Regional Skeletal Muscle Mass Research Articles

Does Aerobic Exercise Increase Skeletal Muscle Mass in Female and Male Adults?

It is uncertain whether aerobic exercise in the form of walking contributes to the preservation or increase in total or regional skeletal muscle mass (SMM). This study aimed to determine the effects of aerobic exercise on total and regional (upper body verses leg SMM) in male ( n = 105) and female ( n = 133) adults with overweight and obesity. A retrospective analysis of data from four randomized controlled trials. Participants included those who completed the given trial (control, n = 63; intervention, n = 175) and with complete magnetic resonance imaging (MRI) measured adipose tissue and SMM pre- and postintervention. Macronutrient intake was assessed for a subsample of participants. Supervised exercise was performed by walking on a treadmill for durations ranging from 12 to 24 wk at intensities between 50% and 75% of V̇O 2peak . All MRI-measured adipose tissue depots were reduced, and cardiorespiratory fitness was increased by aerobic exercise compared with controls ( P < 0.001). Independent of baseline SMM, aerobic exercise was associated with a small reduction (estimated mean difference ± standard error) in whole-body SMM (-0.310 ± 0.150 kg, P = 0.039) and upper body SMM (-0.273 ± 0.121 kg, P = 0.025) compared with control. No between-group difference was observed for change in leg SMM ( P > 0.10). A negative association was observed between the relative change in body weight and change in total ( R2 = 0.37, P < 0.001), upper body ( R2 = 0.21, P < 0.001), and leg SMM ( R2 = 0.09, P = 0.701). The SMM-to-adipose tissue ratio increased in response to aerobic exercise and was positively associated with weight loss ( P < 0.001). Change in SMM was not associated with dietary protein intake ( P > 0.10). Aerobic exercise performed while walking preserves, but does not increase, SMM in exercising muscle of adults. SMM not directly targeted by aerobic exercise may not be maintained.

Correlation between hand grip strength and regional muscle mass in older Asian adults: an observational study

BackgroundPrevious research has demonstrated a correlation between hand grip strength (HGS) and muscle strength. This study aims to determine the relationship between HGS and muscle mass in older Asian adults.MethodsWe retrospectively reviewed the dual-energy X-ray absorptiometry (DXA) records of 907 older adults (239 (26.4%) men and 668 (73.6%) women) at one medical institution in Taipei, Taiwan, from January 2019, to December 2020. Average age was 74.80 ± 9.43 and 72.93 ± 9.09 for the males and females respectively. The inclusion criteria were: 1) aged 60 and older, 2) underwent a full-body DXA scan, and 3) performed hand grip measurements. Patients with duplicate results, incomplete records, stroke history, and other neurological diseases were excluded. Regional skeletal muscle mass was measured using DXA. HGS was measured using a Jamar handheld dynamometer.ResultsTotal lean muscle mass (kg) averaged 43.63 ± 5.81 and 33.16 ± 4.32 for the males and females respectively. Average HGS (kg) was 28.81 ± 9.87 and 19.19 ± 6.17 for the males and females respectively. In both sexes, HGS and regional muscle mass consistently declined after 60 years of age. The rates of decline per decade in upper and lower extremity muscle mass and HGS were 7.06, 4.95, and 12.30%, respectively, for the males, and 3.36, 4.44, and 12.48%, respectively, for the females. In men, HGS significantly correlated with upper (r = 0.576, p < 0.001) and lower extremity muscle mass (r = 0.532, p < 0.001). In women, the correlations between HGS and upper extremity muscle mass (r = 0.262, p < 0.001) and lower extremity muscle mass (r = 0.364, p < 0.001) were less strong, though also statistically significant.ConclusionMuscle mass and HGS decline with advancing age in both sexes, though the correlation is stronger in men. HGS measurements are an accurate proxy for muscle mass in older Asian adults, particularly in males.

Association between height-corrected appendicular and regional skeletal muscle mass and insulin resistance in patients with type 2 diabetes.

[Purpose] The effect of height-corrected skeletal muscle masses on insulin resistance has not been fully investigated in patients with type 2 diabetes. In this study, we aimed to investigate the association between height-corrected appendicular and regional skeletal muscle masses and insulin resistance in patients with type 2 diabetes. [Participants and Methods] We included 136 male and 100 female patients with type 2 diabetes (average age, male 55.7 ± 12.3 years old, female 60.7 ± 11.3 years old, and average height, male 1.67 ± 0.06 m, female 1.54 ± 0.06 m) in this study. Bioelectrical impedance analysis was used to evaluate skeletal muscle mass. We calculated the appendicular skeletal muscle mass index by dividing the appendicular skeletal muscle mass by the square of the patient’s height. The upper limb muscle mass, lower limb muscle mass, and trunk muscle mass figures were also divided by the square of the patient’s height. We used the homeostasis model assessment of insulin resistance as a marker of insulin resistance. [Results] In multiple regression analysis, the homeostasis model assessment of insulin resistance was inversely associated with appendicular skeletal muscle mass index and lower limb muscle mass/height2 in male patients with type 2 diabetes when adjusted for age and body mass index. Similarly, the homeostasis model assessment of insulin resistance was inversely associated with appendicular skeletal muscle mass index and lower limb muscle mass/height2 in non-obese female patients with type 2 diabetes. [Conclusion] We have confirmed that there is an association between appendicular skeletal muscle mass index and lower limb muscle mass/height2 with insulin resistance in male and female patients with type 2 diabetes, except in females with obesity.

Effects of exercise modality on body composition and cardiovascular disease risk factors in adolescents with obesity: a randomized clinical trial.

We compared the effects of aerobic exercise, resistance exercise, and combined aerobic and resistance exercise on total, regional subcutaneous adipose tissue (SAT) and visceral AT (VAT), skeletal muscle (SM), and biomarkers of cardiovascular disease in adolescents. Adolescents with overweight/obesity (N = 118; body mass index ≥ 85th percentile; age, 12-17 years) were randomized to 1 of the following groups for 6 months (3 days/week, 180 min/week): aerobic exercise (n = 38), resistance exercise (n = 40), or combined aerobic and resistance exercise (n = 40). After accounting for age, sex, and baseline value, there was a greater (P < 0.05) reduction in body weight in the aerobic exercise group compared with the resistance exercise group and the combined groups. There were reductions (P < 0.05) in total and regional SAT within the aerobic exercise group only, and the reductions in lower-body SAT were greater (P = 0.02) than the combined group. All groups had reductions (P < 0.01) in VAT, with no group differences. There were significant increases in total and regional SM mass in the resistance exercise and combined group, and not in the aerobic exercise group. Although all exercise modalities are effective in reducing VAT, aerobic exercise is superior at reducing total and regional SAT, but inferior for increasing SM in adolescents with obesity. Despite reductions in VAT, carotid-femoral pulse wave velocity and carotid intima-media thickness did not improve with either exercise. Clinicaltrials.gov identifier: NCT01938950. Novelty Regular exercise (180 min/week) is associated with reductions in visceral fat independent of exercise modality. Resistance exercise alone and combined resistance and aerobic exercise are similarly effective in increasing SM mass.

High-intensity Interval Training Low-volume Vs Moderate-intensity Continuous Aerobic Training On Insulin Resistance In Metabolic Syndrome

Moderate-intensity continuous aerobic training (MICAT) and high-intensity interval training (HIIT) interventions improve insulin resistance (IR) and glycemic control in patients with metabolic syndrome (MS). Moreover, skeletal muscle mass negatively correlates with IR. However, there are contradictory results about the superiority of any of these interventions on the control of the glucose metabolism in MS. PURPOSE: to compare the efficacy of a HIIT-low volume protocol vs MICAT on the Homeostatic assessment model, glycated hemoglobin (HbA1c) and skeletal muscle mass, in adults with MS. METHODS: controlled, randomized, clinical trial using the minimization method, with two parallel groups for the purpose of showing superiority. Sixty patients with MS, of both genders, 40-60 years old, were included. A clinical evaluation, biochemical tests, an ergospirometry and a dual-energy X ray absorptiometry to determine total and regional skeletal muscle mass were carried out before and after a treadmill exercise program of 12 weeks, 3 sessions/week. Participants were assigned to an intervention with HIIT-low volume (n=29) in 22 min sessions that included six intervals at a load of 90% of maximum oxygen consumption (VO2max) for 1 min followed by 2 min at 50% of VO2max. The control group received MICAT (n=31) at an intensity of 60% of VO2max in sessions of 36 min. RESULTS: patients had a mean age of 50.8±6.0 years, body mass index of 30.6±4.0 kg.m-2, body fat percentage of 38.7±7.0% and VO2max of 29.0±6.3 mL O2.kg-1.min-1; 70% were women. Compared to MICAT, HIIT-low volume was not superior in reducing Ln of IR (marginal mean difference: 0.083 [95% CI -0.092―0.257]; Cohen's d: 0.249; p value=0.346) or increasing Ln of total lean mass (kg) (0.004 [-0.014―0.023]; Cohen's d: 0.120; p=0.637) and Ln of thigh lean mass (g) (0.008 [-0,020―0.038]; Cohen's d: 0.154; p=0.599). After the intervention, the HIIT-low volume group, compared to the MICAT, had a higher HbA1c (5.81% vs 5.69%; 0.119 [0.005―0.233]; Cohen's d: 0.554; p=0.040). When comparing before and after the intervention, both training groups decreased IR. CONCLUSION: HIIT-low volume, compared to MICAT, is not superior in reducing IR or increasing skeletal muscle mass in adults with MS. Colciencias 111562638757; Interinstitucional 2016-13041; Doctoral scholarships 727-2015

A cross-sectional study on sarcopenia using EWGSOP1 and EWGSOP2 criteria with regional thresholds and different adjustments in a specific geriatric outpatient clinic.

The aim of this study was to determine the prevalence of sarcopenia according to different methods in older outpatients using regional threshold values of muscle mass and muscle strength. We used data from our university hospital's geriatric outpatient clinic specific to endocrinological problems, retrospectively. Sarcopenia was defined according to European Working Group on Sarcopenia in Older People (EWGSOP)1 and EWGSOP2 criteria using regional threshold values of skeletal muscle mass (SMM) with the use of different adjustments, and also according to EWGSOP2 with regional threshold values of grip strength. Among 248 study participants, 53.6% were obese. There was no sarcopenic patient with the height square adjusted regional SMM thresholds for EWGSOP1 and EWGSOP2. Sarcopenia prevalence was 11.7% with EWGSOP2, and 41.1% by the use of regional grip strength thresholds for EWGSOP2 with body mass index adjustments for SMM. The comparison of EWGSOP1 versus EWGSOP2 was not possible due to lack of sarcopenic patients with height adjustment. The prevalence of sarcopenia varied significantly with the application of different adjustment methods for SMM, and the use of regional grip strength thresholds in the specific patient group with normal to overweight and obese individuals. The use of regional thresholds of grip strength increased the prevalence of EWGSOP2-defined sarcopenia. The impact of the adjustment methods, the characteristics of the study population, and the regional thresholds should be taken into consideration while evaluating the results of sarcopenia studies.

Self Reported Dysphagia is not Associated with Sarcopenia Defined by the Revised EWGSOP2 Criteria and Regional Thresholds at the Hospital Among Ambulatory Older Patients.

Introduction:Dysphagia and sarcopenia are geriatric syndromes, and they are shown to be related. There is no study on dysphagia and sarcopenia with the revised European Working Group on Sarcopenia in Older People (EWGSOP)2 criteria.Aim:We aimed to evaluate dysphagia and sarcopenia with the revised criteria implementing regional thresholds for skeletal muscle mass (SMM) in hospitalized older patients.Methods:Ambulatory patients ≥60 years of age from the Internal Medicine Department of our hospital were taken into the study. Grip strength, SMM via bioelectrical impedance analysis, nutritional status, dysphagia screening with Eating Assessment Tool-10, prior hospitalizations and diet were evaluated. Sarcopenia was defined by EWGSOP2 criteria using regional SMM thresholds adjusted to body mass index (BMI) (SMMI (BMI)).Results:Out of 112, 61 patients were enrolled. Sarcopenia, nutritional risk, and dysphagia were shown in 36.1%, 88.5%, and 14.8% of the patients. The risk of dysphagia was not associated with sarcopenia (p=0.263). Hospitalizations (≥1) in one year with pneumonia, modified diet, malnutrition, and low SMMI (BMI) were more common in patients with dysphagia risk than in the patients without (p=0.001, p<0.01, p=0.011, p=0.008, respectively). The median age and BMI were higher where SMMI (BMI) was lower in the group with dysphagia risk than in the group without (p=0.016, p=0.034, p=0.032), respectively.Conclusion:We found that self-reported dysphagia was not associated with sarcopenia defined by the EWGSOP2 criteria in ambulatory hospitalized patients over 60 years of age. Further studies using revised criteria, different adjustments and thresholds are needed to reveal possible differences.

Predicting skeletal muscle mass from dual-energy X-ray absorptiometry in Japanese prepubertal children.

We aimed to develop regression-based prediction equations for estimating total and regional skeletal muscle mass (SMM) from measurements of lean soft tissue mass (LSTM) using dual-energy X-ray absorptiometry (DXA) and investigate the validity of these equations. In total, 144 healthy Japanese prepubertal children aged 6-12 years were divided into 2 groups: the model development group (62 boys and 38 girls) and the validation group (26 boys and 18 girls). Contiguous MRI images with a 1-cm slice thickness were obtained from the first cervical vertebra to the ankle joints as reference data. The SMM was calculated from the summation of the digitized cross-sectional areas. Total and regional LSTM was measured using DXA. Strong significant correlations were observed between the site-matched SMM (total, arms, trunk and legs) measured by MRI and the LSTM obtained by DXA in the model development group for both boys and girls (R2adj=0.86-0.97, P<0.01, standard error of the estimate (SEE)=0.08-0.44 kg). When these SMM prediction equations were applied to the validation group, the measured total (boys 9.47±2.21 kg; girls 8.18±2.62 kg) and regional SMM were very similar to the predicted values for both boys (total SMM 9.40±2.39 kg) and girls (total SMM 8.17±2.57 kg). The results of the Bland-Altman analysis for the validation group did not indicate any bias for either boys or girls with the exception of the arm region for the girls. These results suggest that the DXA-derived prediction equations are precise and accurate for the estimation of total and regional SMM in Japanese prepubertal boys and girls.

Anti-sarcopenic effects of diamino-diphenyl sulfone observed in elderly female leprosy survivors: a cross-sectional study.

BackgroundIt has been reported that 4,4′‐diamino‐diphenyl sulfone (DDS), the longtime treatment of choice for leprosy, prolongs the lifespan and increases mobility in animal models by reducing the levels of reactive oxygen species and inhibiting muscle pyruvate kinase activity. This study aimed to investigate whether sarcopenic status in leprosy survivors was influenced by recent history of DDS medication.MethodsForty‐one elderly female leprosy survivors were recruited. The DDS group was defined as survivors who had been taking the drug for the past year or more. Body composition measured by dual energy X‐ray absorptiometry, limb muscle strength, short physical performance battery, and International Physical Activity Questionnaire in Korean were compared.ResultsThe DDS group tended to have higher skeletal muscle mass index (24.4 ± 2.7 vs. 22.6 ± 2.2%, P = 0.066) and regional skeletal muscle mass index in non‐dominant leg (8.9 ± 1.0 vs. 7.9 ± 0.9%, P = 0.018) than those of the control group although they had significantly worse leprosy disability than the control group (P = 0.027). The DDS group had greater strength than the control group in non‐dominant shoulder abductor, elbow flexor, hip flexor, and knee extensor (P = 0.005, P = 0.029, P = 0.021, and P = 0.002, respectively). Weekly walking amount was significantly longer (P = 0.020) in the DDS group than the control group. The total lifetime DDS exposure significantly correlated with skeletal muscle mass of the lower extremity in non‐dominant leg (r = 0.379, P = 0.015).ConclusionsDDS‐taking leprosy survivors had larger skeletal muscle mass and greater muscle strength over non‐taking survivors. There was a dose–response relationship between total lifetime DDS exposure and skeletal muscle mass of lower extremity. These findings might suggest potential anti‐sarcopenic effects of DDS.

Muscle and fat mapping of the trunk: a case study

The following case study examines the muscle and fat thickness of the trunk in a 25-year-old, former collegiate gymnast. Previous studies have quantified total and regional skeletal muscle mass using magnetic resonance imaging and muscle volume and distribution using ultrasound. However, to the best of our knowledge, the distribution and symmetry of skeletal muscle and subcutaneous adipose tissue (AT) of the anterior and posterior trunk have never been investigated. Ultrasound was used to identify skeletal muscle and AT thickness of 143 data points on the anterior portion of the trunk and 140 data points on the posterior portion of the trunk. Muscle thickness values in the anterior trunk ranged from 0.5 to 5.6cm, and muscle thickness of the posterior trunk ranged from 0.6 to 6.6cm. Total muscle volume of the trunk was 2935 and 4195cm(3) for the anterior and posterior portions, respectively. The total predicted muscle mass in the anterior and posterior trunk was 7.4kg. This case study begins to provide a picture of the distribution and symmetry of skeletal muscle and AT of the trunk. Future studies are necessary to confirm these findings and examine relationships among different populations.

Prediction of Lower Limb Isometric Strength from Regional Muscle Mass Variables in Adolescents

The relationship between muscle size and strength has been published in the literature, however less is known about its actual association for adolescents. The identification of anthropometric muscle mass indicators that best predict strength across age taking in account growth and maturation processes, must be useful in field settings for screening sport talents, and sport training with young. PURPOSE: To analyze the association between lower-limb strength (LLS) and regional skeletal muscle mass (SMM) variables in young athletes and non-athletes. Secondly, to identify which regional SMM indicators are more successful predictors of LLS after adjusted for maturation. METHODS: SMM variables were assessed by anthropometric measures in 166 adolescents between 12 and 18 years old (15.2 ± 1.7 yrs, BMI = 21.9 ± 3.9 kg·m-2). The volunteers were recruited from local high-schools and local sport clubs. Athletes (AT) and non-athletes (NAT) were identified using an ad hoc questionnaire (NA = 99, 42 boys, 57 girls, and A = 67, 42 boys, 25 girls). Skeletal muscle mass (SMM) was calculated by anthropometric-derived equations. A dynamometer device was used to assess LLS. Partial correlations were carried out to determine associations between BC variables and strength values. The best-correlated variables with LLS performance were included in a stepwise regression analysis to determine SMM predictors. RESULTS: As expected AT were stronger than NA (80.3 ± 32.3 vs 58.4 ± 27.1 kg, p<0.001). The best correlation between SMM variables and LLS test was for total SMM in NAT boys after controlled by height (r = 0.520, p<0.001). When participants were pooled together, SMM, athlete condition and height were predictors of LLS test (R-squared = 0.484, p<0.001). Similar results were found for an alternative model including mid-calf corrected girth (CCG), athlete condition, gender and height (R-squared = 0.485, p<0.001). Surprisingly, age at peak height velocity was not found as a predictor of LLS. CONCLUSIONS: In accordance with other studies, our results confirm that lower-limb strength performance in adolescents was partially dependent on SMM. The main finding was that a simple measure as CCG can contribute to develop youth predictive models of sport performance and talent identification. Funded by Spanish Ministry of Economy and Competiveness (grant: DEP2011-30565)

Assessing skeletal muscle mass: historical overview and state of the art

BackgroundEven though skeletal muscle (SM) is the largest body compartment in most adults and a key phenotypic marker of sarcopenia and cachexia, SM mass was until recently difficult and often impractical to quantify in vivo. This review traces the historical development of SM mass measurement methods and their evolution to advances that now promise to provide in-depth noninvasive measures of SM composition.MethodsKey steps in the advancement of SM measurement methods and their application were obtained from historical records and widely cited publications over the past two centuries. Recent advances were established by collecting information on notable studies presented at scientific meetings and their related publications.ResultsThe year 1835 marks the discovery of creatine in meat by Chevreul, a finding that still resonates today in the D3-creatine method of measuring SM mass. Matiegka introduced an anthropometric approach for estimating SM mass in 1921 with the vision of creating a human “capacity” marker. The 1940s saw technological advances eventually leading up to the development of ultrasound and bioimpedance analysis methods of quantifying SM mass in vivo. Continuing to seek an elusive SM mass “reference” method, Burkinshaw and Cohn introduced the whole-body counting-neutron activation analysis method and provided some of the first detailed reports of cancer cachexia in the late 1970s. Three transformative breakthroughs leading to the current SM mass reference methods appeared in the 1970s and early 1980s as follows: the introduction of computed tomography (CT), photon absorptiometry, and magnetic resonance (MR) imaging. Each is advanced as an accurate and/or practical approach to quantifying whole-body and regional SM mass across the lifespan. These advances have led to a new understanding of fundamental body size-SM mass relationships that are now widely applied in the evaluation and monitoring of patients with sarcopenia and cachexia. An intermediate link between SM mass and function is SM composition. Advances in water-fat MR imaging, diffusion tensor imaging, MR elastography, imaging of connective tissue structures by ultra-short echo time MR, and other new MR approaches promise to close the gap that now exists between SM anatomy and function.ConclusionsThe global efforts of scientists over the past two centuries provides us with highly accurate means by which to measure SM mass across the lifespan with new advances promising to extend these efforts to noninvasive methods for quantifying SM composition.

Age Differences In Total And Regional Skeletal Muscle Mass, Posture Control And Physical Working Capacity

Aging is associated with a progressive decline of muscle mass, strength, bone mineral density (BMD) and quality, i.e., a condition described as sarcopenia from aging. The balance ability in elderly people depends on their muscular strength and physical working capacity. PURPOSE: The purpose of this study was to examine control of sit-to-stand, quiet standing, skeletal muscle mass and muscular strength in young and elderly people. METHODS: Healthy young (n=8, age 21.5±1.1yrs, height 169.1±6.4cm, body weight 60.3±6.7kg) and elderly (n=5, age 68.4±4.3yrs, height 162.2±5.7cm, body weight 63.2±7.4kg) male subjects participated in this study. The grip strength, flexibility (sitting trunk flexion), and knee extension muscular strength (30-second chair-stand test; CS-30) of all subjects were measured. The displacements of COP of ground reaction forces were recorded at a frequency of 20 Hz while the subjects were standing still on a force platform for 30 seconds, and the total length of COP displacements was calculated. The thickness of 9 muscles was measured by B-mode ultrasonograph to estimate the total for the whole body and regional skeletal muscle mass by the method of Sanada et al. (Eur J Appl Physiol, 96: 24-31, 2006). RESULTS: In comparison with the young subjects, the elderly subjects were significantly lower in predicted skeletal muscle mass of trunk (37%), thigh (19%), lower leg (22%) and the total for the whole body (24%), and CS-30 (38±4 vs. 16±2 times, p<0.001). However, there was no significant difference between the tow groups in arm skeletal muscle mass and BMD. A significant age difference did exist for the mean anterior-posterior (A/P) length of COP displacements (31.0±6.2 vs. 41.8±5.0 mm, p<0.01). There was a significant negative correlation between CS-30 and A/P length of COP displacements (r=-0.709, p<0.01). CONCLUSIONS: The results reconfirmed that muscle mass, leg strength, and the ability of balance control reduced in the natural aging process. The present study was suggested that the negative correlation between CS-30 and A/P length of COP displacements indicated a conservative enlargement of the muscle mass of the supporting limb by strength training. This conservative strategy may be related to the prevention of accidental fall that causes injury and death in the elderly people.

Validity Of Equations For Total And Regional Skeletal Muscle Mass By Ultrasound In Japanese Prepubertal-boys

At the present time, there are very few effective methods to accurately and non-invasively estimate skeletal muscle (SM) mass in children. Recently, we developed ultrasound-derived prediction equations for estimating total and regional (i.e. arm, trunk and leg) SM mass in adults males and females (Eur J Appl Physiol 96: 24-31, 2006). However, it is unknown whether these equations are a valid method to estimate SM mass in prepubertal children. PURPOSE: To investigate whether ultrasound-derived prediction equations for estimating total and regional SM mass in adults are applicable for prepubertal children. METHODS: Sixty-one healthy Japanese prepubertal boys (mean age 10yr) volunteered for the study. Contiguous MRI images with a 1-cm slice thickness were obtained from the first cervical vertebra to the ankle joints as reference data. The volume of SM was calculated from the summation of digitized cross-sectional area. The volume units were converted into mass by an assumed SM density of 1.041g/cm3. The regional SM mass was determined by anatomical landmarks visible in the scanned images. Muscle thickness was measured by B-mode ultrasound (5 MHz scanning head) at 9 sites on different muscles (lateral forearm, anterior and posterior upper arm, abdomen, subscapular, anterior and posterior thigh, anterior and posterior lower leg). Total and regional SM mass were estimated using prediction equations for adult males, which were developed based on the relationship between ultrasound-measured muscle thickness and MRI-measured SM mass. RESULTS: The measured SM mass by MRI was 11.3±2.8 kg for total, 1.1±0.3 kg for arm, 4.6±1.2 kg for trunk, 4.2±1.2 kg for thigh and 1.4±0.5 kg for lower leg, and were significantly different from the predicted total and regional SM mass by ultrasound (total 8.0±3.6kg, arm 0.9±0.3kg, trunk 5.9±1.1kg and lower leg 0.9±0.4kg, respectively, p<0.01) except for thigh (4.2±1.3kg). CONCLUSIONS: The ultrasound-derived prediction equations for adults are not applicable for prepubertal boys. The specialized equation for estimating total and regional SM mass in prepubertal children is needed.

Is the use of ultrasound-derived prediction equations for adults useful for estimating total and regional skeletal muscle mass in Japanese children?

The purpose of the present study was to investigate whether ultrasound-derived prediction equations for estimating total and regional skeletal muscle (SM) mass in adults are applicable for prepubertal children and adolescents. Ten Japanese prepubertal children and twenty-one adolescents volunteered for the study. Contiguous MRI images with a 1 cm slice thickness were obtained from the first cervical vertebra to the ankle joints as reference data. The SM volume was calculated from the summation of digitised cross-sectional areas. The regional SM volume was determined by anatomical landmarks visible in the scanned images. The volume units were converted into mass by an assumed SM density (1.041 g/cm3). Muscle thickness was measured by B-mode ultrasound at nine sites on different muscles (lateral forearm, anterior and posterior upper arm, abdomen, subscapular, anterior and posterior thigh, anterior and posterior lower leg). Total and regional SM mass was estimated using adult prediction equations. Mean values between measured and predicted total and regional segments of SM mass were not significantly different for adolescents, but were for prepubertal children. There was a relatively large range of the 95% limits of agreement both in prepubertal children and adolescents. These results suggest that the adult ultrasound-derived prediction equations are useful for estimating total and regional SM mass for adolescents at the group level, but the relatively high degree of variability suggested limited reliability at the individual level both in prepubertal children and adolescents.

The Changes Of One-year Detraining On Anaerobic Power, Total And Regional Skeletal Muscle Mass In Young Male

PURPOSE: The present study investigates the effect of detraining of recreational sports for one-year influences anaerobic power and skeletal muscle mass in the upper and lower extremities of young people. METHODS: Eleven young male subjects (18.6 ± 0.9 years, 174.7 ± 3.9 cm, 68.9 ± 7.4 kg,) who had been recreational sports (martial arts, tennis, basketball, baseball) over 6 years participated in this study. During one-year recess of recreational sports, subjects did not perform any other constant periodical exercise which may affect the result. Two all-out cycle ergometer work tests lasting 30 seconds were used to estimate anaerobic power with leg (pedaling) and arm (cranking) exercises. Loads of the tests were 0.087kp per body weight for pedaling and 0.062kp per body weight for cranking, respectively. Anaerobic power was determined by measuring the highest power output during 30 seconds. Furthermore, peak and mean power in intermittent exercise was determined using a protocol of ten 5-second bouts of full effort pedaling and cranking with 20-seconds rest. Thickness of 18 muscles was measured by B-mode ultrasonograph. Total and regional skeletal muscle mass was predicted by the method of Sanada et al. (Eur J Appl Physiol, 96: 24 - 31, 2006). RESULTS: After one-year recess of the recreational sports, predicted skeletal muscle mass of trunk (14%), thigh (7%), lower leg (24%) and total (12%) was significantly decreased, and anaerobic power and intermittent peak power of leg-pedaling was also significantly decreased (anaerobic power: 8.6 ± 0.8 to 8.2 ± 0.8 W·kg−1, p < 0.05; intermittent peak power: 14.2 ± 1.3 to 12.1 ± 2.1 W·kg−1, p<0.05). Among arm skeletal muscle mass, anaerobic power and intermittent peak power of arm-cranking, on the other hand, did not change. CONCLUSIONS: Results clearly showed that in young male subjects anaerobic power and skeletal muscle mass were remarkably decreased in the trunk and leg but not in the arm by a detraining of recreational sport for one-year. In comparison with the legs, the muscle performance of the arm appears to be conserved during detraining independent of the athletic event, and it suggests that the anaerobic power and skeletal muscle mass of the trunk and leg are an important fitness factor for young males.

Muscle mass and bone mineral indices: does the normalized bone mineral content differ with age?

To investigate the relationships between regional skeletal muscle mass (SM mass) and bone mineral indices and to examine whether bone mineral content (BMC) normalized to SM mass shows a similar decrease with age in young through old age. One hundred and thirty-eight young and postmenopausal women aged 20-76 years participated in this study and were divided into three groups: 61 young women, 49 middle-aged postmenopausal women and 28 older postmenopausal women. Muscle thickness (MTH) was determined by ultrasound, and regional SM mass (arm, trunk and leg) was estimated based on nine sites of MTH. Whole-body and regional lean soft tissue mass (LSTM), bone mineral density (BMD) and BMC (whole body, arms, legs and lumbar spine) were measured using dual-energy X-ray absorptiometry. Ultrasound spectroscopy indicated that SM mass is significantly correlated with site-matched regional bone mineral indices and these relationships correspond to LSTM. The BMC and BMD in older women were significantly lower than those in middle-aged women. When BMC was normalized to site-matched regional SM mass, BMC normalized to SM mass in arm and trunk region were significantly different with age; however, whole-body and leg BMC normalized to SM mass showed no significant difference between middle-aged and older postmenopausal women. The age-related differences in BMC were found to be independent of the ageing of SM mass in the arm and trunk region. However, differences in BMC measures of the leg and whole body were found to correspond to age-related decline of SM mass in postmenopausal women.

Validity of Equations for Total and Regional Skeletal Muscle Mass by Ultrasound in Japanese Adolescents

Validity of Equations for Total and Regional Skeletal Muscle Mass by Ultrasound in Japanese Adolescents

Effects of age on ventilatory threshold and peak oxygen uptake normalised for regional skeletal muscle mass in Japanese men and women aged 20–80 years

Ventilatory threshold (VT) is an important predictor of cardiorespiratory fitness, such as peak oxygen uptake (VO2peak) and is a valuable index of aerobic exercise intensity. However, little is known about the role of skeletal muscle (SM) mass in the age-associated decline of VT. Therefore, the present study was performed to investigate the effects of age on cardiopulmonary fitness normalised for regional SM mass in 1,463 Japanese men and women, and to determine the relevance of VT normalised to SM mass based on age and gender. Total, trunk and thigh SM mass were measured using an ultrasound method, while VO2peak and VT were determined during treadmill walking. VO2peak was estimated using the predicted maximum heart rate (HR) and the HR-VO2 relationship for sub-maximal treadmill walking. There were significant negative correlations between VT normalised for body mass and age in men and women (P < 0.001). Age-associated declines were also observed in VT normalised for body mass in both men and women; however, VT normalised for SM mass was not significantly different with age. Significant correlations were also observed between thigh SM mass and VT in both men and women. These results suggest that thigh SM mass is closely associated with VO2peak and/or VT in both men and women, and the decrease in VT with age is predominantly due to an age-related decline of SM mass. Moreover, this study provides normative cardiorespiratory fitness data regarding VT normalised SM mass in healthy men and women aged 20-80 years.

Prediction and validation of total and regional skeletal muscle mass by ultrasound in Japanese adults

The present study was performed to develop regression-based prediction equations for skeletal muscle (SM) mass by ultrasound and to investigate the validity of these equations in Japanese adults. Seventy-two Japanese men (n=38) and women (n=34) aged 18-61 years participated in this study and were randomly separated into two groups: the model development group (n=48) and the validation group (n=24). The total and regional SM mass were measured using magnetic resonance imaging (MRI) 1.5 T-scanners with spin-echo sequence. Contiguous transverse images (about 150 slices) with a slice thickness of 1 cm were obtained from the first cervical vertebra to the ankle joints. The volume of SM was calculated from the summation of digitized cross-sectional area. The SM volume was converted into mass units (kg) by an assumed SM density of 1.04 kg l(-1). The muscle thickness (MTH) was measured by B-mode ultrasound (5 MHz scanning head) at nine sites on the anatomical SM belly. Strong correlations were observed between the site-matched SM mass (total, arm, trunk body, thigh, and lower leg) by MRI measurement and the MTH x height (in m) in the model development group (r=0.83-0.96 in men, r=0.53-0.91 in women, P<0.05). When the SM mass prediction equations were applied to the validation group, significant correlations were also observed between the MRI-measured and predicted SM mass (P<0.05). The predicted total SM mass for the validation group was 19.6 (6.5) kg and was not significantly different from the MRI-measured SM mass of 20.2 (6.5) kg. Bland-Altman analysis did not indicate a bias in prediction of the total SM mass for the validation group (r=0.00, NS). These results suggested that ultrasound-derived prediction equations are a valid method to predict SM mass and an alternative to MRI measurement in healthy Japanese adults.