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Purpose: Loss of muscle power has a significant impact on mobility in geriatric populations, so this study sought to determine the extent and time course of performance decline in power-centric events throughout the life span via retrospective analyses of masters and elite track-and-field data. Methods: Four track-and-field events were selected based on maximal power output: the 100-m dash, long jump, high jump, and triple jump. Elite and masters athlete data were gathered from the World Masters Outdoor Championships and the International Amateur Athletic Federation World Athletics Championships (17,945 individual results). Data were analyzed by fitting individual and group results to quadratic and linear models. Results: Average age of peak performance in all events was 27.8 (0.8) years for men and 28.3 (0.8) years for women. Athlete performance decline best matched a linear model for the 5 years following peak performance (mean R2 =.68 [.20]) and for ages 35–60, but best matched a quadratic model for ages 60–90 and 35–90 (mean R2 =.75 [.12]). The average rate of decline for the masters data ages 35–60 ranged from 0.55% per year for men's 100-m dash to 1.04% per year for women's long jump. A significant age × sex interaction existed between men and women, with men declining faster throughout life in all events except the 100-m dash. Conclusions: Performance decline begins in the early 30s and is linear through middle age. This pattern of decline provides a basis for further research on power-decline pathophysiology and preventive measures starting in the 30s. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess the longitudinal association between dynapenic abdominal obesity and new-onset arthritis among the middle-aged and older Chinese population. Methods: We included 6863 participants from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study (CHARLS). Dynapenia was defined as handgrip strength < 28 kg for males, and < 18 kg for females. Abdominal obesity was defined as a waist circumference ≥ 90 cm for males and ≥ 85 cm for females. Based on the definitions, all participants were divided into four groups: no dynapenia and no abdominal obesity (ND/NAO), abdominal obesity alone (ND/AO), dynapenia alone (D/NAO), and dynapenia and abdominal obesity (D/AO). The association between dynapenic abdominal obesity and new-onset arthritis was assessed by sex using the Poisson regression models. Results: After a four-year follow-up, 1272 (18.53%) participants reported new-onset arthritis. Those in the D/AO group had a significantly increased risk of new-onset arthritis compared to those in the ND/NAO group (adjusted relative risk (RR): 1.34, 95% confidence interval (CI): 1.01–1.77). In females, the ND/AO (RR: 1.21, 95% CI: 1.03–1.43) and D/AO (RR: 1.39, 95% CI: 1.01–1.93) groups were associated with a higher risk of arthritis. This significant association was not observed in males. Conclusions: Our results indicated that the combined effect of dynapenia and abdominal obesity significantly increased the risk of new-onset arthritis in females, but this association was not observed in males. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated whether anthropometric measurements and the five times sit-to-stand test could be used to identify dynapenia. The cut-off values of accurate screening tools for identifying dynapenia were also established. Materials and methods: This was a cross-sectional study conducted on individuals ≥ 60 years old (N = 529). All participants underwent handgrip strength measurement, anthropometric measurements and the five times sit-to-stand test. The participants whose handgrip strength was < 28 kg for men and < 18 kg for women were considered to have dynapenia. The association between the recorded variables and dynapenia was determined using logistic regression, and cut-off values were established by performing the Receiver Operating Characteristic curve analysis. Results: The prevalence of dynapenia was 35.42% in men and 25.61% in women. For males, both calf circumference (≤ 35.2 cm) and the five times sit-to-stand test (≥ 14.6 s) could be used as accurate tools for dynapenia. For females, only the five times sit-to-stand test (≥ 11.8 s) had sufficient accuracy to be used as a screening tool for dynapenia. Conclusions: The five times sit-to-stand test was an accurate screening tool for identifying dynapenia. The calf circumference could be only used as a screening tool in males. IMPLICATIONS FOR REHABILITATION: Calf circumference and the five times a sit-to-stand test can be used as accurate screening tools in males with dynapenia. Only the five times sit-to-stand test had sufficient accuracy in females with dynapenia. The optimal cut-off values established for older males and females are only applicable to the Asian population. [ABSTRACT FROM AUTHOR]

Dynapenia and multimorbidity are common health problems affecting older adults. However, few studies have systematically reviewed the association between dynapenia and multimorbidity. Therefore, this systematic review aimed to provide a comprehensive overview of studies on the association between these conditions. We searched four electronic databases for relevant articles published in July 2023. The main inclusion criteria were the following: a description of dynapenia, which indicates loss of muscle strength, and a description of multimorbidity with two or more chronic diseases. Five studies met these inclusion criteria. In all five of these studies, the participants were community-dwelling older adults. All the studies showed an association between dynapenia and multimorbidity. The prevalence of dynapenia and multimorbidity ranged from 16% to 25.9%. The results of our systematic review demonstrated that dynapenia in older adults increases the risk of multimorbidity. We propose that interventions and reversible changes in dynapenia can prevent multimorbidity. (PROSPERO Registration No. CRD42023443282) [ABSTRACT FROM AUTHOR]

Aging is associated with decreased muscle strength and power. Power is particularly important for maintaining the independence of older adults when performing activities of daily living. The countermovement jump has been identified as a reliable and safe method to assess lower extremity power across the lifespan. The purpose of this investigation was to study sex differences and age-related changes in countermovement jump peak power among masters weightlifters with the secondary purpose of comparing results to previous reports of community and masters athletes. Female (n = 63, 39 to 70 yrs, med (56 yrs)) and male (n = 39, 35 to 86 yrs, med (59 yrs)) participants of the 2022 World Masters Championships completed three maximal effort countermovement jump repetitions following a dynamic warm-up. Vertical ground reaction forces were recorded, and peak power normalized to body mass was calculated. Results indicated significant age-related peak power among weightlifters, with the decline being significantly more pronounced in males than females. Female weightlifters exhibited less age-related decline compared to normative data as well as the other Master athlete comparison cohorts (short and long-distance runners), whereas the males demonstrated similar age-related declines as the comparison cohorts. While the female weightlifters in the current study generally demonstrated the least age-related declines in CMJ peak power of the comparative literature, the male weightlifters showed similar age-related decline rates. [ABSTRACT FROM AUTHOR]

Aims: Dynapenia is a noteworthy health issue contributing to increased risk of falling, but its co-occurrence with osteoporosis in elderly individuals with type 2 diabetes mellitus (T2DM) has not been well explored. Therefore, this study aimed to establish the association between osteoporosis and dynapenia, focusing on T2DM females due to their high prevalence of osteoporosis and fragility. Methods: We conducted a cross-sectional study to recruit a total of 103 T2DM patients (43 males and 60 females), aged between 50 and 80 years with median 68.0 years. Dual-energy X-ray absorptiometry (DXA) and dominant hand grip strength measurements were performed to define body composition, osteoporosis, and dynapenia in a sex-specific manner. Results: Higher prevalence of dynapenia and dyna-osteoporosis was observed in female T2DM patients with a significantly positive correlation between osteoporosis and dynapenia even after adjustment of body mass index (BMI). By performing a multivariate logistic regression analysis, both BMI and osteoporosis were identified as risk predictors for the development of dynapenia in female T2DM patients with odds ratios (95% CIs) of 1.234 (1.029–1.480) and 4.883 (1.352–17.630), respectively. Conclusions: Our results point out there is high, female-specific co-occurrence of osteoporosis and dynapenia in T2DM patients. Moreover, having osteoporosis and increased BMI might boost the risk of dynapenia in elderly females with T2DM. [ABSTRACT FROM AUTHOR]

Introduction: Muscle strength is known to play an important role in the health of older adults. The health burden of cigarette smoking among older adults remains significant. We investigated the association between smoking cessation and dynapenia among older lifetime smokers in Korea. Methods: This study is a secondary dataset analysis of cross-sectional data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016– 2019. We included 1450 participants aged 65–79 years, excluding those who had never smoked. Dynapenia was defined as grip strength <28 kg for men and <18 kg for women based on the Asian Working Group for Sarcopenia 2019 criteria. Multivariable logistic regression analysis evaluated the association between smoking cessation and dynapenia. Results: Compared with current smokers, the adjusted odds ratio (AOR) of dynapenia in former smokers was 0.66 (95% CI: 0.44–0.99). The AORs for smoking cessation periods of ≤10 years, 10–20 years, 20–30 years, and >30 years were 0.67 (95% CI: 0.39–1.16), 0.61 (95% CI: 0.36–1.03), 0.65 (95% CI: 0.37–1.14), and 0.52 (95% CI: 0.25–1.06), respectively. The AOR for dynapenia significantly decreased with the years since smoking cessation (p for trend=0.043). Conclusions: Our findings suggest that smoking cessation can reduce the likelihood of dynapenia among older lifetime smokers, with a decreasing likelihood trend associated with longer cessation periods. [ABSTRACT FROM AUTHOR]

Background and Aim: The study aims to determine the prognostic impact of obesity, sarcopenic obesity, and dynapenic obesity in patients with chronic liver disease. Methods: This retrospective observational study enrolled patients with chronic hepatitis (n = 746) and liver cirrhosis (n = 434) without hepatocellular carcinoma at entry. The patients were evaluated for sarcopenia and obesity between April 2016 and April 2022. Obesity was defined as a body mass index of ≥ 25 kg/m2. Sarcopenic obesity was defined as low skeletal muscle mass (pre‐sarcopenia) with obesity and dynapenic obesity was defined as low muscle strength (dynapenia) with obesity. The effects of obesity on survival were evaluated retrospectively. Results: The mean observation period was 2.5 years. Obesity, sarcopenic obesity, and dynapenic obesity were found in 271 (45.5%), 17 (2.9%), and 21 (3.5%) men, and 261 (44.7%), 59 (10.1%), and 53 (9.1%) women, respectively. A multivariate Cox proportional hazards model revealed that Child–Pugh class, dynapenia (hazard ratio [HR] 3.89), elderly (≥ 65 years old) (HR 2.11), and obesity (HR 0.58) were independently associated with overall survival (OS). However, neither sarcopenic nor dynapenic obesity were associated with OS. In patients with cirrhosis, the OS of the obese group was significantly higher than that of the non‐obese group. The effect of obesity on OS was significant in elderly patients, but not in younger patients. Conclusions: Sarcopenic and dynapenic obesity seem unrelated to the prognosis of patients with chronic liver disease. Obesity has a positive effect on the prognosis of elderly patients with cirrhosis. [ABSTRACT FROM AUTHOR]

As the global demographic shifts toward an aging population, aging-related problems, particularly in older individuals with dynapenia, are increasingly gaining attention. However, interventional studies focusing on physical and cognitive function and sleep quality in such individuals are limited, indicating a need for further exploration. The present study investigated the effects of whole-body vibration (WBV) training on physical and cognitive function and sleep quality in older people with dynapenia residing in long-term care institutions. This study was a randomized controlled trial. The experimental group underwent WBV training three times a week for 3 months, whereas the control group continued with their regular daily care routine. Statistical analyses were performed using the Traditional Chinese version of SAS Statistics version 9.4. Paired t tests, a one-way analysis of variance, independent t tests, and generalized estimating equation analysis were performed. The results revealed that compared with the control group, the experimental group experienced significant improvements in grip strength, instrumental activities of daily living, cognitive function, and sleep quality in terms of latency and duration. These findings suggest that 3 months of WBV training can effectively enhance physical and cognitive function and sleep quality in older people with dynapenia residing in long-term care institutions. [ABSTRACT FROM AUTHOR]

Introduction Muscle strength is known to play an important role in the health of older adults. The health burden of cigarette smoking among older adults remains significant. We investigated the association between smoking cessation and dynapenia among older lifetime smokers in Korea. Methods This study is a secondary dataset analysis of cross-sectional data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016– 2019. We included 1450 participants aged 65–79 years, excluding those who had never smoked. Dynapenia was defined as grip strength

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Dynapenia refers to muscle weakness related to aging and is defined as a loss of muscle strength associated with muscle quality. The purpose of this study is to identify the prevalence of dynapenia and associated risk factors by gender and age in domestic adults and to provide customized basic data for the prevention of dynapenia through its management. Based on the data from 2014 to 2019 of the Korea National Health and Nutrition Survey, 20,950 adults over the age of 20 who participated in grip strength tests and health surveys were selected as participants. Factors related to dynapenia were analyzed using complex sample multilogistic regression analysis. The prevalence of dynapenia in domestic adults was 6.3%, 4.1% in men, and 8.7% in women. Prevalence in the second decade was 5.3%, in the third decade was 3.2%, in the fourth decade was 3.3%, in the fifth decade was 4.8%, in the sixth decade was 8.9%, and was 24.6% for participants in their seventh decade or beyond. Among the factors related to dynapenia, age, BMI, and alcohol status were common in both men and women; education level, HDL-C, and resistance exercise were common in men; and high blood pressure, high blood sugar, and aerobic exercise were common in women. Our findings indicate that several factors are associated with dynapenia, which should be considered as potential targets for interventions focused on both individual and public health measures. [ABSTRACT FROM AUTHOR]

Sarcopenia and decreased muscle strength (dynapenia) are emerging health issues. However, the study exploring muscle strength changes of both upper and lower limbs at the same time among all age groups is rare. This study aims to investigate the muscle strength and to establish a muscle strength norm of an ostensibly healthy non-diabetic Asian population. From 2018 June to 2020 March, subjects (aged from 20 to <80 years old) undergoing health checkup in Good Liver Medical Examination Center and National Taiwan University Hospital Geriatrics and Gerontology Department were enrolled. A battery of muscle power examinations including handgrip strength (HGS), five times sit-to-stand test (5TSTS), and one-leg standing test (OLST) were performed. A total of 183 participants was enrolled, consisting of 92 females and 91 males. The finding shows the strongest HGS, best 5TSTS, and the longest OLST of both genders appeared in the 20-29-year-old group. Age, gender, and palm length are significantly related to HGS, whereas age is the only factor affecting 5TSTS and OLST. It revealed a progressive decline during ageing process, especially after age 60. Finally, Z-score and T-score norms of these were established. These data will be useful as normal controls for muscle strength of specific disease groups. The application of the cutoffs from these data and their comparisons with the recommended cutoffs from various guidelines worth further exploration. [ABSTRACT FROM AUTHOR]

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 2-3x 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. [ABSTRACT FROM AUTHOR]

BackgroundDynapenic obesity (DO) is the coexistence of excess adipose tissue/body weight and low muscle strength. This condition is associated with an increased risk of suffering from various chronic diseases and physical deterioration in older people.AimTo analyze the association between DO phenotypes and physical performance in middle-aged women living in the community.MethodsThis cross-sectional study was conducted on middle-aged and older women (≥50 years) residing in Guayaquil, Ecuador. Dynapenia was diagnosticated by a handgrip strength (HGS)

Objective: To investigate the associations between dynapenic obesity and the risk of dementia, and the modifying effects of age, sex, and the APOE gene, using a large population-based cohort. Methods: 279,884 participants aged 55 and above from the UK Biobank were included. The participants were classified into four categories based on body mass index and hand grip strength: healthy, obesity, dynapenia, and dynapenic obesity. The incident dementia was identified based on linked hospital records and death register data. Cox proportional hazards regression models were used to estimate the associations, followed by age-, sex-, and apolipoprotein E (APOE) gene-stratified analyses. Results: During the median follow-up of 12.4 years, 5,170 (1.8%) participants developed dementia. Compared with the healthy group, participants with dynapenic obesity had 67% higher dementia risk (hazard ratio [HR]: 1.67, 95% confidence interval [CI]: 1.44–1.94). Compared with the healthy group, higher risks of dementia in participants with dynapenic obesity were respectively observed in male (HR: 2.03, 95% CI: 1.65–2.50), younger (

Objective: The detection and classification of sarcopenia involves the analysis of many variables (50 to 60), which increases the time and costs required to diagnose and manage this condition. The objective of the study was to develop a synthetic statistical index to diagnose and classify sarcopenia in physically active women over 60 years old. Methodology: We conducted a cross-sectional study on 100 physically active women (64.88 ±4.4 years) on whom body composition measurements, muscle strength, and gait tests were performed. One thousand random selections of both training and test sets (80% and 20%, respectively) were made, logistic regression was fitted, and the regularization procedure (Elastic net regression) was performed. Results: the skeletal appendicular mass index (kg/m2), muscle mass (kg/m2) and SAMI (kg/m2) are highly correlated (0.93) and slow gait speed (m/sec) were the variables that contributed the most to the diagnosis of sarcopenia with a visibly high correlation, (94%). Conclusion: appendicular lean mass, gait speed, and explosive strength sufficiently describe the state of muscle and functional deterioration (sarcopenia) in physically active older women. Also, the precise identification and classification of this condition facilitates comprehensive multidisciplinary intervention, increasing the positive impact of health promotion and disease prevention programs

Abstract To identify biomarkers that precede the decline of human function and independence during the lifespan, two important concepts have been introduced in recent decades: sarcopenia and dynapenia. While the former is originally focused on skeletal muscle loss, the latter is on maximal strength loss. Although the dynapenia concept implies the inclusion of skeletal muscle power, in practical terms, this has not been specifically addressed. For instance, only 2 out of 220 studies published between 2008 and 2023 have directly measured muscle power to classify individuals with dynapenia. As previous studies have shown a greater relevance of skeletal muscle power in healthy aging, we hereby propose the introduction of the term “powerpenia” to specifically reflect the loss of skeletal muscle power along lifespan, but also with disease and/or physical inactivity. Together with sarcopenia and dynapenia, we contend that powerpenia should be considered a biomarker of healthy aging.

Aim: The combination of dynapenia (age-related muscle weakness) and obesity is referred to as dynapenic obesity. We examined the associations between dynapenic obesity and cortical bone thickness and trabecular bone density. Methods: The participants were 797 community-dwelling postmenopausal women (with an average age of 62.5 years) who were stratified into normopenia without obesity, dynapenia without obesity (dynapenia), normopenia with obesity (obesity) and dynapenia with obesity (dynapenia obesity) groups based on their grip strength and body fat percentage. Cortical bone thickness and trabecular bone density were measured using ultrasonic bone densitometry. The participants were further divided into those with low cortical bone thickness and low trabecular bone density. Logistic regression analysis was used to identify associated factors. Results: Individuals with dynapenia (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.16-2.68), obesity (OR 2.46, 95% CI 1.62-3.75) and dynapenic obesity (OR 4.07, 95% CI 2.44-6.79) all significantly increased the odds of low cortical bone thickness. Conversely, the odds of low trabecular bone density were significantly lower in the obesity group (OR 0.65, 95% CI 0.43-0.99) and dynapenic obesity group (OR 0.60, 95% CI 0.37-0.97). Conclusions: Dynapenic obesity was found to be associated with cortical bone thinning that might compromise bone health. Postmenopausal women with dynapenic obesity might need to be closely monitored for preserving bone health. [ABSTRACT FROM AUTHOR]

Background: There are few studies that assess the relationship between nutritional status and quality of life in individuals with Parkinson's disease, despite the well-established negative impact of sarcopenia and dynapenia on functional capacity and quality of life. These conditions impair protein-muscular status and are prevalent in individuals with Parkinson's disease. This study aimed to examine the relationship between nutritional status, including body composition, functional capacity, and diagnosis of sarcopenia and dynapenia, and quality-of-life perception in individuals with Parkinson's disease. Methods: This is a cross-sectional study conducted in two Parkinson's disease centers in the northeast of Brazil. The researchers assessed muscle strength, muscle mass, and physical performance to diagnose dynapenia, sarcopenia and functional capacity. Quality of life was estimated using the Parkinson's disease Quality of Life Questionnaire. Results: We found positive correlations between quality of life and variables such as severity and duration of the disease, as well as positive screening for sarcopenia (p<0.001). Negative correlations were observed between quality of life and muscle strength and functional capacity. The study also found that individuals with sarcopenia and dynapenia had significantly worse quality-of-life scores compared to those who did not have these nutritional outcomes (p <0.05; p <0.001). Conclusions: The presence of sarcopenia, dynapenia, low gait speed, disease duration, and severity had an impact on higher scores in the Parkinson's Disease Quality of Life Questionnaire, indicating a worsening perception of quality of life. [ABSTRACT FROM AUTHOR]

To identify biomarkers that precede the decline of human function and independence during the lifespan, two important concepts have been introduced in recent decades: sarcopenia and dynapenia. While the former is originally focused on skeletal muscle loss, the latter is on maximal strength loss. Although the dynapenia concept implies the inclusion of skeletal muscle power, in practical terms, this has not been specifically addressed. For instance, only 2 out of 220 studies published between 2008 and 2023 have directly measured muscle power to classify individuals with dynapenia. As previous studies have shown a greater relevance of skeletal muscle power in healthy aging, we hereby propose the introduction of the term "powerpenia" to specifically reflect the loss of skeletal muscle power along lifespan, but also with disease and/or physical inactivity. Together with sarcopenia and dynapenia, we contend that powerpenia should be considered a biomarker of healthy aging. Key Points: • Skeletal muscle power is more influential than muscle strength and mass in enhancing physical function and reducing falls in older adults, and is a more sensitive marker of disease presence and/or physical inactivity; • The existing concepts of sarcopenia and dynapenia are commonly accepted and used among professionals and researchers in the fields of health and physical exercise. However, concept of dynapenia has been focused on skeletal muscle maximal strength rather than power, and sarcopenia does not include muscle power as a criterion. • We propose the introduction of the term powerpenia to specifically address the loss of skeletal muscle power with aging, disease, and/or physical inactivity. [ABSTRACT FROM AUTHOR]

Background: Timed chair rise tests are frequently used as a substitute for assessing leg muscle strength or power. To determine if timed chair rise tests are an indicator of lower extremity muscle power, we examined the relationship between the repetitions completed in a 30-s chair rise test and the power generated during the test. Methods: Seventy-five individuals participated in this study (n = 30 < 65 years and 45 ≥ 65 years). Participants underwent a 30-s chair rise test while instrumented with a power analyzer. Handgrip strength was also evaluated. Results: The relationship between chair rise repetitions and average chair rise power was R² = 0.32 (p < 0.001). Chair rise repetitions when regressed on a total (i.e., summed) chair rise power, it yielded R² = 0.70 with data from all participants combined (p < 0.001). A mediation analysis indicated that anthropometrics partially mediates the relationship between chair rise repetitions and total chair rise power accounting for 2.8%-6.9% of the variance. Conclusion: Our findings indicate that in older adults, the overall performance of chair rises offers limited information about the average power per rise but is more indicative of the cumulative power exerted. Thus, the total number of chair rises in a 30-s test is likely a more comprehensive metric of overall muscular power, reflecting endurance aspects as well. Additionally, we found that personal physical attributes, such as height and weight, partially influence the link between chair rise count and total power, highlighting the importance of factoring in individual body metrics in assessments of muscular performance. [ABSTRACT FROM AUTHOR]

Abdominal obesity (AO) and dynapenia (DP) are associated with cognitive decline, and the relationship between dynapenic abdominal obesity (DAO), a combination of DP and AO, and mild cognitive impairment (MCI) has been confirmed. This study aims to determine whether this relationship exhibits potential sex differences. The relationship between MCI and DAO was confirmed in 1309 community elderly individuals aged 65 years or older who were not diagnosed with dementia. The MCI was defined as a Korean mini-mental state examination (K-MMSE) score of 18–23 points. Multiple logistic regression analyses were conducted, categorizing participants into groups: a control group without AO or DP, an AO group, a DP group, and a DAO group. The study results showed that in women, both DP and DAO were significantly associated with MCI not only in the unadjusted Model 1 but also in Model 2, which adjusted for general characteristics and health behaviors, and Model 3, which additionally adjusted for chronic diseases and disease-related characteristics. In men, DP was associated with MCI in the unadjusted Model 1. The findings highlight sex differences in the impact of the DAO on MCI. These differences should be considered when studying the factors related to MCI in old age. [ABSTRACT FROM AUTHOR]

Aim: Muscle mass and strength correlate with cognitive function; however, it remains unclear whether dynapenia (i.e., muscle weakness with preserved muscle mass) is relevant. This study aimed to explore whether dynapenia is associated with global cognitive function in community‐dwelling older Japanese adults. Methods: This cross‐sectional study used data from the Integrated Research Initiative for Living Well with Dementia Cohort Study, which pooled data from five community‐based geriatric cohorts. Dynapenia was defined as muscle weakness without muscle mass loss according to the Asian Working Group for Sarcopenia criteria. Cognitive function was assessed using the Mini‐Mental State Examination (MMSE). An ordered logistic regression analysis was conducted with dynapenia as the exposure and with cognitive decline stages, defined as an MMSE score of 27–30 for normal cognition, 24–26 for possible cognitive decline, and <24 for cognitive decline, as the outcome, stratified by sex and adjusted for age, muscle mass, education, alcohol consumption, smoking habits, living alone, and non‐communicable diseases. Results: We analyzed data for 3338 participants (2162 female) with preserved muscle mass. Of these, 449 (13.5%) had dynapenia, and 79 (2.4%) exhibited cognitive decline. Multivariate odds ratios (95% confidence interval) for cognitive decline among those with dynapenia, compared with those without dynapenia, were 1.51 (1.02–2.24) for males and 2.08 (1.51–2.86) for females. Conclusions: Muscle weakness is associated with cognitive decline, even in individuals with preserved muscle mass. Further studies are needed to better understand the association between muscle weakness and cognitive decline over time in order to develop dementia prevention strategies for those with dynapenia. Geriatr Gerontol Int 2024; 24: 123–129. [ABSTRACT FROM AUTHOR]

Sarcopenia is defined as an age-related decline in muscle mass, muscle strength, and physical performance. Eating alone has been linked to various health issues in older adults. This study investigated the relationship between eating alone and handgrip strength (HGS) in older adults using data from 7278 individuals (≥65 years) who participated in the 2014–2019 Korea National Health and Nutrition Examination Survey. HGS was measured using a digital grip strength dynamometer, relative HGS was calculated by dividing HGS by body mass index, and dynapenia was defined as an HGS < 28 kg for men and <18 kg for women. Multivariable logistic regression analysis showed that women who ate two meals alone were more likely to exhibit dynapenia than those who never ate alone (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.03–1.77). If the groups that never ate alone or ate one meal alone were combined as the reference group, the probability of dynapenia was higher in the combined groups that ate two or three meals alone (OR, 1.25; 95% CI, 1.04–1.50). No association was observed between eating alone and dynapenia in men. This suggests that eating alone is a modifiable related factor of dynapenia in older women. [ABSTRACT FROM AUTHOR]

The associations of dynapenic abdominal obesity and transitions with frailty progression remain unclear among middle-aged and older adults. We included 6937 participants from the China Health and Retirement Longitudinal Study (CHARLS) and 3735 from the English Longitudinal Study of Aging (ELSA). Participants were divided into non-dynapenia and non-abdominal obesity (ND/NAO), abdominal obesity alone (AO), dynapenia alone (D), and dynapenic abdominal obesity (D/AO). Frailty status was assessed by the frailty index (FI), and a linear mixed-effect model was employed to analyze the associations of D, AO, D/AO, and transitions with frailty progression. Participants with AO, D, and D/AO had increased FI progression compared with ND/NAO in both cohorts. D/AO possessed the greatest additional annual FI increase of 0.383 (95% CI: 0.152 to 0.614), followed by D and AO in the CHARLS. Participants with D in the ELSA had the greatest magnitude of accelerated FI progression. Participants who transitioned from ND/NAO to D and from AO to D/AO presented accelerated FI progression in the CHARLS and ELSA. In conclusion, dynapenic abdominal obesity, especially for D/AO and D, presented accelerated frailty progression. Our findings highlighted the essential intervention targets of dynapenia and abdominal obesity for the prevention of frailty progression. [ABSTRACT FROM AUTHOR]

Introduction: Magnetic resonance imaging (MRI) enables direct measurements of muscle volume and quality, allowing for an in-depth understanding of their associations with anthropometric traits, and health conditions. However, it is unclear which muscle volume measurements: total muscle volume, regional measurements, measurements of muscle quality: intermuscular adipose tissue (IMAT) or proton density fat fraction (PDFF), are most informative and associate with relevant health conditions such as dynapenia and frailty. Methods: We have measured image-derived phenotypes (IDPs) including total and regional muscle volumes and measures of muscle quality, derived from the neck-to-knee Dixon images in 44,520 UK Biobank participants. We further segmented paraspinal muscle from 2D quantitative MRI to quantify muscle PDFF and iron concentration. We defined dynapenia based on grip strength below sex-specific cut-off points and frailty based on five criteria (weight loss, exhaustion, grip strength, low physical activity and slow walking pace). We used logistic regression to investigate the association between muscle volume and quality measurements and dynapenia and frailty. Results: Muscle volumes were significantly higher in male compared with female participants, even after correcting for height while, IMAT (corrected for muscle volume) and paraspinal muscle PDFF were significantly higher in female compared with male participants. From the overall cohort, 7.6% (N = 3,261) were identified with dynapenia, and 1.1% (N = 455) with frailty. Dynapenia and frailty were positively associated with age and negatively associated with physical activity levels. Additionally, reduced muscle volume and quality measurements were associated with both dynapenia and frailty. In dynapenia, muscle volume IDPs were most informative, particularly total muscle exhibiting odds ratios (OR) of 0.392, while for frailty, muscle quality was found to be most informative, in particular thigh IMAT volume indexed to height squared (OR = 1.396), both with p-values below the Bonferroni-corrected threshold (p < 8.8 × 10−5). Conclusion: Our fully automated method enables the quantification of muscle volumes and quality suitable for large population-based studies. For dynapenia, muscle volumes particularly those including greater body coverage such as total muscle are the most informative, whilst, for frailty, markers of muscle quality were the most informative IDPs. These results suggest that different measurements may have varying diagnostic values for different health conditions. [ABSTRACT FROM AUTHOR]

Background: Dynapenic abdominal obesity (DAO) is the combination of low muscle strength and high central adiposity, which can lead to functional and cardiometabolic impairments. Objective: The aim of this study was to examine the relationship between DAO and metabolic parameters in non-geriatric patients with obesity. Methods: All patients seen in the obesity outpatient clinic during a random month, along with 30 healthy individuals, were included in the study. Body mass index (BMI), waist circumference (WC), hip circumference (HC), serum fasting blood glucose, triglyceride, high-density lipoprotein, low-density lipoprotein (LDL), insulin, and glycated hemoglobin (HbA1c) levels were measured. Muscle function tests were conducted. Hypertension and diabetes mellitus diagnoses were recorded. DAO was determined using handgrip strength and WC. Metabolic syndrome was defined based on International Diabetes Federation (IDF) criteria. Data were analyzed using SPSS. Results: A total of 106 individuals participated in the study, including 76 individuals with obesity as the case group and 30 healthy individuals as the control group. In the case group, BMI, WC, HC, and chair stand test results were higher compared to the control group. There was no significant difference between the case and control groups in terms of gait speed or handgrip test results. In the case group, 30 people (39.5%) had dynapenic obesity (DO), and in the control group, 8 people (26.7%) had DO. There was no significant difference in DO rates between the case and control groups. In the case group, the HbA1c level was higher in DO (+) group than DO (−) group. In the control group, DO (+) group had higher LDL and HbA1c level than DO (−) group. No significant difference was observed in other search parameters between the DO (+) and DO (−) groups in both the case and control groups. Conclusion: DAO is common among people with obesity and contributes to a poor prognosis, increased morbidity, and mortality. Therefore, including its treatment in the management of obesity is crucial for individuals of all age ranges. [ABSTRACT FROM AUTHOR]

Aging is associated with decreased muscle strength and power. Power is particularly important for maintaining the independence of older adults when performing activities of daily living. The countermovement jump has been identified as a reliable and safe method to assess lower extremity power across the lifespan. The purpose of this investigation was to study sex differences and age-related changes in countermovement jump peak power among masters weightlifters with the secondary purpose of comparing results to previous reports of community and masters athletes. Female (n = 63, 39 to 70 yrs, med (56 yrs)) and male (n = 39, 35 to 86 yrs, med (59 yrs)) participants of the 2022 World Masters Championships completed three maximal effort countermovement jump repetitions following a dynamic warm-up. Vertical ground reaction forces were recorded, and peak power normalized to body mass was calculated. Results indicated significant age-related peak power among weightlifters, with the decline being significantly more pronounced in males than females. Female weightlifters exhibited less age-related decline compared to normative data as well as the other Master athlete comparison cohorts (short and long-distance runners), whereas the males demonstrated similar age-related declines as the comparison cohorts. While the female weightlifters in the current study generally demonstrated the least age-related declines in CMJ peak power of the comparative literature, the male weightlifters showed similar age-related decline rates.

As the global demographic shifts toward an aging population, aging-related problems, particularly in older individuals with dynapenia, are increasingly gaining attention. However, interventional studies focusing on physical and cognitive function and sleep quality in such individuals are limited, indicating a need for further exploration. The present study investigated the effects of whole-body vibration (WBV) training on physical and cognitive function and sleep quality in older people with dynapenia residing in long-term care institutions. This study was a randomized controlled trial. The experimental group underwent WBV training three times a week for 3 months, whereas the control group continued with their regular daily care routine. Statistical analyses were performed using the Traditional Chinese version of SAS Statistics version 9.4. Paired t tests, a one-way analysis of variance, independent t tests, and generalized estimating equation analysis were performed. The results revealed that compared with the control group, the experimental group experienced significant improvements in grip strength, instrumental activities of daily living, cognitive function, and sleep quality in terms of latency and duration. These findings suggest that 3 months of WBV training can effectively enhance physical and cognitive function and sleep quality in older people with dynapenia residing in long-term care institutions.

Weakness, one of the key characteristics of sarcopenia, is a significant risk factor for functional limitations and disability in older adults. It has long been suspected that reductions in motor unit firing rates (MUFRs) are one of the mechanistic causes of age-related weakness. However, prior work has not investigated the extent to which MUFR is associated with clinically meaningful weakness in older adults. Forty-three community-dwelling older adults (mean: 75.4 ± 7.4 years; 46.5% female) and 24 young adults (mean: 22.0 ± 1.8 years; 58.3% female) performed torque matching tasks at varying submaximal intensities with their non-dominant leg extensors. Decomposed surface electromyographic recordings were used to quantify MUFRs from the vastus lateralis muscle. Computational modeling was subsequently used to independently predict how slowed MUFRs would negatively impact strength in older adults. Bivariate correlations between MUFRs and indices of lean mass, voluntary activation, and physical function/mobility were also assessed in older adults. Weak older adults (n = 14) exhibited an approximate 1.5 and 3 Hz reduction in MUFR relative to non-weak older adults (n = 29) at 50% and 80% MVC, respectively. Older adults also exhibited an approximate 3 Hz reduction in MUFR relative to young adults at 80% MVC only. Our model predicted that a 3 Hz reduction in MUFR results in a strength decrement of 11–26%. Additionally, significant correlations were found between slower MUFRs and poorer neuromuscular quality, voluntary activation, chair rise time performance, and stair climb power (r's = 0.31 to 0.43). These findings provide evidence that slowed MUFRs are mechanistically linked with clinically meaningful leg extensor weakness in older adults. [ABSTRACT FROM AUTHOR]

Background There is a scarcity of studies examining the longitudinal relationship between dynapenic abdominal obesity (DAO; ie, impairment in muscle strength and high waist circumference) and future fall risk. Therefore, we aimed to investigate the prospective association between DAO at baseline and falls occurring during 2 years of follow-up in a nationally representative sample of middle-aged and older individuals from Ireland. Methods Data from 2 consecutive waves of the Irish Longitudinal Study on Ageing survey were analyzed. Dynapenia was defined as handgrip strength of <26 kg for men and <16 kg for women. Abdominal obesity was defined as a waist circumference of >88 cm for women and >102 cm for men. DAO was assessed at Wave 1 (2009–2011) and was defined as having both dynapenia and abdominal obesity. Falls occurring between Wave 1 and Wave 2 (2012–2013) were self-reported. Multivariable logistic regression analysis was conducted. Results Data on 5 275 individuals aged ≥50 years were analyzed (mean [standard deviation { SD }] age 63.2 [8.9] years; 48.8% males). After adjustment for potential confounders, compared to no dynapenia and no abdominal obesity at baseline, DAO was significantly associated with 1.47 (95% confidence interval [CI]: 1.14–1.89) times higher odds for falls at 2-year follow-up. Dynapenia alone (odds ratio [OR] = 1.08; 95% CI: 0.84–1.40) and abdominal obesity alone (OR = 1.09; 95% CI: 0.91–1.29) were not significantly associated with falls at follow-up. Conclusions DAO increased the risk for falls among middle-aged and older adults in Ireland. Interventions to prevent or reverse DAO may be beneficial for fall reduction. [ABSTRACT FROM AUTHOR]

Objective: Cross-sectional study to verify the association between dynapenic abdominal obesity and the occurrence of single and recurrent falls among Brazilian adults aged 50 years and over. Methods: Baseline data from the Brazilian Longitudinal Study of Aging (ELSI-Brazil), comprising 8374 individuals aged 50 years and over, were analyzed. Participants were categorized according to the report of falls, dynapenic abdominal obesity was determined by combining the presence of abdominal obesity (waist circumference) and dynapenia (handgrip strength). A multinomial regression adjusted for multiple variables was conducted. Results: The prevalence of a fall was 10.4% (95% CI: 9.7–11.2) and 10.8% for single and recurrent (95% CI: 9.9–11.9). Dynapenic abdominal obesity was associated with a single fall (OR: 1.3; 95% CI 1.1–1.7) and showed greater strength of association with recurrent falls (OR: 2.8; 95% CI 2.1–3.8). Conclusions: Our data showed that the coexistence of abdominal obesity and dynapenia in older adults creates additional challenges for aging. [ABSTRACT FROM AUTHOR]

Background: The main objective of this study was to investigate the risk of falls among middle-aged and older adults with dynapenic abdominal obesity. Methods: A systematic literature search was conducted to review and analyze relevant studies. Dynapenia was measured by handgrip strength, and abdominal obesity was measured by waist circumference. The search keywords included "older people" OR "elderly" OR "middle age" AND "dynapenia" AND "abdominal obesity" AND "fall." The search was not limited by time and included articles published up until April 2023. The literature search process followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, involving extraction and examination of the retrieved relevant articles. Systematic literature searches were performed in databases such as Embase, PubMed, MEDLINE, CINAHL, and Cochrane Library. Results: This study collected a total of eight articles with a combined sample size of 15,506 participants. The findings revealed that the average follow-up period for falls was 6.6 years (SD = 3.67). The overall results of the study showed that individuals with dynapenic abdominal obesity had a higher risk of falls compared to those without dynapenic abdominal obesity (RR = 6.91, 95% CI: 5.42–8.80). Subgroup analysis demonstrated that both prospective studies (HR = 6.61; 95% CI = 4.29–10.20) and retrospective studies (OR = 7.37; 95% CI = 5.13–10.59) consistently found a higher risk of falls among individuals with dynapenic abdominal obesity. However, there was no significant difference in fall risk between community-dwelling individuals with dynapenic abdominal obesity and hospitalized individuals with dynapenic abdominal obesity (Qbetweenx2 = 0.29, p = 0.58). Additionally, there was no difference in fall risk between individuals with dynapenic abdominal obesity residing in Europe and Latin America compared to those residing in Asia (Qbetweenx2 = 0.05, p = 0.81). It was worth noting that male individuals with dynapenic abdominal obesity had a higher risk of falls compared to females (Qbetweenx2 = 4.73, p = 0.03). Conclusions: Empirical studies have demonstrated that individuals with dynapenic abdominal obesity have a higher risk of falls. Therefore, healthcare professionals should conduct early fall risk assessments and develop effective preventive strategies specifically targeted at individuals with dynapenic abdominal obesity. [ABSTRACT FROM AUTHOR]

Background: Sarcopenia has recently been recognized as a complication of diabetes. However, there are few results about the prevalence of sarcopenia and dynapenia and the related clinical outcomes in type 1 diabetes mellitus (T1DM). Our objectives were to evaluate the prevalence of sarcopenia and dynapenia and to determine whether there are any associations with disease-related factors in people with T1DM. Methods: A cross-sectional study was conducted in people with T1DM. We assessed appendicular skeletal mass index (ASMI) using bioimpedance 50 Hz (Nutrilab Akern). Muscle function was assessed through handgrip strength (HGS) using a Jamar dynamometer. Sarcopenia was defined as a low HGS with low ASMI, whereas dynapenia was defined as low HGS with a normal ASMI. We used HGS data from the Spanish population percentile table and a cut-off point at p5 as dynapenia. The association of clinical, metabolic, and lifestyle variables with sarcopenia and dynapenia was studied. Results: This study included 62 T1DM patients (66% females, mean age of 38 ± 14 years, body mass index (BMI) of 24.9 ± 4.7 kg/m2). The prevalence of sarcopenia and dynapenia was 8% and 23%, respectively. In our sample, there were more men in the sarcopenic and dynapenic groups. The sarcopenic group showed a significantly higher mean HbA1c value. Lower diabetes duration, PREDIMED score, BMI, and muscle mass measures (fat-free mass index (FFMI), ASMI, and body cell mass index (BCMI)) were significantly associated with sarcopenia. Decreased diabetes duration, PREDIMED score, phase angle (PhA), and HGS values showed a significant association with dynapenia. Conclusions: The prevalence of sarcopenia and dynapenia was high in people with T1DM in our study. Specifically, the proportion of dynapenia was quite high. HGS and ASMI are practical tools for the assessment of muscle health status in T1DM, and low values are associated with poor glycemic control, underweight, and low adherence to the Mediterranean diet. Thus, dynapenia may predict accelerated muscle aging in T1DM. [ABSTRACT FROM AUTHOR]

Objectives: To analyse whether dynapenic abdominal obesity is a risk factor for Metabolic syndrome (MetS) and its components in individuals 50 years of age or older. Design: A longitudinal study was conducted with an eight-year follow-up. Setting: Representative sample of community-dwelling participants of the English Longitudinal Study of Ageing (ELSA). Participants: 3,952 individuals free of MetS at baseline. Measurements: Dynapenic abdominal obesity was defined based on waist circumference (> 102 cm for men and > 88 cm for women) and grip strength (< 26 kg for men and < 16 kg for women). The participants were classified as non-abdominally obese/non-dynapenic (NAO/ND - reference group), abdominally obese/non-dynapenic (AO/ ND), non-abdominally obese/dynapenic (NAO/D) and abdominally obese/dynapenic (AO/D). The outcome was the incidence of MetS based on the presence of three or more of the following criteria: hypertriglyceridemia, hyperglycaemia, low HDL cholesterol, arterial hypertension or body mass index ≥ 30 kg/m2 throughout eight-year follow-up. Additionally, the incidence of each component of MetS was also analyzed. Poisson regression models were run and controlled for sociodemographic, behavioural and clinical variables. Results: The mean age of the participants was 65 years and 55% were women. The prevalence of AO/ND, NAO/D and AO/D were 35.3, 4.3 and 2.2%, respectively. At the end of follow-up 558 incident cases of MetS were recorded. The adjusted model demonstrated that although abdominal obesity was a risk factor for MetS (IRR: 2.26; 95% CI: 1.87–2.73), the IRR was greater in AO/D individuals (IRR: 3.34; 95% CI: 2.03–5.50) compared with ND/NAO group. Furthermore, ND/AO was a risk factor for incidence of hypertriglyceridemia (IRR: 1.27; 95% CI: 1.06–1.52), hyperglycaemia (IRR: 1.41; 95% CI: 1.18–1.69), low HDL cholesterol (IRR: 1.70; 95% CI: 1.32–2.19) and BMI ≥ 30 kg/ m2 (IRR: 2.58; 95% CI: 2.04–3.26) while D/AO was a risk factor for hyperglycaemia (IRR: 1.78; 95% CI: 1.02–3.10), low HDL cholesterol (IRR: 2.36; 95% CI: 1.10–5.08), and BMI ≥ 30 kg/m2 (IRR: 2.79; 95% CI: 1.38–5.62). Conclusions: Dynapenic abdominal obesity increases the risk of MetS, with a higher IRR compared to obesity alone. The understanding of this synergic action could guide specific clinical strategies, enabling the prevention of metabolic changes that can lead to cardiovascular disease, disability and death. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is caused by various factors such as chronic inflammation, oxidative stress, and obesity. Loss of muscle strength and mass is a negative prognostic factor for CKD. Therefore, in this study, we aimed to investigate the association between CKD and dynapenia in the Korean elderly. To this end, we analyzed 7029 participants from the 2014–2019 Korean National Health and Nutrition Examination Survey (KNHANES) aged ≥65 years. After adjusting for all of the covariates that could affect the results, such as physical examinations, lifestyle factors, and exercise, the association between CKD and dynapenia was found to be significant, at 1.207 (95% CI: 1.056–1.379) in CKD stage 2 and 1.790 (95% CI: 1.427–2.246) in CKD stage 3a–5. However, when sexes were analyzed separately, women were significant in both CKD stage 2 and stage 3–5 compared to normal, but only in stage 3–5 for men. Additionally, the prevalence of dynapenia increased significantly as the stage of CKD increased (normal, stage 2, and stage 3–5: 18.5%, 20.8%, and 32.3% in men and 27.5%, 34.4%, and 46.1% in women, respectively). Thus, CKD is significantly related to dynapenia, especially in women, when stratified by sex. [ABSTRACT FROM AUTHOR]

Dehydroepiandrosterone sulfate (DHEAS) is thought to be associated with life expectancy and anti-aging. Although skeletal muscle disorders are often found in diabetic people, the clinical significance of DHEAS in skeletal muscle remains unclear. Therefore, we aimed to determine whether DHEAS is associated with the development of skeletal muscle disorders in individuals with type 2 diabetes (T2D). A cross-sectional study was conducted in 361 individuals with T2D. Serum DHEAS levels, skeletal muscle mass index (SMI), handgrip strength (HS), and gait speed (GS) were measured in the participants. Pre-sarcopenia, sarcopenia, and dynapenia were defined according to the definitions of the AWGS 2019 criteria. DHEAS level was positively associated with HS but not with SMI or GS after adjustment of confounding factors. Multiple logistic regression analyses in total subjects showed that DHEAS level had an inverse association with the prevalence of dynapenia but not with the prevalence of pre-sarcopenia or sarcopenia. Furthermore, a significant association between DHEAS level and dynapenia was found in males but not in females. ROC curve analysis indicated that cutoff values of serum DHEAS for risk of dynapenia in males was 92.0 μg/dL. Therefore, in male individuals with T2D who have low serum levels of DHEAS, adequate exercise might be needed to prevent dynapenia. [ABSTRACT FROM AUTHOR]

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.

Background: Timed chair rise tests are frequently used as a substitute for assessing leg muscle strength or power. To determine if timed chair rise tests are an indicator of lower extremity muscle power, we examined the relationship between the repetitions completed in a 30-s chair rise test and the power generated during the test.Methods: Seventy-five individuals participated in this study (n = 30 < 65 years and 45 ≥ 65 years). Participants underwent a 30-s chair rise test while instrumented with a power analyzer. Handgrip strength was also evaluated.Results: The relationship between chair rise repetitions and average chair rise power was R2 = 0.32 (p < 0.001). Chair rise repetitions when regressed on a total (i.e., summed) chair rise power, it yielded R2 = 0.70 with data from all participants combined (p < 0.001). A mediation analysis indicated that anthropometrics partially mediates the relationship between chair rise repetitions and total chair rise power accounting for 2.8%–6.9% of the variance.Conclusion: Our findings indicate that in older adults, the overall performance of chair rises offers limited information about the average power per rise but is more indicative of the cumulative power exerted. Thus, the total number of chair rises in a 30-s test is likely a more comprehensive metric of overall muscular power, reflecting endurance aspects as well. Additionally, we found that personal physical attributes, such as height and weight, partially influence the link between chair rise count and total power, highlighting the importance of factoring in individual body metrics in assessments of muscular performance.

To estimate the prevalence of dynapenia and examine potential risk factors for dynapenia using a sample of rural middle-aged and elderly Chinese. A cross-sectional study of 253 Chinese adults aged 50 years and older was conducted from June to August in 2022 in Nanjing. A questionnaire was used to collect data on all socioeconomic variables. Body weight, height, body fat percentage, grip strength, waist circumference, calf circumference, and gait speed were measured. The prevalence of dynapenia was 69.6 %, 62.3 % in men and 72.7 % in women respectively. Binary logistic regressions indicated significant associations between dynapenia and age (odds ratio [OR] = 2.59; 95 % confidence interval [CI] 1.63, 4.12; p

Introduction: Magnetic resonance imaging (MRI) enables direct measurements of muscle volume and quality, allowing for an in-depth understanding of their associations with anthropometric traits, and health conditions. However, it is unclear which muscle volume measurements: total muscle volume, regional measurements, measurements of muscle quality: intermuscular adipose tissue (IMAT) or proton density fat fraction (PDFF), are most informative and associate with relevant health conditions such as dynapenia and frailty.Methods: We have measured image-derived phenotypes (IDPs) including total and regional muscle volumes and measures of muscle quality, derived from the neck-to-knee Dixon images in 44,520 UK Biobank participants. We further segmented paraspinal muscle from 2D quantitative MRI to quantify muscle PDFF and iron concentration. We defined dynapenia based on grip strength below sex-specific cut-off points and frailty based on five criteria (weight loss, exhaustion, grip strength, low physical activity and slow walking pace). We used logistic regression to investigate the association between muscle volume and quality measurements and dynapenia and frailty.Results: Muscle volumes were significantly higher in male compared with female participants, even after correcting for height while, IMAT (corrected for muscle volume) and paraspinal muscle PDFF were significantly higher in female compared with male participants. From the overall cohort, 7.6% (N = 3,261) were identified with dynapenia, and 1.1% (N = 455) with frailty. Dynapenia and frailty were positively associated with age and negatively associated with physical activity levels. Additionally, reduced muscle volume and quality measurements were associated with both dynapenia and frailty. In dynapenia, muscle volume IDPs were most informative, particularly total muscle exhibiting odds ratios (OR) of 0.392, while for frailty, muscle quality was found to be most informative, in particular thigh IMAT volume indexed to height squared (OR = 1.396), both with p-values below the Bonferroni-corrected threshold (p

Dynapenia refers to muscle weakness related to aging and is defined as a loss of muscle strength associated with muscle quality. The purpose of this study is to identify the prevalence of dynapenia and associated risk factors by gender and age in domestic adults and to provide customized basic data for the prevention of dynapenia through its management. Based on the data from 2014 to 2019 of the Korea National Health and Nutrition Survey, 20,950 adults over the age of 20 who participated in grip strength tests and health surveys were selected as participants. Factors related to dynapenia were analyzed using complex sample multilogistic regression analysis. The prevalence of dynapenia in domestic adults was 6.3%, 4.1% in men, and 8.7% in women. Prevalence in the second decade was 5.3%, in the third decade was 3.2%, in the fourth decade was 3.3%, in the fifth decade was 4.8%, in the sixth decade was 8.9%, and was 24.6% for participants in their seventh decade or beyond. Among the factors related to dynapenia, age, BMI, and alcohol status were common in both men and women; education level, HDL-C, and resistance exercise were common in men; and high blood pressure, high blood sugar, and aerobic exercise were common in women. Our findings indicate that several factors are associated with dynapenia, which should be considered as potential targets for interventions focused on both individual and public health measures.

Aging is anecdotally associated with a prolonged recovery from resistance training, though current literature remains equivocal. This brief review considers the effects of resistance training on indirect markers of muscle damage and recovery (i.e., muscle soreness, blood markers, and muscle strength) in older males. With no date restrictions, four databases were searched for articles relating to aging, muscle damage, and recovery. Data from 11 studies were extracted for review. Of these, four reported worse symptoms in older compared with younger populations, while two have observed the opposite, and the remaining studies (n = 6) proposed no differences between age groups. It appears that resistance training can be practiced in older populations without concern for impaired recovery. To improve current knowledge, researchers are urged to utilize more ecologically valid muscle-damaging bouts and investigate the mechanisms which underpin the recovery of muscle soreness and strength after exercise in older populations. [ABSTRACT FROM AUTHOR]

Abstract Background The growing population of older adults worldwide is associated with an extended life expectancy and an increasing proportion of older adults with dynapenia. Most research on dynapenia has involved only populations of older adults living in the community; little research has examined the effects of risk factors on sleep quality among older adults with dynapenia residing in assisted living facilities. Aim This study examined the relationships among physical function, nutrition, cognitive function, depression, and sleep quality among older adults with dynapenia residing in assisted living facilities. Methods In this cross-sectional study, data on physical function, nutrition, cognitive function, depression, and sleep quality was collected from 178 older adults with dynapenia residing in assisted living facilities, who were selected using purposive sampling. Descriptive statistical analysis, independent-sample t tests, chi-squared tests, and logistic regression analysis were performed using SPSS 25.0. Results The statistical analyses revealed correlations between sleep quality and age (t = 2.37, p

Background: After hospital discharge, post-COVID-19 syndrome has been observed to be associated with impaired diffusing capacity, respiratory muscle strength, and lung imaging abnormalities, in addition to loss of muscle mass/strength, sarcopenia, and obesity impact exercise tolerance, pulmonary functions, and overall prognosis. However, the relationship between lung function and the coexistence of obesity with low muscle strength and sarcopenia in post-COVID-19 patients remains poorly investigated. Therefore, our aim was to evaluate the association between lung function and the coexistence of obesity with dynapenia and sarcopenia in post-COVID-19 syndrome patients. Methods: This cross-sectional study included subjects who were hospitalized due to moderate to severe COVID-19, as confirmed by PCR testing. Subjects who could not be contacted, declined to participate, or died before the follow-up visit were excluded. Results: A total of 711 subjects were evaluated; the mean age was 53.64 ± 13.57 years, 12.4% had normal weight, 12.6% were dynapenic without obesity, 8.3% had sarcopenia, 41.6% had obesity, 21.2% had dynapenic obesity, and 3.8% had sarcopenic obesity. In terms of pulmonary function, the dynapenic subjects showed decreases of −3.45% in FEV1, −12.61 cmH2O in MIP, and -12.85 cmH2O in MEP. On the other hand, the sarcopenic subjects showed decreases of −6.14 cmH2O in MIP and −11.64 cmH2O in MEP. The dynapenic obesity group displayed a reduction of −12.13% in PEF. Conclusions: In post-COVID-19 syndrome, dynapenia and sarcopenia—both with and without obesity—have been associated with lower lung function. [ABSTRACT FROM AUTHOR]

Despite prior efforts to understand and target dynapenia (age‐induced loss of muscle strength), this condition remains a major challenge that reduces the quality of life in the aged population. We have focused on the neuromuscular junction (NMJ) where changes in structure and function have rarely been systematically studied as a dynamic and progressive process. Our cross‐sectional study found neurotransmission at the male mouse NMJ to be biphasic, displaying an early increase followed by a later decrease, and this phenotype was associated with structural changes to the NMJ. A cross‐sectional characterization showed that age‐induced alterations fell into four age groups: young adult (3–6 months), adult (7–18 months), early aged (19–24 months), and later aged (25–30 months). We then utilized a small molecule therapeutic candidate, GV‐58, applied acutely during the later aged stage to combat age‐induced reductions in transmitter release by increasing calcium influx during an action potential, which resulted in a significant increase in transmitter release. This comprehensive study of neuromuscular ageing at the NMJ will enable future research to target critical time points for therapeutic intervention. Key points: Age‐induced frailty and falls are the leading causes of injury‐related death and are caused by an age‐induced loss of muscle strength due to a combination of neurological and muscular changes.A cross‐sectional approach was used to study age‐induced changes to the neuromuscular junction in a mouse model, and physiological changes that were biphasic over the ageing time course were found.Changes in physiology at the neuromuscular junction were correlated with alterations in neuromuscular junction morphology.An acutely applied positive allosteric gating modifier of presynaptic voltage‐gated calcium channels was tested as a candidate therapeutic strategy that could increase transmitter release at aged neuromuscular junctions.These results provide a detailed time course of age‐induced changes at the neuromuscular junction in a mouse model and test a candidate therapeutic strategy for weakness. [ABSTRACT FROM AUTHOR]

Simple Summary: Much of what we know about the loss of skeletal muscle strength and mass (sarcopenia) in old age comes from studies of small laboratory rodents. In humans, this condition is generally not noticeable until late middle age when it affects our mobility (clinical stage). As muscle wasting progresses with age, it poses a challenge to independent living and worsens the health of those of us already suffering from other diseases. WHO and national health authorities have identified sarcopenia as one of the major age-related diseases we must try to curb. Observations in humans show that the process underlying sarcopenia goes on for decades before we notice it (preclinical phase). In this study, we show that the same disease process is observed in rats as in humans, and that skeletal muscles exhibit a series of adaptive responses to maintain muscle function and mass during the long period that precedes clinical symptoms. When these adaptive mechanisms are exhausted, the disease progresses to a clinical stage. We conclude that the rat is a useful model to further study the triggering mechanisms of this disease and, moreover, is suitable for assessing whether interventions to treat the disease are more successful in the preclinical phase than in the clinical phase. The facultative loss of muscle mass and function during aging (sarcopenia) poses a serious threat to our independence and health. When activities of daily living are impaired (clinical phase), it appears that the processes leading to sarcopenia have been ongoing in humans for decades (preclinical phase). Here, we examined the natural history of sarcopenia in male outbred rats to compare the occurrence of motor behavioral deficits with the degree of muscle wasting and to explore the muscle-associated processes of the preclinical and clinical phases, respectively. Selected metrics were validated in female rats. We used the soleus muscle because of its long duty cycles and its importance in postural control. Results show that gait and coordination remain intact through middle age (40–60% of median lifespan) when muscle mass is largely preserved relative to body weight. However, the muscle shows numerous signs of remodeling with a shift in myofiber-type composition toward type I. As fiber-type prevalence shifted, fiber-type clustering also increased. The number of hybrid fibers, myofibers with central nuclei, and fibers expressing embryonic myosin increased from being barely detectable to a significant number (5–10%) at late middle age. In parallel, TGFβ1, Smad3, FBXO32, and MuRF1 mRNAs increased. In early (25-month-old) and advanced (30-month-old) aging, gait and coordination deteriorate with the progressive loss of muscle mass. In late middle age and early aging due to type II atrophy (>50%) followed by type I atrophy (>50%), the number of myofibers did not correlate with this process. In advanced age, atrophy is accompanied by a decrease in SCs and βCatenin mRNA, whereas several previously upregulated transcripts were downregulated. The re-expression of embryonic myosin in myofibers and the upregulation of mRNAs encoding the γ-subunit of the nicotinic acetylcholine receptor, the neuronal cell adhesion molecule, and myogenin that begins in late middle age suggest that one mechanism driving sarcopenia is the disruption of neuromuscular connectivity. We conclude that sarcopenia in rats, as in humans, has a long preclinical phase in which muscle undergoes extensive remodeling to maintain muscle mass and function. At later time points, these adaptive mechanisms fail, and sarcopenia becomes clinically manifest. [ABSTRACT FROM AUTHOR]

Introduction: Impaired handgrip strength is an indication for sarcopenia and frailty screening, and is associated with increased osteoporotic risks and all-cause mortality. Osteocalcin, secreted by osteoblasts, is a versatile factor that participates in bone turnover and muscle adaptation. The role of osteocalcin in muscle strength has mainly been discussed in animal models and requires more human data. The study aimed to investigate the association between the serum osteocalcin level and handgrip strength in middle-aged individuals and older adults with diabetes. Methods: Adult participants (aged 40 and above, N = 237) with diabetes were enrolled in a medical center in northern Taiwan. Subjects were divided into normal, low muscle mass without dynapenia, dynapenia without low muscle mass, and groups of low muscle mass with dynapenia according to their handgrip strength and muscle mass measurements. Physical performance, including handgrip strength, repeated sit-to-stand tests, walking speed, and short physical performance batteries, was documented. Body composition was measured by bioelectrical impedance analysis. Results: The median serum osteocalcin level was highest in the dynapenic group without low muscle mass (median [Q1, Q3], 14.1 [11.2, 16.3] ng/mL). Multivariate logistic regression showed that a higher serum osteocalcin level was associated with worse handgrip strength (OR: 3.89, 95% CI: 1.66–9.10) after adjusting for body mass index (adiposity), skeletal muscle mass index (muscle), and medication with dipeptidyl peptidase-4 inhibitor. Further sex stratification revealed a more significant association between serum osteocalcin level and impaired handgrip strength in women but not in men. The female groups showed increases in the risk of impaired handgrip strength: 4.84-fold in the osteocalcin T2 group (11.4 ≤ osteocalcin <15.0 ng/mL) and 4.54-fold in the osteocalcin T3 group (osteocalcin ≥15.0 ng/mL). Moreover, after adjusting for various confounders, 8.41-fold and 8.03-fold increases in the risk of impaired handgrip strength were observed in the osteocalcin T2 group (11.4≤ osteocalcin <15.0 ng/mL) and osteocalcin T3 group (osteocalcin ≥14.5 ng/mL), respectively. Conclusion: Higher serum osteocalcin is associated with increased risks of impaired handgrip strength and impaired physical performance. Dose-dependent associations were found especially in postmenopausal women but not in men. [ABSTRACT FROM AUTHOR]