What are the association patterns between handgrip strength and adverse health conditions? A topical review

Associations of Facial Shape With Physical Strength and 2D:4D in a Turkish Male and Female Sample

OBJECTIVE

Human sexual dimorphism in physical strength manifests itself in men having a greater muscle mass than women, reflecting ancestral roles in competition, protection, and provisioning. Prenatal testosterone exposure, approximated via the second-to-fourth digit ratio (2D:4D), is linked to increased muscular strength in both sexes, indicating a developmental influence. Previous research has shown that both physical strength and 2D:4D have facial shape correlates, especially in men, but most studies have focused on Western populations and one trait. We therefore hypothesized a broader relationship between facial shape and both physical strength and 2D:4D.

MATERIALS AND METHODS

In this study, we quantified the association between facial shape, handgrip strength (HGS), and 2D:4D in a non-Western Turkish sample (72 men, 55 women; Md = 22 y, SIR = 1.8 y) using two dimensional geometric morphometrics. Thirty-eight somatometric and 32 semi-landmarks were digitized on facial photographs taken in frontal view. Physical strength was assessed via handgrip strength (HGS), and the second digit length was divided by the fourth digit length to calculate 2D:4D.

RESULTS

Both HGS and 2D:4D were significantly associated with shape in both sexes, but only in men did they explain a significant amount of facial variation. Thin-plates spline deformation grids and geometric morphometric morphs visualized the facial shape changes related to variations in handgrip strength, 2D:4D, and sexual dimorphism, enabling trait comparisons.

CONCLUSION

This study contributes a comparative sample from the Middle East, which is indispensable to discern universalities from Western peculiarities. It provides evidence to better understand the biological basis of facial traits, which can potentially serve as increasingly relevant social cues in today's online and digital environments.

Association of handgrip strength asymmetry and weakness with depression among middle-aged and older population in China: A cohort study

BACKGROUND

Handgrip strength (HGS) weakness and asymmetry were recently reported to be associated with age-related health conditions. However, little is known about their combined effects on depression. We aimed to explore the joint association of HGS asymmetry and weakness with depressive symptoms in Chinese middle and older aged population.

METHODS

8700 participants aged ≥45 years were enrolled from China Health and Retirement Longitudinal Study (2015-2018). HGS weakness was determined as maximal HGS < 28 kg in males and <18 kg in females. HGS asymmetry was measured by HGS ratio and was defined using two different rules. Specifically, HGS ratio < 0.90 or >1.10 (10 % rule) and <0.80 or >1.20 (20 % rule) were considered as asymmetry. Participants were classified into four groups: normal and symmetric HGS, asymmetry only, weakness only, and both weakness and asymmetry. Depressive symptoms were assessed by the 10-item Center for Epidemiologic Studies Depression Scale, with scores ≥12 defined as depression. The logistic regression and multiple linear regression models were conducted to estimate the associations between HGS status and depressive symptoms.

RESULTS

The three-year incidence of depression was 19.2 %. After adjusting for covariates, compared to normal and symmetric HGS, participants with both HGS asymmetry and weakness showed the greatest risk of incident depression (10 % rule: OR 1.55, 95 % CI 1.19-2.02; 20 % rule: OR 1.71, 95 % CI 1.16-2.50). The coexistence of asymmetry and weakness was related to a significant increase in depression score (10 % rule: β 0.96, 95 % CI 0.38-1.54; 20 % rule: β 0.94, 95 % CI 0.08-1.81). The complete case analysis supported the results, and the associations were not modified by age, sex, and hand dominance.

LIMITATIONS

Depressive assessment was based on self-reported screening instrument.

CONCLUSIONS

The presence of both HGS asymmetry and weakness was associated with a higher risk of depression. Examining HGS asymmetry along with weakness may aid in identifying individuals at risk of depression to enable early interventions.

Effects of Spinal Decompression and Segmental Spinal Instrumentation on Lower Limb Functionality in Patients with Spinal Osteoarthritis

Spinal osteoarthritis, a degenerative condition of the spine, significantly impairs quality of life, causing pain, stiffness, and limited mobility. Treatment primarily aims to improve functionality and quality of life. This study investigated the effects of lower back surgery (e.g., spinal decompression with vertebra stabilization) on upper-limb maximum strength, lower limb functionality, and quality of life in osteoarthritis patients. A total of 16 patients (♀ = 10 and ♂ = 6) patients from the orthopedic clinic who were diagnosed with osteoarthritis based on MRI and clinical symptoms underwent the surgery. Their handgrip strength, lower limb functionality (6 min walk test), and quality of life (Flanagan quality of life scale) were assessed before and after the surgery. A repeated measures ANOVA was conducted to assess differences in these metrics pre- and post-surgery across the entire patient cohort, as well as within gender-specific subgroups. A large positive effect was seen in the 6 min walk (p = 0.02, d = -0.83) test but not in the handgrip test or quality of life. However, female patients showed a trend towards better quality of life. The results of this study provide evidence for the effectiveness of surgery in the treatment of spinal osteoarthritis and underscore the need for personalized treatment approaches in the treatment of spinal osteoarthritis.

Factors associated with handgrip strength across the life course: A systematic review

BACKGROUND

Muscle strength is essential for healthy ageing. Handgrip strength (HGS) has been recommended by expert bodies as the preferred measure of muscle strength, in addition to being considered a strong predictor of overall health. Cross-sectional studies have shown several potential factors associated with HGS, but a systematic review of factors predicting HGS over time has not previously been conducted. The aim of this study is to systematically review the literature on the factors associated with adult HGS [at follow-up(s) or its rate of change] across the life course.

METHODS

Searches were performed in MEDLINE via Ebsco, Embase and SPORTDiscus databases. Longitudinal studies assessing potential factors impacting adult HGS over time were included in the analyses. Based on previously established definitions of consistency of results, a semiquantitative analysis was conducted using the proportions of studies supporting correlations with HGS.

RESULTS

A total of 117 articles were included in this review. Factors associated with HGS were grouped into 11 domains: demographic, socioeconomic, genetic, early life, body composition, health markers/biomarkers, health conditions, psychosocial, lifestyle, reproductive and environmental determinants. Overall, 103 factors were identified, of which 10 showed consistent associations with HGS over time (i.e., in at least four studies with ≥60% agreement in the direction of association). Factors associated with greater declines in HGS included increasing age, male sex, higher levels of inflammatory markers and the presence of cardiovascular diseases. Education level, medication use, and self-rated health were not associated with the rate of change in HGS. Increased birth weight was associated with a stronger HGS over time, whereas depressive symptoms were linked to a weaker HGS, and smoking habits showed null associations.

CONCLUSIONS

Comparison between studies and estimation of effect sizes were limited due to the heterogeneity in methods. Although sex and age may be the main drivers of HGS decline, it is crucial to prioritize modifiable factors such as inflammation and cardiovascular diseases in health interventions to prevent greater losses. Interventions to improve birth weight and mental health are also likely to produce positive effects on muscle strength. Our results point to the complexity of processes involving muscle strength and suggest that the need to better understand the determinants of HGS remains.

The relationship between low and asymmetric handgrip strength and low muscle mass: results of a cross-sectional study on health and aging trends in western China

OBJECTIVE

The aim was to determine the relationship between low handgrip strength (HGS) only, asymmetric HGS only, and low HGS combined with asymmetric HGS and low muscle mass in the West China Health and Aging Trends Study (WCHAT) data.

STUDY DESIGN

Individuals aged at least 50 years old were included in this cross-sectional study using WCHAT data. Demographic characteristics, such as age, marital status, education level, ethnicity, and drinking and smoking history, as well as chronic diseases, were recorded for all participants. The HGS of both hands was tested three times using a grip dynanometer with the participant in a standing position with arms extended, before recording the maximum value for both hands. The maximum value referred to values < 28 kg and < 18 kg for males and females, respectively. HGS ratios (non-dominant HGS/dominant HGS) of < 0.90 or > 1.10 suggest asymmetric HGS. The subjects were then allocated to the low HGS, asymmetrical HGS, and combined low and asymmetrical HGS (BOTH group) groups, and those with neither low nor asymmetric HGS (the normal group). The InBody 770 instrument was used for the analysis of muscle mass, with low muscle mass defined as a skeletal muscle mass index (SMI) of < 7.0 kg/m2 or < 5.7 kg/m2 for males and females, respectively. The associations between the different HGS groups and low muscle mass were assessed by logistic regression analysis.

RESULTS

The study included 1748 subjects, of whom 1272 (72.77%) were over the age of 60 years. The numbers of Han, Tibetan, and Qiang were 885 (50.63%), 217 (12.41%), and 579 (33.12%), respectively. A total of 465 individuals (26.60%) were classified as having low muscle mass, while 228 (13.04%), 536 (30.66%), and 125 (7.15%) participants were allocated to the low HGS, asymmetric HGS, and BOTH groups, respectively. The average SMI differed significantly between the normal group and the other groups (normal group vs. asymmetric HGS group vs. low HGS group vs. BOTH group: 6.627 kg/m2 vs. 6.633 kg/m2 vs. 6.492 kg/m2 vs. 5.995 kg/m2, respectively, P < 0.05). In addition, the prevalence of low muscle mass in the normal, asymmetric HGS, low HGS, and BOTH groups increased sequentially, with significant differences (normal group vs. asymmetric HGS group vs. low HGS group vs. BOTH group: 21.5% vs. 22.4% vs. 39.5% vs. 56%, respectively, P = 0.001). Further logistic regression analysis showed that the presence of low HGS (OR = 1.7, 95%CI: 1.203-2.402) and both low and asymmetric HGS (OR = 3.378, 95%CI: 2.173-5.252) were predictive of low muscle mass, with the chance being higher for the latter condition.

CONCLUSION

The findings suggest that although asymmetrical HGS itself does not increase the chances of low muscle mass. When low HGS and a combination of both features (low HGS combined with asymmetric HGS) is present in subjects, the chance of low muscle mass increases.

Body surface scan anthropometrics are associated with grip strength in the general population

BACKGROUND AND AIM

Body shape and anthropometrics are well-known risk factors for cardiovascular diseases (CVD) and mortality. Hand-grip strength (HGS) is also a meaningful marker of health and a promising predictor of CVD and mortality. There is a lack of studies that have systematically investigated associations between body shape and anthropometrics with HGS. In a population-based study, we investigated if anthropometric markers derived from 3D body scanning are related to HGS.

METHODS AND RESULTS

We used the data of 1,599 individuals aged 36 to 93 years, who participated in the Study of Health in Pomerania. A total of 87 anthropometric markers, determined by a 3D body scanner, were included in the analysis. Anthropometric measurements were standardized and used as exposure variables. HGS was measured with a hand dynamometer and used as outcome. Sex-stratified linear regression models adjusted for age and height were used to relate standardized anthropometrics and HGS. Anthropometric markers were ranked according to -log-p-values. In men, left and right forearm circumference, left arm length to neck (C7), left forearm length, and forearm-fingertip length were most strongly related to HGS. In women, right forearm circumference, forearm-fingertip length, shoulder breadth, left forearm circumference, and right wrist circumference showed the most significant associations with HGS. The final prediction models contained 13 anthropometric markers in males (R2=0.54) and eight anthropometric markers in females (R2=0.37).

CONCLUSIONS

The identified parameters may help estimate HGS in the clinical setting. However, studies in clinical settings are essential to validating our findings.

Handgrip strength, and erectile dysfunction among men with metabolic syndrome attending an institutional primary care clinic in Malaysia: A cross-sectional study

Background

Erectile dysfunction (ED) is an independent predictor for cardiovascular diseases (CVD). The prevalence increases with age, but little is known about the relationship between handgrip strength (HGS) and ED, especially among men with a high risk of CVD. This study aimed to determine the prevalence of ED among men aged ≥40 years with metabolic syndrome (MetS) and its association with HGS.

Materials and Methods

A cross-sectional study at an institutional primary care clinic in Malaysia was conducted between June 2021 and October 2021. HGS and erectile function were assessed using a hand dynamometer and International Index of Erectile Function (IIEF-5) questionnaire, respectively. Multiple logistic regression analyses were performed to determine the association between sociodemographics, clinical characteristics, and HGS with ED.

Results

A total of 334 participants were recruited. The prevalence of ED was 79% (95% confidence interval [CI]: 0.75-0.84). ED was associated with elderly aged ≥60 years (odds ratio [OR] 3.27, 95%CI: 1.60-6.69), low HGS (OR 15.34, 95%CI: 5.64-41.81) and high total cholesterol (OR 0.36, 95%CI: 0.16-0.78).

Conclusion

In conclusion, age above 60 years and those with low HGS are at higher risk of ED. Thus, robust screening of ED among men with MetS and improving muscle strength and physical fitness may be warranted.

Weakness Status is Differentially Associated with Time to Diabetes in Americans

Background

The purpose of this study was to evaluate the associations of (1) individual absolute and body size normalized weakness cut-points, and (2) the collective weakness classifications on time to diabetes in Americans.

Methods

We analyzed data from 9577 adults aged at least 50-years from the Health and Retirement Study. Diabetes diagnosis was self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males with HGS <35.5 kg (absolute), <0.45 kg/kg (normalized to body weight), or <1.05 kg/kg/m2 (normalized to BMI) were categorized as weak. Females were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg/kg/m2. Compounding weakness included falling below 1, 2, or all 3 cut-points.

Results

Persons below the body weight normalized weakness cut-points had a 1.29 (95% confidence interval (CI): 1.15-1.47) higher hazard for incident diabetes, while those below the BMI normalized cut-points had a 1.30 (CI: 1.13-1.51) higher hazard. The association between absolute weakness and incident diabetes was insignificant (hazard ratio: 1.06; CI: 0.91-1.24). Americans below 1, 2, or all 3 collective weakness categories had a 1.28 (CI: 1.10-1.50), 1.29 (CI: 1.08-1.52), and 1.33 (CI: 1.09-1.63) higher hazard for the incidence of diabetes, respectively.

Conclusions

Our findings indicate that while absolute weakness, which is confounded by body size, was not associated with time to diabetes, adjusting for the influence of body size by normalizing HGS to body weight and BMI was significantly associated with time to diabetes. This suggests that muscle strength, not body size, may be driving such associations with time to diabetes.

A Reciprocal Relationship between Formal and Informal Social Engagement and Handgrip Strength of Older Adults in South Korea

INTRODUCTION

The relationship between social engagement and handgrip strength has been underexplored. Further, no prior research examined a plausible reciprocal association between them.

METHODS

The study employed the seven waves of data (2006-2018) from the Korean Longitudinal Study of Aging (KLoSA) survey (7,927 respondents, mean age: 59 years old at wave 1 [71 years old at wave 7], women: 58%). It used ML-SEM, a cross-lagged panel model with fixed effects fitted by structural equation modeling with maximum likelihood estimation. In particular, the ML-SEM examined whether a reciprocal relationship existed between formal social engagement (number of association memberships and frequency of organizational activities)/informal social engagement (frequency of contact with familiar persons) and handgrip strength (the average of the four dynamometer measurements).

RESULTS

The empirical analyses identified a systematic reciprocal association between formal social engagement and handgrip strength. Specifically, formal social engagement was positively associated with handgrip strength over time (the number of association memberships standardized coefficient: 0.012*, the frequency of organizational activities standardized coefficient: 0.022***). Conversely, handgrip strength was positively related to the number of memberships (the handgrip strength standardized coefficient: 0.025*) and the frequency of organizational activities (the handgrip strength standardized coefficient: 0.042**).

CONCLUSION

The study thus supports the social causation proposition that formal social engagement in and through diverse associations may be positively associated with handgrip strength. It also validates the health selection argument that handgrip strength may increase the likelihood of formal social engagement.

Hand Grip Force-Time Curve Indicators Evaluated by Dynamometer: A Systematic Review

BACKGROUND

Handgrip strength (HGS) is an indicator of muscular strength, used in the diagnosis of sarcopenia, undernutrition, and physical frailty as well as recovery. Typically, the maximum HGS value is used; however, recent evidence suggests the exploration of new indicators provided based on the force-time curve to achieve a more comprehensive assessment of muscle function. Therefore, the objective was to identify indicators of the HGS profile beyond maximum HGS, based on force-time curves, and to systematize knowledge about their applications to various types of samples, health issues, and physical performance.

METHODS

A systematic review was performed including studies whose participants' HGS was assessed with a digital or adapted dynamometer. The outcome measures were HGS profile indicators calculated from the force-time curve.

RESULTS

a total of 15 studies were included, and the following indicators were identified: grip fatigue, fatigability index, fatigue rate, fatigue resistance, time to 80% maximal voluntary contraction, plateau coefficient of variability, time to maximum value, T-90%, release rate, power factor, grip work, average integrated area, endurance, cycle duration, time between cycles, maximum and minimum force-velocity, rate of grip force, final force, inflection point, integrated area, submaximal control, and response time.

CONCLUSIONS

Various indicators based on the force-time curve can be assessed through digital or adapted dynamometers. Future research should analyze these indicators to understand their implications for muscle function assessment, to standardize evaluation procedures, to identify clinically relevant measures, and to clarify their implications in clinical practice.

Comparison of two electronic dynamometers for measuring handgrip strength

INTRODUCTION

Handgrip strength (HGS) is a strong predictor and easily applicable assessment, indicating a person's physical condition and health. However, many dynamometers are available; therefore, it is essential to ensure that the results of HGS testing using different dynamometers can be used interchangeably. The primary purpose of this study was to investigate the inter-instrument agreement and criterion validity of the Baseline BIMS Digital Grip Dynamometer in comparison with the Jamar electronic dynamometer (Jamar+).

METHODS

Seventy participants, aged between 23-88 (five men and five women in each decade from 20 to 80+), performed three attempts with each dynamometer (30-sec break between attempts) in a randomized order and separated with a 5-minute break between dynamometers. Intraclass correlation coefficient (3.1), standard error of measurement and minimal detectable change were used for comparison of the strongest and average strength measured with dynamometers. Jamar+ and Baseline BIMS Digital Grip Dynamometer were new dynamometers and considered calibrated by the manufacturer.

RESULTS

The overall Intraclass correlation coefficient was excellent (0.98). An average (SD) difference of 0.68 (2.2) kg (p = 0.04) was seen for the comparison of the strongest attempt for Baseline BIMS minus Jamar+, Correspondingly, for the average of three attempts, it was 0.37 (2.29, p = 0.2) kg. The standard error of measurement (%) and minimal detectable change (%) of the strongest attempt was 1.64 kg (4.2%) and 3.55 kg (9.0%), respectively.

CONCLUSIONS

Findings indicate low measurement error with high agreement and criterion validity for the comparison of Baseline BIMS Digital Grip Dynamometer and Jamar+ and that results of the two dynamometers can be used interchangeably.

Collective Weakness and Fluidity in Weakness Status Associated With Basic Self-Care Limitations in Older Americans

Aims

To examine the associations of 1) absolute and normalized weakness cut-points, 2) collective weakness categories, and 3) changes in weakness status on future activities of daily living (ADL) limitations in older Americans.

Methods

The analytic sample included 11,656 participants aged ≥65-years from the 2006-2018 waves of the Health and Retirement Study. ADL were self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males were classified as weak if their HGS was <35.5-kg (absolute), <0.45-kg/kg (body mass normalized), or <1.05-kg/kg/m2 (body mass index (BMI) normalized); females were considered weak if their HGS was <20.0-kg, <0.337-kg/kg, or <0.79-kg/kg/m2. Collective weakness categorized those below 1, 2, or all 3 absolute and normalized cut-points. These collective categories were also used to classify observed changes in weakness status over time (onset, persistent, progressive, recovery).

Results

Older Americans below absolute and normalized weakness cut-points had greater future ADL limitations odds: 1.34 (95% confidence interval (CI): 1.22-1.47) for absolute, 1.36 (CI: 1.24-1.50) for BMI normalized, and 1.56 (CI: 1.41-1.73) for body mass normalized. Persons below 1, 2, or 3 cut-points had 1.36 (CI: 1.19-1.55), 1.60 (CI: 1.41-1.80), and 1.70 (CI: 1.50-1.92) greater odds for future ADL limitations, respectively. Those in each changing weakness classification had greater future ADL limitation odds: 1.28 (CI: 1.01-1.62) for onset, 1.53 (CI: 1.22-1.92) for persistent, 1.72 (CI: 1.36-2.19) for progressive, and 1.34 (CI: 1.08-1.66) for recovery.

Conclusions

The presence of weakness, regardless of cut-point and change in status over time, was associated with greater odds for future ADL limitations.

The predictive value of masticatory function for adverse health outcomes in older adults: a systematic review

Masticatory function is associated with a variety of health outcomes. The aim of this systematic review is to clarify the predictive value of masticatory function for adverse health outcomes, such as frailty, sarcopenia and malnutrition, in older adults. An online literature search covered articles published in English or Dutch in three databases (PubMed, Embase and CINAHL, last searched November 4th 2022). Inclusion criteria were: an observational study design, focus on adults aged ≥65 years and evaluation of the association between masticatory function and health outcomes. Reviews and articles published before the year 2000 were excluded. Methodological quality and risk of bias were assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies of the U.S. National Institutes of Health. Study population demographics, methods for assessing masticatory function, and the association between masticatory function and adverse health outcomes were extracted. From the 34 included studies, 5 studies had a prospective design, 2 had a retrospective design, and the other 27 studies had cross-sectional design. The majority of the studies were conducted in Japan (74%, n = 26). Twenty studies (59%) used one indicator for masticatory function, the other 41% used two (n = 9) or more (n = 5) indicators. Masticatory function was most frequently assessed with the maximum occlusal force (MOF) (79%, n = 27). The identified health outcomes were clustered into 6 categories: physical parameters and sarcopenia, history of falling, nutritional status, frailty, cognitive function and mortality. Despite the complex and multidimensional character of both masticatory function and most identified adverse health outcomes, some significant associations were reported. Prospective studies showed that reduced masticatory function in older adults is associated with incidence of frailty and frailty progression, cognitive decline and all-cause mortality. Regarding the other identified adverse health outcomes, i.e., physical measures and sarcopenia, history of falling and nutritional status, only cross-sectional studies were available and results were less concordant. As all prospective studies showed that reduced masticatory function in older adults is associated with adverse health outcomes, prevention of decline of masticatory function by adequate oral care may contribute to healthy ageing.

Secular trends and sociodemographic, biological, and behavioural factors associated with handgrip strength in adolescents in southern Brazil: An allometric approach

The purpose of this study was to analyse secular trend in handgrip strength (HGS) in adolescents using an allometric approach and identify the factors associated. The sample comprised 657 and 1004 adolescents (14 to 19 years) in 2007 and 2017/2018, respectively, of public schools in Florianópolis, Brazil. The dependent variable was HGS normalised to body mass and height. Covariance analysis was used to examine secular trends in HGS, and multiple linear regression was used to identify associated factors. The independent variables were sociodemographic, biological, and behavioural factors. Comparison of HGS between surveys indicated a negative secular trend in both sexes (p < 0.001). In boys, there was a positive association of HGS with age and FFM in both surveys. In 2017/18, there was a positive association with sexual maturation and a negative association with sitting time and fat percentage. In girls, FFM was positively associated with HGS in both surveys. In 2007, there were positive associations of HGS with age and vigorous physical activity, whereas, in 2017/18, negative associations were observed with economic level and sitting time. The findings of the present study show a decline in adolescent HGS. And behavioural changes appear to be contributing to declines in HGS.

Association of handgrip strength asymmetry and weakness with functional disability among middle-aged and older adults in China

Background

Little is known about the association of handgrip strength (HGS) asymmetry with functional disability in China. We aimed to examine the individual and combined association of HGS asymmetry and weakness with functional disability among middle-aged and older Chinese adults.

Methods

We included participants aged ≥45 years from two waves of the China Health and Retirement Longitudinal Study (2011 and 2015). HGS weakness was defined as the maximal HGS<28 kg for men and <18 kg for women. HGS asymmetry was measured by dividing the maximal nondominant HGS (kg) by the maximal dominant HGS (kg), with the value <0.90 or >1.10 considered as asymmetry. Functional disability was assessed by activities of daily living (ADL) and instrumental activities of daily living (IADL) and was defined as encountering difficulty in completing one or more ADL/IADL tasks. The logistic regression models were used to explore the association between HGS measures and functional disability.

Results

11 950 (mean age 59.2 ± 9.6 years, 47.9% males) and 7540 (mean age 57.5 ± 8.6 years, 50.1% males) participants were included in the cross-sectional and prospective study, respectively. HGS asymmetry and weakness, individually or simultaneously, were associated with an increased prevalence of functional disability. During the four-year follow-up, 1822 (24.2%) participants had incident functional disability. The separate exposure to HGS asymmetry (odds ratio (OR) = 1.18; 95% confidence interval (CI) = 1.05-1.32) or weakness (OR = 1.59; 95% CI = 1.30-1.95) was independently associated with functional disability. For combined associations, those with both weakness and asymmetry showed the greatest risk of new-onset functional disability (OR = 1.91; 95% CI = 1.45-2.52).

Conclusions

HGS asymmetry and weakness were associated with a higher risk of functional disability. Assessing HGS asymmetry together with weakness may help to better identify those at risk of functional disability to enable early interventions.

Multimorbidity patterns and disability and healthcare use in Europe: do the associations change with the regional socioeconomic status?

Multimorbidity, the concurrence of several chronic conditions, is a rising concern that increases the years lived with disability and poses a burden on healthcare systems. Little is known on how it interacts with socioeconomic deprivation, previously associated with poor health-related outcomes. We aimed to characterize the association between multimorbidity and these outcomes and how this relationship may change with socioeconomic development of regions. 55,915 individuals interviewed in 2017 were drawn from the Survey of Health, Ageing and Retirement in Europe, a population-based study. A Latent Class Analysis was conducted to fit multimorbidity patterns based on 16 self-reported conditions. Physical limitation, quality-of-life and healthcare utilization outcomes were regressed on those patterns adjusting for additional covariates. Those analyses were then extended to assess whether such associations varied with the region socioeconomic status. We identified six different patterns, labelled according to their more predominant chronic conditions. After the "healthy" class, the "metabolic" and the "osteoarticular" classes had the best outcomes involving limitations and the lowest healthcare utilization. The "neuro-affective-ulcer" and the "several conditions" classes yielded the highest probabilities of physical limitation, whereas the "cardiovascular" group had the highest probability of hospitalization. The association of multimorbidity over physical limitations appeared to be stronger when living in a deprived region, especially for metabolic and osteoarticular conditions, whereas no major effect differences were found for healthcare use. Multimorbidity groups do differentiate in terms of limitation and healthcare utilization. Such differences are exacerbated with socioeconomic inequities between regions even within Europe.

Establishing thresholds of handgrip strength based on mortality using machine learning in a prospective cohort of Chinese population

Background

The relative prognostic importance of handgrip strength (HGS) in comparison with other risk factors for mortality remains to be further clarified, and thresholds used for best identify high-risk individuals in health screening are not yet established. Using machine learning and nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS), the study aimed to investigate the prognostic importance of HGS and establish sex-specific thresholds for health screening.

Methods

A total of 6,762 participants from CHARLS were enrolled. A random forest model was built using 30 variables with all-cause mortality as outcome. SHapley Additive exPlanation values were applied to explain the model. Cox proportional hazard models and Harrell's C index change were used to validate the clinical importance of the thresholds.

Results

Among the participants, 3,102 (45.9%) were men, and 622 (9.1%) case of death were documented follow-up period of 6.78 years. The random forest model identified HGS as the fifth important prognostic variable, with thresholds for identifying high-risk individuals were < 32 kg in men and < 19 kg in women. Low HGS were associated with all-cause mortality [HR (95% CI): 1.77 (1.49-2.11), p < 0.001]. The addition of HGS thresholds improved the predictive ability of an established office-based risk score (C-index change: 0.022, p < 0.001).

Conclusion

On the basis of our thresholds, low HGS predicted all-cause mortality better than other risk factors and improved prediction of a traditional office-based risk score. These results reinforced the clinical utility of measurement of HGS in health screening.

The Role of Different Weakness Cut-Points for Future Cognitive Impairment in Older Americans

OBJECTIVES

New absolute and normalized handgrip strength (HGS) cut-points may not yield similar predictive value for cognitive performance. We sought to determine the associations of (1) each absolute and normalized weakness cut-point, and (2) compounding weakness on future cognitive impairment in older Americans.

DESIGN

Longitudinal panel.

SETTING AND PARTICIPANTS

The analytic sample included 11,116 participants aged ≥65 years from the 2006 to 2018 waves of the Health and Retirement Study. Participants from the Health and Retirement Study completed detailed interviews that included physical measures and core interviews.

METHODS

The modified Telephone Interview of Cognitive Status assessed cognitive function and persons scoring <11 were classified as having a cognitive impairment. A handgrip dynamometer measured HGS. Men were considered weak if their HGS was <35.5 kg (absolute), <0.45 kg/kg (body mass normalized), or <1.05 kg (body mass index normalized), whereas women were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg. Compounding weakness included those below 1, 2, or all 3 cut-points. Generalized estimating equations quantified the associations.

RESULTS

Persons considered weak under the absolute cut-point had 1.62 (95% CI 1.34-1.96) greater odds for future cognitive impairment, but no significant associations were observed for those classified as weak under the body mass [odds ratio (OR) 1.12, CI 0.91-1.36] and body mass index normalized (OR 1.17, CI 0.95-1.43) cut-points. Older Americans below all 3 weakness cut-points had 1.47 (CI 1.15-1.88) greater odds for future cognitive impairment, but no significant associations were found for persons classified as weak under 1 (OR 1.08, CI 0.83-1.42) or 2 (OR 1.19, CI 0.91-1.55) cut-points.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that each weakness cut-point has differential prognostic value for future cognitive impairment, and aggregating weakness cut-points may improve their predictive utility. Consideration should be given to how weakness categories are uniquely linked to cognitive function.

Prevalence and Trends of Weakness Among Middle-Aged and Older Adults in the United States

ABSTRACT

McGrath, R, FitzSimmons, S, Andrew, S, Black, K, Bradley, A, Christensen, BK, Collins, K, Klawitter, L, Kieser, J, Langford, M, Orr, M, and Hackney, KJ. Prevalence and trends of weakness among middle-aged and older adults in the United States. J Strength Cond Res 37(12): 2484-2490, 2023-Muscle weakness, which is often determined with low handgrip strength (HGS), is associated with several adverse health conditions; however, the prevalence and trends of weakness in the United States is not well-understood. We sought to estimate the prevalence and trends of weakness in Americans aged at least 50 years. The total unweighted analytic sample included 22,895 Americans from the 2006-2016 waves of the Health and Retirement Study. Handgrip strength was measured with a handgrip dynamometer. Men with weakness were below at least one of the absolute or normalized (body mass, body mass index) cut points: <35.5 kg, <0.45 kg/kg, <1.05 kg/kg/m 2 . The presence of any weakness in women was also identified as being below one of the absolute or normalized HGS cut points: <20.0 kg, <0.34 kg/kg, or <0.79 kg/kg/m 2 . There was an increasing trend in the prevalence of any weakness over time ( p < 0.001). The prevalence of weakness was 45.1% (95% confidence interval [CI]: 44.0-46.0) in the 2006-2008 waves and 52.6% (CI: 51.5-53.7) in the 2014-2016 waves. Weakness prevalence was higher for older (≥65 years) Americans (64.2%; CI: 62.8-65.5) compared with middle-aged (50-64 years) Americans (42.2%; CI: 40.6-43.8) in the 2014-2016 waves. Moreover, the prevalence of weakness in the 2014-2016 waves was generally higher in women (54.5%; CI: 53.1-55.9) than in men (50.4%; CI: 48.7-52.0). Differences existed in weakness prevalence across races and ethnicities. The findings from our investigation suggest that the prevalence of weakness is overall pronounced and increasing in Americans. Efforts for mitigating and better operationalizing weakness will elevate in importance as our older American population grows.

Correlation between Physical Performance and Tensiomyographic and Myotonometric Parameters in Older Adults

BACKGROUND

To examine the correlation between physical performance and muscle strength and the variables obtained from tensiomyography and myotonometry.

METHODS

Fifty-two older adults able to complete functional tests participated in this observational study. Variables of maximal radial muscle displacement (Dm) and contraction time (Tc) (using tensiomyography) and muscle stiffness (using myotonometry) of the rectus femoris and vastus lateralis muscles were assessed. Physical performance (Short Physical Performance Battery, Timed Up and Go, Five Times Sit to Stand, and walking speed), isometric knee extension strength, and grip strength were assessed. A correlation analysis was performed between all the variables.

RESULTS

A significant correlation between the Short Physical Performance Battery and the rectus femoris (rho = 0.491) and vastus lateralis Dm (rho = 0.329) was found. Significant correlations between the Five Times Sit to Stand Test and the Dm values of the rectus femoris (rho = -0.340) and Dm (rho = -0.304), and stiffness (rho = -0.345) in the vastus lateralis, were also found. No significant correlations were found between tensiomyography and myotonometry, the Timed Up and Go, and walking speed, nor between tensiomyography and myotonometry and grip strength or isometric knee extension strength.

CONCLUSIONS

Functional tests should be prioritized in the assessment of older adults, but further research into muscle quality using technology is advisable.

Prevalence and Trends of Handgrip Strength Asymmetry in the United States

Background

Strength asymmetries are a type of muscle function impairment that is associated with several health conditions. However, the prevalence of these asymmetries among adults from the United States remains unknown. We sought to estimate the prevalence and trends of handgrip strength (HGS) asymmetry in American adults.

Methods

The unweighted analytic sample included 23,056 persons aged at least 50-years with information on HGS for both hands from the 2006-2016 waves of the Health and Retirement Study. A handgrip dynamometer measured HGS, with the highest recorded values for each hand used to calculate asymmetry. Persons were categorized into the following asymmetry severity categories: (1) >10%, (2) >20.0%, and (3) >30.0%. Survey weights were used to generate nationally-representative asymmetry estimates.

Results

Overall, there were no statistically significant trends in HGS asymmetry categories over time. The prevalence of HGS asymmetry in the 2014-2016 wave was 53.4% (CI: 52.2-54.4), 26.0% (CI: 25.0-26.9), and 11.7% (CI: 10.9-12.3) for asymmetry at >10%, >20%, and >30%, respectively. HGS asymmetry was generally higher in older Americans compared to middle-aged adults at each wave. In the 2014-2016 wave, >30% asymmetry prevalence was 13.7% (CI: 12.7-14.6) in females and 9.3% (CI: 8.4-10.2) in males. Some differences in asymmetry prevalence by race and ethnicity were observed.

Conclusions

The prevalence of asymmetry was generally high, especially in women and older adults. Ongoing surveillance of strength asymmetry will help monitor trends in muscle dysfunction, guide screening for disablement, identify subpopulations at risk for asymmetry, and inform relevant interventions.

Longitudinal association between handgrip strength, gait speed and risk of serious falls in a community-dwelling older population

OBJECTIVE

Both grip strength and gait speed can be used as markers of muscle function, however, no previous study has examined them in the same population with respect to risk of falls.

METHODS

In this prospective cohort study, utilising data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial and ASPREE-Fracture substudy, we analysed the association of grip strength and gait speed and serious falls in healthy older adults. Grip strength was measured using a handheld dynamometer and gait speed from 3-metre timed walks. Serious falls were confined to those involving hospital presentation. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for associations with falls.

RESULTS

Over an average of 4.0±1.3 years, amongst 16,445 participants, 1,533 had at least one serious fall. After adjustment for age, sex, physical activity, body mass index, Short Form 12 (state of health), chronic kidney disease, polypharmacy and aspirin, each standard deviation (SD) lower grip strength was associated with 27% (HR 1.27, 95% CI 1.17-1.38) higher risk of falls. The results remained the same for males and females. There was a dose-response relationship in the association between grip strength and falls risk. The higher risk of falls was observed in males in all body mass index (BMI) categories, but only in obese females. The association between gait speed and falls risk was weaker than the association between grip strength and falls risk.

CONCLUSIONS

All males and only obese females with low grip strength appear to be at the greatest risk of serious falls. These findings may assist in early identification of falls.

Prediction of Lung Function Status Using Handgrip Strength and Anthropometry among the Healthy Malay Population in Malaysia

Lung function depends primarily on the strength of the intercostal muscles and the diaphragm, which is indirectly related to handgrip strength (HGS). This study aims to determine the predictability of lung functions using HGS among healthy adults of Malay ethnicity in Malaysia. This study also aims to compare the equation using HGS with equations without HGS, such as the Global Lung Initiative (GLI). This study was carried out among adults between 35 to 70 years of age residing in urban and rural Malaysia. A series of standardized questionnaires were used to collect socio-demographic information. Lung functions were measured using a portable spirometer and HGS was measured using a Jamar dynamometer. The predictability of lung function indices (FEV1 and FVC) using HGS, age, and height was determined using multiple linear regression (MLR). Prediction of lung function indices was also generated using models without HGS for comparison with the equation that used HGS from this study. Pearson correlation analysis showed that both dominant (r = 0.49; p < 0.001) and non-dominant (r = 0.58; p < 0.001) HGS had a moderate significant correlation with lung function. In the MLR model, HGS was a significant (p < 0.001) predictor of lung function indices (FEV1 and FVC). The correlation of the predicted and measured lung indices using the equation generated in this study, which includes HGS, was higher compared with other lung function test equations that do not include HGS. The equations from MLR could be used to predict lung function indices among healthy Malay adults. The measurement of HGS may be used as a screening tool for lung function status when spirometry is unavailable.

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

BACKGROUND

decreased muscle strength and physical function often precede disability, nursing home admission, home care use and mortality in older adults. Normative values for commonly used physical performance-based tests are not widely available for older adults but are required for clinicians and researchers to easily identify individuals with low performance.

OBJECTIVE

to develop normative values for grip strength, gait speed, timed up and go, single-leg balance and five-repetition chair rise tests in a large population-based sample of Canadians aged 45-85 years.

METHODS

baseline data (2011-2015) from the Canadian Longitudinal Study on Ageing was used to estimate age- and sex-specific normative values for each of the physical tests. Participants were without disability or mobility limitation (no assistance with activities of daily living or use of mobility devices).

RESULTS

of the 25,470 participants eligible for the analyses 48.6% (n = 12,369) were female with a mean age of 58.6 ± 9.5 years. Sex-specific 5th, 10th, 20th, 50th, 80th, 90th and 95th percentile values for each physical performance-based test were estimated. Cross-validation (n = 100 repetitions) with a 30% holdout sample was used to evaluate model fit.

CONCLUSIONS

the normative values developed in this paper can be used in clinical and research settings to identify individuals with low performance relative to their peers of the same age and sex. Interventions targeting these at-risk individuals including physical activity can prevent or delay mobility disability and the resulting cascade of increasing care requirements, health care costs and mortality.

Handgrip strength asymmetry cut points to identify slow gait speed in six low- and middle-income countries: A cross-sectional analysis with 12,669 older adults

BACKGROUND

Handgrip strength (HGS) asymmetry is associated with slow gait speed. Both mark muscle dysfunction, potential risk of falls, and adverse health outcomes. This association was found in older adults from high-income countries, but not yet studied in low- and middle-income countries. Moreover, there is no HGS asymmetry referential to identify the disabling process. Thus, our study aims to verify the association of HGS asymmetry with slowness in older adults from six low- and middle-income countries and to propose cut points to slowness.

METHODS

A cross-sectional study with data from 12,669 older adults (≥60 years) of the Study on Global Aging and Adult Health (SAGE) conducted in six low- and middle-income countries were analyzed. Based in the difference between upper body sides HGS (asymmetry), participants were categorized in groups as 0.0-10.0% (reference group), 10.1-20.1%, 20.1-30.0% or >30.0%. Slow gait speed was established as <0.59 (men) and <0.51 (women) m/s. Associations of HGS asymmetry with gait speed were ascertained with logistic regression. HGS asymmetry index "[(HGS asymmetry*HGS)/(BMI*Age)]*100" cut points to identify slowness were generated with the ROC curve and Youden index (α = 5%).

RESULTS

Compared to HGS reference group, those with HGS asymmetry of 10.1-20%, 20.1-30.0% and >30.0% had a superior odds for slowness [1.18(CI:1.02,1.42); 1.17(CI: 0.97; 1.44); and 1.21(CI:1.03;1.43), respectively]. HGS asymmetry index cut points to identify slowness were ≤1.14 (women) and ≤1.77 (men).

CONCLUSIONS

HGS asymmetry association with slowness is present in economically disadvantaged countries. We proposed a new index for impaired muscle function with acceptable sensibility and specificity.

Effect of combined therapies including nutrition and physical exercise in advanced cancer patients: A pooled analysis

Background and aims

Although many cancer patients suffer from malnutrition or cancer cachexia, there is no standard of care so far due to limited intervention trials. Pooled data from two combined trials were analyzed regarding nutritional status and survival time.

Materials and methods

Data from two trials with advanced cancer patients were included. In both trials, patients in the intervention group received at least three times nutritional counseling and supervised training sessions. Patients in the control group continued being treated according to usual care. Nutritional status was measured using BMI, body composition and handgrip strength. Survival time was analyzed using the Cox proportional hazard model with the period between the beginning of the trial and death as underlying time scale.

Results

68 men (61.8%) and 42 women (38.2%) were randomized either to the intervention (n = 56) or the control (n = 54) group. The inter-group difference for changes in BMI and body composition was not statistically significant after 3 months. Handgrip strength improved significantly from 34.4 ± 10.2 kg to 36.3 ± 9.9 kg at 3 months in the intervention compared to 33.9 ± 9.2 kg to 34.9 ± 9.1 kg in the control group (p = 0.006). The analysis of survival time showed no inter-group difference for all patients. A detailed analysis for different diagnoses showed that in patients with lung cancer, the covariates "CRP value," "days from first diagnosis to randomization" as well as "gender" were significantly associated with survival time. Patients with higher CRP value had a shorter survival time and female patients had a shorter survival time than male patients in our analysis. In addition, patients with pancreatic cancer randomized to the control group had a 20% shorter survival time than those in the intervention group (p = 0.048).

Conclusion

The pooled analysis showed a significant improvement of handgrip strength in advanced cancer patients through the implementation of a combined therapy. Handgrip strength is of prognostic significance in hospitalized patients due to its association with mortality and morbidity. However, no improvements in further tests were detected. There is great need for further investigations examining the effect of nutritional and exercise therapy on survival time with focus on different cancer diagnoses.

[Malnutrition management of hospitalized patients with diabetes/hyperglycemia and heart failure]

Introduction

Heart failure (HF) is one of the leading causes of morbidity and mortality among older people, making it a major public health problem. Cardiovascular diseases in general, and HF in particular, are common comorbidities in people with type 2 diabetes (DM2). The concurrence of DM2 and HF is associated with more severe clinical symptoms and signs, and poorer quality of life and prognosis. Furthermore, due to the hypercatabolic state and nutrient absorption disorders, malnutrition is present in many HF cases. This article describes the results of the expert consensus and the responses of the panelists on the nutritional management in routine clinical practice of patients with diabetes/hyperglycemia hospitalized (non-critically ill) with HF.

Lower body muscle strength, dynapenic obesity and risk of type 2 diabetes -longitudinal results on the chair-stand test from the Survey of Health, Ageing and Retirement in Europe (SHARE)

BACKGROUND

The chair-stand test is a measure of lower body muscle strength. In a longitudinal study with older adults, we investigated whether results of the five-repetition chair-stand test (CST-5) are associated with incident type 2 diabetes, and whether diabetes risk in obese persons is modified by dynapenia (age-related loss of muscle strength) in the lower limbs.

METHODS

We used data of the Survey of Health, Ageing and Retirement in Europe (SHARE), a panel study with eight waves carried out between 2004 and 2020 in 28 European countries and Israel mainly in persons aged 50 years or older. Forty-six thousand one hundred nineteen persons (mean age 63.5 years, 44.1% men) with CST-5 data and follow-up data for diabetes were included from wave 2 and waves 4 to 7. The mean follow-up time was 5.3 years (standard deviation 2.9 years). Relative risks with 95% confidence intervals (CI) were estimated from log-linear models with a Poisson working likelihood and robust standard errors.

RESULTS

In the crude model, increased risks of diabetes were found for persons who considered the CST-5 as not safe, or whose times for the test were in the highest or second highest quartiles (relative risks 2.18 (95% CI: 1.95-2.43), 1.71 (1.54-1.91), 1.44 (95% CI: 1.29-1.61), reference: lowest quartile). These associations were attenuated in the fully adjusted regression model (relative risks 1.32 (95% CI: 1.17-1.48), 1.23 (1.10-1.37), 1.19 (1.06-1.33)). Furthermore, in fully adjusted models, the risk of diabetes in obese persons did not depend on whether they had low muscle strength or not. In obese persons with times for 5 sits and stands > 15 seconds, the adjusted risk of diabetes was 2.56 (95% CI: 2.22-2.95) times higher than in non-obese persons with times ≤15 seconds. The corresponding relative risk in obese persons with times ≤15 seconds was 2.45 (2.25-2.67).

CONCLUSIONS

Poor results in the CST-5 were associated with an increased risk of diabetes. Among obese persons, the risk of diabetes was not modified by results of the CST-5.

Effect of isometric handgrip exercise on cognitive function: Current evidence, methodology, and safety considerations

Cognitive function is essential for most behaviors of daily living and is a critical component in assessing the quality of life. Mounting prospective evidence supports the use of isometric handgrip exercise (IHE) as a small muscle mass practice to promote health-related outcomes in clinical and healthy populations. The aim of the present review was to systematically investigate whether IHE is effective in improving the cognitive function of adults (aged ≥18 years). Studies were identified by searching five databases (CINAHL, MEDLINE, SPORTDiscus, PsychINFO, and Web of Science). Eight out of 767 studies met the inclusion criteria, including three types of studies: 1) acute effect for IHE with various intensity protocols (n = 4); 2) acute effect for IHE with one set exhaustion protocol (n = 2); and 3) chronic effect of IHE on cognitive function (n = 2). To assess the methodological quality of studies, the PEDro scale was used (mean score = 6.75). The evidence on whether IHE exerts acute positive effects on cognitive performance is currently rather inconclusive. However, a trend was discernible that implementing IHE can generate a beneficial chronic effect on cognitive function, although the results should be interpreted with caution. The clinical relevance of IHE as a time-efficient type of physical exercise to improve cognitive function warrants further investigation. Methodology and safety considerations were discussed.

Systematic Review Registration: (https://osf.io/gbzp9).

Relationship between physical fitness and arterial stiffness in Korean older adults

Pulse-wave velocity (PWV) is a widely used clinical marker of arterial stiffness. Associations between several physical fitness measures and arterial stiffness have been examined. However, these results were inconsistent. Therefore, we conducted a cross-sectional study to assess the relationship between various physical fitness parameters and arterial stiffness in older adults. From January 2014 to December 2015, 1500 participants (men, n = 587; mean age, 71.78 ± 5.10 years) in South Korea were enrolled in the study. Koreans aged >65 years who agreed to participate in the study were enrolled. Individuals who were unable to exercise because of underlying conditions were excluded. VO2 max (mL/kg/min), handgrip strength (kg), handgrip strength (kg)/body weight (kg) ratio, one-leg standing time (s), and 10-meter walking speed (m/s) were measured. The brachial-ankle pulse wave velocity (baPWV) was measured using a VP-1000 instrument. VO2 max (mL/kg/min), handgrip (kg)/body weight (kg) ratio, one-leg standing time (s), and 10-meter walking speed (m/s) were significantly inversely associated with baPWV. This association was consistent even after adjusting for confounding factors. Our study revealed a significant association between various aspects of physical fitness and arterial stiffness. This study suggests that physical fitness is a useful predictor of arterial stiffness in older adults.

Neuropathic-like Pain Symptoms and Their Association with Muscle Strength in Patients with Chronic Musculoskeletal Pain

The relationship between sarcopenia and pain remains unclear; thus, this study evaluated whether muscle strength is independently associated with neuropathic-like pain symptoms in patients with chronic musculoskeletal pain. A cut-off score of painDETECT ≥13 was used to indicate a possible neuropathic component. Handgrip strength was measured, and muscle mass was estimated. A total of 2599 patients, including 439 patients who reported neuropathic-like pain symptoms (16.9%), were included for analysis. Handgrip strength was significantly lower in patients experiencing neuropathic-like pain symptoms (23.23 ± 10.57 vs. 24.82 ± 10.43 kg, p < 0.001), and this result was chiefly found in female patients. However, there was no difference in estimated muscle mass. Shorter duration of pain, opioid usage, pain in lower limbs, sleep disturbance, and lower handgrip strength were significantly associated with neuropathic-like pain symptoms. In patients with handgrip strength below the reference values by sex, experiencing radiating pain and at least moderate sensory symptoms by light touch and thermal stimulation were more frequently reported. In conclusion, lower handgrip strength appeared to be an independent factor associated with symptoms suggestive of neuropathic pain in this population. Interventional studies are required to determine whether improvement in muscle strength can reduce the neuropathic pain component in chronic musculoskeletal pain.

Associations between grip strength, brain structure, and mental health in > 40,000 participants from the UK Biobank

BACKGROUND

Grip strength is a widely used and well-validated measure of overall health that is increasingly understood to index risk for psychiatric illness and neurodegeneration in older adults. However, existing work has not examined how grip strength relates to a comprehensive set of mental health outcomes, which can detect early signs of cognitive decline. Furthermore, whether brain structure mediates associations between grip strength and cognition remains unknown.

METHODS

Based on cross-sectional and longitudinal data from over 40,000 participants in the UK Biobank, this study investigated the behavioral and neural correlates of handgrip strength using a linear mixed effect model and mediation analysis.

RESULTS

In cross-sectional analysis, we found that greater grip strength was associated with better cognitive functioning, higher life satisfaction, greater subjective well-being, and reduced depression and anxiety symptoms while controlling for numerous demographic, anthropometric, and socioeconomic confounders. Further, grip strength of females showed stronger associations with most behavioral outcomes than males. In longitudinal analysis, baseline grip strength was related to cognitive performance at ~9 years follow-up, while the reverse effect was much weaker. Further, baseline neuroticism, health, and financial satisfaction were longitudinally associated with subsequent grip strength. The results revealed widespread associations between stronger grip strength and increased grey matter volume, especially in subcortical regions and temporal cortices. Moreover, grey matter volume of these regions also correlated with better mental health and considerably mediated their relationship with grip strength.

CONCLUSIONS

Overall, using the largest population-scale neuroimaging dataset currently available, our findings provide the most well-powered characterization of interplay between grip strength, mental health, and brain structure, which may facilitate the discovery of possible interventions to mitigate cognitive decline during aging.

Relationship between handgrip strength, depression and cognitive functioning among older adults: Evidence from longitudinal ageing study in India

BACKGROUND

Handgrip strength (HGS) is a frequent and general indicator of muscle strength and it may affect several aspects of mental health among older people. This study explored the association of HGS with depression and cognitive impairment among community-dwelling older adults in resource-constrained setting of India.

METHOD

Data were drawn from the Longitudinal Ageing Study in India (LASI), and the analysis was conducted on 27,707 older adults aged 60 years and above. Outcome measures included depression (assessed by the Short Form Composite International Diagnostic Interview (CIDI-SF) and the Center for Epidemiological Studies-Depression (CES-D) scales) and cognitive impairment. Descriptive statistics and mean scores of HGS were reported and multivariable linear regression analyses were conducted to test the research hypotheses of the study.

RESULTS

Mean score of HGS was 24.33 (SD: 7.22) for males and 15.94 (SD: 5.14) for females. Mean age was 68.86 (SD: 7.19) and 68.40 (SD: 7.31) years among males and females respectively. Older participants who had weak HGS were significantly more likely to be depressed in CIDI-SF scale (B: 0.06, CI: 0.01-0.13) and CES-D scale (B: 0.02, CI: 0.01-0.03) in comparison to those who had strong HGS after adjusting for a large number of confounders. Older participants who had weak HGS were significantly more likely (B: 0.92, CI: 0.76-1.07) to have cognitive impairment compared to those who had strong HGS.

CONCLUSION

The findings highlight the independent association of HGS with major depression, depressive symptoms and cognitive impairment that have implications on promoting resistance-training programs among aged population.

The Effectiveness of a Group Kickboxing Training Program on Sarcopenia and Osteoporosis Parameters in Community-Dwelling Adults Aged 50-85 Years

Background

Sarcopenia and osteoporosis are important health issues faced by older people. These are often associated with each other and share common risk factors and pathologic mechanisms. In the recently revised consensus of the European Working Group on Sarcopenia in Older People, low muscle strength has been defined as the first characteristic of sarcopenia rather than a loss in muscle mass, and walking speed has been stated as an indicator of the severity of sarcopenia. It is believed that these markers of muscle function can be potentially reversed via exercise-based interventions. The purpose of this study was to evaluate the effects of kickboxing exercise training on the parameters of sarcopenia and osteoporosis in community-dwelling adults.

Methods

In total, one hundred eligible subjects were randomized into an intervention group (n = 50) with 76% women and control group (n = 50) with 86% women. Both the intervention and control groups were provided with classroom lectures and personal consultations pertaining to sarcopenia and osteoporosis, whereas a 12-week kickboxing exercise training was arranged only for the intervention group. All anthropometric, physical performance, body composition, and bone mineral density measurements along with participant completed questionnaires were conducted before and after the training period.

Results

After 12 weeks, 41 participants in the intervention group and 34 participants in the control group completed the final assessments. There was no difference between the intervention and control groups in terms of basic demographic data. The BMI (+1.14%) of the control group increased significantly during the study period. The waist circumference (−6.54%), waist-to-height ratio (−6.57%), waist–to–hip ratio (−4.36%), total body fat (−1.09%), and visceral fat area (−4.6%) decreased significantly in the intervention group. Handgrip strength (+5.46%) and gait speed (+5.71%) improved significantly in the intervention group. The lean body mass increased by 0.35% in the intervention group and by 0.9% in the control group. The femoral neck bone mineral density (−1.45%) and T score (−3.72%) of the control group decreased significantly. The intervention group had more improvement in the status of sarcopenia (OR 1.91) and osteoporosis over the control group. Finally, the intervention group had less deterioration in the status of sarcopenia (OR 0.2) and osteoporosis (OR 0.86) compared with the control group.

Conclusion

Our study demonstrated that a 12-week kickboxing exercise training program is effective for improving sarcopenic parameters of muscle strength and function, but not muscle mass in adults, aged 50–85 years. Furthermore, markers of osteoporosis also showed improvement. These findings suggest that a 12-week kickboxing program is effective for muscle and bone health among community-dwelling older individuals.

Weak Hand Grip Strength Is Associated with Alexithymia in Outpatients in a Mexican Population

Hand grip strength has been considered as a possible marker for metabolic and psychiatric disease. To date, however, no research has focused on the association between alexithymia and hand grip strength. The objective of the present study was to investigate the correct association between hand grip strength and alexithymia. A cross-sectional study was carried out in Comalcalco, Tabasco, México. A total of 246 individuals were included. Hand grip strength was evaluated in the dominant hand using a Takei^® portable digital dynamometer. Alexithymia was measured using the Toronto Alexithymia Scale (TAS-20). Two linear regression models adjusted by confounders were used to determine the association between alexithymia and hand grip strength. The rate for positive alexithymia was 39.0% (n = 94). Individuals with alexithymia showed a weaker hand grip strength than the comparison group (t = 2.4, 244 df, p = 0.01). Individuals with alexithymia had significantly reduced levels of hand grip strength (β = −0.39 ± 0.14; p = 0.006); after additional adjustment for clinical variables, decreased hand grip strength remained (β = 8.00 ± 1.86; p ≤ 0.001). Our results suggest that a decrease in hand grip strength could be associated with alexithymia. This measurement could be useful as a predictive marker for the identification of alexithymia in Mexican individuals who attend outpatient clinics.

Genetic variation in ALDH4A1 is associated with muscle health over the lifespan and across species

The influence of genetic variation on the aging process, including the incidence and severity of age-related diseases, is complex. Here, we define the evolutionarily conserved mitochondrial enzyme ALH-6/ALDH4A1 as a predictive biomarker for age-related changes in muscle health by combining Caenorhabditis elegans genetics and a gene-wide association scanning (GeneWAS) from older human participants of the US Health and Retirement Study (HRS). In a screen for mutations that activate oxidative stress responses, specifically in the muscle of C. elegans, we identified 96 independent genetic mutants harboring loss-of-function alleles of alh-6, exclusively. Each of these genetic mutations mapped to the ALH-6 polypeptide and led to the age-dependent loss of muscle health. Intriguingly, genetic variants in ALDH4A1 show associations with age-related muscle-related function in humans. Taken together, our work uncovers mitochondrial alh-6/ALDH4A1 as a critical component to impact normal muscle aging across species and a predictive biomarker for muscle health over the lifespan.

Ageing is inevitable, but what makes one person ‘age well’ and another decline more quickly remains largely unknown. While many aspects of ageing are clearly linked to genetics, the specific genes involved often remain unidentified.

Sarcopenia is an age-related condition affecting the muscles. It involves a gradual loss of muscle mass that becomes faster with age, and is associated with loss of mobility, decreased quality of life, and increased risk of death. Around half of all people aged 80 and over suffer from sarcopenia. Several lifestyle factors, especially poor diet and lack of exercise, are associated with the condition, but genetics is also involved: the condition accelerates more quickly in some people than others, and even fit, physically active individuals can be affected.

To study the genetics of conditions like sarcopenia, researchers often use animals like flies or worms, which have short generation times but share genetic similarities with humans. For example, the worm Caenorhabditis elegans has equivalents of several human muscle genes, including the gene alh-6. In worms, alh-6 is important for maintaining energy supply to the muscles, and mutating it not only leads to muscle damage but also to premature ageing. Given this insight, Villa, Stuhr, Yen et al. wanted to determine if variation in the human version of alh-6, ALDH4A1, also contributes to individual differences in muscle ageing and decline in humans.

Evaluating variation in this gene required a large amount of genetic data from older adults. These were taken from a continuous study that follows >35,000 older adults. Importantly, the study collects not only information on gene sequences but also measures of muscle health and performance over time for each individual. Analysis of these genetic data revealed specific small variations in the DNA of ALDH4A1, all of which associated with reduced muscle health.

Follow-up experiments in worms used genetic engineering techniques to test how variation in the worm alh-6 gene could influence age-related health. The resulting mutant worms developed muscle problems much earlier than their normal counterparts, supporting the role of alh-6/ALDH4A1 in determining muscle health across the lifespan of both worms and humans.

These results have identified a key influencer of muscle health during ageing in worms, and emphasize the importance of validating effects of genetic variation among humans during this process. Villa, Stuhr, Yen et al. hope that this study will help researchers find more genetic ‘markers’ of muscle health, and ultimately allow us to predict an individual’s risk of sarcopenia based on their genetic make-up.

Mediation of Grip Strength on the Association Between Self-Rated Health and Estimated Cardiovascular Disease Risk

Background: Grip strength and self-rated health (SRH) have been reciprocally related, and each has been associated with cardiovascular disease (CVD) risk. However, the pathway between SRH and grip strength in the association with CVD risk remains uncertain. This cross-sectional study evaluated whether grip strength mediates the association between SRH and estimated CVD risk. Methods: In 15,930 Koreans 40-79 years of age without CVD history from the 2014 to 2018 Korea National Health and Nutrition Examination Survey, the risk of 10-year atherosclerotic cardiovascular disease (ASCVD) was calculated using Pooled Cohort Equations. Relative grip strength (RGS) was defined as measured grip strength divided by body mass index. SRH was assessed using a single questionnaire. Results: After adjusting for the covariates, males in the non-highest RGS tertiles, the fair/poor/very poor SRH groups, or the other joined categories of RGS tertiles and SRH groups (except the highest RGS tertile and good SRH group) had higher odds for 10-year ASCVD risk ≥7.5% than the reference group. The ASCVD risk was higher in females in the lowest RGS tertile, the poor/very poor SRH group, or the combined category of lowest RGS tertile and poor SRH group than the reference group. RGS significantly mediated the relationship between better SRH and the lower ASCVD risk (indirect effect: β = -0.078, 95% CI [-0.097 to -0.060], P < 0.05) and reduced the total effect of SRH on the ASCVD risk (direct effect: β = -0.225, t = -3.203, P = 0.001). RGS mediated 26% of the association between SRH and ASCVD risk. Conclusion: Grip strength may have a mediating role in the relationship between SRH and the estimated 10-year risk of ASCVD.

Is sleep time associated with handgrip strength in adolescents from the 1997/1998 São Luís Birth Cohort?

This article aims to analyze the association between sleep time and handgrip strength in adolescents belonging to the 1997/1998 São Luís Birth Cohort. This was a cross-sectional study nested in a birth cohort study. One thousand two hundred sixty-nine individuals (18 and 19 years) wore an Actigraph® GTX3+ accelerometer on their wrist 24 hr/day for 7 consecutive days. Handgrip strength was measured using a digital hand dynamometer. We used directed acyclic graphs (DAG) to identify confounding variables. This sample of adolescents was mostly composed of men, with brown skin color, economic class C, which did not work, did not consume alcohol, did not smoke, and never used drugs. The mean value of handgrip strength was 28.2 (±9.3) kgf, and the mean of sleep time was 6 (±1.0) hours per day. The crude analysis showed an association between sleep time and muscle strength. An increase of one hour of sleep reduced the handgrip strength by 1.95 kgf (95%CI:-2.51;-1.39). However, after adjustment for confounders, the association was not maintained (β:-0.07; 95%CI:-0.48;0.36). Sleep time is not associated with handgrip strength in adolescents in São Luís.

Comparison of diet, muscle strength, steps per day and symptoms in people with HIV and HIV-negative peers

People with HIV (PWH) experience a high frequency of symptoms that are associated with poor clinical outcomes. We conducted a secondary analysis of data from an observational study to examine whether diet, muscle strength, or physical activity were associated with symptoms among PWH and their HIV-uninfected peers. One-hundred ninety-one individuals (105 PWH and 86 HIV uninfected) with similar age and race were included. Symptoms were examined using the Patient-Reported Outcomes Measurement Information System (PROMIS-29) questionnaire, for which lower scores indicate higher function or fewer symptoms. The total healthy eating index score and carbohydrates, sugar sweet beverages, alcohol, and fiber consumption per day were obtained through 24-hour dietary recalls. A dynamometer was used to determine muscle strength. Steps per day were examined through 7 days of actigraphy. Linear regression analyses were used to determine the relationship between symptoms and diet, muscle strength, and steps per day. Participants were, on average, 54 years, 83% were African American, and 58% were male. In PWH, less healthy eating, fiber intake, and muscle strength were associated with poorer physical function; more steps per day were associated with fatigue; less daily carbohydrate consumption was associated with more pain. HIV-uninfected individuals demonstrated an association between fewer steps per day and poorer physical function and more pain, and less carbohydrate intake and more sleep disturbance. The relationships between diet, muscle strength, steps per day and PROMIS-29 health domains differed by HIV status.

A Link between Handgrip Strength and Executive Functioning: A Cross-Sectional Study in Older Adults with Mild Cognitive Impairment and Healthy Controls

Older adults with amnestic mild cognitive impairment (aMCI) who in addition to their memory deficits also suffer from frontal-executive dysfunctions have a higher risk of developing dementia later in their lives than older adults with aMCI without executive deficits and older adults with non-amnestic MCI (naMCI). Handgrip strength (HGS) is also correlated with the risk of cognitive decline in the elderly. Hence, the current study aimed to investigate the associations between HGS and executive functioning in individuals with aMCI, naMCI and healthy controls. Older, right-handed adults with amnestic MCI (aMCI), non-amnestic MCI (naMCI), and healthy controls (HC) conducted a handgrip strength measurement via a handheld dynamometer. Executive functions were assessed with the Trail Making Test (TMT A&B). Normalized handgrip strength (nHGS, normalized to Body Mass Index (BMI)) was calculated and its associations with executive functions (operationalized through z-scores of TMT B/A ratio) were investigated through partial correlation analyses (i.e., accounting for age, sex, and severity of depressive symptoms). A positive and low-to-moderate correlation between right nHGS (rp (22) = 0.364; p = 0.063) and left nHGS (rp (22) = 0.420; p = 0.037) and executive functioning in older adults with aMCI but not in naMCI or HC was observed. Our results suggest that higher levels of nHGS are linked to better executive functioning in aMCI but not naMCI and HC. This relationship is perhaps driven by alterations in the integrity of the hippocampal-prefrontal network occurring in older adults with aMCI. Further research is needed to provide empirical evidence for this assumption.

Predicting strength from aggressive vocalizations versus speech in African bushland and urban communities

The human voice carries information about a vocalizer's physical strength that listeners can perceive and that may influence mate choice and intrasexual competition. Yet, reliable acoustic correlates of strength in human speech remain unclear. Compared to speech, aggressive nonverbal vocalizations (roars) may function to maximize perceived strength, suggesting that their acoustic structure has been selected to communicate formidability, similar to the vocal threat displays of other animals. Here, we test this prediction in two non-WEIRD African samples: an urban community of Cameroonians and rural nomadic Hadza hunter-gatherers in the Tanzanian bushlands. Participants produced standardized speech and volitional roars and provided handgrip strength measures. Using acoustic analysis and information-theoretic multi-model inference and averaging techniques, we show that strength can be measured from both speech and roars, and as predicted, strength is more reliably gauged from roars than vowels, words or greetings. The acoustic structure of roars explains 40-70% of the variance in actual strength within adults of either sex. However, strength is predicted by multiple acoustic parameters whose combinations vary by sex, sample and vocal type. Thus, while roars may maximally signal strength, more research is needed to uncover consistent and likely interacting acoustic correlates of strength in the human voice. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part I)'.

Using accelerometers in the assessment of sarcopenia in older adults attending a day hospital service in Ireland

Objectives:

The aim of this study was to describe the associations between sarcopenia and variables derived from wrist accelerometry in community-dwelling older adults attending a day hospital service in Ireland.

Methods:

An observational cross-sectional study was carried out using a consecutive series of older adults attending a day hospital service. Sarcopenia was diagnosed using the latest European Working Group of Sarcopenia in Older People guidelines. Accelerometers were worn by each participant for a 7-day period on their non-dominant wrist.

Results:

Thirty-eight out of forty-one participants (93%) met the accelerometer wear time criterion and were included in statistical analyses. Included participants had a mean age of 81.1 years (standard deviation 6.2). Both sarcopenia (Grip) and sarcopenia (Lower limb) were associated with increased time spent in low physical activity and reduced average of Kcals per hour. Only sarcopenia (Lower limb) was associated with increased time in sedentary behaviour as well as reduced number of steps taken in a week.

Conclusions:

Accelerometer data can be used in an older day hospital population to track physical activity levels and sedentary behaviours. The assessment tool used to assess muscle strength and the cut-off criteria for physical activity behaviour influences the association with sarcopenia.

Relationship between Anthropometric, Physical and Hormonal Parameters among Pre-Pubertal Handball Players

Background: The aims of our study were to investigate the changes in anthropometric and physical parameters and fasting hormonal levels among pre-pubertal female handball players (n = 14, age: 11.53 ± 0.58 yrs, height: 153.36 ± 5.12 cm, body mass: 43.59 ± 6.14 kg) in the pre-season period following 8 weeks of handball training, and to analyze the contribution of hormones, physical performance and anthropometric parameters. Methods: Prior to and immediately following the training period, several anthropometric, strength, and cardiorespiratory variables, including fasting hormonal concentrations (plasma cortisol, estradiol, testosterone and growth hormones) were measured. Athletes performed concurrent resistance and aerobic exercises, including game-based trainings during the 8-week training period. Results: Significant elevations were found in all strength parameters (maximal handgrip strength dominant (D): 16.40%, p < 0.01; non-dominant (ND): 25.15%, p < 0.05; maximal concentric (MVC) torque of quadriceps D: 13.82%, p < 0.05; ND: 12.61%, p < 0.05; MVC torque of hamstring D: 12.14%, p < 0.01; ND: 12.44%, p < 0.01), including plasma cortisol levels (C, 34.30%, p < 0.05) and peak respiratory quotient (5.24%, p < 0.05). Body composition and maximal oxygen uptake (VO_2max) remained unchanged. Percentage changes in thigh (r = 0.316, p < 0.05), hand (r = 0.361, p < 0.05), and hip circumference (r = 0.297, p < 0.05) correlated with C changes. Percentage changes in plasma growth hormone levels (GH) contributed to the magnitude of gains in handgrip strength (r = 0.553, p < 0.05). Percentage changes in maximal exercise pulmonary ventilation (MVE) correlated with elevated C (r = −0.592, p < 0.05). Discussion: Changes in anthropometric variables and fasting hormone levels (estradiol, testosterone and cortisol) were poor indicators of developing VO_2max and strength during pre-pubertal years. Physical adaptation may not be explained in consideration of the athletes’ hormonal or anthropometric characteristics. Conclusion: Gradually increased training volume followed by a summer break should be applied to youth handball, considering the anti-hypertrophic responses and the inhibitory effect of elevating C on pre-pubertal maturation.

Dynapenia, abdominal obesity or both: which accelerates the gait speed decline most?

OBJECTIVE

to investigate whether the combination of dynapenia and abdominal obesity is worse than these two conditions separately regarding gait speed decline over time.

METHODS

a longitudinal study was conducted involving 2,294 individuals aged 60 years or older free of mobility limitation at baseline (gait speed >0.8 m/s) who participated in the English Longitudinal Study of Ageing. Dynapenia was determined as a grip strength <26 kg for men and <16 kg for women. Abdominal obesity was determined as a waist circumference >102 cm for men and >88 cm for women. The participants were divided into four groups: non-dynapenic/non-abdominal obese (ND/NAO); only abdominal obese (AO); only dynapenic (D) and dynapenic/abdominal obese (D/AO). Generalised linear mixed models were used to analyse gait speed decline (m/s) as a function of dynapenia and abdominal obesity status over an 8-year follow-up period.

RESULTS

over time, only the D/AO individuals had a greater gait speed decline (-0.013 m/s per year, 95% CI: -0.024 to -0.002; P < 0.05) compared to ND/NAO individuals. Neither dynapenia nor abdominal obesity only was associated with gait speed decline.

CONCLUSION

dynapenic abdominal obesity is associated with accelerated gait speed decline and is, therefore, an important modifiable condition that should be addressed in clinical practice through aerobic and strength training for the prevention of physical disability in older adults.

Association between handgrip strength asymmetry and falls in elderly Koreans: A nationwide population-based cross-sectional study

PURPOSE

This study aimed to investigate the association between handgrip strength (HGS) asymmetry and fall risk in elderly Koreans.

METHODS

This study used data from the 2016-2018 Korea National Health and Nutrition Examination Survey. A total of 3407 participants aged ≥ 65 years were included. HGS asymmetry was defined as an HGS asymmetry ratio (nondominant HGS/dominant HGS) of ≥ 1.2 or ≤ 0.8. The presence of a fall was defined as a self-reported fall event that needed treatment at a hospital or emergency department in the previous year. Multivariate logistic regression analysis was performed to analyze the association between HGS asymmetry and fall risk.

RESULTS

The odds ratio for falls was 1.89 times higher in the group with HGS asymmetry than in the group without HGS asymmetry after adjusting for age, sex, multimorbidity, obesity, current smoking, alcohol drinking, and physical exercise (95% confidence interval, 1.03-3.49; P < 0.05).

CONCLUSIONS

This study revealed that HGS asymmetry is significantly associated with an increased risk of falls in the Korean elderly population. Therefore, early identification and treatment of HGS asymmetry in the elderly could reduce the incidence of falls and be a potential preventive strategy.

Comparison of risk factors between people with type 2 diabetes and matched controls in Nairobi, Kenya

OBJECTIVE

To identify risk factors associated with type 2 diabetes (T2D) in Nairobi, Kenya.

METHODS

A case-control study comparing 70 (53% women) recently diagnosed T2D cases with age-, sex- and socioeconomic status-matched normoglycemic controls (1:1). Objectively measured data were obtained on anthropometrics, handgrip strength and physical activity (by accelerometer). Self-reported data were collected on demographic characteristics and lifestyle factors. Logistic regression models, adjusted for covariates, were used to analyse the data.

RESULTS

Each standard deviation (SD) increase in height was associated with lower odds for T2D (adjusted odds ratio (AOR) = 0.34 (95% confidence intervals [CIs] 0.17, 0.66), P = 0.0031). Fat-free mass was inversely associated with T2D (AOR = 0.42 (95% CI 0.24, 0.75), P = 0.0032, per SD increase). Grip strength was associated with a lower risk of T2D (AOR = 0.20 (95% CI 0.08, 0.45), P < 0.001, per SD increase). BMI was not associated with T2D, but higher waist-to-hip ratio was associated higher odds of T2D (AOR = 2.28 (95% CI 1.38, 3.79), P = 0.0014, per SD increase). Physical activity was not associated with T2D. Cases reported higher intakes of fruits and vegetables and a lower intake of sugar than controls.

CONCLUSIONS

Central obesity, rather than BMI, may have more utility for T2D risk stratification in Kenya, and interventions that increase muscle mass and strength, as well as support weight loss, may be useful for T2D prevention in this and other SSA populations. However, more evidence is needed to determine whether low muscle mass, strength and height are causally related to T2D risk and/or are indicators of adverse early-life environment.

Assessing Additional Characteristics of Muscle Function With Digital Handgrip Dynamometry and Accelerometry: Framework for a Novel Handgrip Strength Protocol

Maximal handgrip strength (HGS) is a convenient and reliable, but incomplete, assessment of muscle function. Although low HGS is a powerful predictor of poor health, several limitations to maximal HGS exist. The predictive value of HGS is restricted because low HGS is associated with a wide range of unspecified health conditions, and other characteristics of muscle function aside from strength capacity are not evaluated. Current HGS protocol guidelines emphasize the ascertainment of maximal force, which is only a single muscle function characteristic. Muscle function is intrinsically multivariable, and assessing other attributes in addition to strength capacity will improve screenings for age-related disabilities and diseases. Digital handgrip dynamometers and accelerometers provide unique opportunities to examine several aspects of muscle function beyond strength capacity, while also maintaining procedural ease. Specifically, digital handgrip dynamometry and accelerometry can assess the rate of force development, submaximal force steadiness, fatigability, and task-specific tremoring. Moreover, HGS protocols can be easily refined to include an examination of strength asymmetry and bilateral strength. Therefore, evaluating muscle function with new HGS technologies and protocols may provide a more comprehensive assessment of muscle function beyond maximal strength, without sacrificing feasibility. This Special Article introduces a novel framework for assessing multiple attributes of muscle function with digital handgrip dynamometry, accelerometry, and refinements to current HGS protocols. Such framework may aid in the discovery of measures that better predict and explain age-related disability, biological aging, and the effects of comorbid diseases that are amenable to interventions. These additional HGS measures may also contribute to our understanding of concepts such as resilience. Using sophisticated HGS technologies that are currently available and modernizing protocols for developing a new muscle function assessment may help transform clinical practice by enhancing screenings that will better identify the onset and progression of the disabling process.