Musculoskeletal adaptations to strength training in frail elderly: a matter of quantity or quality?

Association Between Changes in Skeletal Muscle Quality and Prognosis in Postoperative Patients with Early Gastric Cancer

BACKGROUND

Identifying accurate prognostic factors is crucial for postoperative management of early gastric cancer (EGC) patients. Skeletal muscle quality (SMQ), defined by muscle density on computed tomography (CT) images, has been proposed as a novel prognostic factor. This study compared the prognostic significance of SMQ changes with the well-established factor of body weight (BW) loss in the postoperative EGC setting.

METHODS

This single-center retrospective study included 297 postoperative EGC patients (median age 69 years, 68.4% male) who had preoperative and 1-year-postoperative gastrectomy CT images. SMQ was defined as the modified intramuscular adipose tissue content (mIMAC = skeletal muscle density-subcutaneous fat density on CT images) and the change as ΔmIMAC. Log-rank test, Kaplan-Meier survival, and Cox proportional hazards regression analyses were used to assess the associations between prognosis and either ΔmIMAC or BW change (ΔBW). Prognosis prediction by ΔmIMAC and ΔBW was compared by using the area under the curve (AUC) of the receiver operating characteristic curve.

RESULTS

ΔmIMAC was significantly associated with prognosis (log-rank test; P = 0.037), but ΔBW was not (P = 0.243). Prognosis was significantly poorer in the severely decreased mIMAC group than in the preserved group (multivariate Cox proportional hazards regression analysis; P = 0.030) but was unaffected by BW changes (P = 0.697). The AUC indicated a higher prognostic value for ΔmIMAC than ΔBW (ΔmIMAC: AUC = 0.697, ΔBW: AUC = 0.542).

CONCLUSIONS

One-year post-gastrectomy SMQ changes may be better prognostic EGC predictors than BW changes.

Non invasive techniques for direct muscle quality assessment after exercise intervention in older adults: a systematic review

BACKGROUND

The aging process induces neural and morphological changes in the human musculoskeletal system, leading to a decline in muscle mass, strength and quality. These alterations, coupled with shifts in muscle metabolism, underscore the essential role of physical exercise in maintaining and improving muscle quality in older adults. Muscle quality's morphological domain encompasses direct assessments of muscle microscopic and macroscopic aspects of muscle architecture and composition. Various tools exist to estimate muscle quality, each with specific technical requirements. However, due to the heterogeneity in both the studied population and study methodologies, there is a gap in the establishment of reference standards to determine which are the non-invasive and direct tools to assess muscle quality after exercise interventions. Therefore, the purpose of this review is to obtain an overview of the non-invasive tools used to measure muscle quality directly after exercise interventions in healthy older adults, as well as to assess the effects of exercise on muscle quality.

MAIN TEXT

To address the imperative of understanding and optimizing muscle quality in aging individuals, this review provides an overview of non-invasive tools employed to measure muscle quality directly after exercise interventions in healthy older adults, along with an assessment of the effects of exercise on muscle quality.

RESULTS

Thirty four studies were included. Several methods of direct muscle quality assessment were identified. Notably, 2 studies harnessed CT, 20 utilized US, 9 employed MRI, 2 opted for TMG, 2 adopted myotonometry, and 1 incorporated BIA, with several studies employing multiple tests. Exploring interventions, 26 studies focus on resistance exercise, 4 on aerobic training, and 5 on concurrent training.

CONCLUSIONS

There is significant diversity in the methods of direct assessment of muscle quality, mainly using ultrasound and magnetic resonance imaging; and a consistent positive trend in exercise interventions, indicating their efficacy in improving or preserving muscle quality. However, the lack of standardized assessment criteria poses a challenge given the diversity within the studied population and variations in methodologies.. These data emphasize the need to standardize assessment criteria and underscore the potential benefits of exercise interventions aimed at optimizing muscle quality.

Association of computed tomography-derived muscle mass and quality with delayed acquisition independent walking after cardiovascular surgery

BACKGROUND

In the context of cardiovascular surgery, the foremost concern lies in delayed functional recovery, as typified by the acquisition of independent walking after surgery, among older patients with decline in skeletal muscle mass and quality. Computed tomography (CT), which is typically employed for the preoperative assessment of pathological conditions in patients undergoing cardiovascular surgery, is also suitable for screening for potential decline in skeletal muscle mass and quality. The aim of this study was to examine the predictive capabilities of CT-derived parameters such as muscle mass and muscle quality for the delayed acquisition of independent walking in the postoperative period.

METHODS

This retrospective study enrolled consecutive Japanese patients who underwent elective cardiovascular surgery between May 2020 and January 2023. In total, 139 patients were included in the analyses. Based on the preoperative CT image, the psoas muscle volume index (PMVI) and psoas muscle attenuation (PMA) were calculated. Information on patient characteristics, including preoperative physical fitness such as handgrip strength/body mass index (GS/BMI), short physical performance battery (SPPB), and 6-min walking distance (6MWD), were obtained from the medical records. We defined delayed acquisition of independent walking after surgery as the inability to walk 100 m within 4 days after surgery.

RESULTS

The median age of the patients was 72 (interquartile: 64-78) years, and 74.8% (104/139) were men; 47.5% corresponded to the delayed group. The areas under the curves of SPPB, GS/BMI, 6MWD, PMVI, and PMA against delayed acquisition of independent walking after surgery were 0.68 [95% confidence interval (CI): 0.59 to 0.77], 0.72 (95% CI: 0.63 to 0.80), 0.73 (95% CI: 0.65 to 0.82), 0.69 (95% CI: 0.60 to 0.78), and 0.78 (95% CI: 0.70 to 0.85), respectively. In the multivariate logistic regression analysis, low PMA was significantly associated with delayed acquisition of independent walking even after adjustment for patient characteristics including physical fitness [model 1: SPPB (OR, 1.14; 95% CI: 1.03-1.25), model 2: GS/BMI (OR, 1.13; 95% CI: 1.03-1.25), and model 3: 6MWD (OR, 1.14; 95% CI: 1.03-1.25)], but PMVI was not.

CONCLUSIONS

Our study revealed a strong association between PMA, a marker of CT-derived muscle quality, and the postoperative delay in achieving independent walking in patients who underwent cardiovascular surgery. The technique to obtain information on muscle quality during the time period before surgery may be an option for timely therapeutic intervention in patients who may have delayed acquisition of independent walking after surgery.

Low Hand Grip Strength, Mid-Upper Arm Muscle Area, Calf Circumference, Serum Albumin Level, and Muscle Fiber Diameter as Risk Factors for Independent Walking Inability in Patients with Hip Fracture 6 Weeks after Bipolar Hemiarthroplasty Surgery

Background

Bipolar hemiarthroplasty, one of the main treatment modalities for hip fracture, does not always promise the ability to walk independently after surgery. Patients with the same fracture characteristics and comorbidities, implants, and operators may also have different outcomes. Sarcopenia is thought to be one of the causes of the inability to walk independently after this operation; however, it has not been widely studied and is often overlooked.

Methods

This study used a case-control design with 23 patients in the case group (patients unable to walk independently) and 23 patients in the control group (patients able to walk independently). Sampling was carried out consecutively according to the inclusion and exclusion criteria based on the medical records of patients with hip fractures after bipolar hemiarthroplasty at our hospital. In the preoperative period, hand grip strength (HGS), mid-upper arm muscle area (MUAMA), calf circumference (CC), serum albumin level, and total lymphocyte count were measured. A muscle biopsy was performed intraoperatively from the gluteus muscle with the amount of 200-350 mg. The patient's walking ability was assessed in the polyclinic using the Timed Up and Go test 6 weeks postoperatively. The statistical tests used were descriptive statistics, proportion comparison analysis with the chi-square test, and multiple logistic regression test.

Results

Univariate analysis using chi-square test proved HGS, MUAMA, CC, serum albumin level, and muscle fiber diameter as risk factors for inability to walk independently 6 weeks after bipolar hemiarthroplasty (p = 0.003, p = 0.003, p = 0.006, p = 0.044, and p = 0.000, respectively). Logistic regression test proved 3 direct risk factors for the inability to walk independently 6 weeks after bipolar hemiarthroplasty, namely MUAMA, serum albumin level, and muscle fiber diameter, as the strongest predictive factor (adjusted odds ratio, 63.12).

Conclusions

Low MUAMA, serum albumin levels, and muscle fiber diameter are direct risk factors for the inability to walk independently in hip fracture patients 6 weeks after bipolar hemiarthroplasty.

Trajectory of Abdominal Skeletal Muscle Changes During Cardiac Rehabilitation in Patients With Aortic Disease

OBJECTIVE

This study focused on routine computed tomography imaging for aortic disease management and evaluated the trajectory of skeletal muscle changes through inpatient and outpatient cardiac rehabilitation.

DESIGN

Prospective observational study included patients who underwent abdominal computed tomography three times (baseline, postacute care, and follow-up). The area and density of the all-abdominal and erector spine muscles and intramuscular adipose tissue were measured. A generalized linear model with patients as random effects was used to investigate skeletal muscle changes.

RESULTS

Thirty-nine patients completed outpatient cardiac rehabilitation, and 60 were incomplete. Skeletal muscle area significantly decreased from baseline to the follow-up period only in the incomplete rehabilitation group. Skeletal muscle density significantly decreased from baseline to postacute care and increased at the follow-up period, but only patients who completed rehabilitation showed recovery up to baseline at the follow-up period. These trajectories were more pronounced in the erector spine muscle. Intramuscular adipose tissue showed a trend of gradual increase, but only the incomplete rehabilitation group showed a significant difference from baseline to the follow-up period.

CONCLUSIONS

The density of skeletal muscle may reflect the most common clinical course; skeletal muscle area and intramuscular adipose tissue are unlikely to improve positively, and their maintenance seemed optimal.

Psoas muscle index and psoas muscle density are associated with functional status in patients with degenerative lumbar spinal stenosis

BACKGROUND

The factors affecting lumbar spinal function in patients with degenerative lumbar spinal stenosis (DLSS) are still unclear.

OBJECTIVE

This study explored psoas major muscle morphology in patients with DLSS and its association with their functional status.

METHODS

A retrospective study was conducted on 288 patients with DLSS and 260 control subjects. Psoas major muscle evaluation included three morphometric parameters at the L3/4 disc level: psoas major index (PMI), muscle attenuation, and psoas major morphological changes (MPM). The association between psoas major morphology and functional status was assessed using the Oswestry disability index (ODI).

RESULTS

Both female and male patients with DLSS had a higher PMI and lower muscle attenuation. PMI and muscle attenuation were inversely correlated with age in the DLSS group. After multivariable analyses, the PMI and psoas major muscle attenuation were positively correlated with patients' functional status.

CONCLUSION

The PMI and muscle attenuation were positively correlated with functional status in patients with DLSS. These findings have important implications for physiotherapy programs of postoperative rehabilitation and conservative management of DLSS.

Are dose-response relationships of resistance training reliable to improve functional performance in frail and pre-frail older adults? A systematic review with meta-analysis and meta-regression of randomized controlled trials

This systematic review with meta-analyses investigates the impact of resistance training (RT), using meta-regressions, on functional performance in frail and pre-frail adults aged ≥ 65 years to determine the key variables of RT. Ten randomized controlled trials involving 1303 participants were analyzed. Five studies assessed habitual walking speed (HWS), three studies evaluated performance in the timed-up-and-go test (TUG), three studies evaluated performance in the Short Physical Performance Battery (SPPB), and three studies assessed performance in the sit-to-stand test (STS). RT alone improved STS time and SPPB scores in frail and pre-frail older adults. RT improved STS performance (Effect Size (ES):- 0.536; 95% CI - 0.874 to - 0.199; p = .002) and led to a 2.261-point increase in SPPB performance (ES:1.682; 95% CI 0.579-2.786; p = .003). At least two weekly training sessions are required to increase SPPB scores, and three sessions seem to optimize the improvements. Higher training volume per exercise and volume per session reduce the gains in SPPB performance. We did not observe any association between different doses of RT and STS time improvements. RT alone positively influenced TUG performance only in community-dwelling older frail and pre-frail adults but not in institutionalized older individuals. RT alone did not improve the HWS compared to the non-active control group.

Recent developments in frailty identification, management, risk factors and prevention: A narrative review of leading journals in geriatrics and gerontology

Frailty is an age-related clinical condition characterised by an increased susceptibility to stressors and an elevated risk of adverse outcomes such as mortality. In the light of global population ageing, the prevalence of frailty is expected to soar in coming decades. This narrative review provides critical insights into recent developments and emerging practices in frailty research regarding identification, management, risk factors, and prevention. We searched journals in the top two quartiles of geriatrics and gerontology (from Clarivate Journal Citation Reports) for articles published between 01 January 2018 and 20 December 2022. Several recent developments were identified, including new biomarkers and biomarker panels for frailty screening and diagnosis, using artificial intelligence to identify frailty, and investigating the altered response to medications by older adults with frailty. Other areas with novel developments included exercise (including technology-based exercise), multidimensional interventions, person-centred and integrated care, assistive technologies, analysis of frailty transitions, risk-factors, clinical guidelines, COVID-19, and potential future treatments. This review identified a strong need for the implementation and evaluation of cost-effective, community-based interventions to manage and prevent frailty. Our findings highlight the need to better identify and support older adults with frailty and involve those with frailty in shared decision-making regarding their care.

Sarcopenia and cardiovascular diseases: A systematic review and meta-analysis

Sarcopenia is an age-related disease and is often accompanied by other diseases. Now, many studies have shown that cardiovascular diseases (CVDs) may raise the incidence rate of sarcopenia. Therefore, the purpose of this study was to conduct a systematic review and meta-analysis to investigate the prevalence of sarcopenia in patients with CVDs compared with the general population, defined as relatively healthy non-hospitalized subjects. The databases of PubMed, Embase, Medline and Web of Science were searched for eligible studies published up to 12 November 2022. Two assessment tools were used to evaluate study quality and the risk of bias. Statistical analysis was conducted using STATA 14.0 and R Version 4.1.2. Thirty-eight out of the 89 629 articles retrieved were included in our review. The prevalence of sarcopenia ranged from 10.1% to 68.9% in patients with CVDs, and the pooled prevalence was 35% (95% confidence interval [95% CI]: 28-42%). The pooled prevalence of sarcopenia was 32% (95% CI: 23-41%) in patients with chronic heart failure (CHF), 61% (95% CI: 49-72%) in patients with acute decompensated heart failure (ADHF), 43% (95% CI: 2-85%) in patients with coronary artery disease, 30% (95% CI: 25-35%) in patients with cardiac arrhythmia (CA), 35% (95% CI: 10-59%) in patients with congenital heart disease and 12% (95% CI: 7-17%) in patients with unclassed CVDs. However, in the general population, the prevalence of sarcopenia varied from 2.9% to 28.6% and the pooled prevalence was 13% (95% CI: 9-17%), suggesting that the prevalence of sarcopenia in patients with CVDs was about twice compared with the general population. The prevalence of sarcopenia was significantly higher only in patients with ADHF, CHF and CA compared with the general population. There is a positive correlation between CVDs and sarcopenia. The prevalence of sarcopenia is higher in patients with CVDs than that in the general population. With global aging, sarcopenia has brought a heavy burden to individuals and society. Therefore, it is important to identify the populations with high-risk or probable sarcopenia in order to do an early intervention, such as exercise, to counteract or slow down the progress of sarcopenia.

Effect of exercise modality and weight loss on changes in muscle and bone quality in older adults with obesity

BACKGROUND

Little is known about the effect of exercise modality during a dietary weight loss program on muscle size and quality, as measured by computed tomography (CT). Even less is known about how CT-derived changes in muscle track with changes in volumetric bone mineral density (vBMD) and bone strength.

METHODS

Older adults (66 ± 5 years, 64 % women) were randomized to 18-months of diet-induced weight loss (WL), WL with aerobic training (WL + AT), or WL with resistance training (WL + RT). CT-derived muscle area, radio-attenuation and intermuscular fat percentage at the trunk and mid-thigh were determined at baseline (n = 55) and 18-month follow-up (n = 22-34), and changes were adjusted for sex, baseline value, and weight lost. Lumbar spine and hip vBMD and finite element-derived bone strength were also measured.

RESULTS

After adjustment for the weight lost, muscle area losses at the trunk were -7.82 cm2 [-12.30, -3.35] for WL, -7.72 cm2 [-11.36, -4.07] for WL + AT, and -5.14 cm2 [-8.65, -1.63] for WL + RT (p < 0.001 for group differences). At the mid-thigh, decreases were -6.20 cm2 [-10.39, -2.02] for WL, -7.84 cm2 [-11.19, -4.48] for WL + AT, and -0.60 cm2 [-4.14, 2.94] for WL + RT; this difference between WL + AT and WL + RT was significant in post-hoc testing (p = 0.01). Change in trunk muscle radio-attenuation was positively associated with change in lumbar bone strength (r = 0.41, p = 0.04).

CONCLUSIONS

WL + RT better preserved muscle area and improved muscle quality more consistently than WL + AT or WL alone. More research is needed to characterize the associations between muscle and bone quality in older adults undertaking weight loss interventions.

Skeletal muscle tissue composition ratio in patients with hip fracture: Comparison of fractured side and non-fractured side

BACKGROUND

The extent of asymmetry in the muscle tissue composition ratios with hip fractures has not been clarified.

OBJECTIVE

To determine whether there is a difference in the muscle tissue composition ratios between the fractured and non-fractured sides of the trunk and thighs immediate measurement.

METHODS

Forty-four patients (84.6 ± 7.0 years) were included. Computed tomography images were used for measurements. The muscle tissue composition ratio was measured using muscle cross-sectional area (CSA) and attenuation coefficient (Hounsfield units; HU). Defined each HU attenuation range as follows: low-density muscle (LDM), low-quality muscle tissue with fat infiltration, normal-density muscle (NDM), muscle contractor tissue, and intramuscular adipose tissue (IMAT), fat infiltration tissue. The CSA of each muscle tissue was expressed as a percentage: %LDM, %NDM, and %IMAT. A paired t-test was performed for comparison.

RESULTS

The %LDM on the fractured side was higher in the thigh and erector spinae. The %NDM on the fractured side was lower in the thigh. There was no significant difference in the %IMAT for all muscles.

CONCLUSION

The thigh on the fractured side showed asymmetry with low %NDM and high %LDM. This characteristic captures a characteristic of muscle tissue that may have importance in hip fracture etiology.

Improving muscle strength and physical function in older people living with sarcopenia and physical frailty: Not all exercise is created equal

Exercise is an increasingly widely used treatment for older people across a range of clinical conditions including sarcopenia and physical frailty. Whilst exercise can have many benefits for older people, adaptations to exercise are specific to the exercise mode that is performed and not all exercise is created equal. The correct type of exercise, at the correct dose, needs to be prescribed to maximise effectiveness in treating sarcopenia and physical frailty where maintaining or improving muscle strength and physical function represent key aims. Resistance exercise (RE) is the most potent approach to improving muscle strength and physical function and should be prioritised within exercise programmes delivered to this group. Resistance exercise programme design should be underpinned by the fundamental principles of exercise prescription in order to deliver an appropriate and individualised exercise dose to maximise the potential of RE as a treatment for older people living with sarcopenia and physical frailty.

Muscle density is an independent risk factor of second hip fracture: a prospective cohort study

BACKGROUND

Patients with a first hip fracture are at high risk of fracturing their other hip. Despite this, preventive therapy is often not given. Because little is known about specific risk factors of a second hip fracture, we investigated the association with areal bone mineral density (aBMD), muscle size, and density. We also investigated whether muscle parameters predict the risk of a contralateral fracture independently of aBMD.

METHODS

Three groups were included, one without hip fracture (a subcohort of the China Action on Spine and Hip Status study), one with a first, and one with a second hip fracture. Subjects with fractures were recruited from the longitudinal Chinese Second Hip Fracture Evaluation (CSHFE). Computed tomography scans of CSHFE patients, which were obtained immediately following their first fracture, were used to measure cross-sectional area and density of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) muscles. Computed tomography X-ray absorptiometry was used to measure aBMD of the contralateral femur. Median follow-up time to second fracture was 4.5 years. Cox proportional hazards models were used to compute hazard ratios (HR) of second hip fracture risk in subjects with a first hip fracture. Multivariate logistic regressions were used to compare odds ratios (OR) for the risk of a first and second hip fracture.

RESULTS

Three hundred and one participants (68.4 ± 6.1 years, 64% female) without and 302 participants (74.6 ± 9.9 years, 71% female) with a first hip fracture were included in the analysis. Among the latter, 45 (79.2 ± 7.1 years) sustained a second hip fracture. ORs for first hip fracture were significant for aBMD and muscle size and density. ORs for a second fracture were smaller by a factor of 3 to 4 and no longer significant for femoral neck (FN) aBMD. HRs for predicting second hip fracture confirmed the results. G.Med/MinM density (HR, 1.68; CI, 1.20-2.35) and intertrochanter aBMD (HR, 1.62; CI, 1.13-2.31) were the most significant. FN aBMD was not significant. G.Med/MinM density remained significant for predicting second hip fracture after adjustment for FN (HR, 1.66; Cl, 1.18-2.30) or total hip aBMD (HR, 1.50; 95% Cl, 1.04-2.15).

CONCLUSIONS

Density of the G.Med/MinM muscle is an aBMD independent predictor of the risk of second hip fracture. Intertrochanteric aBMD is a better predictor of second hip fracture than FN and total hip aBMD. These results may trigger a paradigm shift in the assessment of second hip fracture risk and prevention strategies.

Muscle Strength Is Associated With Physical Function in Community-Dwelling Older Adults Receiving Home Care. A Cross-Sectional Study

Background

Higher maximal- and explosive strength is associated with better physical function among older adults. Although the relationship between isometric maximal strength and physical function has been examined, few studies have included measures of isometric rate of force development (RFD) as a measure of explosive strength. Furthermore, little is known about the oldest old (>80 years), especially individuals who receive home care and use mobility devices. Therefore, the aim of this study was to examine the association between maximal- and explosive muscle strength with physical function in community-dwelling older adults receiving home care.

Methods

An exploratory cross-sectional analysis including 107 (63 females and 43 males) community-dwelling older adults [median age 86 (interquartile range 80–90) years] receiving home care was conducted. Physical function was measured with five times sit-to-stand (5TSTS), timed 8-feet-up-and-go (TUG-8ft), preferred-, and maximal gait speed. Maximal strength was assessed as maximal isometric voluntary contraction (MVC) and explosive strength as RFD of the knee extensors. We used linear regression to examine the associations, with physical function as dependent variables and muscle strength (MVC and RFD) as independent variables.

Results

MVC was significantly associated with 5TSST [standardized regression coefficient β = −0.26 95% CI (−0.45, −0.06)], TUG-8ft [−0.6 (−0.54, −0.17)], preferred gait speed [0.39 (0.22, 0.57)], and maximal gait speed [0.45 (0.27, 0.62)]. RFD was significantly associated with 5TSST [−0.35 (−0.54, −0.17)], TUG-8ft [−0.43 (−0.60, −0.27)], preferred gait speed [0.40 (0.22, 0.57)], and maximal gait speed [0.48 (0.31, 0.66)].

Conclusions

Higher maximal- and explosive muscle strength was associated with better physical function in older adults receiving home care. Thus, maintaining and/or improving muscle strength is important for perseverance of physical function into old age and should be a priority.

Features of trunk muscle wasting during acute care and physical function recovery with aortic disease

BACKGROUND

Low skeletal muscle area or density, such as myosteatosis, identified on computed tomography (CT) is associated with poor prognosis in patients with cardiovascular diseases. However, there is a lack of evidence regarding the clinical process of skeletal muscle decline as a short-term change during acute care settings. This study focused on the use of routine CT imaging for aortic disease management and investigated the changes in skeletal muscle before and after acute care.

METHODS

This prospective study included 123 patients who underwent abdominal CT before and after acute care. The all-abdominal and each abdominal muscle areas were divided into eight parts (e.g. rectus abdominis, psoas, and erector spine), and their areas and densities were measured at the third lumbar vertebra level after the patients were discharged and de-identified with blinding to avoid measurement bias. Short physical performance battery (SPPB) was measured at the start and end of in-hospital cardiac rehabilitation. A generalized linear model with patients as random effects was made to investigate skeletal muscle loss during acute care. Multivariate linear regression analysis was also used to assess the relationship between the change in skeletal muscle during acute care and SPPB during in-hospital cardiac rehabilitation.

RESULTS

The median age of the patients was 70 (interquartile: 58-77) years, and 69.9% (86/123) were men. The median day between acute care from the day of surgery or hospital admission and follow-up CT was 7 (interquartile: 3-8) days. Overall muscle density declined after acute care (estimate value: -3.640, 95% confidence interval [CI]: -4.538 to -2.741), and each abdominal muscle density consistently declined (interaction: F value = 0.099, P = 0.998). In contrast, there was no significant change in the overall muscle area (estimate value: -0.863, 95% CI: -2.925 to 1.200). Changes in the muscle area were different for each skeletal muscle (interaction: F value = 2.142, P = 0.037), and only the erector spine muscle significantly declined (estimate value: -1.836, 95% CI: -2.507 to -1.165). After adjusting for confounding factors, a greater decline in muscle density was associated with lower recovery score on SPPB (β = 0.296, 95% CI: 0.066 to 0.400).

CONCLUSIONS

Muscle density consistently declined after acute care, especially the erector spine muscles, which also significantly decreased in size. A higher decline in muscle density was associated with a slower recovery of physical function during in-hospital cardiac rehabilitation in patients with aortic diseases.

Cross-sectional area of erector spinae muscles is associated with activities of daily living at discharge in middle- to older-aged patients with coronavirus disease 2019

Objectives

Measurement of skeletal muscle wasting using computed tomography (CT) is widely known to be useful in predicting prognosis. Although some reports have been found in patients with coronavirus disease 2019 (COVID-19), few reports have focused on the ability to perform activities of daily living (ADLs). This study retrospectively investigated the relationship between the erector spinae muscle area measured from CT images and ADL at the time of hospital discharge in patients with COVID-19.

Methods

Among patients aged 40 years or older, 271 patients (median age, 65 years; 180/271 male patients) who had CT cross-sectional images of the 12th thoracic vertebral level on admission were included. The Katz index was used to assess ADLs, and patients who were not completely independent were defined as dependent. Multivariable logistic and Poisson regression analyses were applied to examine the relationship between the cross-sectional area of the erector spinae muscles and the onset of ADL dependence at discharge.

Results

A total of 75 (27.7%) patients became dependent on ADL at the time of hospital discharge. Decreased erector spinae muscle area was significantly related to dependent ADL at discharge (adjusted odds ratio: 0.886, 95% confidence interval: 0.805–0.975). In addition, the erector spinae muscle area was significantly related to the number of ADL items for which independence was not achieved (adjusted incidence rate ratio: 0.959, P < 0.001).

Conclusions

The cross-sectional area of the erector spinae muscles from the thoracic CT image was associated with the ability to perform basic ADL at hospital discharge.

Functional improvements to 6 months of physical activity are not related to changes in size or density of multiple lower-extremity muscles in mobility-limited older individuals

Older adults are encouraged to engage in multicomponent physical activity, which includes aerobic and muscle-strengthening activities. The current work is an extension of the Vitality, Independence, and Vigor in the Elderly 2 (VIVE2) study - a 6-month multicenter, randomized, placebo-controlled trial of physical activity and nutritional supplementation in community dwelling 70-year-old seniors. Here, we examined whether the magnitude of changes in muscle size and quality differed between major lower-extremity muscle groups and related these changes to functional outcomes. We also examined whether daily vitamin-D-enriched protein supplementation could augment the response to structured physical activity. Forty-nine men and women (77 ± 5 yrs) performed brisk walking, muscle-strengthening exercises for the lower limbs, and balance training 3 times weekly for 6 months. Participants were randomized to daily intake of a nutritional supplement (20 g whey protein + 800 IU vitamin D), or a placebo. Muscle cross-sectional area (CSA) and radiological attenuation (RA) were assessed in 8 different muscle groups using single-slice CT scans of the hip, thigh, and calf at baseline and after the intervention. Walking speed and performance in the Short Physical Performance Battery (SPPB) were also measured. For both CSA and RA, there were muscle group × time interactions (P < 0.01). Significant increases in CSA were observed in 2 of the 8 muscles studied, namely the knee extensors (1.9%) and the hip adductors (2.8%). For RA, increases were observed in 4 of 8 muscle groups, namely the hip flexors (1.1 HU), hip adductors (0.9 HU), knee extensors (1.2 HU), and ankle dorsiflexors (0.8 HU). No additive effect of nutritional supplementation was observed. While walking speed (13%) and SPPB performance (38%) improved markedly, multivariate analysis showed that these changes were not associated with the changes in muscle CSA and RA after the intervention. We conclude that this type of multicomponent physical activity program results in significant improvements in physical function despite relatively small changes in muscle size and quality of some, but not all, of the measured lower extremity muscles involved in locomotion.

Does the interference phenomenon affect strength development during same-session combined rehabilitation program in hemodialysis patients?

INTRODUCTION

This study aimed to assess if an interference effect could blunt the neuromuscular gains induced by a same-session combined rehabilitation in hemodialysis (HD) patients.

METHODS

Patients exercised twice a week, for 16 weeks, over their HD sessions. They were either always trained with resistance and endurance exercises (continuous training, "CONT") or alternatively with 1 week of resistance alternated with 1 week of endurance (discontinuous training, "DISC"). Adherence and workload were continuously recorded. Short Physical Performance Battery (SPPB) score, one-leg balance test, and handgrip and quadriceps strength were evaluated before and after training intervention.

RESULTS

Adherence to both programs was high (>90%). SPPB score had significantly improved (CONT: +1.5 point, DISC: +1.2 pt, p < 0.001), like one-leg balance test (CONT: +3.7 s, DISC: +5.5 s, p < 0.05), handgrip strength of exercised (CONT: +5.5 kg, DISC: +5.6 kg, p < 0.001) and of nonexercised arm (CONT: +4.4 kg, DISC: +2.8 kg, p < 0.01) as well as maximal quadriceps strength (+22 N·m for dominant and +29 N·m for nondominant leg in both groups, p < 0.001) bearing no difference between the trainings.

CONCLUSION

Same-session combined training does not induce an interference effect in HD patients and temporal separation of exercises does not optimize strength gains. These practical data may be relevant for clinicians and practitioners to alternate endurance and resistance exercises.

Low skeletal muscle density combined with muscle dysfunction predicts adverse events after adult cardiovascular surgery

BACKGROUND AND AIMS

Although muscle dysfunctions are widely known as a poor prognostic factor in patients with cardiovascular disease, no study has examined whether the addition of low skeletal muscle density (SMD) assessed by computed tomography (CT) to muscle dysfunctions is useful. This study examined whether SMDs can strengthen the predictive ability of muscle dysfunctions for adverse events in patients who underwent cardiovascular surgery.

METHODS AND RESULTS

We retrospectively reviewed 853 patients aged ≥40 years who had preoperative CT for risk management purposes and who measured muscle dysfunctions (weakness: low grip strength and slowness: slow gait speed). Low SMD based on transverse abdominal CT images was defined as a mean Hounsfield unit of the psoas muscle <45. All definitions of muscle dysfunction (weakness only, slowness only, weakness or slowness, weakness and slowness), the addition of SMDs was shown to significantly improve the continuous net reclassification improvement and integrated discrimination improvement for adverse events in all analyses (p < 0.05). Low SMDs combined with each definition of muscle dysfunction had the highest risk of all-cause death (hazard ratio: lowest 3.666 to highest 6.002), and patients with neither low SMDs nor muscle dysfunction had the lowest risk of all-cause and cardiovascular-related events.

CONCLUSION

The addition of SMDs consistently increased the predictive ability of muscle dysfunctions for adverse events. Our results suggest that when CT is performed for any clinical investigation, the addition of the organic assessment of skeletal muscle can strengthen the diagnostic accuracy of muscle wasting.

Heterogeneity of the strength response to progressive resistance exercise training in older adults: Contributions of muscle contractility

BACKGROUND

Older adults display wide individual variability (heterogeneity) in the effects of resistance exercise training on muscle strength. The mechanisms driving this heterogeneity are poorly understood. Understanding of these mechanisms could permit development of more targeted interventions and/or improved identification of individuals likely to respond to resistance training interventions. Thus, this study assessed potential physiological factors that may contribute to strength response heterogeneity in older adults: neural activation, muscle hypertrophy, and muscle contractility.

METHODS

In 24 older adults (72.3 ± 6.8 years), we measured the following parameters before and after 12 weeks of progressive resistance exercise training: i) isometric leg extensor strength; ii) isokinetic (60°/sec) leg extensor strength; iii) voluntary (neural) activation by comparing voluntary and electrically-stimulated muscle forces (i.e., superimposed doublet technique); iv) muscle hypertrophy via dual-energy x-ray absorptiometry (DXA) estimates of regional lean tissue mass; and v) intrinsic contractility by electrically-elicited twitch and doublet torques. We examined associations between physiological factors (baseline values and relative change) and the relative change in isometric and isokinetic muscle strength.

RESULTS

Notably, changes in quadriceps contractility were positively associated with the relative improvement in isokinetic (r = 0.37-0.46, p ≤ 0.05), but not isometric strength (r = 0.09-0.21). Change in voluntary activation did not exhibit a significant association with the relative improvements in either isometric or isokinetic strength (r = 0.35 and 0.33, respectively; p > 0.05). Additionally, change in thigh lean mass was not significantly associated with relative improvement in isometric or isokinetic strength (r = 0.09 and -0.02, respectively; p > 0.05). Somewhat surprising was the lack of association between exercise-induced changes in isometric and isokinetic strength (r = 0.07).

CONCLUSIONS

The strength response to resistance exercise in older adults appears to be contraction-type dependent. Therefore, future investigations should consider obtaining multiple measures of muscle strength to ensure that strength adaptations are comprehensively assessed. Changes in lean mass did not explain the heterogeneity in strength response for either contraction type, and the data regarding the influence of voluntary activation was inconclusive. For isokinetic contraction, the strength response was moderately explained by between-subject variance in the resistance-exercise induced changes in muscle contractility.

Feasibility of reducing frailty components in older adults with Alzheimer's dementia: a randomized controlled home-based exercise trial (AD-HOMEX)

OBJECTIVES

There is a need for interventions to reduce frailty in older people with Alzheimer's dementia (AD). The purpose of this study was to investigate the effect of a home-based multimodal exercise program for older adults with AD (AD-HOMEX) on frailty.

DESIGN

A parallel single-blind randomized controlled trial comparing a home-based exercise program and usual care.

SETTING AND PARTICIPANTS

A home-based program in Brazil. Forty individuals aged 65years or older with mild to moderate AD.

METHODS

The intervention group (IG) participated in a 16-week protocol involving three 60-minute sessions per week of progressive individualized physical exercises supervised by a physical therapist. The participants in the control group (CG) maintained their usual care. Frailty was assessed using the FRAIL questionnaire, the Edmonton Frail Scale (EFS) and a subjective assessment by the evaluator (SAE) at baseline and follow-up. Per-protocol analysis was performed.

RESULTS

Thirty-five participants completed the program (IG = 16; CG = 19). Frailty improved in the IG based on the EFS (P = .004) and FRAIL (P ≤ .001). An interaction between group and time (P = .008) and a significant difference between times (P = .047) were found for the SAE responsiveness domain. An improvement in the classification of frailty (EFS and FRAIL) was found between times in the IG (P = .003) and between groups at follow-up (P = .027). A significant difference in the SAE classification was found between groups at follow-up (P = .034), with a worsening between times in the CG (P = .032). Interestingly, a more favorable frailty transition pattern was found in the IG based on both the EFS and FRAIL.

CONCLUSIONS AND IMPLICATIONS

AD-HOMEX seems to reduce frailty and improve frailty transition patterns. Our findings provide a further theoretical basis for designing home-based physical interventions as routine practice for older frail adults with AD.

The influence of resistance training on neuromuscular function in middle-aged and older adults: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Deterioration of neuromuscular function is a major mechanism of age-related strength loss. Resistance training (RT) improves muscle strength and mass. However, the effects of RT on neuromuscular adaptations in middle-aged and older adults are unclear.

METHODS

Randomised controlled RT interventions (≥2 weeks) involving adults aged ≥50 years were identified. Primary outcome measures were voluntary activation (VA), electromyographic (EMG) activity during maximal voluntary contraction (MVC), and antagonist coactivation. Data were pooled using a weighted random-effect model. Sub-analyses were conducted by muscle or muscle group and health status of participants. Sensitivity analysis was based on study quality. P < 0.05 indicated statistical significance.

RESULTS

Twenty-seven studies were included. An effect was found for VA (standardised mean difference [SMD] 0.54, 0.01 to 1.07, P = 0.04), This result remained significant following sensitivity analysis involving only studies that were low risk of bias. Subgroup analyses showed an effect for plantar flexor VA (SMD 1.13, 0.20 to 2.06, P = 0.02) and VA in healthy participants (SMD 1.04, 0.32 to 1.76, P = 0.004). There was no effect for EMG activity or antagonist coactivation of any muscle group (P > 0.05).

DISCUSSION

Resistance training did not alter EMG activity or antagonist coactivation in older adults. Sensitivity analysis resulted in the effect for VA remaining significant, indicating that this finding was not dependent on study quality. Studies predominantly involved healthy older adults (78%), limiting the generalisability of these findings to clinical cohorts. Future research should determine the effects of RT on neuromuscular function in people with sarcopenia and age-related syndromes.

Why Are Masters Sprinters Slower Than Their Younger Counterparts? Physiological, Biomechanical, and Motor Control Related Implications for Training Program Design

Elite sprint performances typically peak during an athlete's 20s and decline thereafter with age. The mechanisms underpinning this sprint performance decline are often reported to be strength-based in nature with reductions in strength capacities driving increases in ground contact time and decreases in stride lengths and frequency. However, an as-of-yet underexplored aspect of Masters sprint performance is that of age-related degradation in neuromuscular infrastructure, which manifests as a decline in both strength and movement coordination. Here, the authors explore reductions in sprint performance in Masters athletes in a holistic fashion, blending discussion of strength and power changes with neuromuscular alterations along with mechanical and technical age-related alterations. In doing so, the authors provide recommendations to Masters sprinters-and the aging population, in general-as to how best to support sprint ability and general function with age, identifying nutritional interventions that support performance and function and suggesting useful programming strategies and injury-reduction techniques.

Effects of acute and chronic strength training on skeletal muscle autophagy in frail elderly men and women

Aging is associated with alterations in skeletal muscle autophagy, potentially affecting both muscle mass and quality in a negative manner. Strength training with protein supplementation has been reported to improve both muscle mass and quality in frail elderly individuals, but whether improvements are accompanied by alterations in protein quality control is not known. To address this issue, we investigated protein degradation markers in skeletal muscle biopsies (m. vastus lateralis) from twenty-four frail elderly men and women (86 ± 7 yr) after acute and chronic (10 weeks) strength training with protein supplementation (ST + PRO) or protein supplementation alone (PRO). Acute increases in mRNA expression of genes related to the ubiquitin proteasome system (MuRF-1, MUSA1), autophagy (ATG7, LC3, p62), and mitochondrial fission (DRP1) were observed after the first, but not after the last training session in ST + PRO. Acute changes in gene expression were accompanied by changes in protein levels of both LC3-I and LC3-II. Hence, the acute training-induced activation of proteasomal degradation and autophagy seems to depend on training status, with activation in the untrained, but not trained state. The ten-week training intervention did not affect basal levels of autophagy mRNAs and proteins, and neither markers of the ubiquitin-proteasome system. This suggests that a relatively short period of strength training may not be sufficient to increase the basal rate of protein degradation in frail elderly.

Musculoskeletal adaptations to strength training in frail elderly: a matter of quantity or quality?

BACKGROUND

The improvement in muscle strength generally exceeds the increase in muscle size following strength training in frail elderly, highlighting the complex aetiology of strength deficit in aging. The aim of this study was to investigate the effect of heavy-load strength training on a broad number of factors related to specific strength in frail elderly.

METHODS

Thirty-four frail elderly men (n = 18) and women (n = 16) aged 67 to 98 (86 ± 7 years) were randomized to either a group performing strength training twice a week for 10 weeks (ST) or a non-exercising control group (CON). Knee extensor muscle strength was tested as one-repetition maximum (1RM) and isometric maximal voluntary contraction (MVC) torque. Muscle activation was assessed by the interpolated twitch technique, and muscle density [mean Hounsfield units (HU)] and intermuscular adipose tissue (IMAT) by computed tomography scans of the quadriceps femoris. Muscle biopsies from the vastus lateralis were obtained to investigate changes in intramyocellular lipids and single-fibre specific tension.

RESULTS

In ST, knee extension 1RM and MVC improved by 17 and 7%, respectively. Muscle cross-sectional area of the quadriceps femoris increased by 7%, accompanied by a 4% increase of muscle density. No changes in IMAT, voluntary activation level, single-fibre specific tension, or lipid content were observed.

CONCLUSIONS

In contrast to several previous reports, the improvements in isometric muscle strength and muscle area were in good agreement in the present study. The training-induced increase in muscle density was not due to changes in skeletal muscle lipid content. Instead, the increase in muscle density may reflect increased packing of contractile material or simply an increased ratio of muscle tissue relative to IMAT.