Relation between body mass index percentile and muscle strength and endurance

Are accelerometer-measured sitting and physical activity times associated with muscle mass and strength in healthy young adults in the UAE?

Background

A high prevalence of obesity, sedentary behavior, and physical inactivity could affect muscle mass and strength in young adults in the United Arab Emirates (UAE). Therefore, we investigated the association of sex, body mass index (BMI), and accelerometer-measured sitting and physical activity (PA) times with skeletal muscle mass index (SMI), hand grip, and thigh muscle strength in healthy young adults in the UAE.

Methods

In this cross-sectional study, 156 healthy young adults (age 21.68 ± 3.01 years, BMI 25.40 ± 4.79 kg/m2, 52.6 % women) were included. BMI and muscle mass were recorded using a bioelectrical impedance analyzer. Maximum hand grip strength and thigh muscle torque were assessed using the Jamar-smart hand-dynamometer and Biodex System-4-Pro, respectively. Participants wore a triaxial Fibion accelerometer on their anterior thigh for >10 h per day for 4-7 days to measure their sitting and PA times. Multiple linear regression analyses were used.

Results

Participants spent most of their time sitting (11.37 ± 1.10 h), followed by standing (2.92 ± 0.86 h), walking (1.58 ± 0.55 h), and vigorous intensity PA (4.79 ± 5.85 min) per 16-h day. Sex (p < 0.001) and BMI (p < 0.001) were negatively associated with all muscle mass and strength variables. Men had more muscle mass and strength than women. As BMI increased, muscle mass and muscle strength decreased. Accelerometer-measured sitting and walking times were negatively associated with concentric hamstrings (p = 0.044) and quadriceps torques (p = 0.031), respectively.

Conclusion

Sex, BMI, and accelerometer-measured sitting and walking times were associated with muscle mass and/or muscle strength in healthy young adults. Women and those with a high BMI need interventions to improve their muscle mass and strength. The paradox regarding the association of PA with muscle mass and strength in younger adults may be due to possible influences from other factors (e.g., resistance training, dietary intakes, etc.) superseding that of accelerometer-measured PA.

Comprehensive Physical Work Capacity Evaluations for Korean Farmers Assessed in Healthy Volunteers

OBJECTIVE

To establish the lower limits of normative values of the physical work capacity for Korean farmers in healthy working individual.

METHODS

We developed a comprehensive set of physical work capacity evaluation items that encompass common farming tasks. These items include measurements of trunk flexion/extension angles, strength (hand grip, trunk flexion/extension, leg/back lifting, and pushing/pulling), and positional tolerances. We calculated the normative values for the items and defined the normal range in 124 healthy volunteers aged 20-79 years. We calculated the intraclass correlation coefficient (ICC) to validate the test-retest reliability of the measurements protocol.

RESULTS

The normal values for each measurement item were as follows: trunk flexion and extension angle (65.3°±11.6° and 29.6°±6.6°), dominant hand grip strength (32.2±10.5 kgf), trunk flexion and extension strength (288.4±119.0 N and 297.3±129.9 N), leg and back lifting strength (452.9±233.5 N and 349.2±166.7 N), pushing and pulling strength (214.7±75.1 N and 221.7±63.3 N), and positional tolerance time (squat: 76.8±9.0 seconds, front: 73.8±7.7 seconds, twist: 82.2±8.8 seconds, upward: 71.9±11.3 seconds). Regarding test-retest reliability, all strength measurements demonstrated excellent absolute agreement (ICC, 0.91-0.96). However, positional tolerance showed poor-to-moderate absolute agreement (ICC, 0.37-0.58).

CONCLUSION

We conducted measurements of muscle strength and positional tolerance in healthy participants of various ages, focusing on tasks commonly performed by Korean farmers. The outcomes hold significant value as they offer a pertinent instrument for assessing the appropriateness of workers, thereby carrying implications for rehabilitation objectives, legal evaluations, and work capacity assessments within the agricultural domain.

The Relationship between Body Composition and Physical Fitness and the Effect of Exercise According to the Level of Childhood Obesity Using the MGPA Model

Childhood obesity can lead to adulthood obesity with adverse effects. Since body composition and physical fitness differ depending on the obesity degree, a systemic analysis could help classify that degree. We used three study designs based on the obesity degree (body mass index [BMI] as a reference) for our objectives. First, we identified the relationship between body composition and physical fitness. Second, we determined the effects of exercise on body composition and physical fitness. Third, we performed a path analysis of the impact of exercise on body composition and physical fitness, and verified those effects among the groups. In study 1, 164 10-year-old subjects were divided into four groups: 33 in the normal weight (NO), 34 in overweight (OV), 54 in obesity (OB), and 43 in the severe obesity (SOB) group. In study 2, 101 participants from study 1 who wished to participate in the exercise program were divided into four groups (same criteria). The exercise program (three times a week for 60 min, for 16 weeks) consisted of sports and reinforcement exercises of increasing intensity. Body composition was measured by body weight, percentage of body fat (%BF), muscle mass, skeletal muscle mass (SMM), and body mass index (BMI). In contrast, physical fitness was measured by muscular strength, flexibility, muscular endurance, agility, and balance. As a result, all body composition variables were higher in the SOB group than in the other groups. Physical fitness, muscular strength and balance, and agility were highest in the SOB, NO, and OV groups, respectively. Pearson’s correlation revealed that muscular strength was associated with height and body weight across all groups. Agility showed a negative correlation with %BF in the NO, OB, and SOB groups. SMM was positively correlated in the OB and SOB groups. After the exercise intervention, BMI and the %BF of the SOB group were significantly reduced (p < 0.01, and p < 0.001, respectively), while SMM presented a significant increase (p < 0.001). Height also showed a significant increase in all groups (p < 0.001). Among physical fitness variables, muscular strength, flexibility, muscular endurance, and balance showed a significant increase in all groups, while a significant increase in power was observed in only the OB and SOB groups. As for the effects of the body composition on physical fitness after exercise intervention, the greatest impact was observed for balance, muscular strength and agility, and muscular endurance in NO, OV, and OB groups, respectively. In conclusion, the body composition, physical fitness relationship, and the effects of exercise intervention on them differed depending on the obesity degree. Furthermore, the results varied according to the obesity degree. Thus, our study highlights the importance of creating particular exercise programs for the effective prevention and treatment of childhood obesity considering the obesity degree.

Physiotherapy combined with therapeutic neuroscience education versus physiotherapy alone for patients with chronic low back pain: A pilot, randomized-controlled trial

Objectives

The aim of this study was to investigate the effect of therapeutic neuroscience education (TNE) combined with physiotherapy on pain, kinesiophobia, endurance, and disability in chronic low back pain (CLBP) patients.

Patients and methods

Between November 2016 and December 2017, a total of 31 patients with CLBP (5 males, 26 females; mean age: 42.3±10.8 years; range, 20 to 58 years) were randomly allocated to receive physiotherapy combined with TNE (experimental group, EG, n=16) and physiotherapy alone (control group, CG, n=15). All participants received physiotherapy consisting of five sessions per week for a total of three weeks. In addition to physiotherapy, the EG received TNE sessions consisting of two sessions per week for a total of three weeks. The primary outcomes were pain intensity as assessed by Visual Analog Scale (VAS) and kinesiophobia by Tampa Scale for Kinesiophobia (TSK), while and the secondary outcomes were trunk muscle endurance as assessed by the partial curl-up test (trunk flexor endurance [TFE]) and modified Sorensen test (trunk extensor endurance [TEE]) and disability by Roland-Morris Disability Questionnaire (RMDQ).

Results

All patients completed the study. The median VAS, TSK, TFE, TEE, and RMDQ scores for the EG significantly improved after three weeks, while there was only significant improvement in the VAS, TSK, and RMDQ scores in the CG. The TSK decreased more in the EG than in the CG. The significant difference was evident in TSK and TFE in favor of the EG (p<0.05).

Conclusion

These results suggest that the combination of TNE with physiotherapy can improve kinesiophobia and trunk flexor muscle endurance of patients with CLBP in the short-term.

Comparison of Shear Wave Elastography and Dynamometer Test in Muscle Tissue Characterization for Potential Medical and Sport Application

Skeletal muscle status and its dynamic follow up are of particular importance in the management of several diseases where weight and muscle mass loss and, consequently, immobilization occurs, as in cancer and its treatment, as well as in neurodegenerative disorders. But immobilization is not the direct result of body and muscle mass loss, but rather the loss of the maximal tension capabilities of the skeletal muscle. Therefore, the development of a non-invasive and real-time method which can measure muscle tension capabilities in immobile patients is highly anticipated. Our aim was to introduce and evaluate a special ultrasound measurement technique to estimate a maximal muscle tension characteristic which can be used in medicine and also in sports diagnostics. Therefore, we determined the relationship between the results of shear wave elastography measurements and the dynamometric data of individuals. The measurements were concluded on the m. vastus lateralis. Twelve healthy elite athletes took part in our preliminary proof of principle study—five endurance (S) and seven strength (F) athletes showing unambiguously different muscle composition features, nine healthy subjects (H) without prior sports background, and four cancer patients in treatment for a stage 3 brain tumor (T). Results showed a high correlation between the maximal dynamometric isometric torque (Mmax) and mean elasticity value (E) for the non-athletes [(H + T), (r = 0.795)] and for the athletes [(S + F), (r = 0.79)]. For the athletes (S + F), the rate of tension development at contraction (RTDk) and E correlation was also determined (r = 0.84, p < 0.05). Our measurements showed significantly greater E values for the strength athletes with fast muscle fiber dominance than endurance athletes with slow muscle fiber dominance (p < 0.05). Our findings suggest that shear wave ultrasound elastography is a promising method for estimating maximal muscle tension and, also, the human skeletal muscle fiber ratio. These results warrant further investigations with a larger number of individuals, both in medicine and in sports science.

[Influence of overweight and obesity on strength in childhood]

Introduction

Introduction: overweight and obesity reach a high prevalence since childhood in Spain. Objective: to describe the effect of overweight and obesity, in schoolchildren of eleven years of age, in tests that assess the strength of both the lower and upper extremities, as well as speed. Method: four hundred and twenty-three schoolchildren of eleven years of age participated in the study. Basic anthropometric characteristics were obtained and several tests of the EUROFIT battery were developed. Results: normal-weight boys and girls had better scores in physical condition tests in general. Therefore, the vertical and horizontal jumps, bar suspension and abdominals were higher in the participants with normal-weight (p < 0.05). In addition, they performed in less time a speed circuit in both sexes (p < 0.001); however, in relation to the manual isometric strength, in the group of girls those who are overweight or obese have better results (p < 0.01). Conclusions: overweight and obese children of eleven year-olds showed a lower muscular performance, except in the case of manual isometric strength. Several equations haven been also determined for predicting the results of physical tests carried out such as jumps, dynamometry and speed, through sex and body mass index (BMI).

Inhibition of myostatin improves muscle atrophy in oculopharyngeal muscular dystrophy (OPMD)

BACKGROUND

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset muscle disease affecting one per 80 000 of the general population characterized by profound dysphagia and ptosis, and limb weakness at later stages. Affected muscles are characterized by increased fibrosis and atrophy. Myostatin is a negative regulator of muscle mass, and inhibition of myostatin has been demonstrated to ameliorate symptoms in dystrophic muscles.

METHODS

In this study, we performed a systemic delivery of a monoclonal antibody to immunologically block myostatin in the A17 mouse model of OPMD. The mice were administered a weekly dose of 10 mg/kg RK35 intraperitonially for 10 weeks, following which histological analyses were performed on the samples.

RESULTS

This treatment significantly (P < 0.01) improved body mass (11%) and muscle mass (for the tibialis anterior and extensor digitorum longus by 19% and 41%) in the A17 mice treated with RK35 when compared to saline controls. Similarly, a significantly (P < 0.01) increased muscle strength (18% increase in maximal tetanic force) and myofibre diameter (17% and 44% for the tibialis anterior and extensor digitorum longus), and reduced expression of markers of muscle fibrosis (40% reduction in area of expression), was also observed. No change in the density of intranuclear inclusions (a hallmark of disease progression of OPMD) was however observed.

CONCLUSIONS

Our study supports the clinical translation of such antibody-mediated inhibition of myostatin as a treatment of OPMD. This strategy has implications to be used as adjuvant therapies with gene therapy based approaches, or to stabilize the muscle prior to myoblast transplantation.

The Differential Association between Muscle Strength and Diabetes Mellitus According to the Presence or Absence of Obesity

Background

Muscle strength can be affected by body mass index. In the present study, we compared the association between the diabetes mellitus (DM) and muscle strength according to obesity.

Methods

We analyzed the association between DM and muscle strength using the Korea National Health and Nutrition Examination Survey 2014 to 2016 data weighted to represent the Korean population aged between 30 and 79 years old. Muscle strength was classified into age- and sex-specific quartiles (Qs) of handgrip strength, with the lowest Q defined as “low muscle strength (LMS).”

Results

Muscle strength was positively associated with body mass index in both sexes (P<0.001); the prevalence of obesity increased by 30% in male (odds ratio [OR], 1.300; 95% confidence interval [CI], 1.231–1.373) and 12% in female (OR, 1.122; 95% CI, 1.062–1.185), respectively, per one Q of muscle strength. In contrast, the prevalence of DM decreased as muscle strength increased (OR per one Q, 0.926; 95% CI, 0.862–0.996 in male and OR per one Q, 0.917; 95% CI, 0.854–0.986 in female). LMS was significantly associated with DM even following adjustment for age, sex, family history of DM, abdominal obesity, dyslipidemia, and hypertension (OR, 1.328; 95% CI, 1.133–1.558). Stratified analysis according to obesity status showed that it remained significant only in nonobese populations (OR, 1.513; 95% CI, 1.224–1.870 in nonobese participants and OR, 1.124; 95% CI, 0.879–1.437 in obese participants).

Conclusion

LMS was independently associated with DM in the Korean population aged between 30 and 79 years. However, obesity-stratified analysis revealed that it was significant only in the nonobese population.

Differential metabolic effects of constant moderate versus high intensity interval training in high-fat fed mice: possible role of muscle adiponectin

Exercise regimens may have differing effects in the presence of obesity. In addition to being fat derived, adiponectin has recently been described as a myokine that regulates insulin sensitivity, which may link to exercise-related metabolic benefits in obesity. Whether skeletal muscle adiponectin varies in different exercise modalities is unclear. This study investigated the comparative effects of 10 weeks of endurance constant-moderate intensity exercise (END) with high intensity interval training (HIIT), on metabolic outcomes, including muscle adiponectin in a mouse model of diet-induced obesity. Ten-week-old male C57BL/6 mice were fed a high-fat diet (HFD) (45% FAT) or standard CHOW diet ab libitum and underwent one of three training regimes: (1) no exercise, (2) END, or (3) HIIT (8 bouts of 2.5 min with eight periods of rest of 2.5 min) for 10 weeks (3 × 40 min sessions/week). Chow-fed mice acted as controls. Compared with HFD alone, both training programs similarly protected against body weight gain (HFD = 45 ± 2; END = 37 ± 2; HIIT = 36 ± 2 g), preserved lean/fat tissue mass ratio (HFD = 0.64 ± 0.09; END = 0.34 ± 0.13; HIIT = 0.33 ± 0.13), and improved blood glucose excursion during an insulin tolerance test (HFD = 411 ± 54; END = 350 ± 57; HIIT = 320 ± 66 arbitrary units [AU]). Alterations in fasting glycemia, insulinemia, and AST/ALT ratios were prevented only by END. END, but not HIIT increased skeletal muscle adiponectin mRNA (14-fold; P < 0.05) and increased protein content of high molecular weight (HMW) adiponectin (3.3-fold), whereas HIIT induced a milder increase (2.4-fold). Compared with HFD, neither END nor HIIT altered circulating low (LMW) or high (HMW) molecular weight adiponectin forms. Furthermore, only END prevented the HFD downregulation of PGC1α (P < 0.05) mRNA levels downstream of muscle adiponectin. These data show that different training programs affect muscle adiponectin to differing degrees. Together these results suggest that END is a more effective regimen to prevent HFD-induced metabolic disturbances in mice.

Examining and comparing the health and performance indices of university undergraduate students according to year of study and gender

This study examined and compared, based on year of study and gender, the health and performance indices of university undergraduate students. Eighty-nine students (mean±standard deviation age, 22.47±2.22 years) were randomly selected for assessment prior to second semester examination of 2015/2016 academic year. body mass index, resting metabolic rate, visceral fat, skeletal muscle mass, body fat, systolic & diastolic blood pressure, resting heart rate, upper & lower body endurance, handgrip strength, and lower back and hamstring flexibility were assessed. The students had sedentary heart rate, low skeletal muscle mass, average upper and lower body endurance, and weak handgrip strength. Significant difference existed in the visceral fat (P=0.008) between third and fourth year students. There were significant gender differences in resting metabolic rate (P=0.000), skeletal muscle mass (P=0.000), body fat (P=0.000), systolic blood pressure (P=0.001), heart rate (P=0.005) and handgrip strength (P=0.000). There are gender differences in association between health and performance indices. Dependable health education and pragmatic involvement of undergraduate university students in structured exercise programmes are recommended.

Utility and reliability of non-invasive muscle function tests in high-fat-fed mice

NEW FINDINGS

What is the central question of this study? Non-invasive muscle function tests have not been validated for use in the study of muscle performance in high-fat-fed mice. What is the main finding and its importance? This study shows that grip strength, hang wire and four-limb hanging tests are able to discriminate the muscle performance between chow-fed and high-fat-fed mice at different time points, with grip strength being reliable after 5, 10 and 20 weeks of dietary intervention. Non-invasive tests are commonly used for assessing muscle function in animal models. The value of these tests in obesity, a condition where muscle strength is reduced, is unclear. We investigated the utility of three non-invasive muscle function tests, namely grip strength (GS), hang wire (HW) and four-limb hanging (FLH), in C57BL/6 mice fed chow (chow group, n = 48) or a high-fat diet (HFD group, n = 48) for 20 weeks. Muscle function tests were performed at 5, 10 and 20 weeks. After 10 and 20 weeks, HFD mice had significantly reduced GS (in newtons; mean ± SD: 10 weeks chow, 1.89 ± 0.1 and HFD, 1.79 ± 0.1; 20 weeks chow, 1.99 ± 0.1 and HFD, 1.75 ± 0.1), FLH [in seconds per gram body weight; median (interquartile range): 10 weeks chow, 2552 (1337-4964) and HFD, 1230 (749-1994); 20 weeks chow, 2048 (765-3864) and HFD, 1036 (717-1855)] and HW reaches [n; median (interquartile range): 10 weeks chow, 4 (2-5) and HFD, 2 (1-3); 20 weeks chow, 3 (1-5) and HFD, 1 (0-2)] and higher falls [n; median (interquartile range): 10 weeks chow, 0 (0-2) and HFD, 3 (1-7); 20 weeks chow, 1 (0-4) and HFD, 8 (5-10)]. Grip strength was reliable in both dietary groups [intraclass correlation coefficient (ICC) = 0.5-0.8; P < 0.05], whereas FLH showed good reliability in chow (ICC = 0.7; P < 0.05) but not in HFD mice after 10 weeks (ICC < 0.5). Our data demonstrate that non-invasive muscle function tests are valuable and reliable tools for assessment of muscle strength and function in high-fat-fed mice.

Overweight or obesity associations with physical aggression in children and adolescents

Being overweight or obese (overweight/obesity) or physically aggressive in childhood and adolescence can have lifelong consequences, hence are important public health problems. Identifying a relationship between these problems would assist in understanding their developmental origins. The present paper sought to review previous studies and use meta-analysis to evaluate whether there is evidence of a relationship between overweight/obesity and physical aggression in children and adolescents. A systematic search of studies that reported the effect of overweight/obesity (in the form of body mass index) on physical aggression was conducted. A total of 23 studies were identified, representing data from 255,377 participants. The results indicate that children and adolescents who are overweight or obese are more physically aggressive than their normal-weight or underweight peers. The average weighted standardized mean difference (the effect size) for aggression in overweight and obese children and adolescents compared to others was found to be 0.27 (95% confidence interval [CI95]: .17–.37), and was significant ( p<.001). Gender sub-analysis indicated that higher physical aggression amongst overweight or obese compared to normal-weight or underweight peers is a slightly larger effect for boys (standardized mean difference of .35, CI95: .18–.52, p<.001) than girls (standardized mean difference of .24, CI95: .07–.42, p<.01). High levels of heterogeneity (94.41%) were found between study-level effect sizes. The developmental processes that may explain the association between overweight/obesity and physical aggression in children and adolescents are discussed.