Relationship between dynapenia and cardiorespiratory functions in healthy postmenopausal women: novel clinical criteria

Gender difference in appendicular muscle strength: determinant of the quality of life in the older Taiwanese

Background: The loss of skeletal muscle mass by aging determines the health status and the quality of life (QoL).

Objective: To examine the relationships between appendicular muscle strength and the QoL of elderly adults in gender difference.

Methods: This was a cross-sectional study, in which 690 subjects who participated in older adults health examination in the health management center of Tri-Service General Hospital from 2018 to 2021. A structured questionnaire was used to collect basic demographic data. The 12-Item Short Form Survey (SF-12) was used to evaluate the QoL of subjects. Their grip strength and gait speed were measured, and Dual-energy X-ray absorptiometry was used to measure muscle mass and other body composition data. Multivariate regression analysis was used to examine the relationships between upper and lower limb muscle strength and the QoL of older adults.

Results: In men, legs muscle mass percentage (LegsMM%) (β = 3.67; 95% CI: 0.64–6.69; p = 0.018) and gait speed (β = 6.09; 95% CI: 3.88–8.30; p < 0.001) were positively associated with physical component summary (PCS) scores, and gait speed (β = 4.63; 95% CI: 2.66–6.60; p < 0.001) was also related to an improvement mental component summary (MCS) scores. In women, arms muscle mass percentage (ArmsMM%) (β = 6.50; 95% CI: 2.34–10.66; p = 0.002) and grip strength (β = 10.54; 95% CI: 6.27–14.81; p < 0.001) had the greatest effect on improving PCS scores, whereas grip strength (β = 7.58; 95% CI 4.00–11.17; p < 0.001) was also found to help improve MCS scores.

Conclusions: Men should focus on lower limb training, whereas females should focus on upper limb training to effectively improve their QoL. Appropriate exercise interventions should be designed for different genders for the promotion of the healthy aging policy.

Handgrip strength, dynapenia, and related factors in postmenopausal women

OBJECTIVE

This study aimed to evaluate the prevalence of dynapenia and factors related to low dominant handgrip strength (HGS) in postmenopausal women.

METHODS

A cross-sectional study was performed on 249 postmenopausal women aged 50 to 84 years. The following variables were recorded: age, age at menopause, smoking status, and the HGS measured with a digital dynamometer, body mass index, and adiposity assessed by bioelectric impedance. The physical activity level was evaluated by using the International Physical Activity Questionnaire. Bone mineral density was reported as T-scores, and blood biochemical parameters (calcium, phosphorus, vitamin D, and parathormone levels) were measured.

RESULTS

31.3% of women had dynapenia, and those aged ≥65 years had lower HGS (P < 0.001). Age at menopause was also associated with HGS, with those with menopause < 51 showing lower HGS (P = 0.005). Likewise, fat content ≥ 40%, and osteopenia/osteoporosis were also related to lower strength (P < 0.001). There was no statistically significant difference among HGS with respect to body mass index, smoking status, and plasma levels of vitamin D. A logistic regression model with lower Akaine Information Criterion showed that for every year in age and for each 1% of adiposity, women were more likely to have dynapenia with odd ratio (OR): 1.09; 95% and confidence interval (CI): 1.04 to 1.14 and OR: 1.06; 95% CI: 1.00 to 1.13, respectively. Conversely, women with higher femoral neck T-score were less likely to have dynapenia (OR: 0.53; 95% CI: 0.35-0.78).

CONCLUSIONS

HGS was associated with age at menopause, bone mineral density, and adiposity adjusted by age. The age and adiposity were significantly associated with a higher risk of dynapenia, whereas women with higher femoral neck T-score were less likely to have dynapenia.

Impaired pulmonary function is associated with dynapenia, but not with abdominal obesity and dynapenic abdominal obesity in older adults

PURPOSE

No studies have previously analyzed the association between dynapenic abdominal obesity (DAO) and pulmonary function in older adults. The aim of this study was to analyze whether there is an association between pulmonary function and abdominal obesity, dynapenia, and DAO in community-dwelling older adults.

METHODS

A cross-sectional study was conducted with community-dwelling older adults (n = 383) of Macapá, Amapá, Brazil. Pulmonary function variables were evaluated with spirometry; and DAO was evaluated with the combination of dynapenia and abdominal obesity. Cutoff points for handgrip strength, 26 kg force for men and 16 kg force for women, were used to detect dynapenia; and cutoff points of abdominal circumference of > 102 cm for men and > 88 cm for women were used to identify abdominal obesity.

RESULTS

Most of the studied pulmonary function variables (obtained values and obtained versus predicted values) were associated with abdominal obesity, dynapenia, and DAO. However, in the adjusted model, there was an association of FVC (β = - 0.163; p < 0.001), FEV₁ (β = - 0.119; p = 0.006), and PEF (β = - 0.110; p = 0.017) only with dynapenia.

CONCLUSIONS

Older adults with abdominal obesity, dynapenia, and DAO presented impaired pulmonary function when compared to those without these conditions. Most of the pulmonary function variables were associated with abdominal obesity, dynapenia, and DAO conditions. However, in the adjusted model, there was an association of reduced FVC, FEV₁, and PEF values only with dynapenia.

Body composition of women with and without dynapenia defined by different cut-off points

ABSTRACT Objective To compare body composition of postmenopausal women with and without dynapenia, defined by different cut-off points. Methods Body composition was assessed by electrical bioimpedance and the nutritional status by the body mass index. Dynapenia was diagnosed according to handgrip strength, using the following cut-off points: handgrip strength <16kgf and <20 kgf. Results A total of 171 women (50 to 92 years of age) participated in the investigation. The mean age of non-dynapenic and dynapenic women (handgrip strength <20kgf) was 69.4±8.2 and 74.5±8.2 years, respectively. The mean age of women with dynapenia (handgrip strength <16kgf) was 75.0±10.1 years and non-dynapenic women, 71.1±8.2 years. It was found that dynapenic women, with handgrip strength <20 and <16kgf, had an average of 2.38 and 2.47kg less muscle mass respectively, when compared to non-dynapenic women (p<0.05). However, there was no difference in muscle mass between the different dynapenic groups. Non-dynapenic women (handgrip strength ≥20kgf) had more total (3.55kg) and central fat (1.47kg) (p<0.05). Conclusion Dynapenic women, diagnosed considering both cutoff points, had less total and segmental muscle mass compared to non-dynapenic women. In addition, dynapenic women with handgrip strength <20kgf had lower total and trunk adiposity.

Obesity-associated poor muscle quality: prevalence and association with age, sex, and body mass index

BACKGROUND

Muscle quality (i.e., the expression of muscle function per unit of muscle mass) has been proposed as a clinically-relevant measure to detect individuals at risk of functional incapacity. Individuals with obesity might be at an increased risk of having poor muscle quality. Thus, we aimed to analyze the prevalence of poor muscle quality in obese individuals, to determine associated variables, and to provide normative values for this population.

METHODS

203 individuals with obesity (103 women, age: 18-75 years, body mass index (BMI): 35-64 kg·m^- 2) participated in this cross-sectional study. Their muscle strength (handgrip dynamometry), muscle power (sit-to-stand test) and muscle mass (bioelectrical impedance analysis) were measured, and muscle quality (strength/power to muscle mass ratio) was compared with reference values obtained in young healthy individuals. Muscle quality was individually categorized as normal, low or poor based on specific muscle strength and power (i.e., strength and power per unit of muscle mass, respectively). Sex and age-specific normative values of specific muscle strength and power were computed for the whole cohort.

RESULTS

Age and being a woman were inversely associated with specific muscle strength, with age being also inversely associated with specific muscle power. A small proportion of participants (6%) presented with an impaired (i.e., low/poor) specific muscle power while most of them (96%) had impaired specific muscle strength. Eventually, 84% of the participants were deemed to have poor muscle quality. Being a woman (odds ratio [OR]: 18.09, 95% confidence intervals [CI]: 4.07-80.38), age (OR: 1.06, 95%CI: 1.03-1.10) and BMI (OR: 1.22, 95%CI: 1.07-1.38) were independently associated with a higher risk of poor muscle quality in adjusted analyses.

CONCLUSIONS

These findings show a high prevalence of poor muscle quality among individuals with obesity, with age, sex and BMI being independent predictors.

Central and Peripheral Neuromuscular Adaptations to Ageing

Ageing is accompanied by a severe muscle function decline presumably caused by structural and functional adaptations at the central and peripheral level. Although researchers have reported an extensive analysis of the alterations involving muscle intrinsic properties, only a limited number of studies have recognised the importance of the central nervous system, and its reorganisation, on neuromuscular decline. Neural changes, such as degeneration of the human cortex and function of spinal circuitry, as well as the remodelling of the neuromuscular junction and motor units, appear to play a fundamental role in muscle quality decay and culminate with considerable impairments in voluntary activation and motor performance. Modern diagnostic techniques have provided indisputable evidence of a structural and morphological rearrangement of the central nervous system during ageing. Nevertheless, there is no clear insight on how such structural reorganisation contributes to the age-related functional decline and whether it is a result of a neural malfunction or serves as a compensatory mechanism to preserve motor control and performance in the elderly population. Combining leading-edge techniques such as high-density surface electromyography (EMG) and improved diagnostic procedures such as functional magnetic resonance imaging (fMRI) or high-resolution electroencephalography (EEG) could be essential to address the unresolved controversies and achieve an extensive understanding of the relationship between neural adaptations and muscle decline.

Relevance to assess and preserve muscle strength in aging field

According to the revised European consensus on sarcopenia, muscle strength is the primary parameter of sarcopenia and is associated with adverse outcomes or physical limitation. This literature review aims to clarify how and why to measure and preserve muscle strength in older population. Overall, the relationship between muscle strength and physical function is impacted by level of muscle mass, the degree of obesity (BMI), age and physical activity. Therefore, these factors are to be considered in the evaluation of muscle strength. It is necessary to have objective, reliable and sensitive tools to assess muscle strength, in different populations to detect and quantify weakness, to adapt physical exercises to patients' capacity and to evaluate the effects of treatment. Handgrip strength measurement might be reasonable for clinical practice while the measurement of knee flexors/extensors strength with both 1RM and dynamometers is increasingly important yet restricted by the requirement of special equipment. Physical activity and nutrition are two important behavioral factors to maintain muscle strength. Combined exercise and nutrition interventions improved muscle strength to a more prominent degree than exercise or nutrition alone.

Effect of a 12-week mixed power training on physical function in dynapenic-obese older men: does severity of dynapenia matter?

INTRODUCTION

Mobility disability affects nearly 15% of people aged 65 or over worldwide. Excess weight or obesity (OB), along with an accentuated loss of muscle strength (dynapenia), is recognized to be one of the most common risk factors for mobility impairment among the elderly.

OBJECTIVE

To investigate the effect of a 12-week mixed power training (MPT high-velocity resistance training mixed with functional exercises) on physical function in obese older men exhibiting different severities of dynapenia.

METHODS

Community-dwelling older men (69 ± 6 years) were assigned to the study if they were considered obese (OB, fat mass ≥ 25% body weight, BW) and to one of the two groups according to severity of dynapenia [(handgrip strength-HS)/BW]: type 1(OB-DY1) or type 2(OB-DY2), < 1 or 2SD from a young reference group. Participants followed a 12-week MPT, three times/week, 75 min/session. Main outcomes included the performance on the 4-m and 6-min walking tests, Timed Up and Go, stair and balance tests.

RESULTS AND DISCUSSION

At baseline, OB-DY1 performed better than OB-DY2 in all functional tests (p < 0.05). Following the intervention, medium-to-large training effect size (ES) were observed for fat (ES = 0.21) and lean (ES = 0.32, p < 0.001) masses, functional performance (ES 0.11-0.54, p < 0.05), HS (ES = 0.10, p < 0.05) and lower limb muscle strength (ES = 0.67, p < 0.001) and power (ES = 0.60, p < 0.05). Training-by-group interaction showed that OB-DY1 lost more FM (ES = 0.11, p = 0.03) and OB-DY2 improved more HS (ES = 0.19, p = 0.006) than their counterparts.

CONCLUSIONS

Seniors with obesity and severe dynapenia have poorer physical function than those in the early stage of dynapenia. Both seem to benefit from a high-velocity resistance training mixed with functional exercises, although by slightly different pathways.

Two weeks of lower body resistance training enhances cycling tolerability to improve precision of maximal cardiopulmonary exercise testing in sedentary middle-aged females

It is not uncommon for sedentary individuals to cite leg fatigue as the primary factor for test termination during a cardiopulmonary exercise test (CPET) on a cycle ergometer. The purpose of this study was to examine the effect of 2 weeks of lower body resistance training (RT) on cardiopulmonary capacity in sedentary middle-aged females. Additionally, the impact of RT on muscle strength was evaluated. Following familiarization, 28 women (18 exercise group, 10 control group) completed a maximal CPET on a cycle ergometer to determine peak oxygen uptake and leg extensor strength assessed using isokinetic dynamometry. Participants in the exercise group performed 2 weeks (6 sessions) of lower body RT, which comprised leg press, leg curl, and leg extension exercises. A 2-way repeated-measures ANOVA was used to evaluate the difference in changes of peak oxygen uptake and peak torque (PT). Peak oxygen uptake significantly improved from 22.2 ± 4.5 mL·kg^-1·min^-1 to 24.3 ± 4.4 mL·kg^-1·min^-1 (10.8%, p < 0.05) as well as PT from 83.1 ± 25.4 Nm to 89.0 ± 29.7 Nm (6.1%, p < 0.05) in the exercise group with no change in the control group. These findings provide initial evidence that 2 weeks of lower body RT prior to a CPET may be a helpful preconditioning strategy to achieve a more accurate peak oxygen uptake during testing, enhancing tolerability to a CPET by improving lower body strength.

Association between skeletal muscle mass and cardiorespiratory fitness in community-dwelling elderly men

BACKGROUND

Sarcopenia reduces physical ability and cardiorespiratory fitness (CRF), leading to poor quality of life.

AIM

The aim of this study was to investigate the relationship between skeletal muscle mass and CRF in elderly men.

METHODS

We assessed 102 community-dwelling men over 60 years old. Appendicular skeletal muscle mass (ASM) was determined using bioelectrical impedance analysis, and the skeletal muscle mass index (SMI) was calculated as ASM divided by the square of height. Subjects with an SMI less than 7.0 kg/m² were included in the sarcopenic group, as recommended by the Asian Working Group for Sarcopenia. To investigate CRF parameters, a cardiopulmonary exercise test was performed using the Bruce protocol. CRF parameters were subdivided into aerobic capacity, cardiovascular response, and ventilatory response.

RESULTS

Of the 102 subjects, 15 (14.7%) were included in the sarcopenic group. There were significant correlations between SMI and peak oxygen consumption (VO_2peak) (r = 0.597, p < 0.001), and between SMI and VO_2peak/weight (r = 0.268, p = 0.024). Moreover, there were positive correlations between SMI and first ventilatory threshold (VT1) (r = 0.352, p = 0.008) and between SMI and VT1/weight (r = 0.189, p = 0.039). Additionally, peak oxygen pulse (O₂pulse_peak) was significantly correlated with SMI (r = 0.558, p < 0.001). VO_2peak, VO_2peak/weight and O₂pulse_peak showed significant differences between the sarcopenic and non-sarcopenic groups (p < 0.05, all). In multiple linear regression analyses, the factor related to VO_2peak was SMI (β = 0.473, p < 0.001) and that related to O₂pulse_peak was also SMI (β = 0.442, p < 0.001).

DISCUSSION AND CONCLUSIONS

This study demonstrated that skeletal muscle mass might be closely associated with CRF. Therefore, sarcopenia should be appropriately managed to improve an individual's CRF.

Effect of High-Intensity Interval Training Combined with L-Citrulline Supplementation on Functional Capacities and Muscle Function in Dynapenic-Obese Older Adults

Background: To compare the effects of high-intensity interval training (HIIT) alone vs. HIIT combined with L-citrulline (CIT) supplementation on functional capacity and muscle function in dynapenic-obese elderly. Methods: A total of 56 obese (fat mass: men > 25%, women > 35%) and dynapenic (grip strength/body weight: women < 0.44, men < 0.61) subjects were recruited and divided in two groups: HIIT+CIT (n = 26; age: 6 5 ± four years) vs. HIIT+Placebo (PLA, n = 30; age: 68 ± four years). Participants followed a 12-week HIIT using an elliptical trainer. Participants took a single and isocaloric 10 g-dose of CIT or PLA every day. Body composition; functional and aerobic capacities; absolute or relative upper and lower limbs muscle strength, muscle power; and energy balance were measured pre and post intervention. Results: Both groups significantly improved functional capacity and muscle function. However, HIIT+CIT demonstrated greater improvements in fast-paced Timed Up & Go (p = 0.04) and upper limbs muscle strength (absolute and relative) (p = 0.05) than HIIT+Placebo. Conclusion: CIT supplementation when combined with HIIT seems to induce greater improvements in upper limbs muscle strength and walking speed in dynapenic-obese elderly. Further studies are needed to confirm our results, to elucidate the mechanisms underlying the beneficial effects of CIT and to define the long-term impact of CIT/HIIT.

Clinical relevance of different handgrip strength indexes and cardiovascular disease risk factors: A cross-sectional study in suburb-dwelling elderly Chinese

BACKGROUND

Reduced muscle strength, as measured by handgrip strength (HS), has been associated with an increased risk of cardiovascular disease (CVD). The aim of this study was to examine the association between different HS indexes and CVD risk factors in elderly Chinese individuals. We also determine optimal cutoffs of HS indexes for predicting CVD risk factors.

METHODS

Data were obtained from 603 men and 789 women aged ≥60 years (average age 66.8 ± 6.4 y). These study participants were recruited in the suburb area of Tianjin, China. An individual was considered a patient when they exhibited any one of three CVD risk factors: diabetes mellitus, hypertension and dyslipidemia. All participants were interviewed face-to-face. In addition, serum samples were collected from all participants, and all participants underwent measures of anthropometry and HS.

RESULTS

The optimal cutoffs were 0.376 of HS/weight in men and 0.726 of HS/body fat mass in women for predicting diabetes mellitus. The adjusted odds ratios (ORs) of at least one CVD risk factor for those with low muscle strength identified by HS/body fat mass were 2.14 (95% confidence interval [CI]: 1.53, 3.44; p < 0.001) in men and 2.32 (95% CI: 1.60, 3.29; p < 0.001) in women.

CONCLUSION

HS/body fat mass appear to be the index best associated with CVD risk factors except diabetes mellitus in men. The optimal cutoffs of HS indexes have the potential to identify elderly adults at risk of CVD.

Influence of menopausal status on the main contributors of muscle quality

BACKGROUND

Muscle quality is a strong independent predictor of physical function. Body mass and fatness, muscle mass and cardiorespiratory fitness are known to influence muscle quality.

OBJECTIVE

To identify the contributors of muscle quality in young and postmenopausal women and whether hormone replacement therapy (HT) could influence this relationship at the age of menopause.

METHODS

Fifty-four postmenopausal women, 27 not on HT (PMW) and 27 on HT (PMW-HT), and 33 young women (YW) were evaluated for (1) body composition (body mass index, BMI), total fat mass (FM, %), appendicular lean mass (ALM, in kg and %), and appendicular skeletal mass index (ASMI = ALM/height² in kg/m²); (2) absolute peak oxygen uptake (VO_2peak, in ml/min) and relative peak oxygen uptake (VO_2peakRel in ml/kg/min); and (3) absolute isometric knee extension strength (iKES in kg) and relative isometric knee extension strength (iKES/BMI and iKES/ALM).

RESULTS

YW, PMW and PMW-HT had similar BMI (32.1 ± 10.2, 27.3 ± 4.7 and 26.7 ± 4 kg/m²) and FM (39.8 ± 10.0, 39.8 ± 7.3 and 39.9 ± 7.1%), respectively. Correlations were found between iKES/BMI index and FM (r = -0.52), ALM (r = 0.32) and VO_2peak (r = 0.31). Regression analysis demonstrated that, in YW, total amount of variance in iKES/BMI was mostly explained by ALM (42%), whereas, in PMW and PMW-HT, it was cumulatively explained by FM along with VO_2peakRel (34 and 46%, respectively).

CONCLUSION

The main contributors of muscle quality differ between young and postmenopausal women and HT does not seem to influence this relationship.

Functional correlates of detailed body composition in healthy elderly subjects

Methods of body composition analysis are now widely used to characterize health status, i.e., nutritional status, metabolic rates, and cardiometabolic risk factors. However, the functional correlates of individual body components have not been systematically analyzed. In this study, we have used a two-compartment model, which was assessed by air displacement plethysmography. Detailed body composition was measured by whole body magnetic resonance imaging in a healthy population of 40 Caucasians, aged 65–81 yr (20 men; body mass index range: 18.6–37.2 kg/m2). Physical, metabolic, as well as endocrine functions included pulmonary function, handgrip strength, gait speed, sit-to-stand test, physical activity, blood pressure, body temperature, resting energy expenditure (REE), liver and kidney functions (glomerular filtration rate), insulin sensitivity [homeostasis model assessment (HOMA)], plasma lipids, plasma leptin, testosterone, dehydroepiandrosterone, insulin-like growth factor I levels, thyroid status, vitamins, and inflammation. Individual body compartments were intercorrelated, e.g., skeletal muscle mass (SM) correlated with visceral adipose tissue ( r = 0.53) and kidneys ( r = 0.62). For the functional correlates, SM ( r = 0.58) and liver volume ( r = 0.63) were associated with REE, SM correlated with handgrip strength ( r = 0.57), and kidneys with glomerular filtration rate ( r = 0.57). While visceral adipose tissue correlated with HOMA ( r = 0.59), subcutaneous adipose tissue was related to plasma leptin levels ( r = 0.84). The subcutaneous adipose tissue-to-leptin relationship was moderated by inflammation increasing the explained variance of leptin levels by 4.0%. In linear regression analysis, detailed body composition explained variances in REE (75.0%), HOMA (41.0%), and leptin (78.0%) compared with a body mass index-based model (REE 16.0%, HOMA 31.0%, leptin 45.0%). In addition, detailed body composition explained 39.0% of the variance in kidney function.

NEW & NOTEWORTHY BCA should be used to address specific body functions only. In clinical practice, there is need of a clear focus on the specific research question related to physical, metabolic, or endocrine functions.

Physical fitness improvement in overweight postmenopausal women who do not lose fat mass in response to exercise training

OBJECTIVE

The aim of this study was to examine if overweight postmenopausal women who do not experience fat mass loss after a 1-year aerobic exercise (AE) and resistance training (RT) program can still improve physical fitness.

METHODS

Thirty-one overweight women (body mass index 28-40 kg/m or waist circumference ≥88 cm) participated in three weekly supervised AE and RT sessions for 1 year. All women were categorized according to their fat mass changes after the intervention: 14 women were considered as responders (fat mass loss ≥5% of initial fat mass) and 17 as nonresponders (fat mass loss <5% of initial fat mass). The main outcome measures were absolute and relative body strength, peak aerobic capacity, lower limbs power, flexibility, and body composition (DXA). Total energy intake (3-day dietary record) and physical activity level (physical activity scale for the elderly questionnaire) were also measured before, halfway through and after the intervention.

RESULTS

At baseline, nonresponders participants had higher body mass index (P = 0.04). After the intervention, relative and absolute upper and lower body strength, peak aerobic capacity (all P < 0.005), and flexibility increased similarly in the nonresponders and responders groups (P = 0.01).

CONCLUSIONS

Although some participants did not respond to exercise by decreasing fat mass, they still experienced important physical fitness benefits from AE and RT. These results suggest that body composition changes should not be the sole indicator of the benefits of exercise in overweight postmenopausal women.

Higher protein intake is associated with improved muscle strength in elite senior athletes

OBJECTIVE

The optimal protein intake for elderly individuals who exercise regularly has not yet been clearly defined. The aim of this study was to test the hypothesis that protein intake level is associated with muscle strength in elderly elite athletes.

METHODS

We evaluated 50 elite senior athletes (38 men and 12 women) participating in the European Master Games 2011 in an observational cross-sectional study. Participants were divided into two groups-lower (LPI) or higher (HPI) protein intake-according to the median value of their ratio of urinary urea nitrogen to urinary creatinine (i.e., 8.8 g/L), as a marker of protein intake. A dietary interview confirmed differences in protein consumption between the LPI and HPI groups. We also evaluated body composition (bioimpedance), muscle strength, and hematochemical indices.

RESULTS

LPI and HPI groups were homogeneous for age (72 [68-74] and 71 [68-74] y, respectively), fat-free mass index (18.4 [17-19.4] and 18.2 [17-19.1] kg/m²), body fat (18.3% [12.3-20.7%] and 16.6% [13.6-21.2%]), and glomerular filtration rate (57.7 [53.8-64.9] and 62.7 [56.1-69.3] mL/min/1.73 m²). The HPI group showed greater leg and trunk muscle strength (N) compared with the LPI group (left leg extension, 339 [238-369] versus 454 [273-561], respectively, P < 0.05; right leg extension, 319 [249-417] versus 432 [334-635], P ≤ 0.05; trunk extension, 435 [370-467] versus 464 [390-568], P ≤ 0.05).

CONCLUSIONS

Higher protein intake in elite senior athletes is associated with a greater muscle strength.

Dynapenia and Metabolic Health in Obese and Nonobese Adults Aged 70 Years and Older: The LIFE Study

OBJECTIVE

The purpose of this study was to examine the relationship between dynapenia and metabolic risk factors in obese and nonobese older adults.

METHODS

A total of 1453 men and women (age ≥70 years) from the Lifestyle Interventions and Independence for Elders (LIFE) Study were categorized as (1) nondynapenic/nonobese (NDYN-NO), (2) dynapenic/nonobese (DYN-NO), (3) nondynapenic/obese (NDYN-O), or (4) dynapenic/obese (DYN-O), based on muscle strength (Foundation for the National Institute of Health criteria) and body mass index. Dependent variables were blood lipids, fasting glucose, blood pressure, presence of at least 3 metabolic syndrome (MetS) criteria, and other chronic conditions.

RESULTS

A significantly higher likelihood of having abdominal obesity criteria in NDYN-NO compared with DYN-NO groups (55.6 vs 45.1%, P ≤ .01) was observed. Waist circumference also was significantly higher in obese groups (DYN-O = 114.0 ± 12.9 and NDYN-O = 111.2 ± 13.1) than in nonobese (NDYN-NO = 93.1 ± 10.7 and DYN-NO = 92.2 ± 11.2, P ≤ .01); and higher in NDYN-O compared with DYN-O (P = .008). Additionally, NDYN-O demonstrated higher diastolic blood pressure compared with DYN-O (70.9 ± 10.1 vs 67.7 ± 9.7, P ≤ .001). No significant differences were found across dynapenia and obesity status for all other metabolic components (P > .05). The odds of having MetS or its individual components were similar in obese and nonobese, combined or not with dynapenia (nonsignificant odds ratio [95% confidence interval]).

CONCLUSION

Nonobese dynapenic older adults had fewer metabolic disease risk factors than nonobese and nondynapenic older adults. Moreover, among obese older adults, dynapenia was associated with lower risk of meeting MetS criteria for waist circumference and diastolic blood pressure. Additionally, the presence of dynapenia did not increase cardiometabolic disease risk in either obese or nonobese older adults.

Is handgrip strength normalized to body weight a useful tool to identify dynapenia and functional incapacity in post-menopausal women?

Objective

To investigate whether handgrip strength normalized to body weight could be a useful clinical tool to identify dynapenia and assess functional capacity in post-menopausal women.

Method

A total of 136 postmenopausal women were recruited. Body composition (Dual Energy X-ray Absorptiometry [DEXA], Bio-electrical Impedence Analysis [BIA]), grip strength (dynamometer) and functional capacity (senior fitness tests) were evaluated. Dynapenia was established according to a handgrip strength index (handgrip strength divided by body weight (BW) in Kg/KgBW) obtained from a reference population of young women: Type I dynapenic (<0.44 kg/KgBW) and type II dynapenic (<0.35 kg/KgBW).

Results

The results show a positive correlation between handgrip strength index (in kg/KgBW) and alternate-step test (r=0.30, p<0.001), chair-stand test (r=0.25, p<0.005) and one-leg stance test (r=0.335, p<0.001). The results also showed a significant difference in non-dynapenic compared to type I dynapenic and type II dynapenic for the chair-stand test (Non-dynapenic: 12.0±3.0; Type I: 11.7±2.5; Type II: 10.3±3.0) (p=0.037 and p=0.005, respectively) and the one-leg stance test (Non-dynapenic: 54.2±14.2; Type I: 43.8±21.4; Type II: 35.0±21.8) (p=0.030 and p=0.004, respectively). Finally, a significant difference was observed between type II dynapenic and non-dynapenic for the chair-stand test (p=0.032), but not with type I dynapenic.

Conclusion

The results showed that handgrip strength was positively correlated with functional capacity. In addition, non-dynapenic women displayed a better functional status when compared to type I and type II dynapenic women. Thus, the determination of the handgrip strength thresholds could be an accessible and affordable clinical tool to identify people at risk of autonomy loss.

Grip Strength as a Marker of Hypertension and Diabetes in Healthy Weight Adults

INTRODUCTION

Muscle strength may play a role in cardiometabolic disease. We examined the relationship between hand grip strength and diabetes and hypertension in a sample of healthy weight adults.

METHODS

In 2015, we analyzed the National Health and Nutrition Examination Survey 2011-2012 for adults aged ≥20 years with healthy BMIs (between 18.5 and <25) and no history of cardiovascular disease (unweighted n=1,467; weighted n=61,587,139). Hand grip strength was assessed with a dynamometer. Diabetes was based on hemoglobin A1c level and reported diabetes diagnosis. Hypertension was based on measured blood pressure and reported hypertension diagnosis.

RESULTS

Individuals with undiagnosed diabetes compared with individuals without diabetes had lower grip strength (51.9 vs 69.8, p=0.0001), as did individuals with diagnosed diabetes compared with individuals without diabetes (61.7 vs 69.8, p=0.008). Mean grip strength was lower among individuals with undiagnosed hypertension compared with individuals without hypertension (63.5 vs 71.5, p=0.008) as well as among individuals with diagnosed hypertension compared with those without hypertension (60.8 vs 71.5, p<0.0001). In adjusted analyses controlling for age, sex, race, smoking status, and first-degree relative with disease, mean grip strength was lower for undiagnosed diabetes (β=-10.02, p<0.0001) and diagnosed diabetes (β=-8.21, p=0.03) compared with individuals without diabetes. In adjusted analyses, grip strength was lower among individuals with undiagnosed hypertension (β=-6.6, p=0.004) and diagnosed hypertension (β=-4.27, p=0.04) compared with individuals without hypertension.

CONCLUSIONS

Among healthy weight adults, combined grip strength is lower in individuals with diagnosed and undiagnosed diabetes and hypertension.

Searching for a relevant definition of sarcopenia: results from the cross-sectional EPIDOS study

BACKGROUND

The diversity of definitions proposed for sarcopenia has been rarely tested in the same population, and so far, their clinical utilities for predicting physical difficulties could not be clearly understood. Our objective is to report the prevalence of sarcopenia and the characteristics of sarcopenic community-dwelling older women according to the different definitions of sarcopenia currently proposed. We also assessed these definitions for their incremental predictive value over currently standard predictors for some self-reported difficulties in physical function and knee extension strength.

METHODS

Cross-sectional analysis included data from 3025 non-disabled women aged 75 years or older without previous history of hip fracture from the inclusion visit of the EPIDémiologie de l'OStéoporose study. A total body composition evaluation was available for 2725 women. Sarcopenia was defined using six different definitions of sarcopenia based on different muscle mass, gait speed, and grip strength cut-offs. Self-reported difficulties in physical function and knee extension strength were collected. Logistic regression and multiple linear regression models were built for each physical dysfunction, and the predictive capacity of sarcopenia (one model for each definition) was studied using the C-statistic, the net reclassification index, or adjusted R(2).

RESULTS

The estimated prevalence of sarcopenia ranged from 3.3-20.0%. Only 85 participants (3.1%) were identified having sarcopenia according to all definitions. All definitions were, to some degree, associated with self-reported difficulties in physical function and knee extension strength, but none improved the predictive ability of the self-reported difficulties in physical function. Conversely, all definitions accounted for a small but significant amount of explained variation for predicting knee extension strength.

CONCLUSIONS

Prevalence of sarcopenia varies widely depending on the definition adopted. Based on this research, the current definitions for sarcopenia does not substantially increment the predictive value of clinical characteristics of patients to predict self-reported physical difficulties and knee extension strength.

Cut points of muscle strength associated with metabolic syndrome in men

INTRODUCTION

The loss of muscle strength with age increases the likelihood of chronic conditions, including metabolic syndrome (MetS). However, the minimal threshold of muscle strength at which the risk for MetS increases has never been established.

OBJECTIVE

This study aimed to identify a threshold of muscle strength associated with MetS in men.

METHODS

We created receiver operating curves for muscle strength and the risk of MetS from a cross-sectional sample of 5685 men age <50 yr and 1541 men age ≥50 yr enrolled in the Aerobics Center Longitudinal Study. The primary outcome measure, the MetS, was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Upper and lower body muscle strength was treated as a composite measure of one-repetition maximum tests on bench and leg press and scaled to body weight. Low muscle strength was defined as the lowest age-specific 20th percentile, whereas high muscle strength was defined as composite muscle strength above the 20th percentile.

RESULTS

In men aged <50 yr, the odds of MetS were 2.20-fold (95% confidence interval = 1.89-2.54) higher in those with low muscle strength, independent of age, smoking, and alcohol intake. The strength of this association was similar for men age ≥50 yr (odds ratio = 2.11, 95% confidence interval = 1.62-2.74). In men age < 50 yr, the composite strength threshold associated with MetS was 2.57 kg·kg body weight, whereas in men age ≥ 50 yr the threshold was 2.35 kg·kg body weight.

CONCLUSION

This study is the first to identify a threshold of muscle strength associated with an increased likelihood of MetS in men. Measures of muscle strength may help identify men at risk of chronic disease.

Exploring the role of muscle mass, obesity, and age in the relationship between muscle quality and physical function

BACKGROUND

Divergent conclusions emerge from the literature regarding the relationship between muscle quality (defined as muscle strength per unit of muscle mass) and physical function. These contrasted results may be due to the influence of factors such as age, obesity, and muscle mass itself. Consequently, the aim of the present study was to explore the role of these factors in the relationship between muscle quality (MQ) and physical function.

METHODS

Data are from 312 individuals (97 men and 215 women) aged 50 years and older. Body composition (dual energy X-ray absorptiometry) and knee extension strength of the right leg (1 repetition maximum) were assessed. Appendicular lean body mass index (AppLBMI) and MQ (knee extension strength /right leg lean mass) were calculated. A composite score of physical function was created based on the timed up-and-go, alternate step, sit-to-stand, and balance tests.

RESULTS

MQ was significantly associated with physical function when AppLBMI (β = 0.179; P = .004) and body mass index (BMI) (β = 0.178; P = .003), but not age (β = 0.065; P = .26), were included in regression analysis. AppLBMI (β = 0.221; P < .001), BMI (β = 0.234; P < .001), and age (β = 0.134; P = .018) significantly interacted with MQ to determine physical function.

CONCLUSIONS

Our results show that muscle mass, obesity, and age influence the relationship between MQ and physical function, suggesting that these factors should be taken into account when interpreting MQ. Even so, higher levels of MQ were associated with higher physical function scores. Nutritional and physical activity interventions may be designed in this regard.

The effects of lifestyle interventions in dynapenic-obese postmenopausal women

OBJECTIVE

The aim of this study was to investigate the impact of caloric restriction (CR) and resistance training (RT) on body composition, metabolic profile and physical capacity in dynapenic-obese postmenopausal women.

METHODS

Thirty-eight dynapenic-obese postmenopausal (age, 62.6 ± 4.1 y) women were randomly assigned to one of four groups (1, CR; 2, RT; 3, CR + RT; and 4, control) for a 12-week intervention. The independent variables were body weight, fat mass, and lean body mass (using dual-energy x-ray absorptiometry), waist circumference, fasting lipids and glucose, resting systolic and diastolic blood pressure, and physical capacity (6-min walk, chair stand, and one-leg stand tests).

RESULTS

Body weight, fat mass, and waist circumference decreased similarly in the CR and CR + RT groups (all P ≤ 0.05). However, only changes in the CR + RT group were significantly different from the control group (all P ≤ 0.05). Total cholesterol, triglycerides, and systolic and diastolic blood pressure significantly decreased in the CR group (all P ≤ 0.05); whereas total cholesterol, low-density lipoprotein cholesterol, and systolic blood pressure decreased in the CR + RT group (P ≤ 0.05). Physical capacity improved significantly in the RT and CR + RT groups (all P ≤ 0.05), with significant greater improvements in the RT group (P ≤ 0.05).

CONCLUSIONS

Our results suggest that CR with or without RT is effective in improving metabolic profile, whereas RT is effective in improving physical capacity. The combination of RT and CR may be particularly relevant in maximizing improvements in physical capacity in dynapenic-obese postmenopausal women.

Relationship between protein intake and dynapenia in postmenopausal women

OBJECTIVE

The purpose of this study was to investigate the relationship between protein intake and dynapenia.

DESIGN

A cross-sectional/observational study.

SETTING

Department of Kinanthropology at the University of Quebec at Montreal.

PARTICIPANTS

Seventy-two non-frail postmenopausal women aged between 50 to 75 years were recruited.

MEASUREMENTS

Body weight (BW), lean body mass (LBM; %) and skeletal muscle mass (bio-electrical impedancemetry analysis), maximum voluntary handgrip strength (using hand dynamometer), aerobic capacity (VO2peak) and dietary intake were measured. Women were divided according to dynapenia criteria.

RESULTS

The strongest correlation between muscle strength and protein intake was observed when we express the amount of protein in g/d/BW. No differences for age, BMI, status of menopause, fat mass and VO2peak were observed between non-dynapenic, type I dynapenic and type II dynapenic women, independently of the criteria used. We observed significant differences in protein intake (g/d/BW) between non-dynapenic and type II dynapenic (p<0.01) as well as between type I dynapenic and type II dynapenic (p<0.01) when dynapenia was expressed in kg/BW and in kg/LBM, respectively. It should be noted that no differences in LBM between the three groups were observed when dynapenia was expressed in kg/BW and kg/LBM. Protein intake for all groups respected the RDA of 0.8 to 1.2 g/d/BW (non-dynapenic: 1.44/1.38; type I dynapenic: 1.30/1.33; type II dynapenic: 1.05/1.08 g/d/BW).

CONCLUSIONS

Protein intake seems to play a role in the development of dynapenia particularly at the level of type II dynapenia. Therefore, an increase in the recommended daily allowance for protein intake may be warranted.

How to assess functional status: a new muscle quality index

Aging is associated with decreases in muscle mass, muscle strength and muscle power, with muscle strength declining at a higher rate than muscle mass, but at a lower rate than muscle power. This progressive mismatch suggests a deterioration of muscle "quality" that may lead to functional incapacities. Although it may be difficult to synthesize the concept of muscle quality, the aim of the present paper was to propose a clinical definition of muscle quality in regard to the functional status. Accordingly, the muscle strength or muscle power per unit of muscle mass ratios appear to be clinically relevant markers of muscle quality. Several mechanisms susceptible to influence these ratios have been described, among which age, gender, sex hormones, obesity, physical activity and fibrosis. Various methods to assess muscle quality in both the clinical and research fields have also been listed, with a particular interest for the tests used to measure muscle power. Finally, we proposed a clinical screening tool to detect individuals at risk of functional incapacities. Briefly, the muscle quality score is based on handgrip strength assessment by hand dynamometer, muscle mass measurement by bioelectrical analysis, and leg muscle power estimation using a chair stand test.

Muscle quality as a potential explanation of the metabolically healthy but obese and sarcopenic obese paradoxes

BACKGROUND

Obesity has been associated with metabolic complications. However, two subgroups of obese individuals (namely "sarcopenic obese" and "metabolically healthy but obese" individuals) with low muscle mass appear to have a better metabolic profile. Despite having a lower muscle mass, these individuals appear to have higher muscle strength, suggesting higher muscle quality. Studies have reported insulin sensitivity to be related to muscle quality. Therefore, the aim of the present study was to test the hypothesis that low muscle mass was associated with better muscle quality in obese individuals.

METHODS

A total of 112 postmenopausal women aged between 50 and 77 years (means, 61±6 years) were recruited. Body composition (bioelectrical impedancemetry), muscle strength (hand dynamometer), and functional capacity (chair stand test, alternate step test and balance test) were measured.

RESULTS

Skeletal muscle mass (SM; kg) was significantly positively correlated with muscle strength (kg) in normal weight (r=0.43; P=0.003) and overweight (r=0.42; P=0.020) women, but not in obese (r=0.28; P=0.13) women. Muscle mass (kg) was significantly negatively correlated with muscle quality (kg/SMkg) in normal weight (r=-0.41, P=0.005), overweight (r=-0.59; P<0.001) and obese (r=-0.59; P<0.001) individuals. Skeletal muscle mass index (kg/m(2)) was significantly negatively correlated with muscle quality in normal weight (r=-0.33, P=0.025), overweight (r=-0.47, P=0.008), and obese (r=-0.43, P=0.015) women. Finally, type II sarcopenic individuals had higher muscle quality than type I sarcopenic (P=0.002) and nonsarcopenic (P=0.001) individuals.

CONCLUSIONS

Our results support our hypothesis and showed that muscle quality increased as muscle mass and muscle mass index decreased. Thus, muscle quality may potentially explain the favorable metabolic profile observed in metabolically healthy but obese and sarcopenic obese postmenopausal women. Further studies including metabolic data are needed to confirm our results.

Dynapenia and aging: an update

In 2008, we published an article arguing that the age-related loss of muscle strength is only partially explained by the reduction in muscle mass and that other physiologic factors explain muscle weakness in older adults (Clark BC, Manini TM. Sarcopenia =/= dynapenia. J Gerontol A Biol Sci Med Sci. 2008;63:829-834). Accordingly, we proposed that these events (strength and mass loss) be defined independently, leaving the term "sarcopenia" to be used in its original context to describe the age-related loss of muscle mass. We subsequently coined the term "dynapenia" to describe the age-related loss of muscle strength and power. This article will give an update on both the biological and clinical literature on dynapenia-serving to best synthesize this translational topic. Additionally, we propose a working decision algorithm for defining dynapenia. This algorithm is specific to screening for and defining dynapenia using age, presence or absence of risk factors, a grip strength screening, and if warranted a test for knee extension strength. A definition for a single risk factor such as dynapenia will provide information in building a risk profile for the complex etiology of physical disability. As such, this approach mimics the development of risk profiles for cardiovascular disease that include such factors as hypercholesterolemia, hypertension, hyperglycemia, etc. Because of a lack of data, the working decision algorithm remains to be fully developed and evaluated. However, these efforts are expected to provide a specific understanding of the role that dynapenia plays in the loss of physical function and increased risk for disability among older adults.