Relevance to assess and preserve muscle strength in aging field

Systematic Evaluation of Isometric Maximal Muscle Strength in an Orthopaedic Cohort

BACKGROUND

Although the lower extremities are essential for movement function and human gait, no normalized isometric maximum strength values, which include the factors gender, age, weight, height, and body mass index (BMI), have been defined to date for orthopaedic patients.

OBJECTIVE

To systematically analyze the isometric maximal muscle strength of a cohort in an orthopaedic outpatient clinic and to evaluate its relation to gender, age, weight, height, BMI, and the differences between diseases.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Isometric maximal muscle strength of knee extension, knee flexion, hip abduction, and hip adduction was measured in orthopaedic patients of an outpatient clinic using a specific muscle strength measurement device. Correlation analysis was performed for age, gender, height, weight, and BMI. Patients were grouped by disease characteristics.

RESULTS

The cohort consisted of 311 subjects (sex: 164 male, 147 female; age: 48.63 years, SD = 16.595; BMI: 26.56 kg/m², SD = 4.9). Age correlated significantly with maximal isometric muscle strength. At the age of 54 years onward, based on 133 patients, a decline in maximum isometric muscle strength was detected. Gender showed a strong influence on maximal isometric muscle strength, with significantly higher values for male patients. Furthermore, weight and height, but not BMI, correlated significantly with muscle strength.

CONCLUSION

For clinical studies comparing different evidence-based training interventions for rehabilitation, it is important to consider determinants such as gender, age, weight, and height for isometric maximum strength measurement. For further validation, follow-up examinations taking into account the performance level, other target groups, and other muscle groups are required to avoid the wide dispersion of isometric maximum strength values. These results and associated determinants are highly clinically relevant and can be used as a reference for further studies in the field of musculoskeletal regeneration.

Arm muscle area is correlated to handgrip strength in postmenopausal women

OBJECTIVE

To analyze the correlation between arm muscle area and handgrip strength among postmenopausal community dwelling low-income women in order to provide an easy anthropometric indicator to assess muscle mass quantity and quality.

METHODS

This was a cross-sectional study involving postmenopausal women (n = 171) from three urban-marginal communities of Guayaquil, Ecuador. Corrected arm muscle area was calculated using the Frisancho formula. Dynapenia was defined as HGS < 16 kg. Spearman's correlation coefficient was calculated at a 5% significance level to test the correlation between corrected arm muscle area and handgrip strength.

RESULTS

Median (interquartile range: IQR) age of the sample was 72.0 years (17.0). The median of corrected arm muscle area was 34.8 cm2 (20.7). The overall prevalence of dynapenia was 57.9% (n = 99). There was a significant decreasing trend with age regarding all anthropometric characteristics and handgrip strength, as well as a higher prevalence of dynapenia with age. For the whole sample, a statistically significant positive correlation was found between corrected arm muscle area and handgrip strength [r = 0.267; p < .001].

There was a significant yet weak positive correlation between corrected arm muscle area and handgrip strength in this postmenopausal sample. There is a need for additional research in this regard.

Effects of bariatric surgery on muscle strength and quality: A systematic review and meta-analysis

Obesity is a major health burden worldwide. Although bariatric surgery (BS) is recognized as an effective strategy for weight loss and comorbidities improvement, its impact on muscle strength and quality is still unclear. We aimed to examine postoperative changes in muscle strength and quality and their relationship with body mass index (BMI) changes among adults undergoing BS. To this end, we systematically searched the WoS, PubMed, EBSCO, and Scopus databases. The meta-analyses, which included 24 articles (666 participants), showed that BS reduces absolute lower-limb isometric strength (ES = -0.599; 95% CI = -0.972, -0.226; p = 0.002). Subjects who experienced a more significant reduction in BMI after BS also suffered a higher loss of absolute muscle strength. Similarly, absolute handgrip strength showed a significant decrease (ES = -0.376; 95% CI = -0.630, -0.121; p = 0.004). We found insufficient studies investigating medium- and long-term changes in muscle strength and/or quality after BS. This study provides moderate-quality evidence that BS-induced weight loss can reduce the strength of appendicular muscles in the short term, which should be addressed in management these subjects. More high-quality studies are needed to evaluate the impact of BS on muscle strength and the different domains of muscle quality in the medium and long term (registered on PROSPERO CRD42022332581).

Intramuscular adipose tissue, muscle area, and power as predictors of performance in breast cancer survivors

PURPOSE

The decline in physical performance, assessed by physical tests such as the timed up and go (TUG) test, is a consequence of reduced physiological reserves at higher levels of a hierarchical process. This occurs due to changes in muscle architecture, including atrophy and fat infiltration into the muscles, which in turn lead to changes in muscle function, resulting in reduced muscle strength and power and, consequently, affecting physical performance. This study investigated predictive factors for physical performance in breast cancer survivor (BCS), focusing on intramuscular adipose tissue (IMAT), quadríceps muscle area (QMA), and muscular power.

METHODS

This observational, analytical, and cross-sectional study included 23 women without a history of cancer (age, 58.5 ± 8.3 years; BMI, 27.2 ± 5.1 kg/m2) and 56 BCS (age, 58.5 ± 8.3 years; BMI, 27.2 ± 5.1 kg/m2). QMA and IMAT were assessed using computed tomography images. Muscular power and physical performance were measured using the 5-repetition sit-to-stand and TUG tests, respectively.

RESULTS

IMAT (r = 0.4, P < 0.01) and muscular power (r =  - 0.4, P < 0.01) were associated with TUG performance in BCS, whereas QMA (r =  - 0.22, P = 0.10) showed no significant association. QMA (r = 0.55, P < 0.01) was associated with muscular power, while no significant association was found between IMAT and muscular power (r =  - 0.05, P = 0.73). Age explained 19% (P < 0.01) of TUG performance variability. Adding muscular power increased explanatory power by 12% (P < 0.01), and including IMAT further increased it by 7% (P = 0.02) for TUG performance. Collectively, age, muscular power, and IMAT accounted for 38% of the performance variance in the TUG test (age, B = 0.06, P = 0.043; muscular power, B =  - 0.01, P = 0.002; IMAT, B =  - 0.05, P = 0.020).

CONCLUSIONS

Our findings suggest that IMAT and muscular power predict the physical performance of BCS, while QMA does not have the same predictive capability.

Effects of measurement protocols and repetitions on handgrip strength weakness and asymmetry in patients with cancer

BACKGROUND

The use of handgrip strength (HGS) in clinical cancer research is surging. The association between HGS and outcomes in patients with cancer varied across studies, which might be due to the different measurement protocols for HGS. We aimed to answer three questions: (1) Did the use of various protocols for HGS, along with different numbers of repetitions, lead to significant differences in maximum HGS values? (2) If yes, were these differences clinically significant? (3) Did the differences in HGS protocols and repetitions affect the identification of HGS weakness or HGS asymmetry?

METHODS

We continuously recruited adult patients with solid tumours. Two protocols were used to measure HGS: Method A, following the American Society of Hand Therapists guidelines, and Method B, following the National Health and Nutrition Examination Survey guidelines. To analyse HGS, we used the maximal value obtained from either two or three repetitions of the dominant hand or four or six repetitions of both hands.

RESULTS

We included 497 patients (326 men and 171 women, median age: 58 years). The maximal HGS values, measured with Method B, were significantly higher than those measured by Method A in both men and women, despite repetitions (all P < 0.05). The maximum HGS values were significantly different across the repetition groups, regardless of measurement protocols and sex (all P < 0.01). The protocol-induced differences in maximal HGS values might be clinically meaningful in over 60% of men and 40% of women despite repetitions. The repetition-induced difference was only clinically significant in 4.3-17.8% of men and 4.1-14.6% of women. To identify HGS weakness, using Method A (six repetitions) as the 'gold' standard, the other protocols demonstrated an overall accuracy of 0.923-0.997 in men and 0.965-1 in women. To identify HGS asymmetry, using Method A (six repetitions) as the 'gold' standard, Method B (six repetitions) demonstrated a diagnostic accuracy of 0.972 in men and 0.971 in women. Method A (four repetitions) showed a diagnostic accuracy of 0.837 in men and 0.825 in women, while Method B (four repetitions) showed a diagnostic accuracy of 0.825 in men and 0.807 in women.

CONCLUSIONS

Both measurement protocols and repetitions significantly affect the maximal HGS values. The identification of HGS weakness is not significantly affected by either protocols or repetitions, while the identification of HGS asymmetry may be affected by different repetitions but not protocols.

Prevalence and factors associated with dynapenia among middle-aged and elderly people in rural southern China

To estimate the prevalence of dynapenia and examine potential risk factors for dynapenia using a sample of rural middle-aged and elderly Chinese. A cross-sectional study of 253 Chinese adults aged 50 years and older was conducted from June to August in 2022 in Nanjing. A questionnaire was used to collect data on all socioeconomic variables. Body weight, height, body fat percentage, grip strength, waist circumference, calf circumference, and gait speed were measured. The prevalence of dynapenia was 69.6 %, 62.3 % in men and 72.7 % in women respectively. Binary logistic regressions indicated significant associations between dynapenia and age (odds ratio [OR] = 2.59; 95 % confidence interval [CI] 1.63, 4.12; p < 0.001), educational level (OR = 0.55; 95 % CI 0.38, 0.80; p = 0.002). Dynapenia was prevalent among rural middle-aged and elderly people in southern China. Age and lower education level were both associated with dynapenia. Nutrition and physical activity should be strongly recommended as important strategies to maintain and improve muscle strength.

Effects of nutritional counseling on physical performance and muscle strength in older adults: a systematic review protocol

OBJECTIVE

The objective of this review is to synthesize the effects of nutritional counseling compared with no intervention (maintaining lifestyle habits) or nutritional counseling in combination with other interventions (eg, nutritional supplementation, physical activity) on physical performance and muscle strength in older adults.

INTRODUCTION

Nutritional counseling, which is considered the first line of nutrition therapy, could play an important role in geriatric care programs by helping older adults understand the importance of nutrition and by promoting healthy, sustainable eating habits. However, the effects of nutritional counseling on physical function and muscle strength among older adults are not clear.

INCLUSION CRITERIA

This review will consider randomized controlled trials and non-randomized controlled trials. Participants aged 65 years or older, who have received nutritional counseling alone or in combination with another intervention (eg, nutritional supplementation, physical exercise) will be considered for inclusion. Comparators will include another intervention or no intervention, but physical performance (ie, gait, endurance, balance) or muscle strength must be measured.

METHODS

This systematic review will be conducted in accordance with the JBI methodology for systematic reviews of effectiveness. The databases to be searched will include MEDLINE (Ovid), Embase, CENTRAL (Ovid), CINAHL (EBSCOhost), and Scopus. Sources of unpublished studies and gray literature will include Google Scholar and protocol registers. Two independent reviewers will select relevant studies, critically appraise the studies, and extract data. Studies will be pooled in a statistical meta-analysis or presented in narrative format. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach will be used to grade the certainty of the evidence.

REVIEW REGISTRATION

PROSPERO CRD42022374527.

Reliability and clinical applicability of lower limp strength using an enhanced paper grip strength

The enhanced paper grip test (EGPT) quantitatively assesses lower limb strength. EGPT assesses the hallux grip force by reacting a pulling force derived from a card, being positioned underneath the participant's hallux. This study aimed to investigate the repeatability and clinical applicability of the EPGT for assessing foot muscle strength. EPGT force was measured using a dynamometer. The reliability of the measurement of EPGT force was assessed by having two examiners performing the test on the same group of healthy adults. Clinical applicability was assessed in community-dwelling adults of both genders. EPGT force was recorded for both feet using the same standardised protocol for all participants. Regarding reliability, 20 healthy adults aged 23.04±5.5 years participated in the present study. The EGPT demonstrated good to excellent test-retest (ICC1,2 0.8 to 0.86) and interrater reliability (ICC1,2 0.82 to 0.88). A convenience sample of 15 community-dwelling adults (71.6±7.8 years, 68.5% women) was recruited for clinical applicability testing. All participants performed the test with mean score 15±5.7 N. EPGT is a reliable measurement of the hallux grip force strength and can be used for clinical and research purposes.

Tele-Assessment of Functional Capacity: Validity, Intra- and Inter-rater Reliability

BACKGROUND

Functional capacity evaluation is a standardized tool that assesses work-related skills. Although there are different test batteries, the most frequently used one is Work Well Systems. This study aims to determine the validity and inter- and intra-rater reliability of remote implementation of functional capacity tests (repetitive reaching, lifting object overhead, and working overhead) in asymptomatic individuals.

METHODS

A total of 51 asymptomatic individuals were included in the study. Participants completed all tests both face-to-face and remotely. Remote assessment videos were rewatched by the same researcher and different researchers for intra- and inter-rater reliability. All processes were scored by two independent researchers.

RESULTS

Remotely performing repetitive reaching (intraclass correlation coefficient [ICC]: 0.85-0.92, p < .001), lifting object overhead (ICC: 0.98, p < .001), and working overhead (ICC: 0.88 p < .001) tests are valid and reliable.

DISCUSSION

Repetitive reaching, lifting an object overhead, and sustained overhead work tests in the Work Well Systems-Functional Capacity Evaluation test battery can be performed remotely through videoconferencing. Remotely evaluating these tests, which are especially important in work-related situations, may be important in pandemic conditions and hybrid working conitions.

Application of mesenchymal stem cells for anti-senescence and clinical challenges

Senescence is a hot topic nowadays, which shows the accumulation of senescent cells and inflammatory factors, leading to the occurrence of various senescence-related diseases. Although some methods have been identified to partly delay senescence, such as strengthening exercise, restricting diet, and some drugs, these only slow down the process of senescence and cannot fundamentally delay or even reverse senescence. Stem cell-based therapy is expected to be a potential effective way to alleviate or cure senescence-related disorders in the coming future. Mesenchymal stromal cells (MSCs) are the most widely used cell type in treating various diseases due to their potentials of self-replication and multidirectional differentiation, paracrine action, and immunoregulatory effects. Some biological characteristics of MSCs can be well targeted at the pathological features of aging. Therefore, MSC-based therapy is also a promising strategy to combat senescence-related diseases. Here we review the recent progresses of MSC-based therapies in the research of age-related diseases and the challenges in clinical application, proving further insight and reference for broad application prospects of MSCs in effectively combating senesce in the future.

Age-Related Differences between Old and Very Old Men in Performance and Fatigability Are Evident after Cycling but Not Isometric or Concentric Single-Limb Tasks

PURPOSE

This study aimed to compare performance and fatigability between young ( n = 13; 18-30 yr), old ( n = 13; 60-80 yr), and very old ( n = 12; >80 yr) men during a single-joint isometric (ISO) and concentric (CON) task performed on an isokinetic dynamometer and a cycling (BIKE) task.

METHODS

Participants randomly performed incremental tasks consisting of stages of 75 contractions (i.e., 120 s, 0.8 s on/0.8 s off) for ISO and CON and 120 s at 37.5 rpm (similar duty cycle) for BIKE. Increments were set as a percentage of body weight. Knee extensor maximal force, voluntary activation, and twitch amplitude were measured at baseline, after each stage, and at task failure (five out of eight contractions below the target force or 6 s in a row at a cadence <37.5 rpm).

RESULTS

Compared with young men, performance (number of stages) was 24% and 40% lower in old and very old men in ISO, 54% and 59% lower in CON, and 36% and 60% lower in BIKE (all P < 0.05). Performance of old and very old differed only in BIKE ( P < 0.01). For the last common stages performed, compared with young, force loss was greater for very old men in ISO and for old and very old men in BIKE (all P < 0.05). Overall, for the last common stage performed and task failure, old and very old men presented similar force loss, alterations in voluntary activation, and twitch amplitude.

CONCLUSIONS

Our findings reveal that, with workloads relative to body weight, differences in performance between old and very old men could only be observed during BIKE (i.e., the more ecologically valid task). Results from isometric or concentric conditions might not be transferable to dynamic exercise with large muscle masses.

Muscle performance in octogenarians: Factors affecting dynapenia

BACKGROUND

The muscle performance is associated with several health outcomes in adults, however modifiable and non-modifiable risk factors in octogenarians have not yet been fully investigated. The aim of this study was to analyze the potential risk factors that negatively affect muscle strength in octogenarians.

METHODS

This observational, descriptive, cross-sectional study included 87 older adult participants (56 women and 31 men) attending a geriatric clinic. General anthropometrics, health history, and body composition data were collected. Muscle strength was assessed by handgrip strength (HGS), appendicular skeletal muscle mass (ASMM) and the percentage of body fat were identified by Dual Energy X-ray Absorptiometry, and muscle quality index (MQI) was defined as the ratio of HGS by upper limbs ASMM. Multiple linear regression was conducted to determine predictive factors of the muscle strength.

RESULTS

Females had lower HGS (1.39 kg) than male participants (p = 0.034). An increase of one unit MQI was associated with an increase of 3.38 kg in the HGS (p = 0.001). Each additional year of age was associated with a decrease of 0.12 kg in the HGS (p = 0.047). Regarding ASMM, an increase of one unit was associated with an increase of 0.98 kg in the HGS (p = 0.001). There was no association between dynapenia, body fat percentage, diseases and polypharmacy (p > 0.05).

CONCLUSION

The gender, age, MQI, and ASMM influenced muscle strength of octogenarians. These intrinsic and extrinsic factors are relevant to improve our understanding of age-related complications and outline treatment guidance by healthcare professionals.

Psychometric performance of the Kannada version of sarcopenia quality of life questionnaire (SarQoL®)

BACKGROUND

The Sarcopenia Quality of Life (SarQoL®) is a patient reported quality-of-life questionnaire specific to sarcopenia. In the Indian context, its availability is limited to Hindi, Marathi and Bengali vernacular languages.

AIMS

This study aimed to translate, cross-culturally adapt the SarQoL® questionnaire into Kannada and investigate its psychometric properties.

METHODS

The SarQoL®-English version was translated into Kannada with the developer's permission and in accordance with their requirements. To validate the discriminative power, internal consistency and floor and ceiling effect of the SarQoL®-Kannada questionnaire were assessed in the first step. In the second step, the construct validity and the test-retest reliability of the SarQoL®-Kannada was determined.

RESULT

There was no difficulty in the translation process. A total of n = 114 participants (sarcopenic participants n = 45 and n = 69 non-sarcopenic participants) were included. The good discriminative power of the SarQoL®-Kannada questionnaire {quality of life for sarcopenic subjects [56.43 ± 11.32] vs. non-sarcopenic ones [79.38 ± 8.16], p < 0.001}. High internal consistency (Cronbach's alpha coefficient was 0.904) and no ceiling/ floor effect were reflected. Excellent test-retest reliability (intraclass correlation coefficient was 0.97, 95% CI 0.92-0.98) were found. A good convergent and divergent validity with similar and different domains of WHOQOL-BREF was observed, while EQ-5D-3L had good convergent and weak divergent validity.

CONCLUSION

The SarQoL®-Kannada questionnaire is valid, consistent and reliable for the measurement of quality of life of sarcopenic participants. SarQoL®-Kannada questionnaire is now available to be used in clinical practice and as a treatment outcome indicator in research.

Associations of physical activity with sarcopenia and sarcopenic obesity in middle-aged and older adults: the Louisiana osteoporosis study

BACKGROUND

This study examined the associations between physical activity, obesity, and sarcopenia in middle-aged and older adults.

METHODS

We analyzed the data of 8, 919 study participants aged between 45 to 97 (mean age = 57.2 ± 8.8) from a Southern state in the United States. Self-reported physical activity was classified to regular exercise ≥ 3 times/week, < 3 times/week, and no regular exercise. Associations between physical activity, obesity and sarcopenia were explored with generalized linear models and ordinal logistic regressions stratified by age (middle-aged and older adults) and gender adjusting for covariates.

RESULTS

In middle-aged and older adults, all examined obesity related traits (e.g., body mass index, waist circumference) were inversely associated with physical activity levels (p < 0.01) in both genders. Exercising ≥ 3 times/week was negatively associated with lean mass indicators (e.g., appendicular lean mass) in middle-aged and older females (p < 0.01), while the negative associations become positive after adjusting for weight. Positive associations between physical activity and grip strength were only found in middle-aged males (p < 0.05). Ordinal logistic regression revealed that those exercising ≥ 3 times/week were less likely to have obesity, sarcopenia, and sarcopenia obesity in all groups (p < 0.01), except for sarcopenia in older males and females (p > 0.05). Positive associations of exercising < 3 times/week with sarcopenia and sarcopenia obesity were only found in middled adults.

CONCLUSION

The associations of exercise frequency with obesity and sarcopenia vary considerably across gender and age groups. Exercise programs need to be individualized to optimize health benefits. Future research exploring physical activity strategies to balance weight reduction and lean mass maintaining is warranted in middle-aged and especially older adults.

Age-Specific Association Between Handgrip Strength and Nutritional Quality in Korean Men: A Nationwide Cross-Sectional Study

This study aimed to determine the potential association between handgrip strength and nutritional quality in Korean men aged ≥20 years using data from the Korea National Health and Nutrition Examination Survey 2016 to 2018. This population-based cross-sectional study included 5,748 men aged ≥20 years. A dietary intake survey was performed using the 24-hr dietary recall method. Nutritional quality was examined using the Index of Nutritional Quality (INQ) score. A high INQ score reflected poor nutritional quality, with insufficient intake of many nutrients. Multivariate linear regression was used to determine the association between handgrip strength and INQ scores after adjusting for other covariates. The intake of carbohydrates, fiber, calcium, and vitamins B2 and C was significantly positively associated with a higher quartile for handgrip strength for those aged ≥65 years (all p < .01). A significant inverse association was found between the quartiles of handgrip strength and INQ scores among men aged ≥65 years after adjusting for all covariates (β = -0.26, p < .01). This association was not found among those aged <65 years (p = .25). The age-specific association between handgrip strength and nutritional quality underscores the importance of public policies that promote sufficient and comprehensive nutrient intake among older adults. Handgrip strength may be useful in clinical practice as a simple and cost-effective tool for screening for nutritional quality in older adults.

Psychometric Properties of the Chinese Version of the Sarcopenia and Quality of Life, a Quality of Life Questionnaire Specific for Sarcopenia

A quality of life questionnaire specific to sarcopenia (SarQoL®) was successfully developed. There is a huge demand for translation and validation in Chinese. The aim of this study was to translate the SarQoL® into Chinese and investigate its psychometric properties. The translation and cross-cultural adaptation process recommended by the developers of the initial questionnaire was followed. A total of 159 participants were investigated. The translation process consists of five steps: (1) two bilinguals independently translate initial English to Chinese; (2) synthesize the two translations into one; (3) backward translations; (4) expert committee review and (5) test of the pre-final version. The validation consists of three parts: (1) validity (discriminative power, construct validity); (2) reliability (internal consistency, test-retest reliability) and (3) floor and ceiling effects. There was no difficulty in translation process. Regarding the validity, good discriminant validity {quality of life for sarcopenic subjects [35.56 (29.73-42.70)] vs. non-sarcopenic ones [73.22 (60.09-82.90)], p < 0.001} and consistent construct validity [high correlations (spearman's r) of SarQoL® with generic Short Form-36 version 2 questionnaire (0.250 to 0.824) and EuroQoL-5-Dimension questionnaire (- 0.114 to - 0.823)] were found in SarQoL®. Regarding reliability, high internal consistency (Cronbach's alpha coefficient was 0.867) and excellent test-retest reliability (intraclass coefficient correlation was 0.997, 95% CI 0.994-0.998) were found. No ceiling/floor effect was reflected. A valid SarQoL® questionnaire is now available for Chinese population. It can provide a better understanding of the sarcopenia disease burden and serve as a therapeutic outcome indicator in research.

Association between physical activity, quadriceps muscle performance and biological characteristics of very old men and women

The present study aimed to evaluate the association between physical activity, knee extensors (KE) performance (i.e. isometric strength and fatigability) and biological parameters (i.e. muscle structural, microvascular and metabolic properties) in healthy very old men and women. Thirty very old adults (82±1 yr, 15 women) performed an isometric quadriceps intermittent fatigue (QIF) test for the assessment of KE maximal force, total work (index of absolute performance) and fatigability. Muscle biopsies from the vastus lateralis muscle were collected to assess muscle fibers type and morphology, microvasculature and enzymes activity. Correlation analyses were used to investigate the relationships between physical activity (steps.day -1, actimetry), KE performance, and biological data for each sex separately.Men, compared to women, showed greater total work at the QIF test (44497±8629 N.s vs. 26946±4707 N.s; P<0.001). Steps.day -1 were correlated with total work only for women (r=0.73, P=0.011). In men, steps.day -1 were correlated with the percentage (r=0.57, P=0.033), shape factor (r=0.75, P = 0.002) and capillary tortuosity of type IIX fibers (r=0.59, P=0.035). No other relevant correlations were observed for men or women between steps.day -1 and biological parameters. Physical activity level was positively associated with the capacity of very old women to perform a fatiguing test, but not maximal force production capacity of the KE. Physical activity of very old men was not correlated with muscle performance. We suggest that very old women could be at higher risk of autonomy loss and increasing the steps.day -1 count could provide a sufficient stimulus for adaptations in less active women.

Age-Related Changes in Shear Wave Elastography Parameters of the Gastrocnemius Muscle in Association with Physical Performance in Healthy Adults

BACKGROUND/AIMS

to investigate new indicators for early recognition of physical performance decline. Shear wave elastrography, a new ultrasound technique, was discussed in this study.

METHODS

Gastrocnemius muscle thickness and muscle stiffness were detected by traditional ultrasound and shear wave elastrography in 108 Chinese aged 20-85 years, and then analyzed with physical performance together.

RESULTS

After 70 years old, the decline rate of muscle stiffness under contractive state was significantly faster than that of muscle thickness, muscle relaxed stiffness, and physical performance indicators. The correlation analysis showed that gastrocnemius contractive stiffness was positively related with handgrip strength, step length, and fast gait speed after adjusted by age and gender. Among physical performance variants, step length had closer relationship with muscle strength than repeated chair stands.

CONCLUSIONS

The detection of gastrocnemius muscle by shear wave elastography reflected the change of lower-limb muscle stiffness with aging. Muscle contractive stiffness and step length measurement supplied novel ways for muscle performance and motor function assessment.

Impact of dietary protein intake on the incidence of low muscle strength in middle-aged and older adults

BACKGROUND

A reduction in skeletal muscle strength is a prognostic indicator of negative consequences, such as physical disability, frailty, and mortality in older adults. Studies investigating associations between the risk of reduction in skeletal muscle strength and the amount of dietary protein which is a factor influenced muscle health are scarce, particularly in Asian populations. Therefore, we investigated the association between the amount and change in daily protein intake and the prospective risk of developing low skeletal muscle strength in middle-aged and older adults.

METHODS

This study used data from the Korean Genome and Epidemiology Study as an ongoing population-based cohort study of adults aged 40 years and over. The amount of daily protein consumed was assessed using a semi-quantitative food frequency questionnaire. Low skeletal muscle strength was measured with a handgrip strength dynamometer.

RESULTS

In total, 32,458 adults (11,358 males and 21,100 females) were evaluated. The amount of daily dietary protein consumed was not associated with the risk of low muscle strength over the 4-year follow-up period after adjusting for covariates. No associations between low muscle strength events according to the change in the amount of protein consumed from the baseline to the follow-up surveys were identified.

CONCLUSIONS

The amount of and change in dietary protein consumed were not associated with developing low muscle strength in middle-aged and older adults. Further studies with a focus on physical activity-protein intake interactions and specific conditions, such as mobility-limited adults or hospitalized patients, are warranted to clarify the relationship between protein intake status and the incidence of low skeletal muscle strength.

Full characterisation of knee extensors' function in ageing: effect of sex and obesity

BACKGROUND/OBJECTIVES

Muscle function is a marker of current and prospective health/independence throughout life. The effects of sex and obesity (OB) on the loss of muscle function in ageing remain unresolved, with important implications for the diagnosis/monitoring of sarcopenia. To characterise in vivo knee extensors' function, we compared muscles torque and power with isometric and isokinetic tests in older men (M) and women (W), with normal range (NW) of body mass index (BMI) and OB.

SUBJECTS/METHODS

In 70 sedentary older M and W (69 ± 5 years), NW and OB (i.e. BMI < 30 kg m^-2 and ≥30 kg m^-2, respectively) we tested the right knee's extensor: (i) isometric torque at 30°, 60°, 75° and 90° knee angles, and (ii) isokinetic concentric torque at 60, 90, 150, 180 and 210° s^-1 angular speeds. Maximal isometric T-angle, maximal isokinetic knee-extensor torque-velocity, theoretical maximal shortening velocity, maximal power, optimal torque and velocity were determined in absolute units, normalised by body mass (BM) and right leg lean mass (LLM_R) and compared over sex, BMI categories and angle or angular speeds by three-way ANOVA.

RESULTS

In absolute units, relative to BM and LLM_R, sex differences were found in favour of M for all parameters of muscle function (main effect for sex, p < 0.05). OB did not affect either absolute or relative to LLM_R isometric and isokinetic muscle function (main effect for BMI, p > 0.05); however, muscle function indices, when adjusted for BM, were lower in both M and W with OB compared to NW counterparts (p < 0.05).

CONCLUSIONS

We confirmed sex differences in absolute, relative to BM and LLM_R muscle function in favour of men. While overall muscle function and muscle contractile quality is conserved in individuals with class I OB, muscle function normalised for BM, which defines the ability to perform independently and safely the activities of daily living, is impaired in comparison with physiological ageing.

The handgrip strength threshold of 16 kg discriminates successful rehabilitation: A prospective short-term study of 258 women with hip fracture

AIM

In 2019 the European Working Group on Sarcopenia in Older People (EWGSOP) indicated weakness as the key characteristic of sarcopenia and released the threshold of 16 kg for handgrip strength to define weakness in women. We aimed to externally validate the 16 kg cut-off point for predicting functional recovery in 258 women with subacute hip fracture admitted to our rehabilitation ward.

METHODS

We assessed handgrip strength by a hand-grip Jamar dynamometer at admission to inpatient rehabilitation and functional ability in activities of daily living by the Barthel index at the end of the rehabilitation course. Successful rehabilitation was defined with a Barthel index score ≥85 and highest possible recovery with a Barthel index effectiveness = 100 %.

RESULTS

A handgrip strength ≥16 kg significantly predicted both successful rehabilitation (χ2 = 23.5, P < 0.001) and highest possible recovery (χ2 = 31.05, P < 0.001). For the women with a handgrip strength ≥16 kg, the odds ratios to gain successful rehabilitation and highest possible recovery were 2.68 (95 % CI from 1.19 to 6.04; P = 0.018) and 2.81 (95 % CI from 1.47 to 5.37; P = 0.002), after adjustment for Barthel index scores before rehabilitation, age, hip-fracture type (either medial or lateral), cognitive impairment and 25-hydroxyvitamin D levels.

CONCLUSION

Our results provide an external validation of the 16 kg handgrip strength threshold recently released to discriminate functional outcomes: it significantly predicted the short-term ability to perform activities of daily living after hip fracture in women.