Significant Increase In Lean Mass Research Articles

Evidence of muscular adaptations within four weeks of barbell training in women

We investigated the time course of neuromuscular and hypertrophic adaptations associated with only four weeks of barbell squat and deadlift training. Forty-seven previously untrained women (mean±SD, age=21±3years) were randomly assigned to low volume training (n=15), moderate volume training (n=16), and control (n=16) groups. The low and moderate volume training groups performed two and four sets, respectively, of five repetitions per exercise, twice a week. Testing was performed weekly, and included dual X-ray absorptiometry and vastus lateralis and rectus femoris B-mode ultrasonography. Bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis and biceps femoris during isometric maximal voluntary contractions of the leg extensors. Significant increases in lean mass for the combined gynoid and leg regions for the low (+0.68kg) and moderate volume (+0.47kg) groups were demonstrated within three weeks. Small-to-moderate effect sizes were shown for leg lean mass, vastus lateralis thickness and pennation angle, and peak torque, but EMG amplitude was unaffected. These findings demonstrated rapid muscular adaptations in response to only eight sessions of back squat and deadlift training in women despite the absence of changes in agonist–antagonist EMG amplitude.

The influence of high-intensity compared with moderate-intensity exercise training on cardiorespiratory fitness and body composition in colorectal cancer survivors: a randomised controlled trial.

Following colorectal cancer diagnosis and anti-cancer therapy, declines in cardiorespiratory fitness and body composition lead to significant increases in morbidity and mortality. There is increasing interest within the field of exercise oncology surrounding potential strategies to remediate these adverse outcomes. This study compared 4weeks of moderate-intensity exercise (MIE) and high-intensity exercise (HIE) training on peak oxygen consumption (V̇O2peak) and body composition in colorectal cancer survivors. Forty seven post-treatment colorectal cancer survivors (HIE = 27months post-treatment; MIE = 38months post-treatment) were randomised to either HIE [85-95% peak heart rate (HRpeak)] or MIE (70% HRpeak) in equivalence with current physical activity guidelines and completed 12 training sessions over 4weeks. HIE was superior to MIE in improving absolute (p = 0.016) and relative (p = 0.021) V̇O2peak. Absolute (+0.28 L.min(-1), p < 0.001) and relative (+3.5 ml.kg(-1).min(-1), p < 0.001) V̇O2 peak were increased in the HIE group but not the MIE group following training. HIE led to significant increases in lean mass (+0.72kg, p = 0.002) and decreases in fat mass (-0.74kg, p < 0.001) and fat percentage (-1.0%, p < 0.001), whereas no changes were observed for the MIE group. There were no severe adverse events. In response to short-term training, HIE is a safe, feasible and efficacious intervention that offers clinically meaningful improvements in cardiorespiratory fitness and body composition for colorectal cancer survivors. HIE appears to offer superior improvements in cardiorespiratory fitness and body composition in comparison to current physical activity recommendations for colorectal cancer survivors and therefore may be an effective clinical utility following treatment.

Reduced fat mass and increased lean mass in response to 1 year of melatonin treatment in postmenopausal women: A randomized placebo-controlled trial.

Apart from regulating the circadian rhythm, melatonin exerts a variety of actions in the living organism. Among these functions, melatonin is believed to have a positive effect on body weight and energy metabolism. So far, the evidence for this relies mainly on animal models. In this study, we aimed to determine the effects of melatonin on body composition, lipid and glucose metabolism in humans. In a double-blind, placebo-controlled study, we randomized 81 postmenopausal women to 1 year of treatment with melatonin (1 or 3 mg nightly) or placebo. Body composition was measured by DXA. Measures were obtained at baseline and after 1 year of treatment along with leptin, adiponectin and insulin. Markers of glucose homeostasis were measured at the end of the study. In response to treatment, fat mass decreased in the melatonin group by 6·9% (95% CI: 1·4%; 12·4%, P = 0·02) compared to placebo. A borderline significant increase in lean mass of 5·2% was found in the melatonin group compared to placebo (3·3%, (IQR:-1·7; 6·2) vs -1·9%, (IQR: -5·7; 5·8), P = 0·08). After adjusting for BMI, lean mass increased by 2·6% (95% CI: 0·1; 5·0, P = 0·04) in the melatonin group. Changes in body weight and BMI did not differ between groups. Adiponectin increased borderline significantly by 21% in the melatonin group compared to placebo (P = 0·08). No significant changes were observed for leptin, insulin or markers of glucose homeostasis. Our results suggest a possibly beneficial effect of melatonin on body composition and lipid metabolism as 1 year of treatment reduces fat mass, increases lean mass and is associated with a trend towards an increase in adiponectin.

Workplace exercise and educational program for improving fitness outcomes related to health in workers: a randomized controlled trial.

To investigate the effects of a workplace fitness and education program intervention on physical fitness of workers. Employees from a chemical plant (n = 60) participated in a 4-month longitudinal study. They were randomly distributed in control and experimental groups. The experimental group had 4 months of exercise training in 15-minute sessions. The following evaluations were performed before and after the training period: body composition, localized muscle strength, and flexibility. The experimental group showed a significant decrease in body fat (24.7%) and a significant increase in lean mass (6.1%), flexibility (17.9%), sit-up test performance (39.8%), and push-up test performance (29.8%) after the workplace fitness and education program compared with initial values. A structured program of physical exercise was effective in improving body composition, abdominal strength, upper limb strength, and flexibility in workers.

Effects of high-resistance circuit training in an elderly population

The aim of this study was to determine the efficacy of a program of high-resistance circuit (HRC) training, and to compare the effects of HRC to traditional heavy strength (TS) training on strength, muscle size, body composition and measures of cardiovascular fitness in a healthy elderly population. Thirty-seven healthy men and women (61.6±5.3years) were randomly assigned to HRC (n=16), TS (n=14), or a control group (CG, n=7). Training consisted of weight lifting twice a week for 12weeks. Before and after the training, isokinetic peak torque in the upper and lower body, and body composition (dual X-ray absorptiometry) were determined. In addition, cardiovascular parameters were evaluated during an incremental treadmill test. Both HRC and TS groups showed significant increases in isokinetic strength (p<0.001), and the increase was significantly greater in the experimental groups than in CG (p<0.03). There were significant increases in lean mass (HRC, p<0.001; TS, p=0.025) and bone mineral density (HRC, p=0.025; TS, p=0.018) in the experimental groups. Only HRC showed a significant decrease in fat mass (p=0.011); this decrease was significantly greater in HRC than in CG (p=0.039). There were significant improvements in walking economy in the HRC group (p<0.049), although there were no statistical differences between groups. There were no changes in any variables in CG. Hence, HRC training was as effective as TS for improving isokinetic strength, bone mineral density and lean mass. Only HRC training elicited adaptations in the cardiovascular system and a decrease in fat mass.

Weight and Body-Composition Change during the College Freshman Year in Male General-Population Students and Army Reserve Officer Training Corps (ROTC) Cadets

To examine relationships between changes in body weight, body composition, and fitness level in male students of the general population and those in the Army Reserve Officer Training Corps (ROTC) program during the freshman year of college. Thirty-seven (18.4 ± 0.7 yr) healthy, nonsmoking, first-semester-resident male students were divided into 3 groups: low active (LA), high active (HA), and ROTC. Baseline (beginning of freshman year) and 6-month follow-up measurements included anthropometry, body composition (by DXA), 3-day food records, and physical activity (PA) assessment. Weight and body-mass index did not change significantly within or among groups. HA participants compared with LA and ROTC had a significant decrease in body fat (-1.6% ± 2.5% vs. 1.9% ± 1.2% and 0.8% ± 2.2%, respectively). They also had a significant increase in lean mass compared with LA and ROTC (1.8 ± 1.1 kg vs. -0.2 ± 2.0 kg and 0.2 ± 1.7 kg, respectively). All p values were <.05. ROTC and LA participants were similar in all measures of body composition and PA and had significantly lower PA levels than the HA group. No significant relationships were observed between dietary variables and body-composition changes. These results suggest that higher PA was the most powerful determinant in achieving favorable body-composition outcomes. In addition, current physical training conducted by ROTC at Florida State University (which seems to be a practice nationwide) might not be sufficient to offset gains in body fat.

Evaluation of Systemic Follistatin as an Adjuvant to Stimulate Muscle Repair and Improve Motor Function in Pompe Mice

Due to the lack of acid alpha-glucosidase (GAA) activity, Pompe mice develop glycogen storage pathology and progressive skeletal muscle dysfunction with age. Applying either gene or enzyme therapy to reconstitute GAA levels in older, symptomatic Pompe mice effectively reduces glycogen storage in skeletal muscle but provides only modest improvements in motor function. As strategies to stimulate muscle hypertrophy, such as by myostatin inhibition, have been shown to improve muscle pathology and strength in mouse models of muscular dystrophy, we sought to determine whether these benefits might be similarly realized in Pompe mice. Administration of a recombinant adeno-associated virus serotype 8 vector encoding follistatin, an inhibitor of myostatin, increased muscle mass and strength but only in Pompe mice that were treated before 10 months of age. Younger Pompe mice showed significant muscle fiber hypertrophy in response to treatment with follistatin, but maximal gains in muscle strength were achieved only when concomitant GAA administration reduced glycogen storage in the affected muscles. Despite increased grip strength, follistatin treatment failed to improve rotarod performance. These findings highlight the importance of treating Pompe skeletal muscle before pathology becomes irreversible, and suggest that adjunctive therapies may not be effective without first clearing skeletal muscle glycogen storage with GAA.

Effects of Intramuscular Testosterone Undecanoate on Body Composition and Bone Mineral Density in Female-to-Male Transsexuals

The most common treatment regimen in female-to-male transsexuals is administration of short-acting testosterone esters intramuscularly every 2 weeks. The aim of this study was to evaluate the effect of long-acting intramuscular testosterone undecanoate on body composition and bone mineral density during cross-sex hormone therapy in female-to-male transsexuals. Forty-five female-to-male transsexuals (FtMs) were treated with injections of testosterone undecanoate 1,000 mg intramuscularly every 12 weeks over 24 months. Body composition, bone mineral density, hormone parameters, and lipids were compared after 12 months and after 24 months with baseline values. Sonographic findings in the ovaries and endometrium, clinical and adverse effects during the study period were recorded. There was a significant increase in lean mass in the FtMs during the study period in comparison with baseline values, whereas no change in BMI, fat mass, and bone mineral density was observed. There was a significant decline in gonadotropins, estradiol, dehydroepiandrosterone sulphate, sex hormone-binding globulin, and high-density lipoprotein, while testosterone and triglyceride levels increased significantly after 12 and 24 months. Ovaries remained unchanged and no noticeable endometrial pathology was observed. No mortality or morbidity was observed during the study period. We observed a cessation of menstrual bleeding, an increase in clitoral growth, libido, body and beard hair growth, deepened voices and decline in breast size. There was a significant increase in hemoglobin, hematocrit, glutamic-pyruvic transaminase, gamma-glutamyl transferase, and an increase in systolic blood pressure during the study period. There was an increase in lean mass during the study period in FtMs treated with testosterone undecanoate. Transsexual patients should be monitored for adverse effects on lipid profiles, blood pressure, and erythrocytosis during intramuscular testosterone undecanoate therapy.

Effects of Supplemental Fish Oil on Resting Metabolic Rate and Body Composition in Middle-Aged Adults

Several studies have shown that rodents accumulate less body fat when fed a diet rich in fish oil (FO) when compared to an iso-energetic diet rich in other types of fat. However, little is known about the effects of dietary FO on body composition and resting metabolic rate (RMR) in humans. PURPOSE: To determine the effects of supplemental FO on RMR and body composition in middle-aged adults. METHODS: A total of 24 middle-aged men and women (45+6y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4g/d of Safflower Oil (SO); or 4g/d of FO supplying 1,600mg/d eicosapentaenoic acid (EPA) and 800mg/d docosahexaenoic acid (DHA). All tests were repeated following 6wk of treatment. Data were analyzed using a group X time repeated measures ANOVA. RESULTS: Compared to the SO group, there was a significant increase in lean mass following treatment with FO (FO= +0.48 + 0.5kg, SO= -0.05 + 0.6kg, p=0.03) and a significant reduction in fat mass (FO= -0.36 + 1.14kg, SO= +0.50 + 0.77kg, p=0.04) and body fat percentage (FO= -0.41 + 1.22% body fat, SO= +0.53 + 0.98% body fat, p=0.05). No significant differences were observed for body mass (FO= +0.11 + 0.83kg, SO= +0.46 + 0.75kg, p>0.05), RMR (FO= +17 + 260kcal, SO= -62 + 184kcal, p>0.05) or respiratory exchange ratio (FO= -0.02 + 0.09, SO= +0.02 + 0.05, p>0.05). CONCLUSION: 6wk of supplementation with FO in middle-aged adults significantly increased lean mass, and decreased fat mass and body fat percentage. However, there were no changes observed for RMR following FO supplementation. Supported by a Gettysburg College Research and Professional Development Grant and Genuine Health Corporation

Testosterone and growth hormone normalization: a retrospective study of health outcomes

Age-related declines in testosterone and growth hormone (GH) are associated with increased adiposity and decreases in lean mass and bone mineral density (BMD). A long-term retrospective study examined the effects of testosterone and/or GH supplementation on body composition and quality of life (QoL). A database survey assessed the records of 91 men and 97 women (ages 25-82) in treatment groups based on their hormonal status: dehydroepiandrosterone but no hormonal supplementation (control); testosterone only (Tes); GH only (GH); and testosterone plus GH (Tes+GH). Pre-and post-treatment assessments recorded changes in fat and lean mass, BMD, and QoL. After an average of 3 years of treatment, weight decreased in women in the control and Tes+GH groups but remained stable in men in all groups. Tes and Tes+GH produced statistically significant increases in lean mass, reductions in fat mass, and improvements in BMD in both sexes; GH produced similar changes in women. QoL and mood improved in all groups. Treatments were generally safe and well tolerated. In this retrospective survey, treatment with testosterone and/or GH was associated with favorable effects in men and women across a wide age range.

Protein Intake for Skeletal Muscle Hypertrophy with Resistance Training in Seniors

Variability in protein consumption may influence muscle mass changes induced by resistance exercise training (RET). We sought to administer a post-exercise protein supplement and determine if daily protein intake variability affected variability in muscle mass gains. Men (N=22) and women (N=30) ranging in age from 60 to 69 y participated in a 12-wk RET program. At each RET session, participants consumed a post-exercise drink (0.4 g/kg lean mass protein). RET resulted in significant increases in lean mass (1.1 +/- 1.5 kg), similar between sexes (P > 0.05). Variability in mean daily protein intake was not associated with change in lean mass (r < 0.10, P > 0.05). The group with the highest protein intake (1.35 g x kg(-1) x d(-1), n=8) had similar (P > 0.05) changes in lean mass as the group with the lowest daily protein intake (0.72 g x kg(-1) x d(-1), n=9). These data suggest that variability in total daily protein intake does not affect variability in lean mass gains with RET in the context of post-exercise protein supplementation.

Safety and Efficacy of Weight Training in Recent Breast Cancer Survivors to Alter Body Composition, Insulin, and Insulin-Like Growth Factor Axis Proteins

This randomized controlled trial assessed the safety and effects of twice-weekly weight training among recent breast cancer survivors. Outcomes included body size and biomarkers hypothesized to link exercise and breast cancer risk. A convenience sample of 85 recent survivors was randomized into immediate and delayed treatment groups. The immediate group trained from months 0 to 12; the delayed treatment group served as a no exercise parallel comparison group from months 0 to 6 and trained from months 7 to 12. Measures at baseline, 6 and 12 months included body weight, height, body fat, lean mass, body fat %, and waist circumference, as well as fasting glucose, insulin, insulin resistance, insulin-like growth factor-I (IGF-I), IGF-II, and IGF-binding protein-1, IGFBP-2, and IGFBP-3. Injury reporting was standardized. The intervention resulted in significant increases in lean mass (0.88 versus 0.02 kg, P < 0.01), as well as significant decreases in body fat % (-1.15% versus 0.23%, P = 0.03) and IGF-II (-6.23 versus 28.28 ng/mL, P = 0.02) comparing immediate with delayed treatment from baseline to 6 months. Within-person changes experienced by delayed treatment group participants during training versus no training were similar. Only one participant experienced a study related injury that prevented continued participation. Twice-weekly weight training is a safe exercise program for recent breast cancer survivors that may result in increased muscle mass, as well as decreased body fat % and IGF-II. The implications of these results on cancer recurrence or survival may become more evident with longer exercise intervention trials among breast cancer survivors.

EFFECTS OF STRENGTH TRAINING ON BODY COMPOSITION, FASTING INSULIN, AND INSULIN-LIKE GROWTH FACTOR-I

Physically active individuals may have decreased risk for cancers of hormonally related etiology, such as breast and colon. Exercise may decrease incidence of these cancers by lowering total and/or bioavailable serum insulin-like growth factor one (IGF-I). IGF-I and its binding proteins (IGFBPs) have been associated with increased risk for breast and colon cancers. PURPOSE: To investigate exercise-induced changes in: IGF-I and IGF-I/IGFBP-3 (as surrogate for bioavailable IGF-I). We compared changes of these variables in women who were lean (n = 28) to those who were overweight (n = 27) at baseline (DEXA assessed body fat %: lean < 39% < overweight). METHODS: 55 healthy women, 30–50 years old, completed this randomized controlled trial, which involved 15 weeks of supervised progressive strength training (2/week, 27 sets/session, 8 to 10 rep. max.), and 24 additional weeks unsupervised. Subjects refrained from change in diet and other activity regardless of group assignment. Measurements were taken at baseline, 15 and 39 weeks. RESULTS: See table 1. By 15 weeks, the overweight subjects also had significant increases in lean mass, no change in fat mass, and significant decreases of fasting insulin. By 39 weeks, levels of IGF-I and IGF-I/IGFBP-3 rose to match controls in overweight subjects, despite further improvements in lean mass and fasting insulin as well as significant fat mass losses. In lean subjects, IGF-I and IGF-I/IGFBP-3 returned to baseline levels by 39 weeks.Table 1: Change at 15 weeks, *p < 0.03 compared to control groupCONCLUSION: 15 weeks of supervised strength training produced significant improvements IGF-I and IGF-I/IGFBP-3 in overweight women, concurrent with improvements in lean mass and fasting insulin. The IGF-I changes were not maintained an additional 24 weeks. Supported by: MNOC, NIH grant 1 P30-DK50456 and UMN GCRC, NIH grant # M01-RR00400

Precocious puberty and body composition: effects of GnRH analog treatment.

Body composition changes with age and sex differences become significant only after puberty. Boys and girls before the age of 8 yr do not differ in fat, lean or bone mineral mass. Hormonal influences during pubertal development determine the physiological adult male and female body composition phenotype. The aim of our study was to evaluate body composition changes due to central precocious puberty (PP) and the specific effects of therapy on these modifications. Sixteen patients (14 girls, 2 boys) were included in the study. They were diagnosed as affected by idiopathic PP according to standard hormonal and clinical criteria; anatomic alterations of hypothalamus-hypophysis region were excluded by MRI. Mean age at diagnosis was 5.9 +/- 1.9 yr. All patients received GnRH analog (Leuprolide or Triptorelin) treatment subcutaneously every 4 weeks for at least 1 yr. Mean period of treatment was 3.4 +/- 1.9 yr. Standard anthropometry and body composition analysis were performed at baseline and every 6-12 months. A group of healthy subjects with normal timing of puberty was matched (for age or for pubertal stage) served as the control group (CA or CP, respectively). Patients with PP showed at baseline a significant increase of BMI and relative body weight; lean and fat compartments were also increased but not significantly. During treatment, the PP group showed increased fat mass compared to CA (p<0.05), while no difference was found between PP and CP. Lean mass was similar to CA but lower than in CP (p<0.05). During treatment a significant increase in lean mass (both as total as well as limb mass) was observed. After stopping treatment there was no difference between PP and CP, except for lower lean mass (p<0.04). When puberty occurs precociously, lean and fat mass are not significantly different from age-matched control subjects. Data collected during treatment confirm a shortening of prepubertal lean mass development and the block of further lean mass development due to puberty itself, while fat mass accumulation continues. The net result of these modifications determines a typical body composition pattern in PP patients, after the end of therapy: lean mass is reduced by a shortening of the prepubertal growing period and by the "menopausal effect" of treatment itself. Fat mass is increased as a consequence of therapy and could lead to future obesity.