Predictive equation for assessing appendicular lean soft tissue mass using bioelectric impedance analysis in older adults: Effect of body fat distribution.

BACKGROUND: Low muscle mass is associated with sarcopenia and increased mortality. Muscle mass, especially that of the limbs, is commonly estimated by dual-energy X-ray absorptiometry (DXA) or bioimpedance analysis (BIA). However, BIA-based predictive equations for estimating lean appendicular soft tissue mass (ALST) do not take into account body fat distribution, an important factor influencing DXA and BIA measurements. OBJECTIVES: To develop and cross-validate a BIA-based equation for estimating ALST with DXA as criterion, and to compare our new formula to three previously published models. METHODS: One-hundred eighty-four older adults (140 women and 44 men) (age 71.5 ±â€¯7.3 years, body mass index 27.9 ±â€¯5.3 kg/m2) were recruited. Participants were randomly split into validation (n = 118) and cross-validation groups (n = 66). Bioelectrical resistance was obtained with a phase-sensitive 50 kHz BIA device. RESULTS: A BIA-based model was developed for appendicular lean soft tissue mass [ALST (kg) = 5.982 + (0.188 × S2 / resistance) + (0.014 × waist circumference) + (0.046 × Wt) + (3.881 × sex) - (0.053 × age), where sex is 0 if female or 1 if male, Wt is weight (kg), and S is stature (cm) (R2 = 0.86, SEE = 1.35 kg)]. Cross validation revealed r2 of 0.91 and no mean bias. Two of three previously published models showed a trend to significantly overestimate ALST in our sample (p < 0.01). CONCLUSIONS: The new equation can be considered valid, with no observed bias and trend, thus affording practical means to quantify ALST mass in older adults.

Resistance exercise training improves mucociliary clearance in subjects with COPD: A randomized clinical trial.

INTRODUCTION: Elastic tubing was recently investigated as an alternative to the conventional resistance training (RT) in chronic obstructive pulmonary disease (COPD). The effects of RT on the mucociliary system have not yet been reported in the literature. OBJECTIVE: The aim of this study was to evaluate the effects of two RT programs on mucociliary clearance in subjects with COPD. METHODS: Twentyeight subjects with COPD were randomly allocated by strata, according to individual strength of lower limbs, to defined groups: conventional resistance training (GCT) or resistance training using elastic tubing (GET). Nineteen subjects (GET: n=9; GCT: n=10) completed the study and were included in the analysis. The measurement of vital signs (blood pressure, heart rate and respiratory rate), lung function (spirometry) and the primary outcome mucociliary clearance analysis (saccharin transit time test (STT)) were performed before and after the 12 weeks of RT. RESULTS: In relation to the mucociliary transportability analysis, no differences were observed between the baseline evaluations of the training groups (p=0.05). There was a significant reduction in the STT values in both training groups, GET (10.64±5.06 to 6.01±4.91) and GCT (12.07±5.10 to 7.36±2.54) with p=0.03. However, no differences between groups were observed on the magnitude of SST changes after interventions (GET: -43.51%; GCT: -38.94%; p=0.97). CONCLUSION: The present study demonstrated that both RT with elastic tubing and conventional training with weights promoted similar gains in the mucociliary transportability of subjects with COPD.

Hypertrophy-type Resistance Training Improves Phase Angle in Young Adult Men and Women.

The main purpose of the present study was to investigate the effect of a hypertrophy-type resistance training protocol on phase angle, an indicator of cellular integrity, in young adult men and women. 28 men (22.2±4.3 years, 67.8±9.0 kg and 174.2±6.8 cm) and 31 women (23.2±4.1 years, 58.7±12.1 kg and 162.7±6.4 cm) underwent a progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, consisting of 10 to 12 whole body exercises with 3 sets of 8-12 repetitions maximum. Phase angle, resistance, reactance and total body water (intra and extracellular water compartments) were assessed by bioimpedance spectroscopy (Xitron 4200 Bioimpedance Spectrum Analyzer). Total body water, intracellular water and phase angle increased significantly (P<0.05) in men (7.8, 8.3, and 4.3%, respectively) and women (7.6, 11.7, and 5.8% respectively), with no significant difference between sexes (P>0.05). Bioimpedance resistance decreased (P<0.05) similarly in both sex (men=-4.8%, women=-3.8%). The results suggest that regardless of sex, progressive RT induces an increase in phase angle and a rise in cellular hydration.

Changes in skeletal muscle mass assessed by anthropometric equations after resistance training.

The aim of this study was to analyze the validity of anthropometric equations to identify changes in skeletal muscle mass (SMM) after resistance training (RT). Anthropometric and dual energy x-ray absorptiometry (DXA) measurements were obtained at baseline and after RT in 15 trained Caucasian college men. Participants performed RT over 8 weeks, consisting of 8-9 exercises of 4 sets with 12/10/8/6 maximal repetitions and 1-2 min interval between sets. The training loads were gradually increased according to gains in muscular strength. 4 anthropometric equations were used for estimation of SMM: EQ1 (SMM, g=height×[0.0553×corrected thigh girth2 + 0.0987×forearm girth2 + 0.0331×corrected calf girth2] - 2445), EQ2 (SMM, g=height×[0.031×medial thigh girth2 + 0.064×corrected calf girth2 + 0.089×corrected arm girth2] - 3006), EQ3 (SMM, kg=height×[0.00744×corrected arm girth2 + 0.00088×corrected thigh girth2 + 0.00441×corrected calf girth2] + 2.4×gender - 0.048×age + race + 7.8) and EQ4 (SMM, kg=0.244×weight + 7.8×height + 6.6×gender - 0.098×age + race - 3.3). EQ1 and EQ2 overestimated the SMM (41.3% and 19.9%, respectively; P<0.05) while EQ3 and EQ4 were similar (P>0.05) to DXA at baseline. Although all equations and DXA revealed a significant increase in SMM after RT, changes were overestimated by EQ1 and EQ2 (P<0.05), but not by EQ3 and EQ4 (P>0.05). In addition, changes in SMM over time between EQ4 and DXA were significantly correlated (r=0.62; P<0.01). Thus, changes in SMM that occur after RT can be detected by EQ4 in trained young men.

Appendicular Lean Soft Tissue: Development and Cross-Validation of Predictive Models for Older Men and Women.

BACKGROUND: Sarcopenia may explain, in a large proportion, physical disability, falls and fractures, especially in aged elderly. However, a diagnosis in an operationally systematic, simple and low cost way is extremely important, particularly for home-based, epidemiological studies. OBJECTIVE: The purpose of this study was to develop and validate predictive equations of appendicular lean soft tissue (ALST) in elderly older than 80 years. DESIGN AND SETTINGS: A validation study was performed in 106 elderly (men and women) aged 80 years and older. MEASUREMENTS: Body weight, height, circumference (arm, midcalf, hip and waist) and triceps skinfold were measured in the elderly. ALST were measured using as the reference method dual-energy X-ray absorptiometry (DXA). RESULTS: Two models were predicted. The first model (ALST, in kg = 0.074*height + 0.277*weight - 0.144*triceps skinfold - 0.103*waist circumference + 1.831*gender -0.966), which considered all possible variables in stepwise multiple regression, presented better statistical performance (r2 = 0.82; SEE = 1.67 kg), compared to the second model (ALST, in kg = 0.138*height + 0.103*weight + 3.061*gender - 12.489), a more practical equation, due to a lesser quantity of predictive variables (r2 = 0.75; SEE = 1.94 kg). Both models were validated, however, it was verified trend (p<0.05) for overestimation of predicted ALST. CONCLUSION: In summary, two models for predicting ALST in men and women with age ≥ 80 years were developed and cross-validated. Model 1, with a greater number of predictive variables, presented a better accuracy than did the model with only three variables (height, weight, and gender). Validation studies are needed to test the usefulness of both models in other populations.