The relationship between muscle quality and incidence of falls in older community-dwelling women: An 18-month follow-up study

Assessing muscle quality as a key predictor to differentiate fallers from non-fallers in older adults

BACKGROUND

Falling is an important public health issue because of its prevalence and severe consequences. Evaluating muscle performance is important when assessing fall risk. The study aimed to identify factors [namely muscle capacity (strength, quality, and power) and spatio-temporal gait attributes] that best discriminate between fallers and non-fallers in older adults. The hypothesis is that muscle quality, defined as the ratio of muscle strength to muscle mass, is the best predictor of fall risk.

METHODS

184 patients were included, 81% (n = 150) were women and the mean age was 73.6 ± 6.83 years. We compared body composition, mean grip strength, spatio-temporal parameters, and muscle capacity of fallers and non-fallers. Muscle quality was calculated as the ratio of maximum strength to fat-free mass. Mean handgrip and power were also controlled by fat-free mass. We performed univariate analysis, logistic regression, and ROC curves.

RESULTS

The falling patients had lower muscle quality, muscle mass-controlled power, and mean weighted handgrip than the non-faller. Results showing that lower muscle quality increases fall risk (effect size = 0.891). Logistic regression confirmed muscle quality as a significant predictor (p < .001, OR = 0.82, CI [0.74; 0.89]). ROC curves demonstrated muscle quality as the most predictive factor of falling (AUC = 0.794).

CONCLUSION

This retrospective study showed that muscle quality is the best predictor of fall risk, above spatial and temporal gait parameters. Our results underscore muscle quality as a clinically meaningful assessment and may be a useful complement to other assessments for fall prevention in the aging population.

Age-Related Reduction of Foot Intrinsic Muscle Function and the Relationship with Postural Stability in Old Adults

Introduction

The risk of falls among the elderly significantly increases, which has become a serious public health concern. Falls can not only lead to serious complications such as fractures and brain injuries but also limit their mobility function, reducing quality of life. Foot intrinsic muscles (FIMs) are an essential part of foot core stability even overall postural stability. This study aimed to investigate the effects of aging on the function of FIMs and to explore the influence of FIMs on postural control in the elderly.

Materials and Methods

56 healthy old participants (60-75 years) and 57 healthy young participants (18-29 years) joined this study. An ergoFet dynamometer was used to determine foot muscle strength (Doming, T1, T23 and T2345), and ankle muscle strength (plantarflexion and dorsiflexion). The morphology of FIMs and extrinsic foot muscle was determined using a Doppler ultrasound system, whereas the postural stability was assessed through Limits of Stability test. Independent samples t-test was used to determine the differences in strength and morphological parameters and Spearman correlation analysis was used to determine whether an association existed between muscle strength and postural stability parameters in the elderly.

Results

Compared with young adults, foot muscle strength and ankle muscle strength (Doming, T1, T23, T2345, dorsiflexion, and plantarflexion, all p <0.05) and the morphology of foot muscles (all p <0.05) were significantly reduced in the elderly. The strength of FIMs and the limit of stability (r = 0.302-0.424, all p <0.05) were significantly correlated in the elderly.

Conclusion

Compared with young adults, the weakness of strength as well as the morphological decline of the intrinsic and extrinsic foot muscles were found in the elderly. In addition, a correlation was observed between FIM's strength and postural stability in the elderly, suggesting their potential role in posture stability.

Task-specific resistance training adaptations in older adults: comparing traditional and functional exercise interventions

Muscle strength declines ∼3% per year after the age of 70. Resistance training guidelines for older adults are often based on free-weight and machine exercises, which may be inaccessible and lack carryover to activities of daily living. We tested the hypothesis that resistance training adaptations in older adults are task-specific. Thirty adults (8 males, 22 females; mean age = 71 years) were randomly assigned to participate in 6 weeks of supervised, high-intensity resistance training (twice per week) utilizing free-weight and machine exercises (traditional) versus functional activities that were overloaded with a weighted vest (functional). Participants were thoroughly familiarized with the exercises and testing prior to beginning the study. Major outcome measures included assessments of functional performance, five-repetition maximum strength, isometric knee extensor force, and quadriceps muscle size. Physical activity and nutrition were monitored. The study results demonstrate that the magnitude of improvement within a given outcome was largely dependent on group assignment, with greater improvements in gait speed and the timed-up-and-go in the functional group, but 2-3× greater five repetition maximum strength improvements for the trap bar deadlift, leg press, and leg extension following traditional resistance training. Both groups showed improvements in isometric knee extensor force and muscle size, suggesting that some aspects of the observed adaptations were generic, rather than specific. Overall, these novel findings suggest that, among older adults, 1) resistance training adaptations exhibit a high degree of task specificity and 2) significant improvements in functional outcomes can be achieved with the use of a weighted vest.

Associations of lower-limb muscle strength performance with static and dynamic balance control among older adults in Taiwan

Background

Aging is an inevitable process of life development. These physical changes can cause a decline in the functional adaptability and health status of older adult individuals.

Aims

The purpose of this study was to investigate the association of lower-limb muscle strength performance with static and dynamic balance control among older adults in Taiwan.

Methods

We conducted a cross-sectional study and reviewed data derived from the National Physical Fitness Survey in Taiwan 2015-2016. A total of 20,846 Taiwanese older adult individuals aged 65 years old or older were recruited as study participants. Demographic characteristics, anthropometric assessments, lifestyle habits, and health-related physical fitness measurements from this dataset were analyzed using the chi-square test, one-way analysis of variance, and linear regression analysis. Lower-limb muscle strength performance was classified into 4 groups based on quartile (Quartile 1 [Q1], Quartile 2 [Q2], Quartile 3 [Q3], and Quartile 4 [Q4]) values.

Results

Increased lower-limb muscle strength levels were significantly associated with static balance in men (Q2: β = 2.539, p < 0.0001; Q3: β = 4.590, p < 0.0001; Q4: β = 7.700, p < 0.0001) and women (Q2: β = 2.022, p < 0.0001; Q3: β = 4.179, p < 0.0001; Q4: β = 6.920, p < 0.0001) after adjusting for potential confounders. In addition, we observed that increased lower-limb muscle strength levels were significantly associated with dynamic balance in men (Q2: β = -1.661, p < 0.0001; Q3: β = -2.434, p < 0.0001; Q4: β = -3.091, p < 0.0001) and women (Q2: β = -1.660, p < 0.0001; Q3: β = -2.548, p < 0.0001; Q4: β = -3.196, p < 0.0001) after adjusting for potential confounders.

Conclusion

Lower-limb muscle strength was the most important factor, as it was an improved method for static and dynamic balance control in both genders.

Lower gastrocnemius muscle stiffness, derived from elastography, is an independent factor for falls in older adults

BACKGROUND AND AIMS

It is well known that components of sarcopenia (i.e., decreased muscle strength and mass) are related to falls in older adults. However, the possible effects of changes in muscle quality on falls have not been identified. This study aimed to evaluate the changes in muscle quality reflected by muscle stiffness derived from shear-wave elastography (SWE) and its association with falls in older adults.

METHODS

A total of 101 geriatric outpatients were included in the study. Assessments of physical performance, muscle strength (handgrip strength), muscle mass (muscle ultrasonography and bioelectrical impedance analysis), and muscle stiffness of the medial head of gastrocnemius (GCM) in relaxation and passive stretching were performed. The history of falls in the previous year was questioned and recorded.

RESULTS

The median (25-75 percentiles) age of participants was 73 (69-77) years, and 66.3% (n = 67) were female. According to fall history, participants were divided into non-fallers and fallers groups, and 72 (71.3%) and 29 (28.7%) participants were in each group, respectively. The median muscle stiffness of (Emean) the GCM in passive stretching was significantly lower in the fallers group (p < 0.001), and it was significantly correlated with the number of falls in the previous year (r: - 0.274, p: 0.010). In regression analyses, the Emean value of GCM in passive stretching was significantly associated with falls independent of confounders (OR: 0.944, 95% CI 0.90-0.98, p = 0.010).

DISCUSSION AND CONCLUSION

This is the first study to reveal the relationship between falls and SWE-defined lower GCM stiffness independently of muscle mass and strength.

A machine learning approach to identify important variables for distinguishing between fallers and non-fallers in older women

Falls are a significant ongoing public health concern for older adults. At present, few studies have concurrently explored the influence of multiple measures when seeking to determine which variables are most predictive of fall risks. As such, this cross-sectional study aimed to identify those functional variables (i.e. balance, gait and clinical measures) and physical characteristics (i.e. strength and body composition) that could best distinguish between older female fallers and non-fallers, using a machine learning approach. Overall, 60 community-dwelling older women (≥65 years), retrospectively classified as fallers (n = 21) or non-fallers (n = 39), attended three data collection sessions. Data (281 variables) collected from tests in five separate domains (balance, gait, clinical measures, strength and body composition) were analysed using random forest (RF) and leave-one-variable-out partial least squares correlation analysis (LOVO PLSCA) to assess variable importance. The strongest discriminators from each domain were then aggregated into a multi-domain dataset, and RF, LOVO PLSCA, and logistic regression models were constructed to identify the important variables in distinguishing between fallers and non-fallers. These models were used to classify participants as either fallers or non-fallers, with their performance evaluated using receiver operating characteristic (ROC) analysis. The study found that it is possible to classify fallers and non-fallers with a high degree of accuracy (e.g. logistic regression: sensitivity = 90%; specificity = 87%; AUC = 0.92; leave-one-out cross-validation accuracy = 63%) using a combination of 18 variables from four domains, with the gait and strength domains being particularly informative for screening programmes aimed at assessing falls risk.

Elasticity of leg muscles and incidence of falls in older adults: a prospective cohort analysis

PURPOSE

Aging impacts muscle strength and elasticity, which in turn influence dynamic balance, walking speed, and physical performance. We aimed to evaluate the relationship between the elasticity of leg muscles and incidence of falls in older adults.

METHODS

We conducted a prospective cohort analysis with outpatients from a geriatric clinic. Any history of falls in the past year was recorded. Timed up and go test, muscle thickness, and handgrip strength tests were performed. Elasticities of the gastrocnemius medialis (GM) and rectus femoris (RF) muscles were evaluated using shear wave elastography. Patients self-recorded their falls, and additional phone calls were made to them each month for 6 months.

RESULTS

The median age of the patients (n = 55) was 72 years (66-86); and 72% were women. The GM showed significantly lower elasticity in patients with history of falls in the past year than in those without it (8.08 kPa [3.90-16.17] vs. 9.70 kPa [4.99-20.95]; p = 0.028). A similar negative correlation between GM and fall incidence was noted among those with additional falls during the follow-up period (6.96 kPa [3.90-12.41] vs. 9.13 kPa [4.99-20.95]; p = 0.019). GM elasticity was significantly correlated with the timed up and go test score (r = - 0.612, p < 0.001), handgrip strength (r = 0.384, p = 0.015), and muscle thickness (r = 0.232, p = 0.049). No such associations were observed for the RF muscles.

CONCLUSION

GM muscle elasticity is associated with alterations in muscle structure that may lead to falls in older adults. Therefore, muscle elasticity may be a fall predictor in older adults.

Supervised high-load resistance training for improving muscle strength and quality in prediabetic older adults: A pilot randomized controlled trial

OBJECTIVE

To investigate the effects of high- and low-load supervised, volume-matched resistance training (RT) on body composition, muscle function, and functional capacity in older adults with prediabetes.

METHODS

Older adults with prediabetes were recruited and randomly assigned to high-load RT (n = 13), low-load RT (n = 12), or control groups (n = 12).

RESULTS

No significant differences were observed in body composition at postintervention. High-load and low-load RT groups exhibited significant improvements in functional tests at postintervention compared with the control group. The high-load RT group exhibited a greater improvement in muscle strength and muscle quality at postintervention compared with the low-load RT group.

CONCLUSION

Supervised RT is useful in the prevention of muscle functional loss in older adults with prediabetes. High-load RT is superior for enhancing muscle strength and muscle quality, despite a similar increase in functional capacity.

Assessment of the Effectiveness of Facial Expression Exercises Stimulation Using Mirror Media in Increasing Facial Muscle Strength in Hemiparetic Stroke Patients

BACKGROUND: Stroke can cause facial muscle weakness that can affect mobility, limitations in daily activities, and quality of life. One alternative solution that is non-invasive to restore facial muscle paralysis in post-stroke patients is facial expression exercises using mirror media. AIM: This study aimed to assess the effectiveness of facial muscle expression exercises stimulation using mirror media and without a mirror as media in increasing facial muscle strength in hemiparetic stroke patients. METHODS: This study used an experimental quantitative design, in which two groups of subjects who met the inclusion criteria were randomly assigned. The number of subjects who participated in this research was 60 samples divided into the intervention group (n = 30) with a mirror for facial muscle expression exercises and the control group (n = 30) without a mirror for five weeks. The research data were collected using the Fisch Facial Grading System sheet. The statistical analysis procedure of the data consisted of One-Way ANOVA, paired-samples T-test, and N-Gain score test with 95% significance. RESULTS: The difference in facial muscle strength increase was significantly greater in the intervention group (mean difference 19.4; p = 0.000). The intervention group was more effective in increasing facial muscle strength than the control group (N-Gain score 56.31%). CONCLUSION: The facial muscle expression exercise procedure using a mirror was more effective in increasing muscle strength than the group without a mirror.

Combined effect of lower muscle quality and quantity on incident falls and fall-related fractures in community-dwelling older adults: A 3-year follow-up study

OBJECTIVE

Falls and fractures are serious geriatric adverse events worldwide, and skeletal muscle is considered to be a key factor in these incidents. The objective of this study was to investigate the combined effect of lower muscle quality and quantity on the incidence of falls and fall-related fractures in a 3-year follow-up period among community-dwelling older adults.

METHODS

We recruited community-dwelling adults aged 65 years and older who were living independently in 2018. A total of 773 older participants were analyzed in this study. The outcomes were incident falls and fall-related fractures during the 3-year follow-up period. At baseline, we assessed muscle quality and quantity using ultrasonography, and we categorized the participants into four groups based on their combination of poor/better muscle quality and poor/better muscle quantity. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of the relationships among items in the four groups and the time to incident falls and fall-related fractures.

RESULTS

During the 3-year follow-up period, 178 participants (23.0 %) had a fall incident and 51 participants (6.6 %) had fall-related fractures. Older adults with lower muscle quality and quantity had significantly elevated risks of incident falls according to multivariate analyses using older adults with better muscle quality and quantity as the reference (adjusted HR: 1.54 [95 % CI 1.06-2.23]). However, there were no significant differences in fall-related fractures among the four groups.

CONCLUSION

We found that lower muscle quality and quantity led to higher incidents of falls; thus, identifying community-dwelling older adults with lower muscle quality and quantity is necessary to provide them fall preventive measures and maybe to reduce fall-related outcomes.

Healthy aging and muscle function are positively associated with NAD+ abundance in humans

Skeletal muscle is greatly affected by aging, resulting in a loss of metabolic and physical function. However, the underlying molecular processes and how (lack of) physical activity is involved in age-related metabolic decline in muscle function in humans is largely unknown. Here, we compared, in a cross-sectional study, the muscle metabolome from young to older adults, whereby the older adults were exercise trained, had normal physical activity levels or were physically impaired. Nicotinamide adenine dinucleotide (NAD+) was one of the most prominent metabolites that was lower in older adults, in line with preclinical models. This lower level was even more pronounced in impaired older individuals, and conversely, exercise-trained older individuals had NAD+ levels that were more similar to those found in younger individuals. NAD+ abundance positively correlated with average number of steps per day and mitochondrial and muscle functioning. Our work suggests that a clear association exists between NAD+ and health status in human aging.

Appendicular and mid-thigh lean mass are associated with muscle strength, physical performance, and dynamic balance in older persons at high risk of falls

BACKGROUND

Falls in older persons are associated with muscle mass and strength alterations, which may also affect balance parameters. However, the most appropriate combined approach to assess muscle and balance components that predict falls in older persons is still lacking.

RESEARCH QUESTION

We hypothesized that appendicular lean and/or mid-thigh mass and muscle strength and performance are positively associated with balance indices and fall risk in older persons.

METHODS

Cross-sectional analyses of retrospective data from 260 participants with risk and/or history of falls examined at a Falls and Fracture Clinic. Assessments included a comprehensive clinical exam, bone densitometry and body composition by DXA, grip strength, gait speed, posturography, timed up and go (TUG) and four-square step (FSST) tests. Retrospective falls and fracture history was collected. Associations between appendicular and mid-thigh lean mass and muscle strength/performance vs balance indicators were determined before and after adjusting for age and gender.

RESULTS

Mean age of participants was 78 ± 6.7 (65-96) years. Both appendicular and mid-thigh lean masses corrected for BMI (but not for height²), and muscle strength and performance measures are associated with better dynamic balance. Conversely, static balance indicators showed less consistent associations with lean mass. Only TUG and sit to stand time consistently showed significant associations with most static balance indicators.

SIGNIFICANCE

Combined with strength and performance parameters, ALM and mid-thigh estimates adjusted by BMI strongly correlate with dynamic balance parameters and could become practical elements of falls risk assessment as well as markers of therapeutic response to falls prevention interventions.

Aerobic capacity and skeletal muscle characteristics in glycogen storage disease IIIa: an observational study

Background

Individuals with glycogen storage disease IIIa (GSD IIIa) (OMIM #232400) experience muscle weakness and exercise limitation that worsen through adulthood. However, normative data for markers of physical capacity, such as strength and cardiovascular fitness, are limited. Furthermore, the impact of the disease on muscle size and quality is unstudied in weight bearing skeletal muscle, a key predictor of physical function. We aim to produce normative reference values of aerobic capacity and strength in individuals with GSD IIIa, and to investigate the role of muscle size and quality on exercise impairment.

Results

Peak oxygen uptake (V̇O₂peak) was lower in the individuals with GSD IIIa than predicted based on demographic data (17.0 (9.0) ml/kg/min, 53 (24)% of predicted, p = 0.001). Knee extension maximum voluntary contraction (MVC) was also substantially lower than age matched predicted values (MVC: 146 (116) Nm, 57% predicted, p = 0.045), though no difference was found in MVC relative to body mass (1.88 (2.74) Nm/kg, 61% of predicted, p = 0.263). There was a strong association between aerobic capacity and maximal leg strength (r = 0.920; p = 0.003). Substantial inter-individual variation was present, with a high physical capacity group that had normal leg strength (MVC), and relatively high V̇O₂peak, and a low physical capacity that display impaired strength and substantially lower V̇O₂peak. The higher physical capacity sub-group were younger, had larger Vastus Lateralis (VL) muscles, greater muscle quality, undertook more physical activity (PA), and reported higher health-related quality of life.

Conclusions

V̇O₂peak and knee extension strength are lower in individuals with GSD IIIa than predicted based on their demographic data. Patients with higher physical capacity have superior muscle size and structure characteristics and higher health-related quality of life, than those with lower physical capacity. This study provides normative values of these important markers of physical capacity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02184-1.

A pilot study on the feasibility and effectiveness of treadmill-based perturbations for assessing and improving walking stability in chronic obstructive pulmonary disease

BACKGROUND

Falls risk is elevated in chronic obstructive pulmonary disease (COPD). However, there is a lack of evidence regarding the contributing factors. Here, we examined the feasibility of, and initial responses to, large walking perturbations in COPD, as well as the adaptation potential of people with COPD to repeated walking perturbations that might indicate potential for perturbation-based balance training in COPD.

METHODS

12 participants with COPD undergoing inpatient pulmonary rehabilitation and 12 age-gender-matched healthy control participants walked on an instrumented treadmill and experienced repeated treadmill-belt acceleration perturbations (leading to a forward balance loss). Three-dimensional motion capture was used to quantify the stability of participants body position during perturbed walking. Feasibility, stability following the initial perturbations and adaptation to repeated perturbations were assessed.

FINDINGS

Using perturbations in this manner was feasible in this population (no harness assists and participants completed the minimum number of perturbations). No clear, specific deficit in reactive walking stability in COPD was found (no significant effects of participant group on stability or recovery step outcomes). There were mixed results for the adaptability outcomes which overall indicated some adaptability to repeated perturbations, but not to the same extent as the healthy control participants.

INTERPRETATION

Treadmill-based perturbations during walking are feasible in COPD. COPD does not appear to result in significant deficits in stability following sudden perturbations and patients do demonstrate some adaptability to repeated perturbations. Perturbation-based balance training may be considered for fall prevention in research and practice in people with COPD.

Adaptations in Reactive Balance Strategies in Healthy Older Adults After a 3-Week Perturbation Training Program and After a 12-Week Resistance Training Program

Both resistance training (RT) and perturbation-based training (PBT) have been proposed and applied as interventions to improve reactive balance performance in older adults. PBT is a promising approach but the adaptations in underlying balance-correcting mechanisms through which PBT improves reactive balance performance are not well-understood. Besides it is unclear whether PBT induces adaptations that generalize to movement tasks that were not part of the training and whether those potential improvements would be larger than improvements induced by RT. We performed two training interventions with two groups of healthy older adults: a traditional 12-week RT program and a 3-week PBT program consisting of support-surface perturbations of standing balance. Reactive balance performance during standing and walking as well as a set of neuro-muscular properties to quantify muscle strength, sensory and motor acuity, were assessed pre- and post-intervention. We found that both PBT and RT induced training specific improvements, i.e., standing PBT improved reactive balance during perturbed standing and RT increased strength, but neither intervention affected reactive balance performance during perturbed treadmill walking. Analysis of the reliance on different balance-correcting strategies indicated that specific improvements in the PBT group during reactive standing balance were due to adaptations in the stepping threshold. Our findings indicate that the strong specificity of PBT can present a challenge to transfer improvements to fall prevention and should be considered in the design of an intervention. Next, we found that lack of improvement in muscle strength did not limit improving reactive balance in healthy older adults. For improving our understanding of generalizability of specific PBT in future research, we suggest performing an analysis of the reliance on the different balance-correcting strategies during both the training and assessment tasks.

Effects of intrinsic-foot-muscle exercise combined with the lower extremity resistance training on postural stability in older adults with fall risk: study protocol for a randomised controlled trial

BACKGROUND

Falls are one of the most common accidents in older adults, often leading to injury, disability and quality-of-life declines. Foot core function contributes to postural stability in most static postures and dynamic activities. As efficient foot core training, the intrinsic-foot-muscle exercise has been proposed to improve postural control. However, the effects of the exercise on postural stability in the elderly remain unclear. Therefore, this study attempts to investigate the effect of 12-week intrinsic-foot-muscle exercise on postural stability in older adults with fall risk.

METHODS

We will conduct a prospective, single-blind randomised controlled trail on 120 older adults with fall risk. Participants will be randomly assigned to an intrinsic-foot-muscle exercise combining the lower extremity resistance training group (IFM group), an extrinsic-foot-muscle exercise combining the lower extremity resistance training group (EFM group) and a control group. The control group will perform lower extremity resistance training. The IFM and EFM groups will be given additional short-foot exercise or towel-curl exercise training, respectively. After the intervention, participants will be followed up for another 12 weeks with no active intervention. The outcome measures will include the postural stability measurements, self-reported postural stability, number of falls, intrinsic-foot-muscle strength and foot arch function. Furthermore, adverse events will be recorded and analysed. If any participant withdraws from the trial, an intention-to-treat analysis will be performed.

DISCUSSION

The trial is designed to investigate the efficacy of a 12-week intrinsic foot muscle training combined with the lower extremity resistance training on postural stability outcomes in elderly people with fall risk. The trial will also examine the comprehensive outcomes of postural stability during static standing and dynamic movements. The function of intrinsic foot muscle to support the arch will also be evaluated. Important features of this trial mainly include intervention setting, outcome measure selection and study duration. The results of this study will determine the effectiveness and provide scientific evidence to establish comprehensive fall prevention intervention.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2000033623. Registered on 7 June 2020. http://www.chictr.org.cn/showproj.aspx?proj=54741.

Impact of aging and exercise on skeletal muscle mitochondrial capacity, energy metabolism, and physical function

The relationship between the age-associated decline in mitochondrial function and its effect on skeletal muscle physiology and function remain unclear. In the current study, we examined to what extent physical activity contributes to the decline in mitochondrial function and muscle health during aging and compared mitochondrial function in young and older adults, with similar habitual physical activity levels. We also studied exercise-trained older adults and physically impaired older adults. Aging was associated with a decline in mitochondrial capacity, exercise capacity and efficiency, gait stability, muscle function, and insulin sensitivity, even when maintaining an adequate daily physical activity level. Our data also suggest that a further increase in physical activity level, achieved through regular exercise training, can largely negate the effects of aging. Finally, mitochondrial capacity correlated with exercise efficiency and insulin sensitivity. Together, our data support a link between mitochondrial function and age-associated deterioration of skeletal muscle.

Aging is associated with a progressive loss of muscle function. Here the authors characterize mitochondrial capacity and muscle function in young and older adults with similar habitual physical activity and also compared to older adults with exercise training or with physical impairment.

Poor handgrip strength determined clinically is associated with falls in older women

Objectives:

To assess the association between poor handgrip strength (HGS) determined by clinical criterion and incidence of falls in older women.

Methods:

The cohort included 195 women (68.1±6.2 years) who were assessed for HGS (Jamar Dynamometer) at baseline and were prospectively followed for 18 months. FNIH Sarcopenia threshold of HGS adjusted for body mass index (<0.56) was used for clinical determination of poor HGS. Association between poor HGS and incidence of falls was analyzed using Cox hazard models in the total cohort and in a stratified analysis by balance status.

Results:

During the follow-up, 53 (27%) women experienced at least one fall. In a multivariable model, poor HGS was associated with approximately 3-fold increased risk for falls [Hazard Ratio (HR)=2.73, 95% Confidence Interval (CI)=1.28–5.82, p=0.009]. In a stratified analysis, women with impaired balance exhibited even greater risk for falls (HR=3.85, 95%CI=1.47–10.12, p=0.011), although no association was found in women with normal balance (p=0.459).

Conclusions:

Poor HGS based on clinical criterion is independently associated with higher risk of falls in older women, particularly in those with impaired balance. These results suggest potential prognostic value of FNIH Sarcopenia threshold for risk stratification and referring high-risk individuals to fall prevention programs.

Effects of pre-dialysis resistance training on sarcopenia, inflammatory profile, and anemia biomarkers in older community-dwelling patients with chronic kidney disease: a randomized controlled trial

BACKGROUND

Sarcopenia and chronic kidney disease (CKD) have been associated with negative outcomes in older people, including inflammatory profile and anemia biomarkers.

AIMS

To investigate the effects of pre-dialysis resistance training (RT) on sarcopenia, inflammatory profile, and anemia biomarkers in older patients with CKD.

METHODS

A total of 107 patients with CKD (65.4 ± 3.7 years) were randomly allocated into four groups: sarcopenic RT (n = 37), non-sarcopenic RT (n = 20), sarcopenic control (n = 28), and non-sarcopenic control (n = 22). DXA and handgrip strength were used to classify sarcopenia according to EWGSOP-2. Treatment groups underwent a 24-week intervention with RT before each dialysis session, three times per week. Blood sample analysis for ferritin, hepcidin, iron availability, and inflammatory profile (TNFα, IL-6, and IL-10) was conducted. All-cause mortality was recorded over 5 years.

RESULTS

Sarcopenic RT group increased iron availability after the intervention, while their counterparts decreased. Ferritin and hepcidin significantly decreased in sarcopenic RT group. RT elicited a reduction in both TNFα and IL-6, while increasing IL-10 in both intervention groups. The rate of sarcopenic subjects substantially decreased after the intervention period (from 37 to 17 in the RT group; p = 0.01). The proportion of deaths was higher (P = 0.033) for sarcopenic subjects (Controls 35.7% vs RT 29.7%) when compared to non-sarcopenic subjects (Controls 18% vs RT 10%). The proportion of deaths decreased according to the randomization group (X2 = 8.704; P < 0.1).

CONCLUSIONS

The 24-week RT intervention elicited a better sarcopenia status, better inflammatory profile, and improved anemia biomarkers. Sarcopenia was associated with higher mortality rate in older patients with CKD.

Does Obesity Increase the Risk and Severity of Falls in People Aged 60 Years and Older? A Systematic Review and Meta-analysis of Observational Studies

BACKGROUND

Recent investigations suggest that obesity may be associated with an increased risk of falls; however, this theory has yet to be definitively confirmed. This systematic review and meta-analysis examined the strength of the association between obesity and falls, multiple falls, fall-related injuries, and fall-related fractures among older adults.

METHODS

MEDLINE, Embase, CINAHL, PsycINFO, SPORTDiscus, LILACS, and Web of Science databases were searched to identify observational studies that assessed the association between obesity and fall-related outcomes in participants aged 60 years and older. Two independent reviewers performed data extraction and quality assessment. Relative risks and 95% confidence intervals (CI) were pooled using random effect meta-analyses.

RESULTS

Thirty-one studies including a total of 1,758,694 participants were selected from 7,815 references. Pooled estimates showed that obese older adults have an increased risk of falls compared with nonobese counterparts (24 studies; relative risk: 1.16; 95% CI: 1.07-1.26; I2: 90%). Obesity was also associated with an increased risk of multiple falls (four studies; relative risk: 1.18; 95% CI: 1.08-1.29; I2: 0%). There was no evidence, however, of an association between obesity and fall-related injuries (seven studies; relative risk: 1.04; 95% CI: 0.92-1.18; I2: 65%). Fall-related fractures were reported in only one study, which demonstrated a lower risk of hip fracture with obesity (odds ratio: 0.65; 95% CI: 0.63-0.68).

CONCLUSIONS

Obesity increases the risk of falls and multiple falls in people aged 60 years and older; however, there is insufficient evidence of an association with fall-related injuries or fractures. Prevention and treatment of obesity may play a role in preventing falls in older age.

The Influence of Body Fat Distribution on Postural Balance and Muscle Quality in Women Aged 60 Years and Over

The aim of this study was to investigate the influence of body fat distribution on postural balance and lower-limb muscle quality in women aged 60 years and over. Two hundred and twenty-two volunteers took part in this cross-sectional analysis. Participants underwent body fat distribution assessment using dual-energy x-ray absorptiometry and were classified as nonobese, gynoid obese, or android obese. Postural balance was assessed during quiet standing, with and without vision restriction, using a force platform. Specific torque was defined as the ratio of knee extensors peak torque (evaluated by an isokinetic dynamometer) to the lean mass of the same limb (evaluated by dual-energy x-ray absorptiometry). Compared with nonobese participants, both obese groups exhibited higher range of postural sway along the anteroposterior and mediolateral axes (P < .05). However, there were no differences between participants with gynoid and android obesity. The android obese group exhibited greater speed of postural sway in the condition without vision restriction than both nonobese (P = .040) and gynoid obese (P = .004) groups. Regarding muscle quality, only participants with gynoid obesity (P = .004) presented lower specific torque than their nonobese peers. These results may be clinically useful when designing falls prevention exercises targeting the obese population.

Muscle Quality Is Associated with History of Falls in Octogenarians

OBJECTIVES

The aim of this study was to compare muscle quality (MQ) between octogenarians classified as non-fallers, fallers and recurrent fallers and identify confounding intrinsic and extrensic factors that impact likelihood for falls.

DESIGN

This observational, descriptive, cross-sectional study included older adults (N=220) aged 80 years or older.

MEASUREMENTS

The Short Physical Performance Battery (SPPB) was used to evaluate physical function and MQ was calculated using the ratio of grip strength to arm muscle mass (in kilograms) quantified by DXA. Variables related to sociodemographic, clinical, cognitive function, and falls were evaluated using a questionnaire and symptoms of depression were evaluated by the Geriatric Depression Scale (GDS). A Kruskal-Wallis H test was used to verify differences between groups. Binomial logistic regression was performed to determine the impact of age, depression, polypharmacy, balance, MQ, and sex on participants having more than four falls in their history.

RESULTS

Increasing MQ was associated with reduced likelihood of more than four falls in their history. Non-fallers were statistically younger (p = 0.012) and took more medications (p = 0.023) than recurrent fallers. Recurrent fallers had lower MQ when compared with fallers (p = 0.007) and non-fallers (p = 0.001) and had a lower GDS score when compared with fallers (p = 0.022). Finally, fallers presented lower scores for balance when compared to non-fallers (p = 0.013).

CONCLUSION

A higher MQ is associated with a reduction in the likelihood falls in octogenarians. Therefore, it may be advantageous for clinicians to evaluate MQ when the screening of the risk of falls in older adults.

A pilot study examining the use of ultrasound to measure sarcopenia, frailty and fall in older patients

INTRODUCTION

The importance of this study is to devise an efficient tool for assessing frailty in the ED. The goals of this study are 1) to correlate ultrasonographic (US) measurements of muscle thickness in older ED patients with frailty and 2) to correlate US-measured sarcopenia with falls, subsequent hospitalizations and ED revisits.

METHODS

Participants were conveniently sampled from a single ED in this prospective cohort pilot study of patients aged 65 or older. Participants completed a Fatigue, Resistance, Ambulation, Illness and Loss of Weight (FRAIL) scale assessment and US measurements of their upper arm muscles, quadricep muscles, and abdominal wall muscles thickness. We conducted one-month follow-up phone calls to assess for falls, ED revisits, and subsequent hospital visits.

RESULTS

We enrolled 43 patients (mean age of 78.5). Ultrasound measurements of the three muscle groups were not significantly different between frail and non-frail groups. Frail participants had greater bicep asymmetry (a difference of 0.47 cm vs 0.24 cm, p < .01). A predictive logistic regression model using average quadriceps thickness and biceps asymmetry was found to identify frail patients (AUC of 0.816). Participants with subsequent falls had smaller quadriceps (1.18 cm smaller, p < .01). Subsequently hospitalized patients were found to have smaller quadriceps muscles (0.54 cm smaller, p = .03) and abdominal wall muscles (0.25 cm smaller, p = .01).

CONCLUSION

US measurements of sarcopenia in older patients had mild to moderate associations with frailty, falls and subsequent hospitalizations. Further investigation is needed to confirm these findings.

Interactions Between Different Age-Related Factors Affecting Balance Control in Walking

Maintaining balance during walking is a continuous sensorimotor control problem. Throughout the movement, the central nervous system has to collect sensory data about the current state of the body in space, use this information to detect possible threats to balance and adapt the movement pattern to ensure stability. Failure of this sensorimotor loop can lead to dire consequences in the form of falls, injury and death. Such failures tend to become more prevalent as people get older. While research has established a number of factors associated with higher risk of falls, we know relatively little about age-related changes of the underlying sensorimotor control loop and how such changes are related to empirically established risk factors. This paper approaches the problem of age-related fall risk from a neural control perspective. We begin by summarizing recent empirical findings about the neural control laws mapping sensory input to motor output for balance control during walking. These findings were established in young, neurotypical study populations and establish a baseline of sensorimotor control of balance. We then review correlates for deteriorating balance control in older adults, of muscle weakness, slow walking, cognitive decline, and increased visual dependency. While empirical associations between these factors and fall risk have been established reasonably well, we know relatively little about the underlying causal relationships. Establishing such causal relationships is hard, because the different factors all co-vary with age and are difficult to isolate empirically. One option to analyze the role of an individual factor for balance control is to use computational models of walking comprising all levels of the sensorimotor control loop. We introduce one such model that generates walking movement patterns from a short list of spinal reflex modules with limited supraspinal modulation for balance. We show how this model can be used to simulate empirical studies, and how comparison between the model and empirical results can indicate gaps in our current understanding of balance control. We also show how different aspects of aging can be added to this model to study their effect on balance control in isolation.

Relationship Between Lower Limb Muscle Strength and Future Falls Among Community-Dwelling Older Adults With No History of Falls: A Prospective 1-Year Study

Objective: To investigate whether lower limb muscle strength could be a risk factor for the first fall among nonfaller community-dwelling older adults. Method: Hip, knee, and ankle peak torque (PT) was measured with an isokinetic dynamometer in 101 older adults with no history of falls in the previous year. Next, the authors followed up the participants on a monthly basis by telephone contact to determine the occurrence of fall episodes over a period of 1 year. Multivariate logistic regression adjusted for confounding variables was applied to assess the relationship between falls and lower limb PT. Results: there was no association between lower limb PT and future falls ( p > .05). Conclusion: Based on these results, it is important to identify other factors that predispose older adults with no history of falls to falling for the first time, so that early and effective preventive strategies may be elaborated.

Body fat distribution in obesity and the association with falls: A cohort study of Brazilian women aged 60 years and over

OBJECTIVES

Obesity is associated with an increased risk of falls in older women; however, it is not certain how body fat distribution affects this relationship. This study examined the association between android and gynoid obesity and the incidence of falls in women aged 60 years and over.

STUDY DESIGN

Participants were recruited from the community in Brasilia, Brazil. At baseline, participants underwent obesity screening using dual-energy x-ray absorptiometry. Participants identified as obese (body fat percentage >42 %) were classified as android or gynoid type, based on the median of the android-gynoid fat percent ratio (0.99). Incident falls were recorded at the end of the 18-month follow-up period via participant recall. Chi-square test and modified Poisson regression were used to examine the association between obesity and falls.

RESULTS

A total of 246 participants were recruited and 204 completed the follow-up. The gynoid obese group had a larger proportion of fallers (n = 27, 41 %) than the android obese (n = 17, 24 %) and non-obese (n = 12, 18 %) groups (p = .009). Compared with non-obese women, participants with gynoid obesity were more likely to experience a fall (RR: 2.09, 95 %CI: 1.13-3.87). The risk of falling did not differ between non-obese participants and those with android obesity (RR: 1.26, 95 %CI: 0.64-2.50).

CONCLUSIONS

Gynoid obesity is associated with an increased risk of falls in women aged 60 years and over. Screening for body fat distribution as a supplement to other risk factors for falls may help to identify older adults at a greater risk of falling and to prompt early implementation of fall prevention programs.

Obesity and falls in older women: Mediating effects of muscle quality, foot loads and postural control

BACKGROUND

Obesity is associated with an increased risk of falls in older women. However, it is not certain whether factors commonly associated with obesity and falls mediate this risk.

RESEARCH QUESTION

Do lower-limb muscle quality, foot loads and postural control mediate the relationship between obesity and falls in women aged 60 years and older?

METHODS

At baseline, 246 female participants underwent obesity screening (BMI≥30 kg/m²), and measurements of muscle quality (isokinetic dynamometer and dual-energy X-ray absorptiometry), foot loads (pressure platform) and postural balance (force platform). Incident falls were recorded at the end of the 18-month follow-up period via participant recall. To test whether, and to what extent, biomechanical factors mediated the relationship between obesity and falls, the Natural Indirect Effects (NIE), Natural Direct Effect (NDE) and proportion mediated were calculated using the counterfactual approach. Significance level was set at p < .05.

RESULTS

204 participants (83 %) completed the follow-up. As expected, obesity was associated with a higher risk of being a faller (RR: 2.13, 95 % CI: 1.39-3.27). Using the counterfactual approach, only specific torque (NIE: 1.11, 95 % CI: 1.01-1.38) and flatfoot (NIE: 1.10, 95 % CI: 1.01-1.32) were significant mediators of the relationship between obesity and falls. Specific torque and flatfoot mediated 19 % and 21 % of the relationship, respectively.

SIGNIFICANCE

Lower-limb muscle quality (specific torque) and foot loads (flatfoot) mediate the relationship between obesity and falls in older women. The inclusion of muscle strengthening and podiatry interventions as part of a fall prevention program may benefit this population.

Metabolic Syndrome and Its Associations with Components of Sarcopenia in Overweight and Obese Older Adults

Ageing, obesity and the metabolic syndrome (MetS) may all contribute to poor muscle health (sarcopenia). This study aimed to determine the cross-sectional associations between MetS (International Diabetes Federation classification) and sarcopenia (revised European Working Group on Sarcopenia in Older People definition) in 84 overweight and obese older adults. Components of sarcopenia included muscle strength (hand grip and leg extension), physical performance (stair climb test and short physical performance battery (SPPB), including gait speed and repeated chair stands time), muscle mass (appendicular lean mass (ALM), dual-energy X-ray absorptiometry), muscle size (peripheral quantitative computed tomography-determined calf and forearm cross-sectional area (CSA)) and muscle quality (muscle density and strength normalised to lean mass). Waist circumference was associated with greater muscle size, but poorer leg extension strength, chair stands and stair climb time, gait speed, SPPB scores and muscle quality measures (all p < 0.05). MetS was positively associated with ALM and forearm muscle CSA, and negatively associated with muscle quality measures and chair stands time (all p < 0.05). MetS is associated with larger muscle size, yet poorer muscle quality in overweight and obese older adults. Assessments of muscle function and quality should be considered for obese older adults and those with MetS.