Increase In Lean Tissue Mass Research Articles

Living-donor transplantation leads to a major improvement in physical functioning: an observational study on the impact on potential donors and their recipients

BackgroundProspective studies combining physical functioning (PF), physical activity (PA), and body composition (BC) after living donor transplantation/donation are scarce. We aimed to study differences in these parameters between kidney transplant recipients and their living donors by examining changes in these parameters in the first post-operative year in both groups.MethodsTwenty-two kidney transplant recipients and 22 healthy kidney donors were included in this prospective longitudinal study with a follow-up until twelve months. PF was assessed by handgrip strength (HGS), and by the physical domains of health-related quality of life (HRQOL) using the Short Form-36 questionnaire [PF (SF-36 PF) and physical component summary (PCS) score]. BC was measured by the Body Composition Monitor©, and PA was measured by the SenseWear™ pro3.ResultsAt baseline, recipients had significantly lower HGS (after adjustment for sex and body weight), SF-36 PF, PCS, and PA, as compared with their donors. In recipients HGS significantly increased in the first year after transplantation, but PA did not change in the first six months after transplantation. Furthermore, no significant increase in lean tissue mass was observed. For healthy donors no significant changes in these parameters were observed, with exception of SF-36 PF, which declined in the first three months after donation, but equaled baseline values after twelve months.ConclusionRecipients showed impressive improvements in PF and the physical domains of HRQOL in the first year after transplantation, reaching levels of healthy kidney donors already three to six months after transplantation. On the contrary, living kidney donation did not show any deterioration of the investigated parameters, supporting little impact for well-screened donors, while there is high benefit for transplant recipients.

Alaska Mountain Wilderness Ski Classic: Alterations in Caloric Expenditure and Body Composition

The Alaska Mountain Wilderness Ski Classic is a self-supported ultramarathon cross-country skiing event that traverses one of the mountain ranges of Alaska each winter. Unique aspects of this event challenge athletes with a significant amount of physical and mental stress while in the chronically cold conditions of the Arctic. Assessment of energy requirements or body composition has never been performed during this event. The objective of the study was to evaluate the influence of the 2016 Alaska Mountain Wilderness Ski Classic on caloric expenditure and body composition. Caloric expenditure was estimated using GT3x+ Actigraph accelerometers and ActiLife software. Lean tissue mass, total fat mass, visceral fat mass, and bone mineral density were measured using a General Electric iDXA before and after the event. Data are presented as mean±SD. Differences were analyzed using paired t tests with significance at P<0.05. Fifteen participants (age=32.7±6.6 years, body mass index=23.7±2.3 kg·m2) completed the study, 8 males and 7 females. Caloric expenditure was 6238±1390 kcal·day-1, and 37,163±8425 kcal for the entire event. Fat mass was reduced from pre-event (∆1.3±0.7 kg, P=0.00003). There was an increase in lean tissue mass (∆1.7±1.3 kg, P=0.0003) and relative skeletal muscle index (∆0.2±0.2 kg·m², P=0.001). There was no change in bone mineral density (∆0±0 g·cm3, P=0.4). Despite the metabolic demands, fat mass was reduced and lean tissue mass was preserved. Future studies of this event should be directed toward assessment of the nutritional provisions utilized and the mechanisms responsible for the preservation of lean tissue mass.

Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis.

The loss of muscle mass and strength with aging results in significant functional impairment. Creatine supplementation has been used in combination with resistance training as a strategy for increasing lean tissue mass and muscle strength in older adults, but results across studies are equivocal. We conducted a systematic review and meta-analysis of randomized controlled trials of creatine supplementation during resistance training in older adults with lean tissue mass, chest press strength, and leg press strength as outcomes by searching PubMed and SPORTDiscus databases. Twenty-two studies were included in our meta-analysis with 721 participants (both men and women; with a mean age of 57–70 years across studies) randomized to creatine supplementation or placebo during resistance training 2–3 days/week for 7–52 weeks. Creatine supplementation resulted in greater increases in lean tissue mass (mean difference =1.37 kg [95% CI =0.97–1.76]; p<0.00001), chest press strength (standardized mean difference [SMD] =0.35 [0.16–0.53]; p=0.0002), and leg press strength (SMD =0.24 [0.05–0.43]; p=0.01). A number of mechanisms exist by which creatine may increase lean tissue mass and muscular strength. These are included in a narrative review in the discussion section of this article. In summary, creatine supplementation increases lean tissue mass and upper and lower body muscular strength during resistance training of older adults, but potential mechanisms by which creatine exerts these positive effects have yet to be evaluated extensively.

Body composition changes in an endurance athlete using two different training strategies.

Swimming, running and cycling are among the most popular and fastest growing sports in the world. Inherent in these sports is a desire to favorably alter body composition. Here we report a ~5.4 kg and ~5.3 kg fat tissue mass (FTM) loss in two separate interventions (12-16 weeks), in the same athlete, separated by 5 years. Whole body composition was assessed using dual X-ray absorptiometry (DXA). Dietary analysis for intervention 2 was completed using Mc Cance and Widdowson's composition of foods. In 2010, the male athlete (23 years, weight 85 kg, height 195 cm, 18.1% body fat) had a reduction of ~5.4 kg of FTM (15.4 vs. 10.0 kg) and an increase of ~5.1 kg of lean tissue mass (LTM) following 16 weeks of moderate intensity running (213±53 min/week) and circuit training (64±46 min/week). In 2015, the same athlete (28 years, 90.6 kg, 195 cm; 18.2%) had a ~5.3 kg loss of FTM and a ~0.8 kg increase in LTM after 12 weeks, predominately (75%) non-weight bearing exercise (49% cycling, 215±88 min/week; 25% running 110±47 min/week; 19% swimming, 83±27 min/week; 7% rowing machine, 29±26 min/week). Weekday and weekend dietary intake during intervention 2 were estimated as 2560 kcal and 3240 kcal per day, respectively. This report provides support for the hypothesis that an extended period of energy deficit is required to reduce body fat levels in amateur athletes independent of the mode of exercise.

The Effect of Creatine Supplementation on Body Composition and Bone Health in the Elderly

Introduction: Ageing is associated with body composition changes, including decreases in muscle mass and bone content and increases in fat mass. Creatine supplementation is associated with increases in lean Tissue mass in athletes, leading to increased strength and power. There has been recent interest in if creatine supplementation may have similar effects in older individuals, to offset the changes seen in body composition and increase quality of life. Aims: This review assesses the current literature on whether creatine supplementation in the presence or absence of resistance training improves body composition and bone health in older adults. Results: In terms of resistance training and creatine supplementation in Combination, there is evidence for increased lean body mass following long-term investigations, above that of resistance training with placebo. Studies without resistance training mostly use acute strategies of creatine supplementation and have produced conflicting reports on lean body mass. Body fat percentage does not seem to be altered by either resistance training or creatine supplementation. The literature on creatine supplementation’s effect on bone health is also inconclusive, with some reports showing significant increases in bone mineral density, whereas several others show no effect. Conclusions: Creatine supplementation in the elderly may lead to increased lean body mass, and increased bone strength; however these results are far from conclusive. Dosing and timing supplementation protocols between studies may be responsible for the different results and future studies should concentrate on determining if acute or chronic creatine supplementation has a more beneficial effect on body composition in the elderly.

Effects Of High Velocity Resistance Training On Body Composition Of Older Adults

Previous studies have shown resistance training programs to reduce total body fat mass. PURPOSE: The purpose of this pilot study was to evaluate the effects of a high-velocity resistance-training program at two different intensities on body composition of older adults. METHODS: The participants of this 14-week pilot study consisted of eight adults over the age of 65. The researchers measured lean tissue mass, fat mass, and total body mass using dual-energy x-ray absorptiometry (DXA) before and after the 14-week training period. Participants were randomly separated into two groups: 30% and 60% of 1 repetition maximum (RM). The training protocol consisted of exercising two days per week, completing eight exercises for three sets of eight repetitions at high velocities. The subjects were instructed to lift the weight as quickly as possible then lower it over 2-3 seconds. A two-way repeated measures ANOVA was then used to analyze the results. RESULTS: A significant group-by-time interaction was observed for lean tissue mass (p=0.05). The increase in lean tissue mass in the 30% 1RM group approached significance (p=0.06) while a non-significant decrease in lean tissue mass was observed in the 60% 1RM group (p=0.24). No significant changes were observed in fat mass (p=0.43) or total mass (p=0.10). CONCLUSION: Researchers concluded that a 14-week community based high-velocity resistance-training program using 30% of 1RM is sufficient enough to produce significant changes in lean tissue. Future studies should use a larger sample size as well as utilize a broader range of intensities to observe changes in body composition.

Effects Of High-velocity Resistance Training On Lean-tissue Mass And Myostatin Among Community-dwelling Older Adults

Among older adults, mobility disability is prominent, affecting 20% of community-dwelling adults over 70 years. This number is expected to rise over the next 35 years as the number of older adults is expected to more than double in size. Factors affecting mobility disability include muscular strength, muscular power, and lean-tissue mass, which all decrease throughout the lifespan. In addition, myostatin, a potent inhibitor of muscle growth, is inversely correlated with reductions in mobility disability variables. However, exercise is the only known treatment for mobility disability and works by improving muscular strength, power, and lean tissue mass, in addition to decreasing myostatin expression. Yet, the optimal exercise intervention has yet to be determined for this age group. PURPOSE: Therefore, the purpose of this study was to examine serum myostatin, muscular strength, muscular power, and lean-tissue mass changes following a 20-week, high-velocity resistance training (HVRT) intervention among community-dwelling older adults. METHODS: Forty-three older adults (77.2 + 6.2 years) were randomly assigned to high-velocity exercise at 70% of their one repetition maximum (1-RM) or a control group. The control group participated in the same exercises; however, only used their body weight as resistance. All participants exercised two days per week. RESULTS: There were no significant group by time interactions for any variable at baseline or after 20-weeks of HVRT. There was a trend for significant interaction in total muscular strength (p = .056); the HVRT group increased strength by 28.4% and the control group by 18.2%. HVRT significantly increased muscular power (23.2%, p = <.001) in both groups; however, there was no statistically significant increase in lean-tissue mass (+1.2%, p = .21) for either group. Serum myostatin had a statistically insignificant reduction after the intervention (-9.0%, p = .08). CONCLUSIONS: HVRT, with or without an external load, is beneficial for increasing muscular strength and power, and decreasing serum myostatin among older adults. Therefore, HVRT presents as an optimal training modality for minimizing mobility disability with age; however, the intensity of the activity should be studied further.

Lean tissue mass and energy expenditure are retained in hypogonadal men with spinal cord injury after discontinuation of testosterone replacement therapy

ObjectiveTo determine whether favorable changes to lean tissue mass (LTM), resting energy expenditure (REE), and testosterone (T) that occurred with 12 months of physiological testosterone replacement therapy (TRT) were retained 6 months after discontinuing treatment.DesignProspective, open-label, controlled drug intervention trial.SettingMetropolitan area hospitals.SubjectsEugonadal (n = 11) and hypogonadal (n = 13) men with chronic spinal cord injury (SCI).InterventionsHypogonadal subjects received a 5 or 10 mg transdermal T patch daily for 12 months, with adjustment of the dose to normalize the serum T concentration; TRT was discontinued after 12 months (TRT-12M) and subjects were followed for an additional 6 months and re-evaluated (Post-TRT). Total body dual energy X-ray absorptiometry and blood draws were performed at baseline (BL) prior to TRT, TRT-12M, and Post-TRT. Eugonadal subjects did not receive treatment and were evaluated at comparable time points.ResultsThere were no significant differences between groups prior to TRT at BL for any of the study endpoints. In the hypogonadal group, a significant increase in LTM was observed from BL to TRT-12M (50.2 ± 7.4 vs. 52.9 ± 6.8 kg, P < 0.01), which persisted Post-TRT compared to BL (52.2 ± 7.8 kg, P < 0.05). The increase in REE from BL to TRT-12M (1283 ± 246 vs. 1410 ± 250 kcal/day) was also retained at Post-TRT (1393 ± 220 kcal/day). These sustained improvements in LTM and REE after termination of anabolic hormonal therapy may be associated with persistent beneficial effects on health and physical function of hypogonadal men with chronic SCI.

Influence of a two-year steroid treatment on body composition as measured by dual X-ray absorptiometry in boys with Duchenne muscular dystrophy

Steroids are nowadays routinely used as a long-term treatment in Duchenne muscular dystrophy (DMD). Their effects on body composition were assessed using dual X-ray absorptiometry. The study followed over 2years 29 genetically confirmed DMD patients: 21 in the steroid-treated group and 8 in the steroid-naïve group. After 2years of steroid treatment, the lean tissue mass values increased significantly (p<0.0001), the percentage of body fat mass remained practically constant (p=0.94) in comparison with the initial visit. In the steroid-naïve patients, there were no significant increases in the lean tissue mass but deterioration in body composition confirmed by a significant increase in the percentage of body fat mass. Besides, significant negative correlations were found between the percentage of body fat mass and the MFM total score (R=−0.79, n=76, p<0.0001). A 2-year steroid treatment improves significantly body composition of boys with DMD through a significant increase in lean tissue mass. We suggest that a thorough check of body composition should be carried out before steroid treatment discontinuation in case of overweight gain.

Moderate-Intensity Exercise Improves Body Composition and Improves Physiological Markers of Stress in HIV-Infected Men

HIV/AIDS and its treatment often alter body composition and result in poorer physical functioning. The aim of this study was to determine the effects of a moderate-intensity exercise program on body composition and the hormones and cytokines associated with adverse health outcomes. HIV-infected males (N = 111) were randomized to an exercise group (EX) who completed 6 weeks of moderate-intensity exercise training, or to a nonintervention control group (CON). In pre- and postintervention, body composition was estimated via DXA, peak strength was assessed, and resting blood samples were obtained. There was a decrease in salivary cortisol at wake (P = 0.025) in the EX and a trend (P = 0.07) for a decrease 1 hour after waking. The EX had a significant increase in lean tissue mass (LTM) (P < 0.001) following the intervention. Those in the EX below median body fat (20%) increased LTM (P = 0.014) only, while those above 20% decreased fat mass (P = 0.02), total fat (N = 0.009), and trunk fat (P = 0.001), while also increasing LTM (P = 0.027). Peak strength increased between 14% and 28% on all exercises in the EX group. These data indicate that 6 weeks of moderate-intensity exercise training can decrease salivary cortisol levels, improve physical performance, and improve body composition in HIV-infected men.

Individual exercise sessions alter circulating hormones and cytokines in HIV-infected men

Exercise has the potential to impact disease by altering circulating anabolic and catabolic factors. It was the goal of this study to determine how different regimens of low-intensity and moderate-intensity exercise affected circulating levels of these anabolic and catabolic factors in HIV-infected men. Exercise-naive, HIV-infected men, medically cleared for study participation, were randomized into one of the following groups: a moderate-intensity group (MOD, who completed 30 min of moderate-intensity aerobic training followed by 30 min of moderate-intensity resistance training; a low-intensity group (LOW), who completed 60 min of treadmill walking; or a control group (CON), who attended the clinic but participated in no activity. Blood and saliva samples were collected at selected time points before, during, and after each of the 3 required sessions. Compared with baseline, the MOD group (n=14) had a 135% increase in growth hormone (GH) (p<0.05) and a 34% decrease in cortisol (CORT) (p<0.05) at the post time point, a 31% increase in interleukin-6 (IL-6) (p<0.05) at 30-min post exercise, and a 23% increase in IL-6 (p<0.05) and a 13% decrease in soluble tumor necrosis factor receptor 2 (sTNFrII) (p<0.05) at 60-min post exercise. The LOW (n=11) group had a 3.5% decrease in sTNFrII (<0.05) at 30-min post exercise compared with baseline and a 49% decrease (p<0.05) in GH at 60-min post exercise. The CON group (n=13) had a decrease in GH at 30-min (62%, p<0.05) and 60-min (61%, p<0.05) post exercise compared with baseline. The increase in GH from baseline to post was greater in the MOD group (p<0.05) and the decrease in CORT from pre to post was greater in the MOD group (p<0.05) than in the other groups. These data suggest that individual sessions of both low-intensity and moderate-intensity exercise can alter circulating anabolic and catabolic factors in HIV-infected men. The changes in the MOD group present potential mechanisms for the increases in lean tissue mass seen with resistance exercise training.

Effect of a soluble activin receptor type IIB on androgen-deprivation-induced effects on body composition

5133 Background: Androgen deprivation therapy (ADT) is a well-established treatment for hormone sensitive prostate cancer, but is associated with adverse side effects including loss of bone and lean mass and increased adipose mass. Activin receptor type IIB (ActRIIB) signaling is necessary for the negative regulation of lean tissue mass and treatment with a non-signaling, decoy ActRIIB results in a robust increase in lean tissue mass. Methods: Similar to ADT patients, orchiectomized (ORX) mice lose bone and lean mass and gain fat mass. To determine the therapeutic potential of inhibiting ActRIIB signaling to reduce the negative effects associated with ADT, we treated sham-operated (SHAM) and orchiectomized (ORX) mice with RAP-031, a fusion protein comprised of a form of the extracellular domain of ActRIIB linked to a murine Fc. Mice received twice weekly injections for 10 weeks with either vehicle (VEH) or 10 mg/kg RAP-031 (RAP). NMR scanning was used to determine body composition and whole body DEXA scans were performed to determine bone mineral density (BMD). Results: ORX resulted in a 4.4% decrease in BMD, an 18% reduction in lean tissue and a 41.6% increase in adiposity compared to the VEH-SHAM cohort. Both RAP-031treated groups of mice had significantly increased BMD and lean tissue mass and decreased adipose mass compared to their respective VEH groups. However, BMD, lean tissue and adiposity were not significantly different between the VEH-SHAM and RAP-ORX groups. These data illustrate that RAP-031 treatment completely attenuates ORX-induced alterations in bone, lean and fat mass. Conclusions: These data support the hypothesis that treatment with a form of soluble ActRIIB can offset negative side effects of ADT and have significant therapeutic implications for the treatment of patients with prostate cancer. [Table: see text] [Table: see text]

Correlation between bone mineral density and body composition in Japanese females aged 18-40 years with low forearm bone mineral density.

To clarify the relationship between bone mineral density (BMD) and body composition in Japanese women aged 18-40 years with low forearm BMD. The subjects were Japanese 199 women who had been selected for inclusion in the study based on a low forearm BMD determined at the Annual Women's Health Examination. The subjects' mean (+/- standard deviation) age, body height, body weight, and body mass index (BMI) were 33.5 (+/-4.3) years, 158.1 (+/-5.1) cm, 49.6 (+/-5.7) kg, and 19.8 (+/-2.1), respectively. The BMD of the lumbar spine, total body, and left arm were measured using dual-energy X-ray absorptiometry (DXA). Fat mass (FM), bone-free lean tissue mass (LTM), and body fat percentage (BF%) were measured simultaneously with DXA. In the structural equation model, the standardized regression weights for the path from BMI to BMD of all sites were 0.273-0.434. Conversely, the BF% to BMD of the total body and left arm were -0.192 and -0.296, respectively. In multiple regression analysis, the FM index (FMI) was significantly associated with the BMD of the lumbar spine as a weight-bearing site. The LTM index (LTMI) was significantly associated with the BMD of the total body and left arm as a non-weight-bearing site. Young females with low forearm BMD had low body weight and BMI. Thinness was shown to be a risk factor for low BMD, in accordance with results reported elsewhere. A gain in body weight may have the effect of increasing BMD, but our results suggest that to increase BMD, the gain in body weight must include increases in LTM, and not FM alone.

Effect of estrogenic compounds (estrogen or phytoestrogens) combined with exercise on bone and muscle mass in older individuals

Exercise has a beneficial effect on bone, possibly by stimulating estrogen receptor alpha. Because estrogen up-regulates this receptor, estrogen therapy combined with exercise training may be optimal for increasing bone mineral density. Studies combining estrogen therapy and exercise training in postmenopausal women show mixed results, but indicate that the combination of interventions may be more effective for increasing bone mass than either intervention alone. Plant-like estrogens (i.e phytoestrogens such as soy isoflavones) may act as weak estrogen agonists or antagonists, have small beneficial effects on bone, and may interact with exercise for increasing bone mineral density. Phytoestrogen derived from flaxseed (flax lignans) has not been evaluated as extensively as soy isoflavones and thus its effect on bone is difficult to determine. Estrogen or soy isoflavones given to postmenopausal women results in a small increase in lean tissue mass that may be mediated through estrogen receptor alpha on muscle or through decreased inflammation.

Discovery of novel orally active ureido NPY Y5 receptor antagonists

We have derived a novel series of neuropeptide Y (NPY) Y5 receptor antagonists from the biphenylurea 3. Cyclohexylurea 21c, a member of the series, is a potent NPY Y5 receptor antagonist that exhibits excellent pharmacokinetic parameters in rats and dogs. On chronic oral administration to diet-induced obese rats, 21c displayed an anti-obesity profile, causing a modest reduction in food intake, a significant decrease in body weight gain, a decrease in adipose mass, and an increase in lean tissue mass.

Effect of in-season creatine supplementation on body composition and performance in rugby union football players

Rugby union football requires muscular strength and endurance, as well as aerobic endurance. Creatine supplementation may enhance muscular performance, but it is unclear if it would interfere with aerobic endurance during running because of increased body mass. The purpose of this study was to determine if creatine supplementation during 8 weeks of a season of rugby union football can increase muscular performance, without negatively affecting aerobic endurance. Rugby union football players were randomized to receive 0.1 g.kg(-1).d(-1) creatine monohydrate (n=9) or placebo (n=9) during 8 weeks of the rugby season. Players practiced twice per week for approximately 2 h per session and played one 80 min game per week. Before and after the 8 weeks, players were measured for body composition (air displacement plethysmography), muscular endurance (number of repetitions at 75% of one repetition maximum (1 RM) for bench press and leg press), and aerobic endurance (Leger shuttle-run test with 1 min stages of progressively increasing speed). There were time main effects for body mass (-0.7+/-0.4 kg; p=0.05), fat mass (-1.9+/-0.8 kg; p<0.05), and a trend for an increase in lean tissue mass (+1.2+/-0.5 kg; p=0.07), with no differences between groups. The group receiving creatine supplementation had a greater increase in the number of repetitions for combined bench press and leg press tests compared with the placebo group (+5.8+/-1.4 vs. +0.9+/-2.0 repetitions; p<0.05). There were no changes in either group for aerobic endurance. Creatine supplementation during a rugby union football season is effective for increasing muscular endurance, but has no effect on body composition or aerobic endurance.

Moderate-Intensity Exercise Alters Circulating Hormones and Cytokines in HIV-Infected Men

PURPOSE: Persons infected with HIV suffer from numerous physiological and psychological alterations that often include changes in circulating levels of various anabolic and catabolic factors. These alterations can result in decreased lean tissue mass (LTM), redistributed fat mass, and declines in physical performance. Exercise training has been shown to beneficially alter these variables in other populations, thus the goal for this study was to examine how mo derate-intensity exercise training alters these factors in HIV-infected men. METHODS: HIV-infected individuals were randomized to an exercise group (EX) who completed 6 weeks (twice per week) of moderate-intensity resistance and aerobic exercise training, or to a control group (CON) that received only the standard of care. Resting blood and saliva samples were collected prior to and following the intervention, and samples were collected before, during, and following the individual exercise or control sessions. RESULTS: Those in the MOD group showed an increase in GH immediately post exercise (P=.014), an increase in IL-6 30 minutes (P=.015) and 60 minutes (P=.016) post exercise, a decrease in cortisol immediately post exercise (P=.026) and a decrease in sTNFrII 60 minutes (P=.029) post exercise. The CON group had a decrease in GH compared to pre at post 30 (P<.001) and post 60 (P<.001). There was a decrease in salivary cortisol at wake (P=.025) in the EX group, and a trend (P=.07) for a decrease 1 hour after waking. There were no other changes detected. CONCLUSIONS: These data suggest that exercise training can transiently decrease the catabolic factor cortisol, while individual sessions of moderate-intensity exercise can beneficially affect multiple circulating anabolic and catabolic factors in HIV-infected men, thereby presenting potential mechanisms for the increase in lean tissue mass that is seen with exercise training in this population. This work was Supported by the A CSM and the NIH.

The effect of unilateral and bilateral strength training on the bilateral deficit and lean tissue mass in post-menopausal women

Some have observed maximal strength of simultaneous bilateral homologous limb contraction is less than the sum of strengths of right and left limbs contracting alone; a phenomenon referred to as the bilateral deficit (BLD). There is controversy on whether there is a BLD for all exercises. We assessed whether a BLD occurs across different exercises (leg press, knee extension, and lat pull-down), whether the BLD could be altered with unilateral or bilateral training, and whether unilateral versus bilateral training was more beneficial for increasing lean tissue mass (LTM). Post-menopausal women (approximately 57 years) were randomized to bilateral (n=14) and unilateral (n=12) training, or non-training control (n=24) groups. Bilateral training involved seven exercises performed with bilateral contractions (two sets, 3 days week-1, 26 weeks). Unilateral training involved the same exercises performed with one limb at a time. A BLD was found for leg press and lat pull-down, but not for knee extension. Bilateral training decreased the BLD; whereas unilateral training had minimal effect on the BLD. The unilateral-training group had a greater increase in lower-body LTM compared to the control group (P<0.05); however, there were no differences between unilateral and bilateral training groups. Both training groups had greater increases in LTM of the upper- and whole-body compared to the control group. We conclude that the BLD is apparent for some exercises (i.e., the leg press and lat pull-down) but not others (i.e., knee extension). Bilateral training reduces the BLD; whereas unilateral training has minimal effect on the BLD.

The Effects of Conjugated Linoleic Acid Supplementation during Resistance Training

We determined the effects of conjugated linoleic acid (CLA) supplementation during resistance training. Seventy-six subjects were randomized to receive CLA (5 g.d(-1)) or placebo (PLA) for 7 wk while resistance training 3 d.wk(-1). Seventeen subjects crossed over to the opposite group for an additional 7 wk. Measurements at baseline, 7 wk, and 14 wk (for subjects in the crossover study) included body composition, muscle thickness of the elbow flexors and knee extensors, resting metabolic rate (RMR), bench and leg press strength, knee extension torque, and urinary markers of myofibrillar degradation (3-methylhistidine (3MH) and bone resorption (cross-linked N-telopeptides (Ntx)). After 7 wk the CLA group had greater increases in lean tissue mass (LTM) (+1.4 vs +0.2 kg; P < 0.05), greater losses of fat mass (-0.8 vs +0.4 kg; P < 0.05), and a smaller increase in 3MH (-0.1 vs + 1.3 micromol.kg LTM.d(-1); P < 0.05) compared with PLA. Changes between groups were similar for all other measurements, except for a greater increase in bench press strength for males on CLA (P < 0.05). In the crossover study subjects had minimal changes in body composition, but smaller increases in 3MH (-1.2 vs +2.2 micromol.kg LTM.d(-1); P < 0.01) and NTx (-4.8 vs +7.3 nmol.kg(-1) LTM.d(-1); P < 0.01) while on CLA versus PLA. Supplementation with CLA during resistance training results in relatively small changes in body composition accompanied by a lessening of the catabolic effect of training on muscle protein.

Lean Tissue Mass And Fat Mass Changes In HIV-infected Persons Following Moderate Intensity Exercise Training

BACKGROUND HIV-infected persons experience decreases in lean tissue mass (LTM), which are associated with increased morbidity and mortality. Persons infected with HIV also experience lipodystrophy, which is a combination of fat accumulation in the trunk with a loss of fat from the arms, legs, and face. PURPOSE Determine if exercise training, which has increased LTM and decreased fat stores in healthy and clinical populations, is effective in treating both of these body composition conditions. METHODS Thirty-nine HIV-infected individuals, who were medically cleared for study participation, were randomized to an exercise group (EX) who completed 6 weeks of moderate intensity exercise training, or to a control group (CON) that did not receive the exercise intervention. Twice a week, the exercise group completed 30 minutes of moderate intensity aerobic training followed by moderate intensity upper body and lower body resistance training. Each subject before and following the 6-week training period received a DEXA scan for determination of body composition. RESULTS The EX (N=21) had a significant increase in LTM (P=0.006) following the intervention, while the CON (N=18) had no significant changes in body composition. Both groups were then divided into those above 20% body fat (BF) and those below 20% BF prior to the intervention. The EX below 20% BF group had significantly more LTM than the EX above 20% BF group. Analysis of the EX then revealed that those below 20% BF increased lean tissue mass (P=0.03) only, while those above 20% BF decreased weight (P=0.03), fat mass (P=0.03) and total fat % (P=0.05) while showing a trend for decreased trunk fat % (P=0.09). There were no changes observed in the CON. Nutritional status was unchanged during the intervention. CONCLUSIONS These data indicate that 6 weeks of combined moderate intensity aerobic and resistance training in HIV-infected individuals benefits lean persons by increasing lean tissue mass and benefits overweight persons by decreasing total body weight and fat mass while retaining lean tissue mass. Results suggest that combined aerobic and resistance exercise training may have differential effects on HIV-infected persons based on body composition. This work is supported by the NINR/NIH-funded Center for Health Promotion and Risk Reduction in Special Populations and the Arnold School of Public Health.