Effect of 12-month resistance and endurance training on quality, quantity, and function of skeletal muscle in older adults requiring long-term care

Sarcopenia interventions in long-term care facilities targeting sedentary behaviour and physical inactivity: A systematic review

BACKGROUND

Sedentary behaviour and physical inactivity are independent risk factors for sarcopenia for long-term care facility residents. Understanding the components, mechanisms and context of interventions that target change in these risk factors can help optimize sarcopenia management approaches. This study aimed to identify, appraise and synthesize the interventions targeting sedentary behaviour and physical inactivity, construct a Theory of Change logic model, inform complex sarcopenia intervention development and identify areas for improvement.

METHODS

Eight electronic databases, including Embase and Web of Science, were searched for eligible interventional studies from inception until February 2024. Narrative synthesis was used. The Theory of Change was applied to develop a logic model presenting the synthesized results. A Cochrane risk of bias assessment tool was used for quality appraisal.

RESULTS

The study included 21 articles involving 1014 participants, with mean ages ranging from 72.5 to 90.4 years. The proportion of female participants ranged from 8.0% to 100.0%. The applied sarcopenia diagnosis criteria varied, including those of the Asian Working Group for Sarcopenia and the European Working Group on Sarcopenia in Older People. The overall risk of bias in the included studies was moderate. Interventions primarily targeted physical inactivity, with resistance training being the most common intervention type. The reporting of intervention adherence was insufficient (only 11 out of 21 included studies provided adherence reports), and adherence overall and by intervention type was not possible to discern due to inconsistent criteria for high adherence across these studies. Four categories of intervention input were identified: educational resources; exercise equipment and accessories; monitoring and tailoring tools; and motivational strategies. Intervention activities fell into five categories: determining the intervention plan; educating; tailoring; organizing, supervising, assisting and motivating; and monitoring. While sarcopenia-related indicators were commonly used as desired outcomes, intermediate outcomes (i.e., sedentary time and physical activity level) and other long-term outcomes (i.e., economic outcomes) were less considered. Contextual factors affecting intervention use included participant characteristics (i.e., medical condition and education level) and intervention provider characteristics (i.e., trustworthiness).

CONCLUSIONS

The findings led to the development of a novel logic model detailing essential components for interventions aimed at managing sarcopenia in long-term care facilities, with a focus on addressing sedentary behaviour and physical inactivity. Future sarcopenia interventions in long-term care facilities should fully attend to sedentary behaviour, enhance adherence to interventions through improved education, monitoring, tailoring and motivation and establish an agreed standard set of outcome measures.

Dietary factors may be associated with measures of ultrasound-derived skeletal muscle echo intensity

Skeletal muscle echo intensity (EI) is affected by ageing and physical activity; however, the effects of nutrition are less understood. The aim of this study was to explore whether habitual nutrient intake may be associated with ultrasound-derived EI. Partial least squares regression (PLSR) models were trained on an initial sample (n = 100, M = 45; F = 55; 38 ± 15 years) to predict EI of two quadriceps muscles from 19 variables, using the "jack-knife" function within the "pls" package (RStudio), which was then tested in an additional dataset (n = 30, M = 13; F = 17; 38 ± 16 years). EI was determined using B-mode ultrasonography of the rectus femoris (RF) and vastus lateralis (VL) and nutritional intake determined via 3-day weighed food diaries. Mean daily intake of specific nutrients were included as predictor variables with age, sex, and self-reported physical activity. PLSR training model 1 explained ∼52% and model 2 ∼46% of the variance in RF and VL EI, respectively. Model 1 also explained ∼35% and model 2 ∼30% of the variance in RF and VL EI in the additional testing dataset. Age and biological sex were associated with EI in both models (P < 0.025). Dietary protein (RF: β = -7.617, VL: β = -7.480), and selenium (RF: β = -7.144, VL: β = -4.775) were associated with EI in both muscles (P < 0.05), whereas fibre intake (RF: β = -5.215) was associated with RF EI only and omega-3 fatty acids (n-3/ω-3 FAs, RF: β = 3.145) with VL EI only (P < 0.05). Therefore, absolute protein, selenium, fibre, and n-3 FAs may be associated with skeletal muscle EI, although further mechanistic work is required before claiming causal inference.

Effect of lower-extremity muscle power training on muscle strength, balance function and walking ability in older adults with heart failure: a randomized controlled trial

PURPOSE

This study investigated the combined effect of lower-extremity muscle power training and regular cardiac rehabilitation on muscle strength, balance function, and walking ability of older adults with heart failure.

METHODS

Thirty-one patients, comprising 17 males and 14 females, aged between 66 and 89 years and diagnosed with non-severe heart failure, were randomly assigned to either the intervention group (n = 15) or control group (n = 16). Both groups participated in a 12-week regular rehabilitation program, with the intervention group receiving additional lower-extremity muscle power training. Various outcome measures, including muscle strength (the five-times-sit-to-stand test and knee extensor peak torque), balance function (Berg balance scale and functional reach test), and walking ability (4-m walk and Timed Up-and-Go tests) were assessed at baseline and 12 weeks after the intervention.

RESULTS

Of the 31 participants, 27 completed the study protocol. The intervention group demonstrated significantly greater improvement in the five-times-sit-to-stand test time, indicating enhanced lower-extremity muscle power compared to the control group. Both groups showed significant differences in the Berg balance scale, functional reach test, 4-m walk test, and Timed Up-and-Go test between baseline and 12 weeks. However, the effect sizes for the changes during the study period were larger in the intervention group (d = 0.74-1.19) than the control group (d = 0.57-0.96).

CONCLUSION

Combining lower-extremity muscle power training with regular cardiac rehabilitation may lead to additional improvements in muscle function for older adults with heart failure, resulting in enhanced dynamic balance and walking ability.

TRIAL REGISTRATION NUMBER/DATE OF REGISTRATION

UMIN000032087/April 4, 2018.

Developing a predictive equation of muscular age to evaluate muscle health in Chinese community-dwelling older women

Muscle health plays an important role in most common age-related diseases and injuries. To date, a standardized quantitative method to assess muscle health has not yet been developed. Principal component analysis was employed to develop a predictive equation of muscular age based on muscle health variables including skeletal muscle mass of lower limb, grip strength and maximal gait speed. Then validity of muscular age was tested by comparing chronological age to muscular age of the elderly. A predictive equation of muscular age was developed. Muscular age = 0.690 × chronological age - 1.245 × skeletal muscle mass of lower limb + 0.453 × grip strength - 1.291 × maximal walking speed + 40.547. Cross-sectional validity test showed that the predictive equation of muscular age is a valid method to assess muscle health. It is applicable not only to the normal elderly but to the elderly with pre-sarcopenia or sarcopenia.

Effect of subcutaneous adipose tissue and muscle thicknesses on rectus femoris and vastus intermedius ultrasound echo intensities: a cadaver study

PURPOSE

The purpose of this study was to examine the effect of subcutaneous adipose tissue (SCAT) thickness and rectus femoris (RF) muscle thickness on RF and vastus intermedius (VI) echo intensity using human cadavers.

METHODS

The echo intensity of the RF and VI was measured in 11 legs of seven cadavers under three conditions: intact condition (Model 1), SCAT removed (Model 2), and SCAT and RF removed (Model 3).

RESULTS

RF echo intensity in Model 1 (69.2 ± 20.3 a.u.) was significantly lower than that in Model 2 (83.4 ± 15.9 a.u.) (P = 0.003). VI echo intensity in Models 1 to 3 showed similar results to RF echo intensity (P = 0.003 to 0.001). Regarding the relationship between VI echo intensity and VI muscle thickness, the regression lines shifted upward in a parallel fashion in the order Model 1, Model 2, and Model 3. Multiple regression analysis revealed that the variation in RF echo intensity was explained by RF muscle thickness (P = 0.036) and SCAT thickness (P = 0.001), while the variation in VI echo intensity was explained by RF muscle thickness (P = 0.035).

CONCLUSION

These results suggest that SCAT thickness and RF muscle thickness induce lower RF echo intensity, while RF muscle thickness induces lower VI echo intensity.

Mitigating Sarcopenia with Diet and Exercise

Sarcopenia is the loss of muscle mass and function from aging, inactivity, or disuse. It is a comorbidity to numerous conditions that exacerbates their severity and adversely impacts activities of daily living. While sarcopenia now receives more attention from the medical community, people with sarcopenia as a comorbidity nevertheless still sometimes receives less attention than other presenting diseases or conditions. Inevitable doctors' visits or hospital stays for those with sarcopenia as a comorbidity have far higher healthcare costs than those without this condition, which imposes a greater financial burden on the medical insurance and healthcare industries. This review offers information and guidance on this topic. Treatments for sarcopenia include dietary, exercise, and pharmacological interventions. Yet, the latter treatment is only recommended in extreme cases as it may evoke numerous side effects and has little support in the scientific literature. Currently, a more holistic approach, with an emphasis on lifestyle modification, to reduce the likelihood of sarcopenia is examined. The current review discusses dietary and exercise interventions to limit the occurrence and severity of sarcopenia. References cited in this review conformed to the Declaration of Helsinki requirements for the use of human research subjects. Most of this review's references (~97%) came from a PubMed search that spanned from 1997 to 2023. Search terms included "sarcopenia" OR "muscle wasting" OR "geriatrics"; OR "ageing"; and AND "diet" OR "exercise". In addition, papers relevant or supportive of the topic as well as those considered seminal were included in the review. Over 96% of the references were peer-reviewed articles.

Rehabilitation in the long-term care insurance domain: a scoping review

PURPOSE

Since the enactment of the long-term care insurance (LTCI) act in 2000, the number of LTCI users has increased annually. However, evidence regarding what is being carried out as rehabilitation treatment under LTCI is lacking. In this study, a scoping review was performed to bridge this knowledge gap.

METHODS

Articles related to rehabilitation in connection with LTCI published between April 2000 and November 2020 were searched for in PubMed, CINAHL, CENTRAL (Cochrane Central Register of Controlled Trials), Ichushi Web Ver.5, and CiNii and randomized controlled trials (RCTs) of rehabilitation provided under LTCI were examined.

RESULTS

Of the 15,572 publications identified, 15 RCTs, including rehabilitation treatment by physiatrists and therapists, met the eligibility criteria of our review and were included. The rehabilitation trials in the 15 RCTs varied and included balance training, exercise therapy, cognitive tasks, and activities such as singing and dancing. The results allowed us to focus on three categories: fall prevention, dementia, and theory and tools interventions related to occupational therapy practice.

CONCLUSION

The focal points of attention in the rehabilitation treatment of LTCI were identified. However, the physical function, quality of life, and activities of daily living (ADL) of those who "need support" vary from person to person. Therefore, the consolidation of evidence on rehabilitation treatment of LTCI must be continued.

Nutritional and swallowing statuses but not intramuscular adipose tissue and muscle mass are related to activities of daily living in older inpatients who are judged as severely low body mass index in the Global Leadership Initiative on Malnutrition criteria

BACKGROUND & AIMS

Which factors are related to activities of daily living (ADL) in older inpatients who are judged as the severely low body mass index (BMI) in the Global Leadership Initiative on Malnutrition (GLIM) criteria is unclear. This study aimed to examine the related factors to ADL in older inpatients who are judged as severely low BMI in the GLIM criteria.

METHODS

This cross-sectional study included 377 inpatients aged ≥70 years. We divided the participants into the following three groups: the severely low BMI group (<17.8 kg/m²) (n = 106), moderately low BMI group (≥17.8 to < 20.0 kg/m²) (n = 87), and normal BMI group (≥20.0 kg/m²) (n = 184). ADL were assessed using the motor-Functional Independence Measure (FIM). Multiple regression analyses were used to identify the factors independently associated with the motor-FIM score in each group.

RESULTS

The Food Intake Level Scale (FILS) and Geriatric Nutritional Risk Index (GNRI) were significantly related to the motor-FIM score of the severely low BMI group. The FILS, GNRI, updated Charlson comorbidity index (UCCI), and quadriceps echo intensity were significantly related to the motor-FIM score of the moderately low BMI group. The FILS, GNRI, UCCI, quadriceps thickness, and subcutaneous fat thickness of the thigh were significantly related to the motor-FIM score of the normal BMI group.

CONCLUSIONS

Our findings indicate that nutritional and swallowing statuses but not intramuscular adipose tissue and muscle mass are related to ADL in older inpatients who are judged as severely low BMI in the GLIM criteria. Intervention for nutritional and swallowing statuses may be prioritized over an exercise intervention to improve ADL of older inpatients who are judged as severely low BMI.

Skeletal muscle and abdominal circumference explain intramuscular fat, independent of exercise frequency, in middle-aged Japanese men

The purpose of this study was to examine how intramuscular adipose tissue (IntraMAT) can be characterized using physical and functional characteristics, muscle size, and/or adipose tissue in four different exercise frequency groups of middle-aged Japanese men. One thousand twenty-eight middle-aged men (age, 47.5 ± 8.1 years; height, 170.5 ± 5.8 cm; body mass, 67.0 ± 9.3 kg; body mass index, 21.9 ± 5.3 kg/m²) were allocated to four groups on the basis of their weekly exercise frequency: Group 1, no exercise, n = 334; Group 2, once a week, n = 271; Group 3, a few days a week, n = 269; and Group 4, every day, n = 154. Their body composition, blood pressure, and handgrip strength were assessed. A single-slice computerized tomography image at the level of the umbilicus was acquired and the CSAs of IntraMAT, muscle tissue, and subcutaneous and visceral adipose tissues (SCAT and VAT) were calculated. The %IntraMAT significantly correlated with physical characteristics, such as age, BMI, abdominal circumference, and muscle tissue CSA. Stepwise multiple regression analysis was performed, with the %IntraMAT as the dependent variable. Muscle tissue CSA and abdominal circumference were the common independent variables across groups to explain the variability of the %IntraMAT. It was also extracted %body fat and age for Group 2, age, handgrip strength, and BMI for Group 3, and smoking category for Group 4. These results suggested that muscle tissue size and abdominal circumference would be the strong predictors to explain %IntraMAT of the trunk muscle across four groups, and that age, %body fat, BMI, and SCAT, handgrip strength and smoking category were also good predictors for each group with different exercise frequency in middle-aged Japanese men.

Association between the recognition of muscle mass and exercise habits or eating behaviors in female college students

This study aimed to examine the association between muscle mass and perception of body shape, desired body shape, physical strength, exercise habits, and eating behaviors. Height, weight, and body composition in 270 female university students were measured. The questionnaire on body shape perception, desired body shape, dieting experience, current, and past exercise habits, exercise preference, and eating behaviors were administered. The analysis of covariance with body fat mass as the covariate found that the skeletal muscle index (SMI) was different among each group on each of body perception or desired body shape (all, p < 0.001). In the post hoc test on body shape perception, the SMI in "obese" was significantly more than that in "slim" (p < 0.001) and "normal" (p < 0.001). In the desired body shape, the SMI in "become thin" was more than that in "maintain as current shape" (p < 0.001). Further, a significant difference was found among the categories of diet experience, with body fat mass as the covariate. In the post hoc test, the SMI in "yes" was more than that in "no" (p < 0.001). These results indicate that not only body fat mass but skeletal muscle mass drives young females' desire for thinness even with exercise advantages.

Examination of Changes in Echo Intensity Following Resistance Exercise among Various Regions of Interest

AIM

Within the resistance exercise literature, echo intensity (EI) is often quantified using different regions of interest (ROI).

PURPOSE

To compare changes in the EI of images of the biceps muscle using different ROI immediately following exercise as well as 24 and 48 h following exercise.

METHODS

Twenty seven non-resistance trained individuals visited the laboratory 4 times. One arm was assigned to the experimental condition, and the other was a non-exercise control. During visit 1, paperwork and strength were measured. During visit, 2 participant's muscles were imaged before performing biceps curls. Additional muscle images were taken immediately after exercise, as well as 24 and 48 h post. EI was measured using three different ROI: 1) Trace around the entire muscle; 2) Small box placed in the middle of the muscle (2 × 2cm); and 3) Maximal rectangular box. Results are displayed as means (95%CI).

RESULTS

There was no condition (experimental vs. control) x time (pre, post, 24h and 48h) x box size (small, large, full trace) interaction (p = 0·592). However, there was a main effect for box size (p < 0·001). EI values were higher with the small box [28·2 (23·3, 33·1) AU] compared to the large box [26·8 (22·3, 31·2) AU, p = 0·016] and compared to the full trace [24·2 (20·3, 28·0) AU p < 0·001)]. In addition, EI values were higher with the large box compared to the full trace technique (p = 0·001).

CONCLUSION

Similar changes in EI are detected when using different commonly used ROI for analysing EI. However, when larger ROI are examined, EI values appear to be lower.

Evaluation of rehabilitation exercise effects by using gradation-based skeletal muscle echo intensity in older individuals: a one-group before-and-after trial study

Background

Higher muscle echo intensity (EI) reflects higher content of fat and/or connective tissue within skeletal muscle, eventually inducing lower muscle strength, physical dysfunction, and metabolic impairment. Continuous exercise decreases muscle EI in older individuals; however, it is not well understood how several months’ rehabilitation exercise affects gradation-based EI. The purpose of this study was to investigate the effects of 6 months of rehabilitation exercise on gradation-based higher and lower EI in older men and women.

Methods

Twenty-seven men and women (7 men, 20 women; age, 75.6 ± 6.4 years; height, 154.3 ± 8.5 cm; weight, 55.8 ± 9.7 kg) participated in this study. This study was a one-group before-and-after trial. They needed long-term care for activities of daily living. They performed rehabilitation exercises consisting of resistance exercises using a hydraulic resistance machine, stretching, and aerobic exercises using a recumbent bicycle once or twice a week for 6 months. B-mode ultrasonographic transverse image was taken from thigh muscles, e.g., rectus femoris, vastus lateralis, and biceps femoris. We calculated gradation-based cross-sectional area (CSA) from thigh muscles by dividing 256 greyscale level to 10 different components levels (e.g., 0–24, 25–49, 50–74, …, 200–224 and 225–249 a.u.).

Results

Lowest EI (e.g., 0–24 a.u.) CSA of thigh muscle was significantly increased after the exercise (0.3 ± 0.3 to 1.0 ± 0.8 cm²; P < 0.05). Middle to higher EI (e.g., 50–74, 75–99, 100–124, 125–149, 150–174, 175–199 and 200–224 a.u.) CSAs were significantly decreased from 23.0 to 68.7% after the exercise (P < 0.05).

Conclusions

Several months’ rehabilitation exercise affected both lower and higher EI in older men and women. This result suggests that rehabilitation exercise changes muscle composition by increasing contractile muscle tissue and decreasing fat and connective tissues.

Skeletal Muscle Quality: A Biomarker for Assessing Physical Performance Capabilities in Young Populations

Muscle quality (MQ), defined as the amount of strength and/or power per unit of muscle mass, is a novel index of functional capacity that is increasingly relied upon as a critical biomarker of muscle health in low functioning aging and pathophysiological adult populations. Understanding the phenotypical attributes of MQ and how to use it as an assessment tool to explore the efficacy of resistance exercise training interventions that prioritize functional enhancement over increases in muscle size may have implications for populations beyond compromised adults, including healthy young adults who routinely perform physically demanding tasks for competitive or occupational purposes. However, MQ has received far less attention in healthy young populations than it has in compromised adults. Researchers and practitioners continue to rely upon static measures of lean mass or isolated measures of strength and power, rather than using MQ, to assess integrated functional responses to resistance exercise training and physical stress. Therefore, this review will critically examine MQ and the evidence base to establish this metric as a practical and important biomarker for functional capacity and performance in healthy, young populations. Interventions that enhance MQ, such as high-intensity stretch shortening contraction resistance exercise training, will be highlighted. Finally, we will explore the potential to leverage MQ as a practical assessment tool to evaluate function and enhance performance in young populations in non-traditional research settings.

The Relationship Between Muscle Size and Strength Does not Depend on Echo Intensity in Healthy Young Adults

Muscle quality is typically defined as muscle strength relative to muscle size. Echo intensity has gained popularity as an index of skeletal muscle quality. There is common agreement that muscle size is related to strength at baseline and echo intensity is purported to impact this relationship. Thus, the purpose of this study was to examine whether echo intensity can be used as a physiological marker for muscle quality by investigating the moderating effect of echo intensity on the relationship between muscle size and strength. A sample of 96 participants was used for the upper body analysis and a separate sample of 96 participants was used for the lower body analysis. Echo intensity, muscle thickness, and strength measurements were measured on each limb. For strength, participants performed unilateral elbow flexion (upper body analysis) and knee extension (lower body analysis) to quantify 1-repetition maximum. Muscle thickness and echo intensity were determined from images captured using B-mode ultrasound. Muscle size correlated with muscle strength for all limbs. However, the relationship between muscle size and strength was not significantly moderated by echo intensity for Arm 1 (b = 0.042, p = 0.54) or Arm 2 (b = -0.002, p = 0.97). At the proximal site, no significant moderating effect of echo intensity was found in Leg 1 (b = 0.037, p = 0.67) or Leg 2 (b = -0.085, p = 0.29). Similarly, no significant moderating effect was observed at the distal site for Leg 1 (b = 0.03, p = 0.69) or Leg 2 (b = -0.026, p = 0.75). The results would indicate that the relationship between muscle size and strength does not depend on echo intensity. Therefore, the use of echo intensity as an index of muscle quality in healthy young adults may need to be reconsidered.

Chair sit-to-stand performance is associated with diagnostic features of sarcopenia in older men and women

BACKGROUND

Standing from a chair is a fundamental activity of daily living, and it can be applied to assess the physical function, especially in older individuals.

AIM

The aim of this study was to elucidate the characteristics of mechanical and temporal parameters during chair stand based on the relationship with skeletal muscle and physical functional parameters in older men and women.

METHODS

Eighty older men and women participated in this study. We measured four parameters of chair stand performance: ground reaction force (GRF), rate of force development (RFD), and chair rise time (CRT) were calculated from the foot-floor force data; sit-to-stand (STS) was also assessed by measuring the time needed to complete 10 chair stand repetitions. The muscle thickness (MT) and echo intensity, as indexes of muscle size and quality, respectively, were measured using axial B-mode ultrasound images from quadriceps femoris. The gait speed and handgrip strength were measured as physical functional parameters.

RESULTS

Partial correlation was used to determine the association of chair stand performance with MT, echo intensity, and physical parameters while considering the height, body mass, and age. GRF, RFD, and STS were significantly correlated with MT (r = 0.35, 0.26, and -0.49), gait speed (r = 0.32, 0.31, and -0.67), and handgrip strength (r = 0.57, 0.59, and -0.49). As the result of regression analysis, MT, gait speed, and handgrip strength were estimated by GRF and STS.

CONCLUSION

These results suggest that chair stand performance is useful as it reflects the muscle size and physical functions in older individuals.

Does skeletal muscle morphology or functional performance better explain variance in fast gait speed in older adults?

BACKGROUND

Fast gait speed is being increasingly recognized as an important clinical tool in older adults. However, the underlying muscular and functional contributors to fast gait speed performance remain poorly understood.

AIM

We sought to determine predictors of fast gait speed in older adults. We hypothesized that lower-extremity skeletal muscle size and quality would be strong predictors.

METHODS

Ninety community-dwelling older adults (33 men, 57 women; mean ± SD age = 74 ± 6 years) participated. B-mode ultrasonography was used to capture images of the vastus lateralis, rectus femoris, and gastrocnemius in the transverse plane. Each participant performed 30-second chair stand, heel-rise, functional reach, and grip strength tests. Fast gait speed was measured using the NIH Toolbox 4-Meter Walk Test. ImageJ software was used to quantify cross-sectional area (CSA), subcutaneous tissue thickness, and echo intensity. Two separate stepwise regression analyses were performed, one using muscle morphology variables as independent variables, and another including the functional outcomes.

RESULTS

The ultrasound variables exhibited weak-to-moderate correlations with fast gait speed (|r| range = 0.168-0.416). The initial regression analysis indicated that the combination of medial gastrocnemius CSA and subcutaneous tissue thickness explained 22.8% of the variance in fast gait speed. The secondary analysis indicated that 30-second chair stand, heel-rise, and grip strength performance explained 45.5% of the variance.

CONCLUSION

While medial gastrocnemius morphology is important, measures of upper and lower-extremity muscle function are better predictors of fast gait speed. These results highlight a dissociation between skeletal muscle morphology and fast gait speed.

Effect of isometric exercises on the masseter muscle in older adults with missing dentition: a randomized controlled trial

Maintaining oral function in older individuals with missing teeth is important for leading a healthy and independent life. This study aimed to evaluate whether simple isometric exercises can maintain and improve the oral function [maximum occlusal force (MOF) and masticatory ability (MA)] and the masticatory muscle properties [masseter muscle thickness (MMT) and echo intensity (MMEI)] in older adults during the maintenance phase of removable prosthetic treatment. Participants were randomly categorized into the intervention and control groups. The mouthpieces were distributed, and participants were instructed to use them for exercising. The intervention group was instructed to perform maximum clenching for 10 s, whereas the control group was instructed to tap the teeth at an arbitrary speed for 10 s. Both were repeated five times at an interval of 5 s between each activity and twice daily for 4 weeks. The outcomes were measured after a month of exercise. The intervention group showed a significant improvement in the MOF, MMT during contraction, MMT at rest and MMEI during contraction. There were no significant differences in the MA and MMEI at rest. In the control group, no improvement was observed in any of the parameters. When the isometric exercises were performed using a mouthpiece, there was an improvement in the oral function and masseter muscle properties in older individuals with Eichner B status who used dentures.

Impact of home-based squat training with two-depths on lower limb muscle parameters and physical functional tests in older adults

This study investigated the effect of home-based shallow and deep squat trainings on knee extension peak torque, muscle thickness, one-repetition maximum (1RM) leg press, and physical function in older individuals. Sixteen participants were randomly assigned to the shallow squat group (SS group; age, 71.0  ±  4.0 years) or deep squat group (DS group, age; 68.6  ± 3.6 years). Chairs of 40-cm height and chairs with a cushion of 20-cm height (60-cm in total) were used as the depth targets for squats, with participants instructed to sink until their hip touched the chair and cushion. Participants performed four sets of squats per day (35 repetitions per set), three days per week, for 12 weeks at their home. Knee extension peak torque, muscle thickness of quadriceps femoris (e.g., vastus lateralis, rectus femoris, and vastus intermedius), and physical function were measured at weeks 0 (baseline), 4, 8, and 12. Maximal isometric knee extension peak torque, muscle thickness, and walking speed did not change significantly over the 12-week training period in either group (P > 0.05). However, compared with the baseline, there was significant improvement in the results of 30-s sit-to-stand repetition tests after weeks 8 and 12 in both groups (P < 0.05). Additionally, 1RM leg press results were significantly improved after weeks 4 and 12 in the DS group, and weeks 4, 8, and 12 in the SS group (P < 0.05). Results indicate that home-based weight-bearing squat training improves lower limb function in older adults, as well as performance in physical functional tests related to activities of daily living. Moreover, such training benefits older adults regardless of whether squats are shallow or deep.

Dance intervention effects on physical function in healthy older adults: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Dancing is a form of physical exercise associated with health benefits in older adults. Regular dancing can prolong healthy aging, maintain or even improve physical function, and thus enhance their quality of life. The aim of this review was to evaluate the effects of dance intervention on physical function performance in healthy older adults in randomized-controlled trials (RCTs).

METHODS

Five electronic databases (Cochrane Library, PsycINFO, PubMed, Scopus, and Web of Science) were searched systematically until the end of June 2018 by two independent reviewers. These searches were limited to the English language and persons with average age older than 65. The tool from the Cochrane Collaboration was used to assess the risk of bias. A standard meta-analysis was performed using Review Manager Software version 5.3.

RESULTS

Thirteen RCTs from a total of 1029 older participants were included in this meta-analysis. The results showed that dance intervention significantly improved mobility function and endurance performance when compared with control groups for healthy older adults. However, gait was not significantly improved through dancing. Studies included in this review were not enough to perform meta-analysis for the effectiveness of dance on balance and general health in healthy older adults.

CONCLUSION

Overall, dance intervention was effective to improve physical function performance in healthy older adults. The results from this meta-analysis strengthen the evidence from previous individual studies. Properly organized dance intervention would be a safe and effective exercise to incorporate into daily life.

Comparison of muscle quality and functional capacity between Japanese and Brazilian older individuals

Muscle quality is well-known to decrease with aging and is a risk factor for metabolic abnormalities. However, there is a lack of information on race-associated differences in muscle quality and other neuromuscular features related to functional performance. This study aimed to compare muscle quality, function, and morphological characteristics in Japanese and Brazilian older individuals. Eighty-four participants aged 65–87 years were enrolled in the study (42 Japanese: 23 men, 19 women, mean age 70.4 years; 42 Brazilians: 23 men, 19 women, mean age 70.8 years). Echo intensity (EI) and muscle thickness (MT) of the quadriceps femoris were measured using B-mode ultrasonography. A stepwise multiple linear regression analysis with EI as a dependent variable revealed that MT was a significant variable for Japanese participants (R² = 0.424, P = 0.001), while MT and subcutaneous adipose tissue (SCAT) thickness were significant variables for Brazilian participants (R² = 0.490, P = 0.001). A second stepwise multiple linear regression analysis was performed after excluding MT and SCAT thickness from the independent variables. Sex and age for Japanese participants (R² = 0.381, P = 0.001) and lean body mass and body mass index for Brazilian participants (R² = 0.385, P = 0.001) were identified as significant independent variables. The present results suggest that MT is closely correlated with muscle quality in Japanese and Brazilian older individuals. Increases in muscle size may induce decreases in intramuscular adipose tissue and/or connective tissues, which are beneficial for reducing the risks of metabolic impairments in Japanese and Brazilian older individuals.

Relationship Between Aging and Intramuscular Adipose Tissue in Older Inpatients

OBJECTIVE

Although older inpatients are known to develop various conditions, whether aging affects intramuscular adipose tissue in older inpatients remains unclear. In particular, an increase in intramuscular adipose tissue in persons aged ≥85 years has previously not been revealed in either older inpatients or community-dwelling older individuals. This study therefore aimed to examine whether aging affects intramuscular adipose tissue in older inpatients.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

This study was clinical-based and included 404 inpatients aged ≥65 years.

METHODS

We divided the participants into the following age groups: 65-74 years (n = 63), 75-84 years (n = 171), and ≥85 years (n = 170). B-mode ultrasound imaging was performed, and the intramuscular adipose tissue of the quadriceps was assessed based on echo intensity. One-way analysis of variance and analysis of covariance were used to compare the echo intensity of the quadriceps between the 65-74-year, 75-84-year, and ≥85-year groups.

RESULTS

The median (25th-75th percentile) ages of the 65-74-year group, 75-84-year group, and ≥85-year group were 70.0 (68.0-73.0), 80.0 (77.0-82.0), and 89.0 (87.0-91.0), respectively. In the one-way analysis of variance, the quadriceps echo intensity of the ≥85-year group was significantly higher than that of the 65-74-year and 75-84-year groups. In addition, the ≥85-year group had significantly higher quadriceps echo intensity than the 65-74-year group, even after adjusting for other confounding factors.

CONCLUSIONS AND IMPLICATIONS

The current study revealed that intramuscular adipose tissue in older inpatients increases with age, and the levels of intramuscular adipose tissue of older inpatients aged ≥85 years is higher than those of older inpatients aged 65-74 years.

Approaches to Assessment of Muscle Mass and Myosteatosis on Computed Tomography: A Systematic Review

BACKGROUND/OBJECTIVE

There is increasing use of computed tomography (CT) in sarcopenia research using a wide variety of techniques. We performed a systematic review of the CT literature to identify the differences between approaches used.

METHODS

A comprehensive search of PubMed from 1983 to 2017 was performed to identify studies that used CT muscle measurements to assess muscle mass and myosteatosis. The CT protocols were evaluated based on anatomic landmark(s), thresholding, muscle(s) segmented, key measurement (ie, muscle attenuation, cross-sectional area, volume), derived variables, and analysis software. From the described search, 657 articles were identified and 388 studies met inclusion criteria for this systematic review.

RESULTS

Muscle mass was more commonly assessed than myosteatosis (330 vs. 125). The most commonly assessed muscle or muscle groups were total abdominal wall musculature (142/330 and 49/125 for muscle mass and myosteatosis, respectively) and total thigh musculature (90/330 and 48/125). The most commonly used landmark in the abdomen was the L3 vertebra (123/142 and 45/49 for muscle mass and myosteatosis, respectively). Skeletal muscle index and intermuscular adipose tissue were the most commonly used measures of abdominal wall muscle mass (114/142) and myosteatosis (27/49), respectively. Cut points varied across studies. A significant majority of studies failed to report important CT technical parameters, such as use of intravenous contrast and slice thickness (94% and 63%, respectively).

CONCLUSIONS

There is considerable variation in the CT approaches used for the assessment of muscle mass and myosteatosis. There is a need to develop consensus for CT-based evaluation of sarcopenia and myosteatosis.

Exercise induced changes in echo intensity within the muscle: a brief review

Echo intensity is the mean pixel intensity of a specific region of interest from an ultrasound image. This variable has been increasingly used in the literature as a physiological marker. Although there has been an increased interest in reporting changes in echo intensity in response to exercise, little consensus exists as to what a change in echo intensity represents physiologically. The purpose of this paper is to review some of the earliest, as well as the most up to date literature regarding the changes in echo intensity in response to exercise. Echo intensity has been used to measure muscle quality, muscle damage, acute swelling, and intramuscular glycogen. The changes in echo intensity, however, are not consistent throughout the literature and often times lead to conclusions that seem contrary to the physiologic effects of exercise. For example, echo intensity increases in conjunction with increases in strength, contrary to what would be expected if echo intensity was a marker of muscle quality/muscle damage. It is conceivable that a change in echo intensity represents a range of physiologic effects at different time points. We recommend that these effects should be determined experimentally in order to rule out what echo intensity might and might not represent. Until this is done, caution should be employed when interpreting changes in echo intensity with acute and chronic exercise.

Higher and Lower Muscle Echo Intensity in Elderly Individuals Is Distinguished by Muscle Size, Physical Performance and Daily Physical Activity

This study was performed to identify factors that discriminate muscle echo intensity (EI) among parameters of body composition, physical function and daily physical activity in elderly individuals. A total of 209 men and women (73.7 ± 2.8 y) were evaluated. EI was measured on ultrasonographic axial thigh muscle images. The participants were categorized into the low, mid and high EI groups. We measured the skeletal muscle mass index (SMI) and physical functions. The high EI group exhibited a significantly lower SMI, slower 5-m walking time and shorter 6-min walking distance than the low EI group and had a shorter moderate-intensity activity time than the mid EI group. As a result of the discriminant analysis, elderly individuals were categorized into EI groups by SMI, daily activity and physical function. The data indicate that morphologic and functional parameters and the daily activity level help to discriminate higher and lower muscle EI.

Twenty-Four Months' Resistance and Endurance Training Improves Muscle Size and Physical Functions but Not Muscle Quality in Older Adults Requiring Long-Term Care

OBJECTIVES

To assess the effects of 24 months training on muscle quality, size, strength, and gait abilities in older adults who need long-term care.

DESIGN

Non-randomized controlled trial Setting: Kawai Rehabilitation Center and Kajinoki Medical Clinic.

PARTICIPANTS

Ten older participants who needed long-term care (age, 76.7 ± 5.6 years) were participated as training group (Tr-group) and 10 older men and women who did not require long-term care (age, 72.9 ± 6.6 years) comprised the control group (Cont-group).

INTERVENTION

Tr-group performed resistive and endurance exercises once or twice a week for 24 months.

MEASUREMENTS

Using ultrasound images, echo intensity (EI) and muscle thickness were measured in the rectus femoris and biceps femoris as an index of muscle quality and size. Physical performance was measured before and after the training; performance parameters included knee extension peak torque, 5-m normal and maximal walk test, sit-to-stand and timed up and go test.

RESULTS

After the training, there was no change in EI, while BF thickness was increased (pre; 1.82 ± 0.29 cm, 24 months; 2.14 ± 0.23 cm, p < 0.05) in Tr-group. Walk-related performances were improved after the training in Tr-group (i.e. 5-m walk test and timed up and go test). The percent change of knee extension peak torque explained the percent change of EI in the rectus femoris (regression coefficient = 1.24, R = 0.91, adjusted R2 = 0.82, p < 0.001).

CONCLUSIONS

Twenty-four months' training induced muscle hypertrophy and improved physical functions. Increased muscle quality in the rectus femoris could be a key to improved knee extension peak torque, with the potential to eventually reduce the need for long-term care in older individuals.

Effects of 10-week walking and walking with home-based resistance training on muscle quality, muscle size, and physical functional tests in healthy older individuals

Background

Older individuals have been shown to present muscle atrophy in conjunction with increased fat fraction in some muscles. The proportion of fat and connective tissue within the skeletal muscle can be estimated from axial B-mode ultrasound images using echo intensity (EI). EI was used to calculate the index of muscle quality. Walking, home-based weight-bearing resistance training, and its combinations are considered simple, easy, and practical exercise interventions for older adults. The purpose of this study was to quantify the effects of walking and walking with home-based resistance training on muscle quality of older individuals.

Methods

Thirty-one participants performed walking training only (W-group; 72 ± 5 years) and 33 participants performed walking and home-based resistance training (WR-group; 73 ± 6 years). This study was a non-randomized controlled trial with no control group. All participants were instructed to walk 2 or 3 sets per week for 10 weeks (one set: 30-min continuous walking). In addition, the WR-group performed home-based weight-bearing resistance training. EI was measured as a muscle quality index using axial B-mode ultrasound images of the rectus femoris and vastus lateralis of the mid-thigh. We further averaged these parameters to obtain the EI of the quadriceps femoris (QF). Participants further performed five functional tests: sit-ups, supine up, sit-to-stand, 5-m maximal walk, and 6-min walk.

Results

QF EI was significantly decreased in both groups after training (W-group 69.9 ± 7.4 a.u. to 61.7 ± 7.0 a.u., WR-group 64.0 ± 9.5 a.u. to 51.1 ± 10.0 a.u.; P < 0.05), suggesting improved muscle quality. QF EI was further decreased in the WR-group compared with the W-group. The sit-up test in both groups and the sit-to-stand and 5-m maximal walk tests in the W-group were significantly improved after training.

Conclusion

These results suggest that training-induced stimulation is associated with a decrease in EI in some thigh regions. Furthermore, the addition of home-based resistance training to walking would be effective for a greater reduction of EI.

Association between echo intensity and attenuation of skeletal muscle in young and older adults: a comparison between ultrasonography and computed tomography

Background

Skeletal muscle experiences both quantitative and qualitative changes with aging. Echo intensity (EI) of the skeletal muscle obtained by ultrasonography (US) has been considered to reflect muscle quality. This technique is noninvasive, easily accessible, and is relatively inexpensive than that of other imaging techniques such as computed tomography (CT). Previous studies have reported that EI is related to several physical performances. However, few studies have investigated the validity of EI against other imaging methods in case of imaging of the skeletal muscle. We compared quantitative and qualitative indices evaluated by the US and CT imaging systems to strengthen their validity.

Participants and methods

A total of 40 adults participated in this study: 19 young (10 men and 9 women; their mean (±SD) age was 22.7±1.5 years) and 21 older adults (13 men and 8 women; their mean age was 70.6±4.8 years). Both thighs of each participant were evaluated using US and CT imaging systems.

Results

With respect to the US indices, the young group had significantly higher muscle thickness (MT) of the front thigh (P<0.001) and lower EI (P=0.001) than that of the older group. With respect to the CT indices, the cross-sectional area (CSA) and mean CT value (Hounsfield unit [HU]) of the muscle were found to be significantly higher in the young group (P<0.001) than that of the older group, whereas the percentage of low-density muscle area (%LDMA) was found to be significantly higher in the older group (P<0.001) than that of the young group. A significant, strong, and positive correlation was observed between MT and CSA, which reflects the muscle quantity (r=0.774; P<0.001). With respect to the indices of muscle quality, we found significant and moderate correlations between EI and CT values (r=−0.502; P<0.001) and between EI and %LDMA (r=0.441; P<0.001). However, these correlations were found to be decreased in the older group [between EI and CT value (r=−0.363; P=0.018) and between EI and %LDMA (r=0.257; P=0.100)].

Conclusion

Results of this study indicate that the EI is moderately associated with muscle attenuation as assessed by CT, which means that higher EI at least partly reflects intramuscular lipid infiltration.

Association of physical activity with age-related changes in muscle echo intensity in older adults: a 4-year longitudinal study

Ultrasonic echo intensity (EI), an easy-to-use measure of intramuscular fat and fibrous tissues, is known to increase with aging. However, age-related changes in EI have not been examined in a longitudinal design. The objective of this study was to investigate 4-yr longitudinal changes in the EI of the quadriceps femoris in older adults, based on difference in physical activity (PA). This study included 131 community-dwelling older adults with a mean age of 72.9 ± 5.2 yr. Subcutaneous fat thickness (FT), muscle thickness (MT), and EI of the quadriceps femoris were measured by ultrasound. Isometric knee extensor strength was also measured. PA was assessed using a questionnaire at baseline, and participants were classified into the high or low PA groups. In 4 yr, a significant decrease in FT, MT, and strength was observed in both groups ( P < 0.05), whereas a significant decrease in EI was observed only in the high PA group ( P < 0.05). Multiple linear regression analyses revealed that the difference in PA was a significant predictor of 4-yr changes in MT (β = 0.189, P = 0.031) and EI (β = -3.145, P = 0.045) but not in the body mass index, FT, or strength adjusted for potential confounders. The present findings suggest that greater PA has a positive effect on longitudinal changes in the MT and EI of the quadriceps femoris in older adults. In addition, greater PA may contribute to a future decrease in EI, and an increase in EI may not occur in 4 yr, even in older adults with lesser PA. NEW & NOTEWORTHY Our results suggest that greater physical activity (PA) may mitigate future changes in muscle thickness and echo intensity (EI). A decrease in EI over 4 yr was observed in older adults with greater PA, and an increase in EI was not observed, even in older adults with smaller PA. Several cross-sectional studies demonstrated an increase in EI with aging. Additionally, the results of our longitudinal study suggest that an age-related increase in EI may be moderated after the old-age period.

Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors: A cross-sectional study

Objective

Improving muscle mass and intramuscular fat in the mid-thigh increases the muscle strength of the paretic and non-paretic limbs in ambulatory chronic stroke survivors. There is a remarkable decrease in muscle mass and muscle strength and an increase in intramuscular fat in the quadriceps of both limbs of non-ambulatory compared with ambulatory survivors. Therefore, given that paretic lower extremity function does not recover sufficiently in the chronic phase, it may be helpful to improve muscle mass and intramuscular fat to increase muscle strength in the quadriceps of non-ambulatory chronic stroke survivors. However, these relationships remain unclear. The purpose of this study was to clarify the relationships between muscle strength, muscle mass, and intramuscular fat of the quadriceps in non-ambulatory chronic stroke survivors.

Methods

Study design: A cross-sectional study.

Participants: Fifty non-ambulatory chronic stroke survivors.

Main outcome measures: Quadriceps muscle strength was measured using a handheld dynamometer. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular fat of the quadriceps were assessed based on muscle thickness and echo intensity, respectively.

Data analysis: Stepwise multiple regression analyses were used to identify the factors independently associated with the quadriceps muscle strength of the paretic and non-paretic limbs. To avoid multicollinearity, muscle thickness and echo intensity were entered into separate multiple regression models. Muscle thickness or echo intensity of the paretic or non-paretic limbs and other confounding factors were set as the independent variables.

Results

Muscle thickness was positively related and echo intensity was negatively related to the quadriceps muscle strength of the paretic and non-paretic limbs.

Conclusions

Muscle mass and intramuscular fat of the quadriceps are related to muscle strength in non-ambulatory chronic stroke survivors. Increasing muscle mass and decreasing intramuscular fat of the quadriceps of both limbs may improve muscle strength.