking were 29.8%, 37.7%, and 35.1%, respectively. During the 24-month follow-up period, 246 participants (5.3%) required LTCI certification. The Youden Index was used to determine the cut-points of the incident long-term care needs in the comfortable, complicated balance, and Go-stop walking conditions, which were 1.055 m/s, 0.936 m/s, and 3.205 seconds, respectively. Participants classified as exhibiting low performance included 1,381 (29.8%) under comfortable walking, 1,746 (37.7%) under complicated balance walking, and 1,623 (35.1%) under the Go-stop walking tests. The C-indices of the comfortable, complicated balance, and Go-stop walking tests were 0.72 (95% confidence interval (CI) 0.69-0.76), 0.71 (95% CI 0.67-0.74), and 0.65 (95% CI 0.61-0.69), respectively. Cox proportional hazards regression model revealed significant relationships between the incident long-term care needs and the comfortable (hazard ratio (HR) 2.14, 95% CI 1.62-2.84), complicated balance (1.81, 1.36-2.41), and Go-stop (1.46, 1.12-1.91) walking conditions.

CONCLUSIONS AND IMPLICATIONS

The findings suggest that slow walking speed has a considerably greater impact on the incident long-term care needs in older adults. However, the complex walking task did not improve the predictive performance. Comfortable walking speed tests, which can easily be measured to predict the future incident long-term care needs, are effective tools in community health promotion and primary care.

The demography of idiopathic normal pressure hydrocephalus: data on 3000 consecutive, surgically treated patients and a systematic review of the literature

OBJECTIVE

The objective of this study was to describe the demographic characteristics of patients with idiopathic normal pressure hydrocephalus (iNPH) through an analysis of 3000 consecutive, surgically treated Swedish patients and a systematic review of the literature.

METHODS

Data on age, sex, comorbidities, diagnostic delay, initial symptoms, and severity of symptoms at diagnosis were extracted from the Swedish Hydrocephalus Quality Registry. In addition, a systematic PRISMA-based review of the literature published from database inception until August 2019 was performed using the PubMed, Cochrane, and Scopus databases on the basis of two concepts: normal pressure hydrocephalus and demography and their association with related terms. Of 1020 unique articles, 16 were eligible for study inclusion and were assessed for quality using the Newcastle-Ottawa Scale. Mean and weighted mean values were calculated.

RESULTS

The mean patient age at the time of surgery was 74.4 years, 79% of patients were in their 70s, and 60% of the patients were men. Almost 50% of the patients had symptoms from four main domains (i.e., balance, gait, cognition, and urinary dysfunction) at disease onset. Patients aged < 60 years (2%) reported more headaches and fewer balance problems than those aged ≥ 60. Women were more impaired in function than men at the time of diagnosis. Dementia (Mini-Mental State Examination score < 25) was found in 47% of the patients. Men had more diabetes, heart disease, hypertension, and stroke than women, and comorbidity correlated with increased impairment. The incidence of surgery for iNPH was 20%-40% of the disease incidence according to survey and operation-based studies.

CONCLUSIONS

Most iNPH patients undergo surgery in their 70s. Those aged < 60 years show slightly different symptomatology and probably present with a specific disease entity, indicating that the lower age limit for iNPH should be 60 years. iNPH patients have severe impairment preceded by a long diagnostic delay. Even though the included study designs differed, the systematic review showed that the disorder has a very low treatment incidence. The importance of diagnosing and treating iNPH is further emphasized by the fact that iNPH may account for a considerable part of all cases of dementia.

Three-week exercise and protein intake immediately after exercise increases the 6-min walking distance with simultaneously improved plasma volume in patients with chronic cerebrovascular disease: a preliminary prospective study

Background

Blood volume (BV) is a critical factor for physical endurance in chronic stroke patients, while hypervolemia can worsen hypertension in these patients. This prospective study assessed whether rehabilitation combined with protein supplementation immediately after each exercise for 3 weeks would improve plasma volume (PV) and BV as well as physical endurance without worsening hypertension.

Methods

Ambulatory patients with chronic cerebrovascular disease who received a 3-week rehabilitation program with high protein jelly (intervention group [PG]; n = 8; 10-g protein) or protein-free jelly (control group [CG]; n = 8) consumed within 30 min after each exercise. PV and BV were assessed while measuring the 6-min walking distance (6MWD), peak oxygen consumption (VO_2peak), strength of knee extension, and resting blood pressure before and after the intervention. Two-way ANOVA was used to determine whether there was an interaction of time × group. The difference between before and after intervention or between the groups by post-hoc test (Tukey’s test) at the level of P < 0.05.

Results

The 6MWD increased only in the PG (P = 0.001; an interaction of Group and Time, P = 0.037). PV and BV increased only in the PG (P < 0.05). VO_2peak and strength of knee extension in the paralysed limb increased in both groups (P < 0.05). The resting blood pressure did not worsen after the intervention.

Conclusions

In chronic post-stroke patients, 3-week rehabilitation combined with protein intake immediately after exercise increased 6MWD simultaneously with increased PV and BV, but it did not increase resting blood pressure. The present regimen is acceptable and effective for ambulatory patients with chronic cerebrovascular disease.

Name of the registry Examining effects of protein supplementation on functional improvement during rehabilitation intervention in chronic stroke patients

Trial registration number UMIN000028009; date of registration: 30/06/2017. This study was registered prospectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-022-00429-x.

Unexplained anemia of aging: Etiology, health consequences, and diagnostic criteria

BACKGROUND

Up to 15% of people aged 60 and over are anemic, and the prevalence of anemia increases with age. In older men and women, anemia is associated with increases in the risk of death and all-cause hospitalization, poor functional capacity, quality of life, and depression.

METHODS AND RESULTS

We reviewed the literature describing anemia in aging populations, focusing on the specific diagnostic criteria of anemia and potential causes in older men and women. Even after extensive etiologic workup that involves careful medical history, physical examination, laboratory measurements, and additional studies such as bone marrow biopsy, anemia of aging is unexplained in up to 40% of older patients with anemia. As a result, treatment options remain limited.

CONCLUSIONS

The prevalence of unexplained anemia of aging (UAA; also called unexplained anemia of the elderly, UAE), its deleterious impacts on health, physical function, and quality of life, and the lack of effective treatment or therapy guidelines represent a compelling unmet clinical need. In this review and consensus document, we discuss the scope of the problem, possible causes of UAA, diagnostic criteria, and potential treatment options. Because even mild anemia is strongly linked to poor clinical outcomes, it should receive clinical attention rather than simply being considered a normal part of aging.

Standard Error of the Mean and Minimal Detectable Change of Gait Speed in Older Adults Using Japanese Long-Term Care Insurance System

Evaluation of motor function, such as gait ability, can accurately predict the subsequent occurrence of disability in older adults. There are no reports of standard error of the mean (SEM) or minimal detectable change (MDC) with respect to gait in Japanese long-term care insurance-certified individuals. The purpose of this study was to investigate the values of preferred gait, fast gait, and the timed up and go (TUG) test. This study included 46 participants using the Japanese long-term care insurance system. (age 86.5 ± 6.6 years, 12 men, 34 women). The duration of three gait were measured twice using a stopwatch. The SEM was 0.07 for preferred gait, 0.09 for fast gait and 2.59 for TUG. The MDC was 0.19 for preferred gait, 0.26 for fast gait, and 7.17 for TUG. The SEM and MDC values of preferred gait, fast gait, and TUG in this study corroborated with those of previous studies, whereas others were different. Considering that gait speed differs with the country, it may be difficult to compare it among different population groups. We obtained the results of gait speed of Japanese long-term care insurance-certified individuals, which is a new finding

Walking cadence (steps/min) and intensity in 61-85-year-old adults: the CADENCE-Adults study

BACKGROUND

Heuristic (i.e., evidence-based, rounded) cadences of ≥100 and ≥ 130 steps/min have consistently corresponded with absolutely-defined moderate (3 metabolic equivalents [METs]) and vigorous (6 METs) physical activity intensity, respectively, in adults 21-60 years of age. There is no consensus regarding similar thresholds in older adults.

PURPOSE

To provide heuristic cadence thresholds for 3, 4, 5, and 6 METs in 61-85-year-old adults.

METHODS

Ninety-eight community-dwelling ambulatory and ostensibly healthy older adults (age = 72.6 ± 6.9 years; 49% women) walked on a treadmill for a series of 5-min bouts (beginning at 0.5 mph with 0.5 mph increments) in this laboratory-based cross-sectional study until: 1) transitioning to running, 2) reaching ≥75% of their age-predicted maximum heart rate, or 3) reporting a Borg rating of perceived exertion > 13. Cadence was directly observed and hand-tallied. Intensity (oxygen uptake [VO2] mL/kg/min) was assessed with indirect calorimetry and converted to METs (1 MET = 3.5 mL/kg/min). Cadence thresholds were identified via segmented mixed effects model regression and using Receiver Operating Characteristic (ROC) curves. Final heuristic cadence thresholds represented an analytical compromise based on classification accuracy (sensitivity, specificity, positive and negative predictive value, and overall accuracy).

RESULTS

Cadences of 103.1 (95% Prediction Interval: 70.0-114.2), 116.4 (105.3-127.4), 129.6 (118.6-140.7), and 142.9 steps/min (131.8-148.4) were identified for 3, 4, 5, and 6 METs, respectively, based on the segmented regression. Comparable values based on ROC analysis were 100.3 (95% Confidence Intervals: 95.7-103.1), 111.5 (106.1-112.9), 116.0 (112.4-120.2), and 128.6 steps/min (128.3-136.4). Heuristic cadence thresholds of 100, 110, and 120 were associated with 3, 4, and 5 METs. Data to inform a threshold for ≥6 METs was limited, as only 6/98 (6.0%) participants achieved this intensity.

CONCLUSIONS

Consistent with previous data collected from 21-40 and 41-60-year-old adults, heuristic cadence thresholds of 100, 110, and 120 steps/min were associated with 3, 4, and 5 METs, respectively, in 61-85-year-old adults. Most older adults tested did not achieve the intensity of ≥6 METs; therefore, our data do not support establishing thresholds corresponding with this intensity level.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02650258 . Registered 24 December 2015.

Identification of Disability Risk in Addition to Slow Walking Speed in Older Adults

INTRODUCTION

A cutoff speed of 1.0 m/s for walking at a comfortable pace is critical for predicting future functional decline. However, some older adults with walking speeds below the cutoff point maintain an independent living. We aimed to identify specific predictors of disability development in older adults with slow walking speeds in contrast to those with a normal walking speed.

METHODS

This prospective cohort study on 12,046 community-dwelling independent Japanese older adults (mean age, 73.6 ± 5.4 years) was conducted between 2011 and 2015. Participants were classified into slow walking speed (comfortable walking speed slower than 1.0 m/s) and normal walking speed (speed of 1.0 m/s or faster) groups and followed up to assess disability incidence for 24 months after baseline assessments. Cox proportional hazards regression models were used to identify predictors of disability development in the slow and normal walking groups.

RESULTS

Overall, 26.8% of participants had a slow walking speed. At follow-up, 17.3% and 5.1% of participants in the slow and normal walking groups, respectively, developed disability (p < 0.01). Cox regression models revealed that age (hazard ratio 1.07, 95% confidence interval 1.05-1.09), walking speed (0.12, 0.07-0.22), grip strength (0.97, 0.95-0.99), Parkinson's disease (4.65, 2.59-8.33), word list memory-immediate recognition score (0.90, 0.85-0.97), word list memory-delayed recall score (0.94, 0.89-1.00), Symbol Digit Substitution Test (SDST) score (0.98, 0.96-0.99), and 15-item Geriatric Depression Scale (GDS) score (1.04, 1.01-1.07) were significantly associated with disability incidence in the slow walking group. In the normal walking group, age, grip strength, depression, diabetes, cognition, GDS score, and reduced participation in outdoor activity were significantly associated with disability incidence; however, there was no significant association with walking speed.

CONCLUSIONS

Decreased walking speeds have considerably greater impact on disability development in older adults with a slow walking speed than in those with a normal walking speed. Health-care providers should explore modifiable factors for reducing walking speed; they should also encourage improvement of risk factors such as muscle weakness and depression to reduce disability risk in older adults with slow walking speeds.

Multidimensional Sleep Health and Physical Functioning in Older Adults

Objective: To examine the association between multidimensional sleep health and objective measures of physical functioning in older adults. Method: We conducted a secondary analysis of 158 adults ≥65 years who participated in Midlife in the United States (MIDUS) 2 and MIDUS Refresher studies. Physical functioning was assessed using gait speed during a 50-foot timed walk, lower extremity strength via chair stand test, and grip strength via hand-held dynamometers. Composite multidimensional sleep health scores were derived from 1 week of sleep diaries and wrist actigraphy. Results: Multiple linear regression was used to examine the associations between multidimensional sleep health and physical functioning measures. In adjusted regression analyses, multidimensional sleep health was significantly positively associated with gait speed but not lower extremity strength or grip strength. Discussion: These findings suggest multidimensional sleep health may contribute to physical functioning in older adults. Longitudinal examinations are needed to determine the value of multidimensional sleep health as a therapeutic target to optimize physical functioning.

Using a Deep Learning Method and Data from Two-Dimensional (2D) Marker-Less Video-Based Images for Walking Speed Classification

Human body measurement data related to walking can characterize functional movement and thereby become an important tool for health assessment. Single-camera-captured two-dimensional (2D) image sequences of marker-less walking individuals might be a simple approach for estimating human body measurement data which could be used in walking speed-related health assessment. Conventional body measurement data of 2D images are dependent on body-worn garments (used as segmental markers) and are susceptible to changes in the distance between the participant and camera in indoor and outdoor settings. In this study, we propose five ratio-based body measurement data that can be extracted from 2D images and can be used to classify three walking speeds (i.e., slow, normal, and fast) using a deep learning-based bidirectional long short-term memory classification model. The results showed that average classification accuracies of 88.08% and 79.18% could be achieved in indoor and outdoor environments, respectively. Additionally, the proposed ratio-based body measurement data are independent of body-worn garments and not susceptible to changes in the distance between the walking individual and camera. As a simple but efficient technique, the proposed walking speed classification has great potential to be employed in clinics and aged care homes.

Impact of frailty in cardiac surgical patients-Assessment, burden, and recommendations

Elderly patients undergoing cardiac surgery are at an increased risk of adverse postoperative outcomes. Frailty, a state of decreased physiological reserve, is highly prevalent among elderly patients. Despite being associated with adverse surgical outcomes, no universally accepted definition or measurement tool for frailty exists. Moreover, regardless of all the recommendations, a routine perioperative frailty assessment is often ignored. In addition to complications, frailty increases the burden to the healthcare system, which is of particular concern in Southeast Asia due to its socioeconomically disadvantaged and resource limited settings. This narrative review focuses to develop clinical practice plans for perioperative frailty assessment in the context of a cardiac surgical setting.

Does the 1-year Decline in Walking Speed Predict Mortality Risk Beyond Current Walking Speed in Adults With Knee Osteoarthritis?

OBJECTIVE

To investigate whether walking speed at 1 timepoint, decline over the past 12 months, or both predict mortality risk over 11 years in adults with, or at risk of, knee osteoarthritis (OA).

METHODS

Using the data from the Osteoarthritis Initiative, we defined slow versus adequate walking speed as walking < 1.22 versus ≥ 1.22 m/s on a 20m walk test during the 12-month follow-up visit. We defined meaningful decline (yes/no) as slowing ≥ 0.08 m/s over the past year. At the 12-month visit, we classified adequate sustainers as those with adequate walking speed and no meaningful decline, slow sustainers as slow walking speed and no meaningful decline, adequate decliners as adequate walking speed and meaningful decline, and slow decliners as slow walking speed and meaningful decline. Mortality was recorded over 11 years. To examine the association of walking speed with mortality, HR and 95% CI were calculated using Cox regression, adjusted for potential confounders.

RESULTS

Of 4229 participants in the analytic sample (58% female, age 62 ± 9 yrs, BMI 29 ± 5 kg/m²), 6% (n = 270) died over 11 years. Slow sustainers and slow decliners had 2-times increased mortality risk compared to adequate sustainers (HR 1.96, 95% CI 1.44-2.66 for slow sustainers, and HR 2.08, 95% CI 1.46-2.96 for slow decliners). Adequate decliners had 0.43 times the mortality risk compared with adequate sustainers (HR 0.57, 95% CI 0.32-1.01).

CONCLUSION

In adults with, or at risk of, knee OA, walking slower than 1.22 m/s in the present increased mortality risk, regardless of decline over the previous year.

The association between walking speed from short- and standard-distance tests with the risk of all-cause mortality among adults with radiographic knee osteoarthritis: data from three large United States cohort studies

OBJECTIVE

Adults with radiographic knee OA (rKOA) are at increased risk of mortality and walking difficulty may modify this relation. Little is known about specific aspects of walking difficulty that increase mortality risk. We investigated the association of walking speed (objective measure of walking difficulty) with mortality and examined the threshold that best discriminated this risk in adults with rKOA.

METHODS

Participants with rKOA from the Johnston County Osteoarthritis Project (JoCoOA, longitudinal population-based cohort), Osteoarthritis Initiative and Multicenter Osteoarthritis Study (OAI and MOST, cohorts of individuals with or at high risk of knee OA) were included. Baseline speed was measured via 2.4-meter (m) walk test (short-distance) in JoCoOA and 20-m walk test (standard-distance) in OAI and MOST. To examine the association of walking speed with mortality risk over 9 years, hazard ratios (HR) and 95% confidence intervals (CI) were calculated from Cox regression models adjusted for potential confounders. A Maximal Likelihood Ratio Chi-square Approach was utilized to identify an optimal threshold of walking speed predictive of mortality.

RESULTS

Deaths after 9 years of follow-up occurred in 23.3% (290/1244) of JoCoOA and 5.9% (249/4215) of OAI + MOST. Walking 0.2 m/s slower during short- and standard-distance walk tests was associated with 23% (aHR [95%CI]; 1.23 [1.10, 1.39]) and 25% (1.25 [1.09, 1.43]) higher mortality risk, respectively. Walking <0.5 m/s on short-distance and <1.2 m/s standard-distance walk tests, best discriminated those with and without mortality risk.

CONCLUSION

Slower walking speed measured via short- and standard-distance walk tests was associated with increased mortality risk in adults with rKOA.

Combined diabetes and arthritis are associated with declined gait speed

This study investigated the association of combined arthritis and diabetes, diabetes only, and arthritis only compared with neither with gait speed in the general population. This cross-sectional study included data from the second wave of Midlife in the United States-2 (MIDUS 2) project 4: Biomarker Project, 2004-2009. The MIDUS 2 biomarker project included 1255 individuals aged between 34 and 84 years. Participants were categorized into four groups: combined arthritis and diabetes, diabetes only, arthritis only, or neither. The main outcome measure was gait speed measured by the 50-ft walk test. Covariates included age, gender, body mass index (BMI), depression symptoms, and number of chronic conditions/symptoms. A total of 1255 participants were included with mean age 54.52 ± 11.71, of those 713 (56.8%) participants were females. The results showed that combined arthritis and diabetes was significantly associated with a greater decline in gait speed (B = - 0.11, 95% confidence interval (CI) [- 0.17 to - 0.6], p < 0.001). Arthritis and diabetes were independently significantly associated with decreased gait speed (B = - 0.072, 95% CI [- 0.10 to - 0.043], p < 0.001), (B = - 0.064, 95% CI [- 0.12 to - 0.012], p = 0.015), respectively. Combined arthritis and diabetes was associated with a greater decline in gait speed compared with diabetes only, arthritis only, or neither group. Key Points • Combined arthritis and diabetes were associated with declined gait speed. • Gait speed did not differ between people with arthritis compared with people with diabetes. • We recommended including gait speed assessment in regular clinical visits to capture gait speed declines for further health assessments.

The Association of Diabetes With Knee Pain Locations, Pain While Walking, and Walking Speed: Data From the Osteoarthritis Initiative

OBJECTIVE

Osteoarthritis (OA) and diabetes mellitus (DM) often coexist and can result in negative outcomes. DM can affect pain and walking speed in people with knee OA; however, the impact of DM on OA is understudied. The purpose of this study was to investigate the association between diabetes and knee pain locations, pain severity while walking, and walking speed in people with knee OA.

METHODS

A cross-sectional analysis was used. Data from 1790 individuals from the Osteoarthritis Initiative (mean [SD] age = 69 [8.7] years) with knee pain were included and grouped into knee OA and diabetes (n = 236) or knee OA only (n = 1554). Knee pain locations were categorized as no pain, localized pain, regional pain, or diffuse pain. Knee pain during a 20-m walk test was categorized as no pain, mild, moderate, or severe knee pain. Walking speed was measured using the 20-m walk test. Multinomial and linear regression analyses were performed.

RESULTS

Diabetes was associated with regional knee pain (odds ratio [OR] = 1.77; 95% CI = 1.01-3.11). Diabetes was associated only with moderate (OR = 1.78; 95% CI = 1.02-3.10) or severe (OR = 2.52; 95% CI = 1.01-6.28) pain while walking. Diabetes was associated with decreased walking speed (B = -0.064; 95% CI = -0.09 to -0.03).

CONCLUSIONS

Diabetes was associated with regional knee pain but not with localized or diffuse knee pain and was associated with moderate to severe knee pain while walking and slower walking speed in people with knee OA.

IMPACT

Clinicians can use a knee pain map for examining knee pain locations for people with diabetes and knee OA. Knee pain during walking and walking speed should be screened for people with knee OA and diabetes because of the influence of diabetes on these parameters in this population.

LAY SUMMARY

Diabetes might be associated with specific knee pain locations, pain during activities such as walking, and reduced walking speed in people with knee OA.

Physical effort of middle-aged women in a university hospital - Field tests in comparison to standardized cardiopulmonary exercise testing (CPET)

Physical effort of workload of female employees in the healthcare system is perceived to rise. Research focused mainly on physical activity levels of registered nurses (RN). Therefore, we investigated physical strain during daily routine of other hospital workers next to RN. O₂uptake, heart rate, breathing frequency and ventilation were measured in 33 female medical (associate) professionals (MAP) and Cleaners&Helpers (Cl&H) using Oxycon Mobile. Physical work load was compared to standardized CPET. Wilcoxon-test and ANOVA were calculated using SPSS 20.0. Cl&H performed heavy-lifting and had the lowest power during CPET. The O₂-uptake for heavy-lifting as strong effort, differed significantly from office work (p < 0.001) and bedside-patient-care (p = 0.001). Compared with metabolic equivalent (MET) cleaning, heavy-lifting, and office work are underestimated. Bedside-patient-care, walking, pushing performed by MAP are overestimated. While Cl&H had the lowest maximal power in CPET, their work required the highest O₂-uptake. The tasks are underestimated in the MET-tables.

Impact of Gait Speed on the Obesity Paradox in Older Patients With Cardiovascular Disease

PURPOSE

The purpose of this study was to determine whether gait speed affects the obesity paradox in older patients with cardiovascular disease.

METHODS

The study population consisted of 2224 patients ≥60 years old with cardiovascular disease admitted to hospital between May 1, 2006, and January 31, 2018. Body mass index (BMI) and gait speed before hospital discharge were determined, and patients were divided into two groups: slow and preserved gait speed (≤0.8 and >0.8 m/s, respectively), according to the algorithm for sarcopenia diagnosis. The slow and preserved gait speed groups were also further subdivided according to BMI: <18.5 kg/m², 18.5-24.9 kg/m², and BMI ≥25.0 kg/m². The study endpoint was all-cause mortality.

RESULTS

The study population (male: 66.7%) had a mean age of 73.1 ± 7.6 years. Over a median follow-up period of 1.69 years (interquartile range 0.67-3.67 years), 283 patients died. Higher BMI was associated with favorable prognosis in the group with preserved gait speed but not in the group with slow gait speed after adjusting for other prognostic factors. Adding BMI to the clinical model significantly increased the area under the receiver operating characteristic curve in the group with preserved gait speed (0.744 vs 0.726, P = 0.028) but not in the group with slow gait speed (0.716 vs 0.716, P = 0.789).

CONCLUSIONS

Higher BMI was consistently associated with favorable prognosis in patients with cardiovascular disease and preserved gait speed but not in those with slow gait speed. These findings indicated that physical frailty influences the obesity paradox in older patients with cardiovascular disease.

State-of-the-art research in robotic hip exoskeletons: A general review

Ageing population is now a global challenge, where physical deterioration is the common feature in elderly people. In addition, the diseases, such as spinal cord injury, stroke, and injury, could cause a partial or total loss of the ability of human locomotion. Thus, assistance is necessary for them to perform safe activities of daily living. Robotic hip exoskeletons are able to support ambulatory functions in elderly people and provide rehabilitation for the patients with gait impairments. They can also augment human performance during normal walking, loaded walking, and manual handling of heavy-duty tasks by providing assistive force/torque. In this article, a systematic review of robotic hip exoskeletons is presented, where biomechanics of the human hip joint, pathological gait pattern, and common approaches to the design of robotic hip exoskeletons are described. Finally, limitations of the available robotic hip exoskeletons and their possible future directions are discussed, which could serve a useful reference for the engineers and researchers to develop robotic hip exoskeletons with practical and plausible applications in geriatric orthopaedics.

The translational potential of this article

The past decade has witnessed a remarkable progress in research and development of robotic hip exoskeletons. Our aim is to summarize recent developments of robotic hip exoskeletons for the engineers, clinician scientists and rehabilitation personnel to develop efficient robotic hip exoskeletons for practical and plausible applications.

Declínio da velocidade da marcha e desfechos de saúde em idosos: dados da Rede Fibra

RESUMO A velocidade da marcha (VM) tem sido considerada um marcador de saúde em idosos capaz de predizer desfechos adversos de saúde, mas a compreensão de fatores associados a ela ainda é limitada e controversa. O objetivo deste trabalho é identificar desfechos adversos de saúde relacionados ao declínio da velocidade de marcha em idosos comunitários. Trata-se de estudo transversal e multicêntrico, que avaliou o autorrelato de doenças crônicas e de hospitalização no último ano, polifarmácia e velocidade de marcha. Utilizou-se análise de regressão logística para estimar os efeitos de cada variável independente na chance de os idosos apresentarem declínio na velocidade de marcha inferior (VM<0,8m/s) (α=0,05). Participaram da pesquisa 5.501 idosos. A menor velocidade da marcha mostrou-se associada a portadores de doenças cardíacas (OR=2,06; IC: 1,67-2,54), respiratórias (OR=3,25; IC: 2,02-5,29), reumáticas (OR=2,16; IC: 1,79-2,52) e/ou depressão (OR=2,51; IC: 2,10-3,14), hospitalizados no último ano (OR=1,51; IC: 1,21-1,85) e polifarmácia (OR=2,14; IC: 1,80-2,54). Assim, os resultados indicaram que idosos com velocidade de marcha menor que 0,8m/s apresentam maior risco de eventos adversos de saúde. Dessa forma, sugere-se que a velocidade de marcha não seja negligenciada na avaliação de idosos comunitários, inclusive na atenção básica.

The Metabolic Cost of Walking in healthy young and older adults - A Systematic Review and Meta Analysis

The Metabolic Cost of Walking (MCoW) is an important variable of daily life that has been studied extensively. Several studies suggest that MCoW is higher in Older Adults (OA) than in Young Adults (YA). However, it is difficult to compare values across studies due to differences in the way MCoW was expressed, the units in which it was reported and the walking speed at which it was measured. To provide an overview of MCoW in OA and YA and to investigate the quantitative effect of age on MCoW, we have conducted a literature review and performed two meta-analyses. We extracted data on MCoW in healthy YA (18-41 years old) and healthy OA (≥59 years old) and calculated, if not already reported, the Gross (GCoW) and Net MCoW (NCoW) in J/kg/m. If studies reported MCoW measured at multiple speeds, we selected those values for YA and OA at which MCoW was minimal. All studies directly comparing YA and OA were selected for meta-analyses. From all studies reviewed, the average GCoW in YA was 3.4 ± 0.4 J/kg/m and 3.8 ± 0.4 J/kg/m in OA (~12% more in OA), and the average NCoW in YA was 2.4 ± 0.4 J/kg/m and 2.8 ± 0.5 J/kg/m in OA (~17% more in OA). Our meta-analyses indicated a statistically significant elevation of both GCoW and NCoW (p < 0.001) for OA. In terms of GCoW, OA expended about 0.3 J/kg/m more metabolic energy than YA and about 0.4 J/kg/m more metabolic energy than YA in terms of NCoW. Our study showed a statistically significant elevation in MCoW of OA over YA. However, from the literature it is unclear if this elevation is directly caused by age or due to an interaction between age and methodology. We recommend further research comparing MCoW in healthy OA and YA during "natural" over-ground walking and treadmill walking, after sufficient familiarization time.

Movement Vigor as a Reflection of Subjective Economic Utility

To understand subjective evaluation of an option, various disciplines have quantified the interaction between reward and effort during decision making, producing an estimate of economic utility, namely the subjective 'goodness' of an option. However, variables that affect utility of an option also influence the vigor of movements toward that option. For example, expectation of reward increases speed of saccadic eye movements, whereas expectation of effort decreases this speed. These results imply that vigor may serve as a new, real-time metric with which to quantify subjective utility, and that the control of movements may be an implicit reflection of the brain's economic evaluation of the expected outcome.

Geographical Accessibility of Community Health Assist System General Practitioners for the Elderly Population in Singapore: A Case Study on the Elderly Living in Housing Development Board Flats

Accessible primary healthcare is important to national healthcare in general and for older persons in particular, in societies where the population is ageing rapidly, as in Singapore. However, although much policy and research efforts have been put into this area, we hardly find any spatial perspective to assess the accessibility of these primary healthcare services. This paper analyzes the geographical accessibility of one major healthcare service in Singapore, namely, General Practitioners (GPs) services under the Community Health Assist Scheme (CHAS) for older persons. A Python script was developed to filter the website data of the Housing Development Board (HDB) of Singapore. The data derived was comprehensively analyzed by an Enhanced 2-Step Floating Catchment Area (E2SFCA) method based on a Gaussian distance-decay function and the GIS technique. This enabled the identification of areas with relatively weak geographical accessibility of CHAS-GPs. The findings are discussed along with suggestions for health practitioners, service planners and policy makers. Despite its initial nature, this study has demonstrated the value of innovative approaches in data collection and processing for the elderly-related studies, and contributed to the field of healthcare services optimization and possibly to other human services.

Randomized Controlled Trial of Exercise to Improve Walking Energetics in Older Adults

Background and Objectives

Mobility limitation is common and has been linked to high energetic requirements of daily activities, including walking. The study objective was to determine whether two separate forms of exercise could reduce the energy cost of walking and secondary outcomes related to activity and participation domains among older adults with mobility limitation.

Research Design and Methods

Community-dwelling older adults with self-reported mobility limitation (n = 72) were randomized to 12 weeks of twice-weekly, group-based, instructor-led timing and coordination, aerobic walking, or stretching and relaxation (active control) programs. The primary outcome was the energy cost of walking (mL O₂/kg/m), assessed by a 5-minute treadmill walking test (0.8 m/s). Secondary outcomes were fatigability, physical activity, endurance, physical function, and life-space. Baseline-adjusted ANCOVAs were used to determine mean differences between exercise and control groups at 12 and 24 weeks.

Results

Exercise session attendance was high: 86% for timing and coordination, 81% for aerobic walking, and 90% for stretching and relaxation. At 12 weeks, timing and coordination reduced the mean energy cost of walking by 15% versus stretching and relaxation (p = .008). Among those with high baseline cost, timing and coordination reduced mean energy cost by 20% versus stretching and relaxation (p = .055). Reductions were sustained at 24 weeks. Aerobic walking had no effect on the energy cost of walking at 12 or 24 weeks. At 12 weeks, there was a trend toward faster gait speed (by 0.1 m/s) in timing and coordination versus stretching and relaxation (p = .074). Fatigability, physical activity, endurance, physical function, and life-space did not change with timing and coordination or aerobic walking versus stretching and relaxation at 12 or 24 weeks.

Discussion and Implications

Twelve weeks of timing and coordination, but not aerobic walking, reduced the energy cost of walking among older adults with mobility limitation, particularly among those with high baseline energy cost; reductions in energy cost were sustained following training cessation. Timing and coordination also led to a trend toward faster gait speed.

Effects of physical exercise in older adults with reduced physical capacity: meta-analysis of resistance exercise and multimodal exercise

Older adults with reduced physical capacity are at greater risk of progression to care dependency. Progressive resistance strength exercise and multimodal exercise have been studied to restore reduced physical capacity. To summarize the best evidence of the two exercise regimes, this meta-analysis study appraised randomized-controlled trials from published systematic reviews. Medline, Embase, and the Cochrane Database of Systematic Review and Cochrane Central Register of Controlled Clinical Trials were searched for relevant systematic reviews. Two reviewers independently screened the relevant systematic reviews to identify eligible trials, assessed trial methodological quality, and extracted data. RevMan 5.3 software was used to analyze data on muscle strength, physical functioning, activities of daily living, and falls. Twenty-three eligible trials were identified from 22 systematic reviews. The mean age of the trial participants was 75 years or older. Almost all multimodal exercise trials included muscle strengthening exercise and balance exercise. Progressive resistance exercise is effective in improving muscle strength of the lower extremity and static standing balance. Multimodal exercise is effective in improving muscle strength of the lower extremity, dynamic standing balance, gait speed, and chair stand. In addition, multimodal exercise is effective in reducing falls. Neither type of exercise was effective in improving activities of daily living. For older adults with reduced physical capacity, multimodal exercise appears to have a broad effect on improving muscle strength, balance, and physical functioning of the lower extremity, and reducing falls relative to progressive resistance exercise alone.

Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study

OBJECTIVE

Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not.

METHODS

Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance-based clinical tests: 5 times sit-to-stand test, walking speed (tested over 20 meters), and 400-meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80-95%) to predict walking ≥6,000 steps/day.

RESULTS

Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m² , and 55% female) with valid accelerometer data, 54.9% walked ≥6,000 steps/day. High specificity thresholds of physical function for walking ≥6,000 steps/day ranged 11.4-14.0 seconds on the 5 times sit-to-stand test, 1.13-1.26 meters/second for walking speed, or 315-349 seconds on the 400-meter walk test.

CONCLUSION

Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function.

[Gait speed and the appearance of neurocognitive disorders in older adults: Results of a Peruvian cohort]

INTRODUCTION

The prevention and management of neurocognitive disorders (NCD) among older adults can be improved by early identification of risk factors such as walking speed. The objective of the study is to assess the association between gait speed and NCD onset in a population of Peruvian older adults.

MATERIAL AND METHODS

Cohort conducted in older adults who attended the geriatrics service of Naval Medical Center (Callao, Peru). During the baseline assessment, participants' gait speed was recorded. Subsequently, participants were followed-up annually for 5 years, with a mean of 21 months. NCD onset was defined as the occurrence of a score ≤24 points on the Mini Mental State Examination (screening test) during follow-up. The hazard ratios (HR) and their 95% confidence intervals (95% CI) were calculated using Cox regression.

RESULTS

The study included 657 participants, with a mean age of 73.4±9.2 (SD) years, of whom 47.0% were male, 47.8% had a gait speed <0.8 m/s, and 20.1% developed NCD during the follow up. It was found that older adults who had gait speed <0.8 m/s at baseline were more likely to develop NCD than those who had a gait speed ≥0.8 m/s (adjusted HR=1.41, 95% CI=1.34-1.47).

CONCLUSION

A longitudinal association was found between decreased gait speed and NCD onset, suggesting that gait speed could be useful to identify patients at risk of NCD onset.

Harmony as a convergence attractor that minimizes the energy expenditure and variability in physiological gait and the loss of harmony in cerebellar ataxia

BACKGROUND

The harmony of the human gait was recently found to be related to the golden ratio value (ϕ). The ratio between the duration of the stance and that of the swing phases of a gait cycle was in fact found to be close to ϕ, which implies that, because of the fractal property of autosimilarity of that number, the gait ratios stride/stance, stance/swing, swing/double support, were not significantly different from one another. We studied a group of patients with cerebellar ataxia to investigate how the differences between their gait ratios and the golden ratio are related to efficiency and stability of their gait, assessed by energy expenditure and stride-to-stride variability, respectively.

METHODS

The gait of 28 patients who were affected by degenerative cerebellar ataxia and of 28 healthy controls was studied using a stereophotogrammetric system. The above mentioned gait ratios, the energy expenditure estimated using the pelvis reconstructed method and the gait variability in terms of the stride length were computed, and their relationships were analyzed. Matching procedures have also been used to avoid multicollinearity biases.

FINDINGS

The gait ratio values of the patients were farther from the controls (and hence from ϕ), even in speed matched conditions (P=0.011, Cohen's D=0.76), but not when the variability and energy expenditure were matched between the two groups (Cohen's D=0.49). In patients with cerebellar ataxia, the farther the stance-swing ratio was from ϕ, the larger the total mechanical work (R²_adj=0.64). Further, a significant positive correlation was observed between the difference of the gait ratio from the golden ratio and the severity of the disease (R=0.421, P=0.026).

INTERPRETATION

Harmony of gait appears to be a benchmark of physiological gait leading to physiological energy recovery and gait reliability. Neurorehabilitation of patients with ataxia might benefit from the restoration of harmony of their locomotor patterns.

A Wearable Hip Assist Robot Can Improve Gait Function and Cardiopulmonary Metabolic Efficiency in Elderly Adults

The aims of this paper were to investigate the effectiveness of a newly developed wearable hip assist robot, that uses an active assist algorithm to improve gait function, muscle effort, and cardiopulmonary metabolic efficiency in elderly adults. Thirty elderly adults (15 males/ 15 females) participated in thispaper. The experimental protocol consisted of overground gait at comfortable speed under three different conditions: free gait without robot assistance, robot-assisted gait with zero torque (RAG-Z), and full RAG. Under all conditions, muscle effort was analyzed using a 12-channel surface electromyography system. Spatio-temporal data were collected at 120 Hz using a 3-D motion capture system with six infrared cameras. Metabolic cost parameters were collected as oxygen consumption per unit (ml/min/kg) and aerobic energy expenditure (Kcal/min). In the RAG condition, participants demonstrated improved gait function, decreased muscle effort, and reduced metabolic cost. Although the hip assist robot only provides assistance at the hip joint, our results demonstrated a clear reduction in knee and ankle muscle activity in addition to decreased hip flexor and extensor activity. Our findings suggest that this robot has the potential to improve stabilization of the trunk during walking in elderly adults.

31P Magnetic Resonance Spectroscopy Assessment of Muscle Bioenergetics as a Predictor of Gait Speed in the Baltimore Longitudinal Study of Aging

BACKGROUND

Aerobic fitness and muscle bioenergetic capacity decline with age; whether such declines explain age-related slowing of walking speed is unclear. We hypothesized that muscle energetics and aerobic capacity are independent correlates of walking speed in simple and challenging performance tests and that they account for the observed age-related decline in walking speed in these same tests.

METHODS

Muscle bioenergetics was assessed as postexercise recovery rate of phosphocreatine (PCr), k _PCr, using phosphorus magnetic resonance spectroscopy (³¹P-MRS) in 126 participants (53 men) of the Baltimore Longitudinal Study of Aging aged 26-91 years (mean = 72 years). Four walking tasks were administered-usual pace over 6 m and 150 seconds and fast pace over 6 m and 400 m. Separately, aerobic fitness was assessed as peak oxygen consumption (peak VO₂) using a graded treadmill test.

RESULTS

All gait speeds, k _PCr, and peak VO₂ were lower with older age. Independent of age, sex, height, and weight, both k _PCr and peak VO₂ were positively and significantly associated with fast pace and long distance walking but only peak VO₂ and not k _PCr was significantly associated with usual gait speed over 6 m. Both k _PCr and peak VO₂ substantially attenuated the association between age and gait speed for all but the least stressful walking task of 6 m at usual pace.

CONCLUSION

Muscle bioenergetics assessed using ³¹P-MRS is highly correlated with walking speed and partially explains age-related poorer performance in fast and long walking tasks.

Relationship between frequent knee pain, obesity, and gait speed in older adults: data from the Osteoarthritis Initiative

Background

Knee pain (KP) causes gait difficulties in older adults and is associated with slow gait speed (GS). Obesity has negative effects on health. GS is an important indicator of health, well-being, and mean life span in older adults and is a strong predictor of future disability and mortality. The relationship between frequent KP, obesity, and GS in older adults remains unclear. Therefore, the present study aimed at examining the relationship between baseline frequent KP and obesity status on GS over time. We hypothesized that frequent KP, obesity, or both would be associated with decreased GS over time.

Methods

The data from the Osteoarthritis Initiative were used for this 6-year longitudinal cohort study. We studied 3,118 adults aged between 45 years and 79 years. We grouped the participants into the following four categories according to KP frequency and obesity status at baseline: 1) no KP and nonobese, 2) frequent KP and nonobese, 3) no KP and obese, and 4) frequent KP and obese. GS measurements were based on a 20 m walking test timed using a stopwatch; testing was performed at baseline and over a 6-year follow-up period. Walk pace (m/sec) was calculated as the average pace over two trials conducted at clinic visits. General linear mixed models were used to examine the relationships between frequent KP, obesity, and GS.

Results

After adjusting for all covariates, at baseline, all the nonobese group with frequent KP (β=−0.06, 95% confidence interval [CI]: −0.07 to −0.04), the obese group with no KP (β=−0.07, 95% CI: −0.1 to −0.04), and the obese group with frequent KP (β=−0.08, 95% CI: −0.1 to −0.05) exhibited decreased GS compared with the nonobese and no KP group. However, the associations between frequent KP, obesity, and GS over time were not statistically significant.

Conclusion

Frequent KP alone, obesity alone, and the combination of frequent KP and obesity were all associated with decreased GS in older adults. These associations did not change in any of the groups longitudinally; as such, the slopes corresponding to the data remained unchanged.

Rising Energetic Cost of Walking Predicts Gait Speed Decline With Aging

BACKGROUND

Slow gait is a robust biomarker of health and a predictor of functional decline and death in older adults, yet factors contributing to the decline in gait speed with aging are not well understood. Previous research suggests that the energetic cost of walking at preferred speed is inversely associated with gait speed, but whether individuals with a rising energetic cost of walking experience a steeper rate of gait speed decline has not been investigated.

METHODS

In participants of the Baltimore Longitudinal Study of Aging, the energetic cost of overground walking at preferred speed (mL/kg/m) was assessed between 2007 and 2014 using a portable indirect calorimeter. The longitudinal association between the energetic cost of walking and usual gait speed over 6 meters (m/s) was assessed with multivariate linear regression models, and the risk of slow gait (<1.0 m/s) was analyzed using Cox proportional hazards models.

RESULTS

The study population consisted of 457 participants aged 40 and older who contributed 1,121 person-visits to the analysis. In fully adjusted models, increases in the energetic cost of walking predicted the rate of gait speed decline in those older than 65 years (β = -0.008 m/s, p < .001). Moreover, those with a higher energetic cost of walking (>0.17mL/kg/m) had a 57% greater risk of developing slow gait compared with a normal energetic cost of walking (≤0.17mL/kg/m; adjusted hazard ratio = 1.57, 95% confidence interval: 1.01-2.46).

CONCLUSIONS

These findings suggest that strategies to maintain walking efficiency hold significant implications for maintaining mobility in late life. Efforts to curb threats to walking efficiency should focus on therapies to treat gait and balance impairments, and reduce clinical disease burden.

The effects of respiratory muscle strengthening exercise using a sling on the amount of respiration

[Purpose] The purpose of this study was to present aerobic exercise that can be performed together with respiratory muscle strength training and examine whether the vital capacity of individuals can be enhanced when respiratory muscle strength training is conducted together with aerobic exercise. [Subjects and Methods] The subjects were 10 male students and 8 female students. The sling exercise method was used to conduct three types of training to strengthen the muscles around the shoulder joints. A maximal respiratory quotient measurement device was used to measure the vital capacity of the subjects five times. [Results] There was a significant difference in each respiratory training time point compared with before the performance of respiratory training. [Conclusion] This study presented respiratory muscle strength training using a sling as a training method for respiratory training.

Factors associated with lower gait speed among the elderly living in a developing country: a cross-sectional population-based study

Background

Among community-dwelling older adults, mean values for gait speed vary substantially depending not only on the population studied, but also on the methodology used. Despite the large number of studies published in developed countries, there are few population-based studies in developing countries with socioeconomic inequality and different health conditions, and this is the first study with a representative sample of population. To explore this, the association of lower gait speed with sociodemographic, anthropometric factors, mental status and physical health was incorporated participants’ weight (main weight) in the analysis of population of community-dwelling older adults living in a developing country.

Methods

This was a cross-sectional population based on a sample of 1112 older adults aged 60 years and over from Health, Wellbeing and Aging Study cohort 2010. Usual gait speed (s) to walk 3 meters was stratified by sex and height into quartiles. Multiple regression analysis was performed to investigate the independent effect of each factor associated with a slower usual gait speed.

Results

The average walking speed of the elderly was 0.81 m/s – 0.78 m/s among women and 0.86 m/s among men. In the final model, the factors associated with lower gait speed were age (OR = 3.56), literacy (OR = 3.20), difficulty in one or more IADL (OR = 2.74), presence of cardiovascular disease (OR = 2.15) and sedentarism. When we consider the 50% slower, we can add the variables handgrip strength, and the presence of COPD.

Conclusions

Gait speed is a clinical marker and an important measure of functional capacity among the elderly. Our findings suggest that lower walking speed is associated with age, education, but especially with modifiable factors such as impairment of IADL, physical inactivity and cardiovascular disease. These results reinforce how important it is for the elderly to remain active and healthy.

A Novel Analytic Technique to Measure Associations Between Circulating Biomarkers and Physical Performance Across the Adult Life Span

Understanding associations between circulating biomarkers and physical performance across the adult life span could aid in better describing mechanistic pathways leading to disability. We hypothesized that high concentrations of circulating biomarkers would be associated with lower functioning across study populations representing the adult life span. The data were from four intervention and two observational studies with ages ranging 22-89 years. Biomarkers assayed included inflammatory, coagulation, and endothelial function markers. Physical performance was measured either by VO2peak (studies of young and middle-aged adults) or usual gait speed (studies of older adults). Partialled (by age, body mass index, race, and sex) and weighted common correlations were calculated between biomarkers and physical performance. Homogeneity of the associations was also assessed. Interleukin-6 (weighted r = -.22), tumor necrosis factor receptor 2 (weighted r = -.19), D-dimer (weighted r = -.16), tumor necrosis factor receptor 1 (weighted r = -.15), granulocyte colony-stimulating factor (weighted r = -.14), and tumor necrosis factor alpha (weighted r = -.10) were all significantly inversely correlated with physical performance (p < .05). All significant correlations were homogeneous across studies. In summary, we observed consistent inverse associations between six circulating biomarkers and objective measures of physical performance. These results suggest that these serum biomarkers may be broadly applicable for detection, trajectory, and treatment monitoring of physical function across the life span or possibly for midlife predictors of functionally deleterious conditions.

Gait energetic efficiency in older adults with and without knee pain: results from the Baltimore Longitudinal Study of Aging

With aging, customary gait patterns change and energetic efficiency declines, but the relationship between these alterations is not well understood. If gait characteristics that develop with aging explain part of the decline in energetic efficiency that occur in most aging individuals, then efforts to modify these characteristics could delay or prevent mobility limitation. This study characterizes gait patterns in older persons with and without knee pain and tests the hypothesis that changes in gait characteristics due to knee pain are associated with increased energetic cost of walking in older adults. Study participants were 364 men and 170 women aged 60 to 96 years enrolled in the Baltimore Longitudinal Study of Aging (BLSA), of whom 86 had prevalent knee pain. Gait patterns were assessed at participant self-selected usual pace in the gait laboratory, and the energetic cost of walking was assessed by indirect calorimetry during self-selected usual pace walking over 2.5 min in a tiled corridor using a portable equipment. Participants with knee pain were less energetically efficient than those without pain (oxygen consumption 0.97 vs. 0.88 ml/(10 m · 100 kg); p = 0.002) and had slower gait speed and smaller range of motion (ROM) at the hip and knee joints (p < 0.05, for all). Slower gait speed and lower knee ROM in participants with knee pain and longer double support time and higher ankle ROM in participants without knee pain were associated with lower energetic efficiency (p < 0.05, for all). Slower gait speed and lower knee ROM were correlates of knee pain and were found to mediate the association between age and oxygen consumption. Although knee pain is associated with a higher energetic cost of walking, gait characteristics associated with energetic efficiency differ by pain status which suggests that compensatory strategies both in the presence and absence of pain may impact gait efficiency.

It is not just muscle mass: a review of muscle quality, composition and metabolism during ageing as determinants of muscle function and mobility in later life

Worldwide estimates predict 2 billion people will be aged over 65 years by 2050. A major current challenge is maintaining mobility and quality of life into old age. Impaired mobility is often a precursor of functional decline, disability and loss of independence. Sarcopenia which represents the age-related decline in muscle mass is a well-established factor associated with mobility limitations in older adults. However, there is now evidence that not only changes in muscle mass but other factors underpinning muscle quality including composition, metabolism, aerobic capacity, insulin resistance, fat infiltration, fibrosis and neural activation may also play a role in the decline in muscle function and impaired mobility associated with ageing. Importantly, changes in muscle quality may precede loss of muscle mass and therefore provide new opportunities for the assessment of muscle quality particularly in middle-aged adults who could benefit from interventions to improve muscle function. This review will discuss the accumulating evidence that in addition to muscle mass, factors underpinning muscle quality influence muscle function and mobility with age. Further development of tools to assess muscle quality in community settings is needed. Preventative diet, exercise or treatment interventions particularly in middle-aged adults at the low end of the spectrum of muscle function may help preserve mobility in later years and improve healthspan.