Reduced Range of Gait Speed: A Parkinson's Disease-Specific Symptom?

Reduced range of gait speed (RGS) may lead to decreased environmental adaptability in persons with Parkinson's disease (PwPD). Therefore, lab-measured gait speed, step time, and step length during slow, preferred, and fast walking were assessed in 24 PwPD, 19 stroke patients, and 19 older adults and compared with 31 young adults. Only PwPD, but not the other groups, showed significantly reduced RGS compared to young adults, driven by step time in the low and step length in the high gait speed range. These results suggest that reduced RGS may occur as a PD-specific symptom, and different gait components seem to contribute.

Spatio-Temporal Gait Parameters of Hospitalized Older Patients: Comparison of Fallers and Non-Fallers.

Gait disorders are predisposing factors for falls. They are accessible to rehabilitation and can be analyzed using tools that collect spatio-temporal parameters of walking, such as the GAITRite® mat. The objective of this retrospective study was to find differences between the spatio-temporal parameters in patients who had fallen compared to patients who did not fall in a population of older patients hospitalized in acute geriatrics department. Patients over 75 years were included. For each patient, spatio-temporal parameters were collected using the GAITRite® mat. The patients were divided into two groups according to whether they had a history of fall. The spatio-temporal parameters were compared between the two groups and in relation to the general population. Sixty-seven patients, with an average age of 85.9 ± 6 years, were included. The patients had comorbidities, cognitive impairment and were polymedicated. The mean walking speed was 51.4 cm/s in non-fallers group and 47.3 cm/s in fallers group (p = 0.539), indicating pathological walking in comparison with the general population of the same age (average 100 cm/s). No association was found between the spatio-temporal parameters and fall, probably linked to many confounding factors such as the pathogenicity of walking of our patients and their comorbidities.

The Bidirectional Association Between Cognitive Function and Gait Speed in Chinese Older Adults: Longitudinal Observational Study.

BACKGROUND: Cognitive and gait speed decline are common conditions in older adults and are often associated with future adverse consequences. Although an association between cognitive function and gait speed has been demonstrated, its temporal sequence remains unclear, especially in older Chinese adults. Clarifying this could help identify interventions to improve public health in older adults. OBJECTIVE: This study aims to examine the longitudinal reciprocal association between gait speed and cognitive function and the possible temporal sequence of changes in both factors in a national longitudinal cohort. METHODS: Data were derived from 2 waves (2011 baseline and 2015 follow-up) of the China Health and Retirement Longitudinal Study (CHARLS). Participants 60 years or older, without dementia or Parkinson disease at baseline, and with completed data on gait speed and cognition at both baseline and follow-up were included. Usual gait speed was measured over two 2.5-m walks. Mental intactness and episodic memory were used to assess global cognitive function. Cross-lagged panel models and linear mixed-effects models were used to examine the association between cognition and gait speed over time. Standardized coefficients were reported. RESULTS: A total of 3009 participants (mean age 66.4 years, SD 5.4 years; 1422/3009, 47.26%, female participants) were eligible for inclusion in our analyses. Cross-lagged panel analyses revealed that after accounting for baseline gait speed, cognition, and potential confounders, baseline global cognition (ß=.117, 95% CI 0.082-0.152; P<.001), mental intactness (ß=.082, 95% CI 0.047-0.118; P<.001), and episodic memory (ß=.102, 95% CI 0.067-0.137; P<.001) were associated with subsequent gait speed. Simultaneously, baseline gait speed was also associated with subsequent global cognition (ß=.056, 95% CI 0.024-0.087; P=.001), mental intactness (ß=.039, 95% CI 0.008-0.069; P=.01), and episodic memory (ß=.057, 95% CI 0.023-0.092; P=.001). The comparison of standardized cross-lagged coefficients suggested that the effect size of baseline global cognition on subsequent gait speed was significantly larger than the reverse effect (χ12=6.50, P for difference=.01). However, the effects of both mental intactness and episodic memory on subsequent gait speed were not significantly stronger than those of the reverse pathway (χ12=3.33, P for difference=.07 and χ12=3.21, P for difference=.07). Linear mixed-effects analyses further supported these bidirectional relationships, revealing that lower baseline cognitive scores predicted steeper declines in gait speed trajectory, and slower baseline gait speed predicted more declines in cognitive trajectory over time. CONCLUSIONS: There is a longitudinal bidirectional association between usual gait speed and both global cognitive function and specific domains of mental intactness and episodic memory among Chinese older adults. Baseline global cognition is likely to have a stronger association with subsequent gait speed than the reverse pathway. This interlinkage is noteworthy and may have implications for public health. Maintaining normal cognitive function may be an important interventional strategy for mitigating age-related gait speed reduction.

Trunk Velocity Changes in Response to Physical Perturbations Are Potential Indicators of Gait Stability.

Response to challenging situations is important to avoid falls, especially after medial perturbations, which require active control. There is a lack of evidence on the relationship between the trunk's motion in response to perturbations and gait stability. Eighteen healthy adults walked on a treadmill at three speeds while receiving perturbations of three magnitudes. Medial perturbations were applied by translating the walking platform to the right at left heel contact. Trunk velocity changes in response to the perturbation were calculated and divided into the initial and the recovery phases. Gait stability after a perturbation was assessed using the margin of stability (MOS) at the first heel contact, MOS mean, and standard deviation for the first five strides after the perturbation onset. Faster speed and smaller perturbations led to a lower deviation of trunk velocity from the steady state, which can be interpreted as an improvement in response to the perturbation. Recovery was quicker after small perturbations. The MOS mean was associated with the trunk's motion in response to perturbations during the initial phase. Increasing walking speed may increase resistance to perturbations, while increasing the magnitude of perturbation leads to greater trunk motions. MOS is a useful marker of resistance to perturbations.

Determinants of age-related decline in walking speed in older women.

Background: Walking speed is reduced with aging. However, it is not certain whether the reduced walking speed is associated with physical and coordination fitness. This study explores the physical and coordination determinants of the walking speed decline in older women. Methods: One-hundred-eighty-seven active older women (72.2 ± 6.8 years) were asked to perform a 10-m walk test (self-selected and maximal walking speed) and a battery of the Senior fitness test: lower body strength, lower body flexibility, agility/dynamic balance, and aerobic endurance. Two parameters characterized the walking performance: closeness to the modeled speed minimizing the energetic cost per unit distance (locomotor rehabilitation index, LRI), and the ratio of step length to step cadence (walk ratio, WR). For dependent variables (self-selected and maximal walking speeds), a recursive partitioning algorithm (classification and regression tree) was adopted, highlighting interactions across all the independent variables. Results: Participants were aged from 60 to 88 years, and their self-selected and maximal speeds declined by 22% and 26% (p < 0.05), respectively. Similarly, all physical fitness variables worsened with aging (muscle strength: 33%; flexibility: 0 to -8 cm; balance: 22%; aerobic endurance: 12%; all p < 0.050). The predictors of maximal walking speed were only WR and balance. No meaningful predictions could be made using LRI and WR as dependent variables. Discussion: The results suggest that at self-selected speed, the decrease in speed itself is sufficient to compensate for the age-related decline in the motor functions tested; by contrast, lowering the WR is required at maximal speed, presumably to prevent imbalance. Therefore, any excessive lowering of LRI and WR indicates loss of homeostasis of walking mechanics and invites diagnostic investigation.

The Interplay Between Walking Speed, Economy, and Stability After Stroke.

BACKGROUND AND PURPOSE: Energy minimization is thought to underlie the naturally selected, preferred walking speed; however, people post-stroke walk slower than their most economical speed, presumably to optimize other objectives, such as stability. The purpose of this study was to examine the interplay between walking speed, economy, and stability. METHODS: Seven individuals with chronic hemiparesis walked on a treadmill at 1 of 3 randomized speeds: slow, preferred, and fast. Concurrent measurements of speed-induced changes in walking economy (ie, the energy needed to move 1 kg of bodyweight 1 ml O 2 /kg/m) and stability were made. Stability was quantified as the regularity and divergence of the mediolateral motion of the pelvic center of mass (pCoM) during walking, as well as pCoM motion relative to the base of support. RESULTS: Slower walking speeds were more stable (ie, pCoM motion was 10% ± 5% more regular and 26% ± 16% less divergent) but 12% ± 5% less economical. Conversely, faster walking speeds were 9% ± 8% more economical, but also less stable (ie, pCoM motion was 17% ± 5% more irregular). Individuals with slower walking speeds had an enhanced energetic benefit when walking faster ( rs = 0.96, P < 0.001). Individuals with greater neuromotor impairment had an enhanced stability benefit when walking slower ( rs = 0.86, P = 0.01). DISCUSSION AND CONCLUSIONS: People post-stroke appear to prefer walking speeds that are faster than their most stable speed but slower than their most economical speed. The preferred walking speed after stroke appears to balance stability and economy. To encourage faster and more economical walking, deficits in the stable control of the mediolateral motion of the pCoM may need to be addressed.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A416 ).

Relationship between stair ascent gait speed, bone density and gait characteristics of postmenopausal women.

Stair ascent is a biomechanically challenging task for older women. Bone health may affect gait stability during stair walking. This study investigated the gait biomechanics associated with stair ascent in a group of postmenopausal women in relation to walking speed and bone health, quantified by T-score. Forty-five healthy women (mean (SD) age: 67 (14) years), with bone density ranging from healthy to osteoporotic (T-score range +1 to -3), ascended a custom-made five-step staircase with two embedded force plates, surrounded by 10 motion capture cameras, at their self-selected speed. Multivariate regression analyses investigated the explained variance in gait parameters in relation to stair ascent speed and T-score of each individual. Stair ascent speed was 0.65 (0.1) m·s-1 and explained the variance (R2 = 9 to 47%, P ≤ 0.05) in most gait parameters. T-score explained additional variance in stride width (R2 = 20%, P = 0.014), pelvic hike (R2 = 19%, P = 0.011), pelvic drop (R2 = 21%, P = 0.007) and hip adduction (R2 = 7%, P = 0.054). Increased stride width, and thereby a wider base of support, accompanied by increased frontal plane hip kinematics, could be important strategies to improve dynamic stability during stair ascent among this group of women. These findings suggest that targeted exercises of the hip abductors and adductors, including core trunk musculature, could improve dynamic stability during more challenging locomotor tasks. Balance exercises that challenge base of support could also benefit older women with low bone mineral density who may be at risk of falls.

The association between anticholinergic burden and mobility: a systematic review and meta-analyses.

BACKGROUND: As people age, they accumulate several health conditions, requiring the use of multiple medications (polypharmacy) to treat them. One of the challenges with polypharmacy is the associated increase in anticholinergic exposure to older adults. In addition, several studies suggest an association between anticholinergic burden and declining physical function in older adults. OBJECTIVE/PURPOSE: This systematic review aimed to synthesise data from published studies regarding the association between anticholinergic burden and mobility. The studies were critically appraised for the strength of their evidence. METHODS: A systematic literature search was conducted across five electronic databases, EMBASE, CINAHL, PSYCHINFO, Cochrane CENTRAL and MEDLINE, from inception to December 2021, to identify studies on the association of anticholinergic burden with mobility. The search was performed following a strategy that converted concepts in the PECO elements into search terms, focusing on terms most likely to be found in the title and abstracts of the studies. For observational studies, the risk of bias was assessed using the Newcastle Ottawa Scale, and the Cochrane risk of bias tool was used for randomised trials. The GRADE criteria was used to rate confidence in evidence and conclusions. For the meta-analyses, we explored the heterogeneity using the Q test and I2 test and the publication bias using the funnel plot and Egger's regression test. The meta-analyses were performed using Jeffreys's Amazing Statistics Program (JASP). RESULTS: Sixteen studies satisfied the inclusion criteria from an initial 496 studies. Fifteen studies identified a significant negative association of anticholinergic burden with mobility measures. One study did not find an association between anticholinergic intervention and mobility measures. Five studies included in the meta-analyses showed that anticholinergic burden significantly decreased walking speed (0.079 m/s ± 0.035 MD ± SE,95% CI: 0.010 to 0.149, p = 0.026), whilst a meta-analysis of four studies showed that anticholinergic burden significantly decreased physical function as measured by three variations of the Instrumental Activities of Daily Living (IADL) instrument 0.27 ± 0.12 (SMD ± SE,95% CI: 0.03 to 0.52), p = 0.027. The results of both meta-analyses had an I2 statistic of 99% for study heterogeneity. Egger's test did not reveal publication bias. CONCLUSION: There is consensus in published literature suggesting a clear association between anticholinergic burden and mobility. Consideration of cognitive anticholinergic effects may be important in interpreting results regarding the association of anticholinergic burden and mobility as anticholinergic drugs may affect mobility through cognitive effects.

A Novel Movement-Evoked Pain Provocation Test for Older Adults With Persistent Low Back Pain: Safety, Feasibility, and Associations With Self-reported Physical Function and Usual Gait Speed.

OBJECTIVES: Low back pain (LBP) is highly prevalent and disabling for older adults. Movement-evoked pain is an emerging measure that may help to predict disability; but is not currently a part of geriatric LBP clinical care. This study tested the safety and feasibility of a new Movement-Evoked Provocation Test for Low Back Pain in Older Adults (MEPLO). We also compared associations between movement-evoked pain via 2 different scoring methods and disability-associated outcomes. MATERIALS AND METHODS: Thirty-nine older adults with persistent LBP provided baseline recalled and resting pain ratings, self-reported physical function, and usual gait speed. Participants then completed MEPLO, involving 4 tasks essential for functional independence: chair rises, trunk rotation, reaching, and walking. Movement-evoked pain was then quantified using the traditional change score (delta) method of pain premovement to postmovement; and also, a new aggregate method that combines pain ratings after the 4 tasks. RESULTS: No safety or feasibility issues were identified. Compared with the delta score, the aggregate score was more strongly associated with self-reported physical function (beta: -0.495 vs. -0.090) and usual gait speed (beta: -0.450 vs. -0.053). Similarly, the aggregate score was more strongly associated with self-reported physical function than recalled and resting pain (beta: -0.470, -0.283, and 0.136, respectively). DISCUSSION: This study shows the safety and feasibility of testing movement-evoked pain in older adults with persistent LBP, and its potential superiority to traditional pain measures. Future studies must validate these findings and test the extent to which MEPLO is implementable to change with geriatric LBP standard of care.

Activity patterns are associated with fractional lifespan, memory, and gait speed in aged dogs.

Maintaining an active lifestyle is considered a hallmark of successful aging. Physical activity significantly reduces the risk of cognitive decline and Alzheimer's disease in humans. However, pain and lack of motivation are important barriers to exercise. Dogs are a remarkable model for translational studies in aging and cognition as they are prone to Canine Cognitive Dysfunction syndrome, which has many similarities with Alzheimer's disease. According to owner reports, changes in activity levels are characteristic of this syndrome, with decreased daytime activity, but also excessive pacing, especially at sleep time. We used physical activity monitors to record the activity of 27 senior dogs and evaluated the association between activity level and age, fractional lifespan, cognitive status measured by an owner questionnaire and cognitive tests. We also assessed the relationship between activity and joint/spinal pain, and the off/on leash gait speed ratio (a potential marker of gait speed reserve and motivation). We found that activity patterns in dogs are associated with fractional lifespan and working memory. Additionally, dogs with higher on/off leash gait speed are more active in the afternoon of weekdays. These results encourage future studies evaluating how physical activity can improve or delay cognitive impairment in senior dogs.

Dual task cost in adults with persistent concussion symptoms.

BACKGROUND: Persistent concussion symptoms (PCS) negatively affects common activities of daily living including deficits in both single and dual-task (DT) gait. DT gait deficits are present post-concussion; however, task prioritization and the effects of differing cognitive challenge remain unexplored in the PCS population. RESEARCH QUESTION: The purpose of this study was to investigate single and dual-task gait performance in individuals with persistent concussion symptoms and to identify task priorization strategies during DT trials. METHODS: Fifteen adults with PCS (age: 43.9+11.7 y.o.) and 23 healthy control participants (age: 42.1+10.3 y.o.) completed five trials of single task gait followed by fifteen trials of dual task gait along a 10-m walkway. The cognitive challenges consisted of five trials each of visual stroop, verbal fluency, and working memory cognitive challenges. Groups were compared on DT cost stepping characteristics with independent samples t-test or Mann-Whitney U tests. RESULTS: There were significant overall gait Dual Task Cost (DTC)difference between groups for gait speed (p = 0.009, d=0.92) and step length (p = 0.023, d=0.76). Specific to each DT challenge, PCS participants were slower during Verbal Fluency (0.98 + 0.15 m/s and 1.12 + 0.12 m/s, p = 0.008; d=1.03), Visual Stroop (1.06 + 0.19 m/s and 1.20 + 0.12 m/s, p = 0.012, d=0.88), and Working Memory (1.02 + 0.15 m/s and 1.16 + 0.14 m/s, p = 0.006, d=0.96). There were significant cognitive DTC differences between groups for WM accuracy (p = 0.008, d=0.96), but not for VS accuracy (p = 0.841, d=0.061) or VF total words (p = 0.112, d=0.56). SIGNIFICANCE: The PCS participants displayed a posture-second strategy whereby gait performance generally decreased in the absence of cognitive changes. However, during the Working Memory DT, PCS participants had a mutual interference response whereby both motor and cognitive performance decreased suggesting the cognitive task plays a key role in the DT gait performance of PCS patients.

Susceptibility to the sound-induced flash illusion is associated with gait speed in a large sample of middle-aged and older adults.

BACKGROUND: Multisensory integration is the ability to appropriately merge information from different senses for the purpose of perceiving and acting in the environment. During walking, information from multiple senses must be integrated appropriately to coordinate effective movements. We tested the association between a well characterised multisensory task, the Sound-Induced Flash Illusion (SIFI), and gait speed in 3255 participants from The Irish Longitudinal Study on Ageing. High susceptibility to this illusion at longer stimulus onset asynchronies characterises older adults, and has been associated with cognitive and functional impairments, therefore it should be associated with slower gait speed. METHOD: Gait was measured under three conditions; usual pace, cognitive dual tasking, and maximal walking speed. A separate logistic mixed effects regression model was run for 1) gait at usual pace, 2) change in gait speed for the cognitive dual tasking relative to usual pace and 3) change in maximal walking speed relative to usual pace. In all cases a binary response indicating a correct/incorrect response to each SIFI trial was the dependent variable. The model controlled for covariates including age, sex, education, vision and hearing abilities, Body Mass Index, and cognitive function. RESULTS: Slower gait was associated with more illusions, particularly at longer temporal intervals between the flash-beep pair and the second beep, indicating that those who integrated incongruent sensory inputs over longer intervals, also walked slower. The relative changes in gait speed for cognitive dual tasking and maximal walking speed were also significantly associated with SIFI at longer SOAs. CONCLUSIONS: These findings support growing evidence that mobility, susceptibility to falling and balance control are associated with multisensory processing in ageing.

Dual tasking affects gait performance but not automaticity in functional gait disorders: A new diagnostic biomarker.

INTRODUCTION: Functional gait disorders (FGDs) are disabling symptoms of Functional Motor Disorders. Clinical observations show improvement with distraction suggesting an association with higher-level control mechanisms. Dual tasking is a valuable tool for exploring the interplay between gait and cognition. Our research question was: how do different dual task paradigms shape spatio-temporal gait parameters in FGDs?. METHODS: In all, 29 patients with FGDs (age 43.48 ± 15.42 years; female 75%) and 49 healthy controls (age 43.33 ± 15.41 years; female 62%) underwent spatio-temporal gait analysis during a single task and during performance on a motor, a cognitive, and a visual-fixation dual-task. The dual-task effect was a measure of interference of the concurrent task on gait speed, stride length (a measure of gait performance), and stride time variability (a measure of automaticity and steadiness). RESULTS: Overall lower gait speed, shorter stride length, and higher stride time variability were noted in FGDs compared to healthy controls (for all, p < 0.019). The was a significant effect of group and Task × Group interaction for the dual-task effect on gait speed (p = 0.023) and stride length (p = 0.01) but not for stride time variability. CONCLUSION: Poorer gait performance and less automaticity and steadiness were noted in FGDs. However, dual tasking affected gait performance but, unlike different neurological diseases, not automaticity and steadiness compared to controls. Our findings shed light on higher-level gait control mechanisms in FGDs and suggest stride time variability could be a diagnostic and prognostic biomarker.

Analysis of Diabetic Foot Deformation and Plantar Pressure Distribution of Women at Different Walking Speeds.

Official guidelines state that suitable physical activity is recommended for patients with diabetes mellitus. However, since walking at a rapid pace could be associated with increased plantar pressure and potential foot pain, the footwear condition is particularly important for optimal foot protection in order to reduce the risk of tissue injury and ulceration of diabetic patients. This study aims to analyze foot deformation and plantar pressure distribution at three different walking speeds (slow, normal, and fast walking) in dynamic situations. The dynamic foot shape of 19 female diabetic patients at three walking speeds is obtained by using a novel 4D foot scanning system. Their plantar pressure distributions at the three walking speeds are also measured by using the Pedar in-shoe system. The pressure changes in the toes, metatarsal heads, medial and lateral midfoot, and heel areas are systematically investigated. Although a faster walking speed shows slightly larger foot measurements than the two other walking speeds, the difference is insignificant. The foot measurement changes at the forefoot and heel areas, such as the toe angles and heel width, are found to increase more readily than the measurements at the midfoot. The mean peak plantar pressure shows a significant increase at a faster walking speed with the exception of the midfoot, especially at the forefoot and heel areas. However, the pressure time integral decreases for all of the foot regions with an increase in walking speed. Suitable offloading devices are essential for diabetic patients, particularly during brisk walking. Design features such as medial arch support, wide toe box, and suitable insole material for specific area of the foot (such as polyurethane for forefoot area and ethylene-vinyl acetate for heel area) are essential for diabetic insole/footwear to provide optimal fit and offloading. The findings contribute to enhancing the understanding of foot shape deformation and plantar pressure changes during dynamic situations, thus facilitating the design of footwear/insoles with optimal fit, wear comfort, and foot protection for diabetic patients.

Walking speed and dual task input modality impact performance on a self-paced treadmill.

Interference between a walking task (target speeds on a self-paced treadmill) and dual visual and tactile-visual response time task was investigated. Ambulatory dual-task scenarios reveal how attention is divided between walking and additional tasks, but the impact of walking speed and dual-task modality on gait characteristics and dual-task performance is unclear. The purpose of this study was to evaluate the effect of visual and tactile-visual dual-task on gait performance. Participants (n=15) targeted four speeds (0.5, 1.0, 1.3, and 1.5 m/s) on a self-paced treadmill with a visual speed indicator (a green region centered at the target speed). Participants completed the same speed profile on the treadmill without (Self-Paced) and with a response time dual task (Self-Paced with Dual Task) requiring finger-tap responses to go/no-go cues. Six gait characteristics were calculated: proportion of time in the desired speed green region (GTP), speed ratio (ratio of mean to target speed), time to green region after target speed change (NRT), normalized stride width (NSW), normalized stride length (NSL), and stride time (ST). Both stride length and width were normalized by participant leg length. Lower GTP and greater speed ratio at slower speeds during dual tasking indicate speed-dependent changes in gait characteristics. Changes in NSL and ST were more affected by speed than dual task. These findings support that when speed is a parameter that is tracked, participants do not universally decrease speed in the presence of a dual task. These findings can support the decisions made when designing new wearable technologies that support navigation, communication, and mobility.

Outdoor gyms and physical function: A cross-sectional comparative study between active and sedentary older adults.

Outdoor gyms (OG) are public places designed for physical activity, especially for older adults. This is a cross-sectional study that aimed to compare morphofunctional characteristics of sedentary and active older adults regarding OG. The participants consisted of 194 older people divided into three groups: sedentary (n = 76, mean age = 70.5 ± 6.4 years, 38.7% male); OG + walking (n = 86; mean age = 69 ± 6.1 years; male 50.6%); and OG (n = 32; mean age = 70.3 ± 8.3 years; male 56.3%). Socioeconomic and morphofunctional characteristics, anthropometric measurements, body composition, and functional tests were collected. For comparison among groups ANOVA, for categorical variables the chi-square test or Fisher's exact test, and to verify factors related to gait speed logistic regression were used. We found that sedentary older adults had lower educational level and lower prevalence of polypharmacy. OG + walking participants had lower waist circumference and fat percentage, and better gait speed. Older people in the OG + walking were less likely to show gait difficulty (i.e., <1.0 m/s) in reference to the sedentary group. In addition, strength and better performance on the Timed Up and Go were also associated with gait speed >1 m/s. It is understood that the higher volume of physical activity performed by OG + walking may be one of the reasons why they obtained better indicators in health aspects. The findings, especially regarding the characterization of profiles of older adults who use OG, leads to the definition of public policies aimed at the real needs of this public.

Bodyweight support alters the relationship between preferred walking speed and cost of transport.

Humans tend to select a preferred walking speed (PWS) that minimizes the metabolic energy consumed per distance traveled, i.e. the Cost of Transport (CoT). The aims of this study were to: 1. compare PWS overground vs. on a treadmill at 100 and 50% of body weight, and 2. explore whether with body weight support, PWS corresponds to the speed that minimizes CoT. Fifteen healthy adults walked overground and on a lower body positive pressure treadmill with and without bodyweight support. Walking speeds (m.s-1) were recorded for each condition. Rate of energy expenditure (J.kg-1.min-1) and CoT (J.kg-1.m-1) were then determined from 5-min walking trials with 50% bodyweight support at PWS and ± 30% of the self-selected walking speed for that condition. PWS did not differ across conditions. With 50% body weight support, for each 30% increase in walking speed, rates of metabolic energy expenditure increased ∼15% while CoT decreased by ∼14%. Thus, with 50% body weight support, PWS did not correspond with the speed that minimized CoT. Bodyweight support decreases cost of maintaining an upright body but does not decrease the metabolic demand of limb advancement, contributing to the linear yet not proportional changes in rates of energy expenditure and CoT. We conclude that bodyweight support via an AlterG® treadmill disconnects the association between PWS and minimum CoT. These findings have implications for clinical populations (e.g., obese, elderly) who may benefit from walking on a bodyweight supporting treadmill but may select speeds incompatible with their physical activity goals.

Effectiveness of intensive versus regular or no exercise in older adults after hip fracture surgery: A systematic review and meta-analysis.

BACKGROUND: Individuals commonly experience age-related systemic decreases in skeletal muscle strength, physical function, and mobility, leading to falls and potential associated hip fractures. OBJECTIVE: To evaluate whether intensive exercise can improve physical function, mobility, and independence in activities of daily living (ADL) and shorten the length of hospital stay in older adults after hip fracture surgery. METHODS: This systematic review was conducted under the PRISMA guidelines. Searches were performed on January 5, 2022 in eight databases. Randomized controlled trials (RCTs) were included. The participants included older adults with hip fracture, and the intervention studied was intensive exercise. The outcomes were physical function, mobility, ADLs, and the length of hospital stay. Meta-analyses were conducted using RevMan 5.3. RESULTS: Fifteen studies were included in this review. After hip fracture surgery, intensive exercise improved participants' physical function to a greater extent than regular or no exercise (standardized mean difference [SMD] = 0.74; 95% CI: 0.25, 1.23). Intensive exercise was particularly more effective for gait speed (SMD = 0.15, 95% CI: 0.01, 0.30), the timed up-and-go test results (mean difference [MD] = -4.34, 95%CI: -6.74, -1.94), balance (SMD =0.42, 95% CI: 0.38, 0.89), and ADLs (SMD = 0.55, 95% CI: 0.24, 0.87). The quality of the evidence was low due to risk of bias, inconsistency, and imprecision. CONCLUSIONS: Intensive exercise early post-operation provides potential additional benefits compared to no or regular exercises on older adults after hip fracture surgery.

Characteristics of reproductive history, use of exogenous hormones and walking speed among women: Data from the CONSTANCES French Cohort Study.

OBJECTIVE: To investigate the cross-sectional associations of reproductive history and use of exogenous hormones with fast walking speed (WS) in women. STUDY DESIGN: Between 2012 and 2020, 33,892 French women aged 45 years or more, recruited at health centers, underwent physical function tests and self-reported information on reproductive history and use of exogenous hormones. Linear mixed models with the center as random intercept were used to estimate the association of exposures with WS. MAIN OUTCOME MEASURES: Fast WS. RESULTS: Mean WS was 172.2 cm/s. WS increased with age at menarche (ß+1y = 0.23, 95 % confidence interval = 0.05 to 0.40), age at first birth (ß+1y = 0.20, 95 % CI = 0.13 to 0.27) and duration of breastfeeding (ßfor ≥10 vs ≤5months = 1.38; 95 % CI = 0.39 to 2.36). In addition, parity was quadratically associated with WS, with women with 3 children having the highest WS (p for U-shaped relationship < 0.01). Menopausal status had no impact on WS but age at menopause was positively associated with WS (ß+5y = 0.52, 95 % CI = 0.17 to 0.87) and partly explained the deleterious impact of artificial menopause on WS. WS increased with reproductive lifetime duration (ß+5y = 0.49, 95 % CI = 0.16 to 0.83) and decreased with time since onset of menopause (ß+5y = -0.65, 95 % CI = -0.99 to -0.31). By contrast, there was no association of WS with oral contraception and postmenopausal hormone therapy. CONCLUSION: Our findings suggest that reproductive life characteristics may be associated with WS and timing of exposure could play a role.

Analysis of walking speeds and success rates on mid-block crossings using virtual reality simulation.

A focus is set worldwide to study pedestrian behavior in road situations associated with a high frequency of crashes. This paper presents the results from a virtual reality simulation study that recorded pedestrians performing mid-block crossings on a straight segment of an urban street. The experiment was designed with eight scenarios with combinations of one or two lanes, two vehicle speeds, and constant or variable gaps between vehicles. The experiment was conducted with 48 subjects producing 538 crossing observations. The results show that subjects, on average, watched about 5 vehicle gaps in traffic before crossing the street and accepted a gap of 4.5 s between vehicles to cross. A regression model showed that the vehicle speed, the number of lanes, and subjects in the 66-85 years old group had a significant effect on the gap value accepted to cross. An interaction term based on gender and number of lanes also had a significant effect on the accepted gap. The study found average walking speeds between 4.1 and 4.8 ft/s (1.2-1.4 m/s) for different scenarios. A regression model revealed that the gender, the number of lanes, and the gap accepted to cross influenced the walking speed. Significant effects of interactions of the age with gender, number of lanes, and vehicle speed variables were also found that explain the differences in walking speed. The results for the success rate when crossing the street showed the overall worst performance in the scenario with traffic generated with a 25-mph (40 km/h) speed and a constant 3-s gap between vehicles. A Logit model showed that the probability of a pedestrian being hit by a vehicle increased with age, with traffic at the top vehicle speed, and with the constant 3-s vehicle gap. In contrast, the probability decreased with increases in the vehicle gap accepted to cross and the walking speed.