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.

Limb and joint kinetics during walking in individuals with Mild-Moderate Parkinson's disease.

Given the known deficits in spatiotemporal aspects of gait for people with Parkinson's disease (PD), we sought to determine the underlying gait abnormalities in limb and joint kinetics, and examine how deficits in push-off and leg swing might contribute to the shortened step lengths for people with PD. Ten participants with PD and 11 age-matched control participants walked overground and on an instrumented treadmill. Participants with PD then walked on the treadmill with a posteriorly directed restraining force applied to 1) the pelvis to challenge push-off and 2) the ankles to challenge leg swing. Spatiotemporal, kinematic, and force data were collected and compared between groups and conditions. Despite group differences in spatiotemporal measures during overground walking, we did not observe these differences when the groups walked on a treadmill at comparable speeds. Nevertheless, the hip extension impulse appeared smaller in the PD group during their typical walking. When challenging limb propulsion, participants in the PD group maintained step lengths by increasing the propulsive impulse. Participants with PD were also able to maintain their typical step length against resistance intended to impede swing limb advancement, and even increased step lengths with cuing. The presence of reduced hip extension torque might be an early indicator of gait deterioration in this neurodegenerative disease. Our participants with PD were able to increase hip extension torque in response to needed demands. Additionally, participants with PD were able to increase limb propulsion and leg swing against resistance, suggesting a reserve in limb mechanics.

Effects of a 12-week telehealth exercise intervention on gait speed and gait deviations in adults with Down syndrome.

BACKGROUND: Altered gait patterns and reduced walking speed are commonly reported in adults with Down syndrome (DS). Research on the effects of DS-specific exercise programmes on adults with DS is lacking. The purpose of this quasi-experimental study was to evaluate the changes in gait deviations and walking speed in adults with DS after a DS-specific exercise programme. METHODS: Twenty participants underwent a 12-week, DS-specific exercise programme in a telehealth format. Before and after the intervention, gait deviations were assessed with the Ranchos Los Amigos Observational Gait Analysis form, and comfortable walking speed was evaluated with the 4-m walk test. RESULTS: We observed increased comfortable walking speed and reduced gait deviations in the whole gait cycle in adults with DS after the intervention. There were fewer gait deviations during single-leg stance and swing-limb advancement and at the hip, knee and ankle joints after the 12-week exercise programme. CONCLUSIONS: Gait speed and observable gait impairments in adults with DS significantly improved following a 12-week telehealth exercise programme.

Laboratory-assessed gait cycle entropy for classifying walking limitations among community-dwelling older adults.

Among older people, walking difficulty results from actual and perceived declines in physical capacities and environmental requirements for walking. We investigated whether the physiological complexity of the gait cycle covaries with experience of walking difficulty. Walking difficulty, gait speed, and gait cycle complexity were evaluated among 702 community-dwelling older people aged 75, 80, and 85 years who took part in the six-minute walking test in the research laboratory. Walking difficulty for 500 m was self-reported. Complexity was quantified as trunk acceleration multiscale entropy during the gait cycle. Complexity was then compared between those with no reported walking difficulty, walking with modifications but no difficulty, and those reporting walking difficulty. Higher entropy differentiated those reporting no difficulty walking from those reporting walking difficulties, while those reporting having modified their walking, but no difficulty formed an intermediate group that could not be clearly distinguished from the other categories. The higher complexity of the gait cycle is associated with slower gait speed and the presence of self-reported walking difficulty. Among older people, gait cycle complexity which primarily reflects the biomechanical dimensions of gait quality, could be a clinically meaningful measure reflecting specific features of the progression of walking decline. This encourages further investigation of the sensitivity of gait cycle complexity to detect early signs of gait deterioration and to support targeted interventions among older people.

The Relationship Between Isometric Midthigh Pull Force-Time Characteristics and 2-km Load-Carrying Performance in Trained British Army Soldiers.

ABSTRACT: Nevin, JP, Bowling, K, Cousens, C, Bambrough, R, and Ramsdale, M. The relationship between isometric midthigh pull force-time characteristics and 2-km load-carrying performance in trained British army soldiers. J Strength Cond Res 38(2): 360-366, 2024-Load carriage is a fundamental military occupational task. As such, the aim of this study was to assess the relationship between isometric force-time characteristics and loaded march performance. Furthermore, this study aimed to investigate the relationship between isometric force-time characteristics and standing long jump (SLJ) performance. Thirty-nine, full-trained, male British Army infantry soldiers (age 31 ± 6.1 years; height 176 ± 7.3 cm; body mass 85.8 ± 11.5 kg) performed three isometric midthigh pull trials, three SLJ trials, and a 2-km loaded march carrying an external load of 25 kg. Both the isometric midthigh pull test (intraclass correlation coefficient [ICC] 0.965) and SLJ (ICC 0.916) demonstrated excellent reliability. Relationships between all variables were assessed using Pearson's correlation coefficient. Isometric peak force (r = -0.059), relative peak force (r = -0.135), and rate of force development (r = -0.162) displayed a small correlation with loaded march time to completion. However, isometric relative peak force displayed a large relationship with SLJ performance (r = 0.545; p = <0.01). Our data demonstrate that isometric lower-limb strength measures account for <2% of the total variance observed in 2-km loaded march performance. As such, the use of isometric lower-limb force-time characteristics as a proxy measure of load-carrying ability should be questioned. However, relative isometric strength seems to demonstrate a significant relationship with SLJ performance. As such, isometric testing may have utility in regard to assessing explosive strength, monitoring neuromuscular fatigue, and assessing training readiness in military populations.

Comparing the associations between muscle strength, walking speed, and mortality in community-dwelling older adults of two birth cohorts born 28 years apart.

Reduced age-specific mortality and increased muscle strength and walking speed of current older adults may have altered the relationships between these factors as more people may be above the reserve capacity threshold. We compared the cross-sectional associations between muscle strength and walking speed, and the associations of muscle strength and walking speed with five-year mortality between two population-based cohorts of 75- and 80-year-old people born 28 years apart. Maximal isometric grip and knee extension strength and walking speed were measured in 2017-2018 (n = 726). Mortality was ascertained from registers. The associations were compared with data of same-aged people studied in 1989-1990 with identical protocols (n = 500). The knee extension strength-walking speed relationship showed plateauing at higher strength levels among the later-born men, whereas the earlier-born men and women of both cohorts with lower strength levels were on the linear part of the curve. In the later-born women with lower five-year mortality rate (1.16 vs. 5.88 per 100 person-years), the association between grip strength and mortality was markedly different from the earlier cohort (HR 1.13 [95% CI 0.47-2.70] vs. 0.57 [0.37-0.86]). For knee extension strength and walking speed, the mortality hazards were similar between the cohorts, although statistically non-significant in the later-born women. In men, the later-born cohort showed similar associations as observed in the earlier-born cohort despite having lower mortality rate (2.93 vs. 6.44). Current older adults have more functional reserve that will likely help them to maintain walking ability for longer while also contributing to better survival.

Association Between Typologies of Sedentary Behavior and Muscle Strength, Gait Speed, and Balance in Community-Dwelling Older Adults.

Knowledge of how the different types of sedentary behaviors (SB) are associated with functional limitations can guide professionals who work with older adults on better recommendations about the amount of daily time that should be encouraged in each type of SB. The objective was to estimate the associations between two SB typologies (SB television [TV] and SB computer/internet) and the presence of handgrip strength, lower limb strength, gait speed, and balance limitations in Brazilian community-dwelling older adults. This is a cross-sectional study with 1,298 community-dwelling older adults (≥60 years). SB was assessed by self-reporting daily time spent watching TV or using computer/internet (categorized into <2, 3-4, and ≥5 hr/day). Outcomes were handgrip strength, lower limb strength, gait speed, and balance limitations considering referenced cutoff points. Older adults in SB TV ≥5 hr/day had 1.75 (95% confidence interval [CI] [1.07, 2.86]) and 1.88 (95% CI [1.02, 3.46]) times more chances of handgrip strength and gait speed limitations, respectively. On the other hand, those who spent 3-4 and ≥5 hr/day in SB computer/internet had 0.45 (95% CI [0.20, 0.99]) and 0.37 (95% CI [0.15, 0.93]) had less chances of lower limb strength and balance limitations, respectively. In conclusion, functional limitations would be associated differently depending on the type of SB in the older adults sampled.

Relationship between walking speed, respiratory muscle strength, and dynamic balance in community-dwelling older people who required long-term care or support and used a daycare center.

Background: Focusing on the relationship between frail older people and gait speed is vital to minimize the need for long-term care or increased support. The relationship between gait speed, respiratory muscle strength, and dynamic balance, is not well understood in older people requiring long-term care or support. Therefore, this study aimed to provide new insights into the relationship between gait speed, respiratory muscle strength, and dynamic balance in community-dwelling older people who required long-term care or support and used a daycare center. Methods: This was a cross-sectional study of 49 community-dwelling older people (21 men, 28 women) aged ≥65 years who were certified as requiring long-term care or support under the Japanese system. The participants' maximal inspiratory pressure (PImax), maximal expiratory pressure (PEmax), walking speed (maximal and normal walking speed), and maximal double-step length test (MDST) results were recorded. The measurement data were evaluated using Pearson's correlation coefficient and multiple regression analysis. Results: Pearson's correlation coefficient revealed correlations between PImax and the following: maximal walking speed (r = 0.606, p < 0.001), normal walking speed (r = 0.487, p < 0.001), and MDST (r = 0.435, p = 0.002). Correlations were also observed between PEmax and the following: maximal walking speed (r = 0.522, p < 0.001), normal walking speed (r = 0.467, p < 0.001), and MDST (r = 0.314, p = 0.028). Moreover, a correlation was found between MDST and both maximal walking speed and (r = 0.684, p < 0.001) and normal walking speed (r = 0.649, p < 0.001). The effect size was 0.379. Multiple regression analysis using a forced entry method with maximal walking speed as the dependent variable showed that maximal walking speed was significantly associated with MDST (p < 0.001) and PEmax (p = 0.036), with an effect size of 0.272. The model's adjusted coefficient of determination was 0.593 (p < 0.001). Multiple regression analysis using a forced entry method with normal walking speed as the dependent variable showed that normal walking speed was significantly associated with MDST (p < 0.001) and PEmax (p = 0.021), with an effect size of 0.272. The model's adjusted coefficient of determination was 0.497 (p < 0.001). Multiple regression analysis using a forced entry method with MDST as the dependent variable showed that MDST was significantly associated with PImax (p < 0.025), with an effect size of 0.243. The model's adjusted coefficient of determination was 0.148 (p = 0.017). Conclusions: Respiratory muscle strength and dynamic balance were related to walking speed in older people requiring long-term care or support.

Muscle activity variability patterns and stride to stride fluctuations of older adults are positively correlated during walking.

It has been found that fractal-like patterns are present in the temporal structure of the variability of healthy biological rhythms, while pathology and disease lead to their deterioration. Interestingly, it has recently been suggested that these patterns in biological rhythms are related with each other, reflecting overall health or lack of it, due to their interaction. However, the underlying neurophysiological mechanisms responsible for such dependency remain unknown. In addition, this relationship between different elements needs to be first verified before we even pursue understanding their interaction. This study aimed to investigate the relationship between two elements of the neuromuscular system, gait and muscle activity variability patterns in older adults. Twenty-one older adults walked at their preferred walking speed on a treadmill. Inter-stride intervals were obtained through an accelerometer placed on the lateral malleoli to assess the temporal structure of variability of stride-to-stride fluctuations. Inter muscle peak intervals were obtained through the electromyographic signal of the gastrocnemius to assess the temporal structure of the variability of the simultaneous muscle activity. The temporal structure of variability from both signals was evaluated through the detrended fluctuation analysis, while their magnitude of variability was evaluated using the coefficient of variation. The Pearson's Correlation coefficient was used to identify the relationship between the two dependent variables. A significant strong positive correlation was found between the temporal structure of gait and muscle activity patterns. This result suggests that there is an interdependency between biological rhythms that compose the human neuromuscular system.

Biomechanical investigation of tasks concerning manual materials handling using response surface methodology.

In typical manual material handling, the variations in walking pattern are decided by various factors, such as load being handled, frequency of handling, walking surface, etc. Traditional gait analysis protocols commonly evaluate individual factor within specified ranges associated with particular activities or pathologies. However, existing literature underscores the concurrent impact of multiple factors on gait. This study identifies five pivotal factors-walking speed, surface slope, load carried, carrying method, and footwear-as contributors to gait alterations. To address risk factors in manual material handling activities, we propose a unique design-of-experiment-based approach for multi-task gait analysis. Unraveling the relationship between manual handling attributes and human gait holds paramount importance in formulating effective intervention strategies. We optimized the five input factors across a cohort of 15 healthy male participants by employing a face-centered central composite design experimentation. A total of 29 input factor combinations were tested, yielding a comprehensive dataset encompassing 18 kinematic gait parameters (such as cadence, step length etc., measured using inertial measurement system), the isolated impacts of factors, and the interplay of two-factor interactions with corresponding responses. The results illuminate the optimal scenarios of input factors that enhance individual gait performance-these include wearing appropriate footwear, employing a backpack for load carriage, and maintaining a moderate walking pace on a medium slope with minimal load. The study identifies walking speed and load magnitude as primary influencers of gait mechanics, followed by the chosen carrying method. In consequence, the insights gained advocate for the refinement of manual material handling tasks based on the outcomes, effectively mitigating the risk of musculoskeletal disorders by suggesting the interventions for posture correction.

[Reactive dynamic balance in the geriatric setting : Possibilities for evaluation and quantification in functionally heterogeneous persons]. / Reaktive dynamische Balance im geriatrischen Setting : Möglichkeiten zu Bewertung und Quantifizierung bei funktionell heterogenen Personen.

BACKGROUND: Most falls in older persons occur during walking and are often due to maladaptation in response to gait perturbations. Therefore, the assessment of reactive dynamic balance is highly relevant for determining the individual risk of falling and could enable an early initiation of interventions. OBJECTIVE: The methods available for perturbation of gait and for evaluating the corresponding reaction patterns are critically discussed in order to approach the assessment of reactive dynamic balance. MATERIAL AND METHODS: A diagnostic protocol for perturbation of gait on a treadmill was developed based on the literature. The application of the protocol to map reactive dynamic balance as comprehensively as possible is presented. RESULTS: After the initial determination of the individually preferred gait speed over ~ 6 min, the participant's gait is disrupted with 9 different types of perturbations over a time period of ~ 4:30 min. The evaluation options include spatiotemporal parameters and their variability, the margin of stability and the Lyapunov exponent. CONCLUSION: Dynamic reactive balance is a promising and specific parameter for quantifying the risk of falling in older persons. The comprehensive evaluation of the documented parameters is currently insufficient because there are no established methods or references. The development of a unified method for the sensitive determination of reactive dynamic balance is essential for its use in assessment of the risk of falling in the clinical context and for measuring the success of training.

Faster Walking Speeds Require Greater Activity from the Primary Motor Cortex in Older Adults Compared to Younger Adults.

Gait speed declines with age and slower walking speeds are associated with poor health outcomes. Understanding why we do not walk faster as we age, despite being able to, has implications for rehabilitation. Changes in regional oxygenated haemoglobin (HbO2) across the frontal lobe were monitored using functional near infrared spectroscopy in 17 young and 18 older adults while they walked on a treadmill for 5 min, alternating between 30 s of walking at a preferred and fast (120% preferred) speed. Gait was quantified using a triaxial accelerometer (lower back). Differences between task (preferred/fast) and group (young/old) and associations between regional HbO2 and gait were evaluated. Paired tests indicated increased HbO2 in the supplementary motor area (right) and primary motor cortex (left and right) in older adults when walking fast (p < 0.006). HbO2 did not significantly change in the young when walking fast, despite both groups modulating gait. When evaluating the effect of age (linear mixed effects model), greater increases in HbO2 were observed for older adults when walking fast (prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex) compared to young adults. In older adults, increased step length and reduced step length variability were associated with larger increases in HbO2 across multiple regions when walking fast. Walking fast required increased activation of motor regions in older adults, which may serve as a therapeutic target for rehabilitation. Widespread increases in HbO2 across the frontal cortex highlight that walking fast represents a resource-intensive task as we age.

Mortality, falls and slow walking speed are predicted by different muscle strength and physical performance measures in women and men.

BACKGROUND: Different measures of muscle strength, physical performance and body size/composition are used in various sarcopenia definitions. This study investigated which baseline measures best predict incident mortality and falls, and prevalent slow walking speed in older women and men. MATERIALS AND METHODS: Data for 899 women (mean age±standard deviation, 68.7 ± 4.3 years) and 497 men (69.4 ± 3.9 years) from the Dubbo Osteoporosis Epidemiology Study 2, comprising sixty variables for muscle strength (quadriceps strength), physical performance (walking speed, timed up and go (TUG) test, sit to stand (STS) test), body size (weight, height, body mass index) and body composition (lean mass, body fat) were included. Sex-stratified Classification and Regression Tree (CART) analyses calculated baseline variable accuracy for predicting incident mortality and falls, and prevalent slow walking speed (<0.8 m/s). RESULTS: Over 14.5 years, 103/899 (11.5%) women and 96/497 (19.3%) men died, 345/899 (38.4%) women and 172/497 (34.6%) men had ≥1 fall, and 304/860 (35.3%) women and 172/461 (31.7%) had baseline slow walking speed (<0.8 m/s). CART models identified age and walking speed adjusted for height as the most important predictors for mortality in women, and quadriceps strength (with adjustments) as the most important predictor for mortality in men. In both sexes, STS (with adjustments) was the most important predictor for incident falls, and TUG test was the most important predictor for prevalent slow walking speed. Body composition measures were not important predictors for any outcome. CONCLUSIONS: Muscle strength and physical performance variables and cut points predict falls and mortality differently in women and men, suggesting targeted sex-specific application of selected measures may improve outcome prediction in older adults.

Enforcing walking speed and step-length affects joint kinematics and kinetics in male and female healthy adults.

BACKGROUND: Individuals increase walking speed by increasing their step-length, increasing their step-frequency, or both. During basic training military recruits are introduced to marching "in-step", and thus the requirement to walk at fixed speeds and step-lengths. The extent to which individuals are required to under- or over-stride will vary depending on their stature, and the stature of others in their section. The incidence of stress fractures in female recruits undergoing basic training is higher than that for their male counterparts. RESEARCH QUESTION: Therefore, the purpose of this study was to determine how joint kinematics and kinetics are affected by walking speed, step-length, and sex. METHODS: Thirty-seven (19 female) aerobically active non-injured individuals volunteered for this study. Synchronised three-dimensional kinematic and kinetic data were collected while participants walked overground at prescribed speeds. Audio and visual cues were used to control step-lengths. Linear mixed models were run to analyse the effects of speed, step-length condition, and sex on peak joint moments. RESULTS AND SIGNIFICANCE: The findings of this study showed that, in general, walking faster and over-striding predominantly increased peak joint moments, suggesting that over-striding is more likely to negatively affect injury risk than under-striding. This is especially important for individuals unaccustomed to over-striding as the cumulative effect of increased joint moments may affect a muscles capability to withstand the increased external forces associated with walking faster and with longer step-lengths, which could then lead to an increased risk of developing an injury.

Statin Therapy Induces Gut Leakage and Neuromuscular Disjunction in Patients With Chronic Heart Failure.

ABSTRACT: Statins are commonly used to limit the risk of cardiovascular diseases, including ischemic heart attack and stroke. However, treatment often leads to myopathy and muscle weakness. Therefore, a better understanding of underlying pathomechanism is needed to improve the clinical outcomes. Here, we assessed the physical performance, including handgrip strength (HGS), gait speed (GS), and short physical performance battery, in 172 patients diagnosed with chronic heart failure (CHF) treated with (n = 50) or without (n = 122) statin and 59 controls. The plasma biomarkers, including sarcopenia marker C-terminal agrin fragment-22 (CAF22), intestinal barrier integrity marker zonulin, and C-reactive protein (CRP), were measured and correlated with the physical performance of patients. The HGS, short physical performance battery scores, and GS were significantly compromised in patients with CHF versus controls. Irrespective of etiology, significant elevation of plasma CAF22, zonulin, and CRP was observed in patients with CHF. There were strong inverse correlations of CAF22 with HGS (r 2 = 0.34, P < 0.0001), short physical performance battery scores (r 2 = 0.08, P = 0.0001), and GS (r 2 = 0.143, P < 0.0001). Strikingly, CAF22 and zonulin were positively correlated with each other (r 2 = 0.10, P = 0.0002) and with the level of CRP in patients with CHF. Further investigations revealed a significant induction of CAF22, zonulin, and CRP in patients with CHF taking statin versus nonstatin group. Consistently, HGS and GS were significantly lower in the statin versus nonstatin CHF patients' group. Collectively, statin therapy adversely affects the neuromuscular junction and intestinal barrier, which potentially induces systemic inflammation and physical disability in patients with CHF. Further prospective confirmation of the findings is required in a well-controlled study.

Predictors of Usual and Peak Gait Speed in Community-Dwelling Older Adults With Mild-to-Moderate Alzheimer's Dementia.

Gait speed significantly affects functional status and health outcomes in older adults. This cross-sectional study evaluated cognitive and physical fitness contributors to usual and peak gait speed in persons with Alzheimer's dementia. Multiple hierarchal linear regression was used to obtain squared semipartial correlation coefficients (sr2) and effect sizes (Cohen's ƒ2). Participants (n = 90; 56% male) averaged 77.1 ± 6.6 years of age and 21.8 ± 3.4 on Mini-Mental State Examination. Demographic/clinical, physical fitness, and cognition variables explained 45% and 39% of variance in usual and peak gait speed, respectively. Muscle strength was the only significant contributor to both usual (sr2 = .175; Cohen's ƒ2 = 0.31; p < .001) and peak gait speed (sr2 = .11; Cohen's ƒ2 = 0.18; p < .001). Women who were "slow" walkers (usual gait speed <1.0 m/s) had significantly lower cardiorespiratory fitness and executive functioning compared with "fast" walkers. In conclusion, improving muscle strength may modify gait and downstream health outcomes in Alzheimer's dementia.

Comparison of spatiotemporal gait parameters and their variability in typically developing children aged 2, 3, and 6 years.

Independent walking is an important milestone in a child's development. The maturation of central nervous system, changes in body proportions, spatiotemporal parameters of gait and their variability change are dependent on age. The first aim of this study was to compare non-normalized and normalized spatiotemporal parameters and their variability in children. The second aim was to determine which spatiotemporal parameters are most affected by aging. Data from 64 typically developing children (age: 2.0-6.9 years), who walked at a self-selected speed along a 10m walkway, were collected with a motion capture system. Spatiotemporal parameters were normalized based on leg length. The main effect of the non-normalized walking speed revealed a moderate effect size (ES = 0.72) comparing 2- and 3-years-old, a large effect size comparing 2- and 6-years-old (ES = 1.77), and a large ES comparing 3- and 6-years-old (ES = 1.22). The normalized stride width parameter showed a statistically significant difference with large effect size between 2 vs 3 (ES = 1.00), 2 vs 6 (ES = 3.17), and 3 vs 6 (ES = 1.96). A statistically significant decrease in intra-individual gait variability with increasing age was observed in all parameters except for stride width. The variability of stride width may serve as a parameter in 2-year-olds to assess deviations from typically developing children. The assessment of effect size could be a useful indicator for clinical practice.

Leg skeletal muscle mass asymmetry is independently associated with gait speed in older adults requiring long-term care.

AIM: Decreased gait speed in older adults has been associated with incident disability, cognitive impairment, institutionalization, falls, deterioration in level of care, and mortality. Gait speed has been reported to be related to leg asymmetry. However, the relationship between gait speed and leg skeletal muscle mass asymmetry in older adults requiring long-term care has not been clarified. In this study, we examined the association between gait speed and leg skeletal muscle mass asymmetry and the cutoff values of leg skeletal muscle mass asymmetry that may affect gait speed. METHODS: The asymmetry index of leg skeletal muscle mass was measured in 230 older adults under the Japanese long-term care insurance system using bioelectrical impedance analysis. This cross-sectional study used multiple regression analysis and receiver operating characteristic (ROC) curve analysis to determine the relationship between gait speed and the asymmetry index of leg skeletal muscle mass. RESULTS: Multiple regression analysis revealed that the asymmetry index of leg skeletal muscle mass (ß = -0.19, P = 0.002, R2 = 0.261) was independently and significantly associated with gait speed. Furthermore, ROC analysis showed that the cutoff value of the asymmetry index of leg skeletal muscle mass that identified reduced gait speed (<1.0 m/s) was 3.02% (Area under the curve = 0.62, sensitivity 47.3%, specificity 81.0%, P = 0.014). CONCLUSIONS: The asymmetry index of leg skeletal muscle mass was associated with gait speed in older adults requiring long-term care. Future assessment and interventions directed towards symmetry of leg skeletal muscle mass may help to improve gait speed in older adults. Geriatr Gerontol Int 2023; 23: 371-375.

Normative values for grip strength, gait speed, timed up and go, single leg balance, and chair rise derived from the Canadian longitudinal study on ageing.

BACKGROUND: decreased muscle strength and physical function often precede disability, nursing home admission, home care use and mortality in older adults. Normative values for commonly used physical performance-based tests are not widely available for older adults but are required for clinicians and researchers to easily identify individuals with low performance. OBJECTIVE: to develop normative values for grip strength, gait speed, timed up and go, single-leg balance and five-repetition chair rise tests in a large population-based sample of Canadians aged 45-85 years. METHODS: baseline data (2011-2015) from the Canadian Longitudinal Study on Ageing was used to estimate age- and sex-specific normative values for each of the physical tests. Participants were without disability or mobility limitation (no assistance with activities of daily living or use of mobility devices). RESULTS: of the 25,470 participants eligible for the analyses 48.6% (n = 12,369) were female with a mean age of 58.6 ± 9.5 years. Sex-specific 5th, 10th, 20th, 50th, 80th, 90th and 95th percentile values for each physical performance-based test were estimated. Cross-validation (n = 100 repetitions) with a 30% holdout sample was used to evaluate model fit. CONCLUSIONS: the normative values developed in this paper can be used in clinical and research settings to identify individuals with low performance relative to their peers of the same age and sex. Interventions targeting these at-risk individuals including physical activity can prevent or delay mobility disability and the resulting cascade of increasing care requirements, health care costs and mortality.

Diagnostic power of relative sit-to-stand muscle power, grip strength, and gait speed for identifying a history of recurrent falls and fractures in older adults.

PURPOSE: To compare the diagnostic value of relative sit-to-stand muscle power with grip strength or gait speed for identifying a history of recurrent falls and fractures in older adults. METHODS: Data from an outpatient clinic included anthropometry (height/weight), bone density, 5 times sit-to-stand time (stopwatch and standardized chair), grip strength (hydraulic dynamometer), and gait speed (4 m). Relative sit-to-stand muscle power (W.kg-1, normalised to body mass) was calculated using a validated equation. Outcomes of falls (past 1 year) and fractures (past 5 years) were self-reported and verified by medical records wherever possible. Binary logistic regression considering for potential confounders (age, sex, BMI, Charlson comorbidity index, femoral neck bone density) and receiver operating characteristics (ROC) curves were used in statistical analysis. RESULTS: 508 community-dwelling older adults (median age: 78 years, interquartile range: 72, 83, 75.2% women) were included. Compared to greater relative sit-to-stand muscle power (1.62-3.78W.kg-1 for women; 2.03-3.90W.kg-1 for men), those with extremely low relative sit-to-stand muscle power were 2.35 (95% CI 1.54, 3.60, p < 0.001) and 2.41 (95% CI 1.25, 4.65, p = 0.009) times more likely to experience recurrent falls and fractures, respectively, in fully adjusted model. Compared to grip strength or gait speed, relative sit-to-stand muscle power showed the highest area under the ROC curve for identifying recurrent falls (AUC: 0.64) and fractures (AUC: 0.62). All tests showed low diagnostic power (AUC: < 0.7). CONCLUSION: Relative sit-to-stand muscle power performed slightly (but not statistically) better than grip strength or gait speed for identifying a history of recurrent falls and fractures in older adults. However, all tests showed low diagnostic power.