Significant Changes In Body Composition Research Articles

Energy Balance in Women With Breast During Adjuvant Treatment

Objective To compare weight, body composition, and major determinants of energy balance of women treated with adjuvant chemotherapy (n=8) using Adriamycin and cyclophosphamide (AC), or radiation therapy (n=10). Design The study used a nonrandomized prospective design. Pretreatment and posttreatment measurements, obtained at baseline and 12 weeks, respectively, included weight, body composition (determined using dual-energy x-ray absorptiometry), energy intake (determined using 3-day food records), resting energy expenditure (determined in indirect calorimetry), and physical activity (determined using 3-day physical activity records). Poststudy follow-up weights were obtained for 13 women. Subjects/setting Eighteen premenopausal women with breast cancer in the early stage, recruited from outpatient clinics, participated in and completed the study. Statistical analyses performed Unpaired Student t tests or χ 2 tests were used to test for differences in baseline subject characteristics, and repeated measures analysis of variance was used to compare groups before and after treatment. Results Body weight was unchanged in both treatment groups during the study, although poststudy follow-up weights (n=13) suggested a tendency for weight gain in both groups. Significant changes in body composition for both groups included a mean loss of 0.8 kg total lean body mass (LBM), a mean loss of 0.4 kg LBM in the leg region, and a mean 1.3% increase in percent body fat, from 40.0% to 41.3%. Overall, no between-group differences were observed in any factors associated with energy balance. Applications In this short-term study, AC chemotherapy using fewer antineoplastic agents and number of treatments than most chemotherapy protocols for breast cancer, did not result in weight gain during treatment. Regardless of weight gain, changes in body composition may occur in women with breast cancer during or after treatment. These potential changes have important implications for preventive nutrition counseling. J Am Diet Assoc. 1999;99:1222–1227.

Obesity attenuates the growth hormone response to exercise.

Resting serum GH concentrations are decreased in obesity. In nonobese (NonOb) individuals, acute exercise of sufficient intensity increases GH levels; however, conflicting data exist concerning the GH response to exercise in obese individuals. To examine the exercise-induced GH response in obese individuals, we studied 8 NonOb, 11 lower body obese (LBO), and 12 upper body obese (UBO) women before, during, and after 30 min (0800-0830 h) of treadmill exercise at 70% oxygen consumption peak. Blood samples were taken every 5 min (0700-1300 h) and were analyzed for GH concentrations with a sensitive (0.002 microg/L) chemiluminescence assay. The impact of 16 weeks of aerobic exercise training on the GH response to exercise was also examined in the obese women. In response to exercise, the 6-h integrated GH concentration was significantly greater (P < 0.05) in the NonOb women (1006 +/- 220 min/microg x L) than in either of the obese groups (LBO, 435 +/- 136; UBO, 189 +/- 26 min/microg x L). No differences were found between the LBO and UBO women. The increased integrated GH concentrations could be accounted for by a greater 6-h GH production rate [micrograms per L distribution volume (Lv)] in the NonOb women than in either of the obese groups (NonOb, 45.6 +/- 12.3; LBO, 16.9 +/- 1.2; UBO, 8.7 +/- 0.64 microg/Lv; P < 0.05). This increase was attributed to a greater mass of GH secreted per pulse in the NonOb women (NonOb, 10.8 +/- 2.5; LBO, 4.9 +/- 0.8; UBO, 4.0 +/- 0.5 microg/Lv; P < 0.05, NonOb vs. both obese groups). After 16 weeks of aerobic training, maximal oxygen consumption increased from 44.7 +/- 2.2 to 48.5 +/- 1.9 mL/kg fat-free mass x min; P < 0.05), but no significant change in body composition occurred in the 10 obese women who completed the training. No change was observed in the GH response to exercise after training (n = 10; pre, 379 +/- 144; post, 350 +/- 55 min/microg x L). In conclusion, the GH response to exercise was attenuated in the obese women compared to NonOb women. Short term aerobic training improved fitness, but did not increase the GH response to exercise.

Body Composition Trends in Women Collegiate Track-and-Field Athletes Across Two Consecutive Competitive Seasons

Longitudinal body composition assessment can uncover the trends of body composition change that are indicative of high-performance track-and-field training. This descriptive study was conducted to determine body composition changes in women collegiate track-and-field athletes across 8 months of training and competition in both indoor and outdoor seasons. Body composition was estimated monthly by hydrostatic weighing from the first month of training (September) until the final month (April) for all throwers, jumpers, and sprinters. Thirty-two cases were obtained, which consisted of no less than 7 or more hydrostatic measurements. Repeated-measures analyses of variance of lean body mass (LBM), body density (BD), total body mass (TBM), percent fat (%FAT), and body mass index (BMI) revealed significant time effects for all variables. These results indicate that significant changes in body composition of women collegiate track-and-field athletes occur throughout 8 months of continuous training.

CREATINE SUPPLEMENTATION AND ACUTE DEHYDRATION

1276 Creatine (Cr), a widely used dietary supplement, has been demonstrated to enhance muscular strength and anaerobic power. However, coaches, trainers, professional sports teams, and physicians have raised concerns regarding its safety. There is specific concern with numerous anecdotal reports suggesting that Cr supplementation will compromise an individual's heat tolerance during exercise, subsequently leading to an increase of skeletal muscle cramping and tearing. The purpose of this study was to investigate the effects of oral Cr supplementation and acute dehydration on plasma volume, electrolyte and mineral balance, and anaerobic exercise performance. Using a randomized double-blind design, 15 subjects ingested either 20 g·d1 of Cr monohydrate (CR) (N=8) or a placebo (PL) (N=7) for 5-d and then undertook two consecutive 80-min dehydration protocols resulting in −1.5% (D1) and −3% (D2) decreases in body mass (BM). After 5-d of supplementation, there was a significant increase in BM in both groups (PL: 0.6 ±0.5; CR:1.5 ±0.1 kg), but there was no difference between groups (P = 0.09). There were no significant changes in body composition; plasma volume (PV); serum electrolytes (Na, K, CI), minerals (Mg, Zn, Ca), osmolality; and anaerobic exercise performance measures of maximum power (MP), total work (TW), or fatigue index (FI) as determined from ten, 6-s sprints on a cycle ergometer. As expected, the two 80-min dehydration sessions resulted in a significant ΔPV in both groups at D1 (PL: −10.9±2.0; CR: −9.2±1.6%) and D2 (PL: −15.6±2.1; CR: −16.5±1.6%) but, no difference between groups. There were no significant differences between groups at either D1 or D2 for measures of serum electrolytes, minerals, osmolality, MP, TW, or FI. The results suggest that a 5-d loading dose of Cr does not negatively affect plasma volume or serum electrolyte and mineral balance. However, it also does not appear to enhance the performance of repeated bouts of anaerobic exercise. Supplement provided by Experimental and Applied Sciences, Inc.

The role of physical activity in the management of obesity.

Sedentary lifestyle is associated with obesity and obesity-related chronic diseases. Increased physical activity can produce clinically significant changes in body composition and a reduction in risk of obesity-related chronic diseases in obese people. Because a great proportion of a primary care physician's patient population will be obese, it is essential that physicians know the scientific facts about the role of physical activity in the treatment of obesity and how to effectively prescribe it. This article summarizes significant research conclusions about the relationship between physical activity, obesity, and health. It also provides practical strategies for helping obese patients integrate physical activity into their lives.

Chromium picolinate effects on body composition and muscular performance in wrestlers

The purpose of this study was to assess the effects of 14 wk of chromium picolinate supplementation during the final 16 wk of a preseason resistance and conditioning program on body composition and neuromuscular performance in NCAA Division I wrestlers. During this phase of training, wrestlers are primarily interested in trying to improve physical performance and wrestling technique and are not engaged in severe, acute weight loss practices commonly employed before competition. This double-blinded, randomized placebo-controlled study involved 20 wrestlers from the University of Oklahoma assigned to either a treatment group (Cr+3; N = 7; 20.4 yr +/- 0.1) receiving 200 micrograms chromium picolinate daily, a placebo group (P; N = 7; 19.9 yr +/- 0.2), or a control group (C; N = 6; 20.2 yr +/- 0.1) using a stratified random sampling technique based on weight classification. Body composition, neuromuscular performance, metabolic performance, and serum insulin and glucose were measured before and immediately following the supplementation and training period. Repeated measures ANOVA indicated no significant changes in body composition for any of the groups. Aerobic power increased significantly (P < 0.002) in all groups, independent of supplementation. There were significant trial and group x trial interactions for upper body endurance (P = 0.038) and relative bench press power (P = 0.050). Post-hoc analyses revealed that the C group increased upper body endurance (P = 0.006), but none of the pre- to post-test changes in bench press power were significant. These results suggest that chromium picolinate supplementation coupled with a typical preseason training program does not enhance body composition or performance variables beyond improvements seen with training alone.

EFFECTS OF EXOGENOUS PYRUVATE ON BODY COMPOSITION AND ENERGY LEVELS

882 Well controlled human studies have demonstrated that pyruvate (PYR) in doses ranging from 31-100 g per day enhanced fat loss and increased endurance. The objective of this study was to evaluate the effects of a smaller, more practical dose of pyruvate (6 g/d) as part of a pyruvate formula on body composition as well as vigor and fatigue levels. Fifty three healthy subjects with a body mass index (BMI) > 25 participated in the six week double blind, placebo controlled study. Body composition was determined by bioelectric impedance analysis (BIA). The fifty three subjects were randomized to one of three groups; 1) control (CON), 2) placebo (PLA), 3) pyruvate-based formula (PYR+). Significant changes in body composition were observed. Compared to baseline,% bodyfat (%BF) was reduced 12.4% (p<0.001) at 6 weeks, in the PVR+ group. Reduction in absolute bodyfat (BF) level of 4.8 lbs.(p<0.001) were observed in the PYR+ group at 6 weeks. Compared to CON and PLA, the changes in%BF found in the PYR+ group were significant at 6 weeks(p<0.0001) as were the changes in absolute%BF at 6 weeks. Compared to baseline, lean body mass (LBM) increased 3.4lbs (p=0.001) in the PYR+ group at 6 weeks. The increase in LBM observed in the PYR+ group was significantly different at 6 weeks (p<0.001) when compared to CON and PLA. Body Composition Improvement (BCI), which reflect positive changes in body composition, were also significant in the PYR+ group at 6 weeks. Compared to baseline, calculated basal metabolic rate (BMR) increased 2.2% (p=0.003) in the PYR+ group at 6 weeks. Compared to CON and PLA, vigor scores, as determined by Profile of Mood States(POMS), increased significantly in PYR+ group at 6 (p=0.05) weeks, although when compared to baseline, only the 17.7% increase seen within the PYR+ group was significant (p=0.003). No significant changes in%BF, BF, LBM, BCI, BMR, or vigor scores were observed in either PLA or CON groups, PYR+, a dietary supplement consisting primarily of calcium pyruvate, was found to significantly reduce%BF, BF, and fatigue scores, while increasing LBM, calculated BMR, and vigor scores. Based on the results of this study, 6 g PYR+ as the major component of a formula appears to be an effective daily dose.

Increase in diet-induced thermogenesis at the start of refeeding in severely malnourished anorexia nervosa patients

Many reports describe the difficulty for anorexia nervosa patients to gain weight during refeeding. To assess whether an increase in diet-induced thermogenesis (DIT) participates to this resistance, we studied DIT by indirect calorimetry in 11 severely malnourished anorexia nervosa patients [body mass index (BMI; in kg/m2) = 13] to accomplish two purposes: 1) to compare DIT in a strict semistarvation state with that obtained after 1 wk refeeding, when metabolism is shifted to a dynamic trend toward regaining weight, without significant change in body composition; 2) to study the effect on DIT of two energetic loads representing each one-third of the energy intake during semistarvation and refeeding, respectively: 1.25 and 2.92 MJ. To avoid bias, the two liquid loads were infused intragastrically in a random double-blind fashion. A significant increase in DIT during refeeding was observed for the two loads (204 +/- 23 kJ for the 1.25-MJ liquid meal and 482 +/- 78 kJ for the 2.92-MJ one, P < 0.02). The higher the load, the larger the increase with refeeding (P < 0.001). This increment in DIT exceeded the increase in active lean body mass and was poorly correlated with lean body mass. These results provide clear evidence of a strong cellular "waste" mechanism in anorexia nervosa patients during the early phase of refeeding, which enhances the adaptative resistance to overfeeding that we have already shown for resting energy expenditure.

Chronic ammonia toxicity in juvenile turbot ( Scophthalmus maximus)

Chronic effects of ammonia were studied in three batches of turbot ( Scophthalmus maximus) juveniles (14, 23 and 104 g) exposed for 4–6 weeks to constant ammonium chloride solutions. Under the environmental conditions used (16.5–17.5 °C, pH 7.92–8.03, salinity 34.5 ppt, over 80% oxygen saturation), no mortalities occurred up to 0.4 mg unionised ammonia (UIA-N) l −1, i.e. 10 mg total ammonia nitrogen (TAN) l −1. Estimated 28-day LC 50s averaged 0.95 mg UIA-N l −1 and growth was stopped from 0.8 mg UIA-N l −1. In 14 and 23 g turbot, LOEC (lowest-observable-effect concentration) values for growth were 0.41 and 0.21 mg UIA-N l −1, respectively, compared with 0.10 mg UIA-N l −1 in 104 g turbot. In 14 g fish, the most tolerant group in terms of growth, NOEC (no-observable-effect concentration) and MATC (maximum-acceptable-toxic-concentration) values were 0.18 and 0.30 mg UIA-N l −1, respectively. Reduced growth rate was due to a decrease in food intake, not to poorer food utilisation. The food conversion ratio was 0.9 and PER (protein efficiency ratio) and PUC (protein utilisation coefficient) averaged 2.5 and 45%, respectively. No significant changes in body composition were observed up to 0.4–0.5 mg UIA-N l −1. In adapted small turbot, no major physiological disturbances were observed up to 0.4–0.5 mg UIA-N l −1, while large turbot were more sensitive to ammonia. Major changes were observed in blood plasma TAN contents which were positively correlated with ambient ammonia concentrations. Chronic lethal levels and chronic adaptation levels of TAN were respectively about 20 and 13–15 mg l −1 plasma. Significant increases in plasma urea-N contents and urea-N daily excretion rates were only observed for the highest ammonia concentrations tested.

Reduced rates of metabolism and decreased physical activity in breast cancer patients receiving adjuvant chemotherapy

Weight gain, a common side effect among breast cancer patients receiving adjuvant chemotherapy, may decrease quality of life and impair survival. Weight gain during treatment is a well-known problem and has been studied by many investigators. However, few controlled studies have been conducted to determine reasons to explain this apparent energy imbalance. An exploratory study was undertaken to quantitate potential changes in energy intake and specific components of energy expenditure in breast cancer patients receiving adjuvant chemotherapy. The research hypothesis was that a reduction in resting metabolic rate (RMR) would be observed during the period in which women received adjuvant chemotherapy. Twenty premenopausal patients with stage I or II breast cancer and receiving cyclophosphamide+doxorubicin+5-fluorouracil; cyclophosphamide +methotrexate+5-fluorouracil+/-doxorubicin; doxorubicin +cyclophosphamide+/-leucovorin; or methotrexate+5-fluorouracil +leucovorin chemotherapy were recruited. RMR, diet-induced thermogenesis, energy intake, physical activity, and body composition were assessed before the initiation and throughout the course of therapy. Complete data on 18 subjects suggest that RMR decreased significantly from baseline to midtreatment (P = 0.02) and rebounded to levels similar to those at baseline on completion of chemotherapy. Overall, levels of physical activity and energy intake also decreased significantly during treatment compared with baseline levels (P = 0.04 and P = 0.03, respectively). These findings suggest that chemotherapy provokes many significant changes in body composition and metabolic requirements. Additional research in this area will provide valuable insight into creating optimal interventions to curb weight gain in women with breast cancer.

Assessing body composition before and after resistance or endurance training.

This study's purpose was to determine the validity of near-infrared interactance (NIR) and bioelectric impedance (BIA) in tracking changes in body composition over 12 wk of either a high intensity endurance (ET) or resistance (RT) training program in nondieting weight-stable untrained males. Prior to and following the control or training period, each subject completed a series of body composition analyses including hydrostatic weighing (HW) with a measurement of residual volume: anthropometric measurements including height, weight, skinfold, and girth: BIA measurement: and NIR measurements. Based on the HW results, there were no significant body composition changes in the control group. For the ET group, a significant decline in relative body fat resulted from a reduction in fat weight (FW) with no change in fat-free weight (FFW). In the RT group, both a significant decline in FW and an increase in FFW contributed to this group's decline in relative body fat. Tracking changes in relative body fat, FW, and FFW, skinfolds agree reasonably well with HW in all groups while BIA and NIR did not always track body composition changes well. For example, SF and BIA were significantly correlated with the changes in FFW (HW = +4.1%, SF = +4.5%. BIA = +3.1%. NIR = -0.7%) observed in the RT group compared to HW (SF: r-value = 0.45, SEE = 2.5; BIA: r = 0.33, SEE = 3.4) while the NIR measurements were nonsignificant (r = 0.09, SEE = 5.0). Interestingly, NIR underestimated the gain in FFW in the resistance trained group while BIA underestimated the changes in relative body fat. FW, and FFW in the endurance trained group. Based on these results, BIA and NIR appear not to be appropriate measurement tools for tracking body composition changes in endurance and resistance training individuals respectively.

Moderate intermittent doses of exercise improves insulin and insulin/glucose in overweight females 899

Despres et al. (Am J Physiol, 1991) have demonstrated that changes in metabolic fitness, including fasting insulin, glucose, and insulin/glucose may occur independent of changes in aerobic capacity in obese females who participated in an aggressive exercise program. Since most adults will not exercise aggressively (Powell, Ann Rev Pub Health, 1988) our purpose was to explore the possibility that long-term, moderate, intermittent exercise may reduce fasting insulin, glucose, and insulin/glucose. 12 females% fat = 40.6± 8.8 exercised at a moderate intensity which was 50-65% of the heart rate reserve determined from a maximal exercise test. Walking was performed in 10 min bouts, 3X/day, 5d/week for 32 weeks at the individual worksite. Total energy expenditure of exercise estimated from Caltrac was 137676 ± 30756 kJ. Subsequent to training, there were no changes in aerobic capacity, body composition (BC), or fasting insulin and glucose values. We then separated the subjects into “responders and non-responders” based on a 7% increase in aerobic capacity. Nine subjects met the criteria of responders and showed no significant change in BC or glucose. However, there were significant decreases in fasting insulin and insulin/glucose of 7.0± 6.9 mcu/ml p<0.01 and 0.09±0.09 p<0.02, respectively. The correlations between the change in aerobic capacity and insulin and insulin/glucose were 0.17 and 0.14, respectively (NS). No changes in BC or insulin, glucose and insulin/glucose were shown for the 3 non-responders. This seems to suggest a threshold effect for exercise rather than a dose response relationship to the improvement of insulin and insulin/glucose. Moderate intermittent exercise which improves aerobic capacity may provide enough stimulus to invoke improvements in insulin and insulin/glucose in moderately obese females.

Effects of weight loss vs aerobic exercise training on risk factors for coronary disease in healthy, obese, middle-aged and older men. A randomized controlled trial

<h3>Objective.</h3> —To compare the effects of weight loss vs aerobic exercise training on coronary artery disease risk factors in healthy sedentary, obese, middle-aged and older men. <h3>Design.</h3> —Randomized controlled trial. <h3>Subjects.</h3> —A total of 170 obese (body mass index, 30±1 kg/m²[mean±SEM]), middle-aged and older (61 ±1 years) men. <h3>Interventions.</h3> —A 9-month diet-induced weight loss intervention, 9-month aerobic exercise training program, and a weight-maintenance control group. <h3>Main Outcome Measures.</h3> —Change in body composition, maximal aerobic capacity (Vo₂max), blood pressure, lipoprotein concentrations, and glucose tolerance. <h3>Results.</h3> —Forty-four of 73 men randomized to weight loss completed the intervention and had a 10% mean reduction in weight (-9.5±0.7 kg;<i>P</i>&lt;.001), with no change in Vo₂max. Forty-nine of 71 men randomized to aerobic exercise completed the intervention, increased their Vo₂max by a mean of 17% (<i>P</i>&lt;.001), and did not change their weight, whereas the 18 men who completed in the control group had no significant changes in body composition or Vo₂max. Weight loss decreased fasting glucose concentrations by 2%, insulin by 18%, and glucose and insulin areas during the oral glucose tolerance test (OGTT) by 8% and 26%, respectively (<i>P</i>&lt;.01). By contrast, aerobic exercise did not improve fasting glucose or insulin concentrations or glucose responses during the OGTT but decreased insulin areas by 17% (<i>P</i>&lt;.001). In analysis of variance, the decrement in fasting glucose and insulin levels and glucose areas with intervention differed between weight loss and aerobic exercise when compared with the control group (<i>P</i>&lt;.05). Similarly, weight loss but not aerobic exercise increased high-density lipoprotein cholesterol levels (+13%) and decreased blood pressure compared with the control group. In multiple regression analyses, the improvement in lipoproteins and glucose metabolism was related primarily to the reduction in obesity. <h3>Conclusions.</h3> —These results suggest that weight loss is the preferred treatment to improve coronary artery disease risk factors in overweight, middle-aged and older men. (<i>JAMA</i>. 1995;274:1915-1921)

The Supplemental Benefits of Strength Training for Aerobically Active Postmenopausal Women

This study examined the supplemental benefits of strength training in aerobically active postmenopausal women. Eighteen women (61-71 yrs) who had been participating in regular aerobic exercise for the preceding 8 months were randomly assigned to control (n = 9) and experimental (n = 9) groups. Both groups continued aerobic exercise 3 times a week for the 8-week training period. In addition, the experimental group performed 3 sets (8–12 repetitions) of standard knee extension and flexion exercises at 80% of their 1-repetition maximum (1-RM). In the experimental group, highly significant increases in knee flexion and extension strength were observed. No changes in strength were noted in the control subjects. There were no significant changes in body composition for either group. The data suggest that aerobically active older individuals can greatly increase strength with resistance training, which is consistent with recent recommendations that resistance training should be used to supplement aerobic exercise.

Consumption of diets containing raw soya beans (Glycine max), kidney beans (Phaseolus vulgaris), cowpeas (Vigna unguiculata) or lupin seeds (Lupinus angustifolius) by rats for up to 700 days: effect on body composition and organ weights

Feeding trials have been done with rats to assess the effects of long-term (700 d) consumption of diets based on raw cowpeas (Vigna unguiculata; moderate Bowman-Birk inhibitor content, low lectin content), lupin seeds (Lupinus angustifolius; low lectin and protease inhibitor content) or soya beans (Glycine max; high Kunitz inhibitor content, moderate Bowman-Birk inhibitor content, moderate lectin content) or diets containing low levels of raw kidney bean (Phaseolus vulgaris; high lectin content, low Bowman-Birk inhibitor content) on body weight and composition and organ weights. All the legume-based diets reduced feed conversion efficiency and growth rates during the initial 250 d. However, after 250 d the weight gains by rats given legume-based diets were similar to those of controls given the same daily feed intake. Long-term consumption of diets containing low levels of kidney bean significantly altered body composition of rats. The levels of lipid in the body were significantly reduced. As a result, carcasses of these rats contained a higher proportion of muscle/protein than did controls. Small-intestine relative weight was increased by short- and long-term consumption of the kidney-bean-based diet. However, the increase in relative pancreatic weight observed at 30 d did not persist long term. None of the other legume-based diets caused any significant changes in body composition. However, long-term exposure to a soya-bean- or cowpea-based diet induced an extensive increase in the relative and absolute weights of the pancreas and caused an increase in the incidence of macroscopic pancreatic nodules and possibly pancreatic neoplasia. Long-term consumption of the cowpea-, kidney-bean-, lupin-seed- or soya-bean-based diets by rats resulted in a significant increase in the relative weight of the caecum and colon.

A comparison of multifrequency bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DEXA) in HIV +/AIDS patients

Malnutrition and wasting are frequent problems in patients with HIV-infection and/or AIDS, and often result in clinically significant changes in body composition. Previous studies have demonstrated alterations in both fat free mass (FFM) and fat mass. The present study was designed to compare two methods for determining body composition: multifrequency BIA and DEXA. Twenty-five male patients with HIV-infection, aged 39.9 ± 1.8 yrs (mean ± SEM) (age range 27 to 60 years) were evaluated. Height and weight of this group were 174.9 ± 1.8 cm and 63.7 ± 2.2 kg, respectively. Percent weight loss from usual weight was 13.0 ± 1.0 %, suggesting that these patients were experiencing active wasting syndrome as a result of their disease. All subjects were outpatients and came into the clinic for measurement of body composition. Mean FFM as determined by DEXA and multifrequency BIA were identical at 51.5 ± 1.5 kg, and resulted in a correlation coefficient (r) of 0.9018. These values represent approximately 81% of total body weight as FFM. Subsequent determination of fat mass (the difference between total body weight and FFM) revealed analogous agreement between the two techniques (DEXA and BIA), yielding average fat masses of 12.2 ± 1.0 kg and 12.2 ± 1.2 kg, respectively. These values represent approximately 19% of total body weight as fat, and further support the parity between the two methods with a correlation coefficient (r) of 0.8484. We conclude that both multifrequency BIA and DEXA provide comparable estimations of FFM in the HIV-infected/AIDS patient. Furthermore, whereas DEXA is a rather expensive technique, BIA is an equally reliable, inexpensive technique for evaluation of body composition in the clinical and home care setting.

Alterations in Concentric Strength Consequent to Powercise and Universal Gym Circuit Training

The purpose of this study was to evaluate the efficacy of a resistance training program using the Powercise Fitness System and the specificity of training/testing by comparing Powercise (constant resistance, concentric-only contraction) and Universal Gym (constant resistance, concentric and eccentric contractions) training. Pre- and post-measures of concentric strength, body composition and anthropometry were done. Subjects randomly assigned to a Universal (U, n=15) or Powercise group (P, n=16) trained three times a week for 12 weeks. A control group (C, n=8) did not train. Training included three sets of 8–12 repetitions for eight different movements. The P group improved significantly on six P lifts and three U lifts and the U group improved significantly on five U lifts and two P lifts. The P group improved significantly more than the U group on one P lift and the U group improved significantly more than the P group on three U lifts. No significant changes in body composition occurred in either group. It was concluded that general resistance training programs for beginners using equipment that elicits concentric-only contractions or concentric and eccentric contraction, produce significant improvements in concentric strength and that there was support for the concept of specificity of training/testing.

Alternation in Concentric Strength Consequent to Powercise and Universal Gym Circuit Training

The purpose of this study was to evaluate the efficacy of a resistance training program using the Powercise Fitness System and the specificity of training/testing by comparing Powercise (constant resistance, concentric-only contraction) and Universal Gym (constant resistance, concentric and eccentric contractions) training. Pre- and post-measures of concentric strength, body composition and anthropometry were done. Subjects randomly assigned to a Universal (U, n=15) or Powercise group (P, n=16) trained three times a week for 12 weeks. A control group (C, n=8) did not train. Training included three sets of 8-12 repetitions for eight different movements. The P group improved significantly on six P lifts and three U lifts and the U group improved significantly on five U lifts and two P lifts. The P group improved significantly more than the U group on one P lift and the U group improved significantly more than the P group on three U lifts. No significant changes in body composition occurred in either group. It was concluded that general resistance training programs for beginners using equipment that elicits concentric-only contractions or concentric and eccentric contraction, produce significant improvements in concentric strength and that there was support for the concept of specificity of training/testing.

Exogenous Human Growth Hormone Reduces Body Fat in Obese Women

The effects of biosynthetic methionyl human growth hormone (met-hGH) on body composition and endogenous secretion of insulin-like growth factor I (IGF-I) were studied in obese women ranging between 138 and 226% of ideal body weight. Following double-blind procedures, 12 subjects were assigned at random to either treatment with met-hGH (n = 6, 0.08 mg/kg desirable body weight) or placebo (n = 6, bacteriostatic water diluent). Treatments were delivered intramuscularly three times per week for a period of 27-28 days. Subjects were instructed to follow a weight-maintaining diet and their pre- and posttreatment kilocaloric intake was monitored for verification. The baseline peak serum GH response to L-dopa/arginine stimulation for the study population as a whole, was in the hyposecretory range (9.6 +/- 1.9 ng/ml), accompanied by a low level of circulating IGF-I (0.56 +/- 0.09 U/ml). Hydrodensitometry revealed that the met-hGH-treated subjects had a significant reduction in body fat, while an observed mean increase in fat-free mass (FFM) approached significance. The percent change in body fat was unrelated to pretreatment levels of body fat, total body weight, or initial endogenous GH status. Changes in circulating IGF-I were similar to those for FFM, with increases approaching significance. There were no significant changes in body composition or IGF-I in the placebo-treated subjects. No significant differences were observed in the self-reported dietary intake of kilocalories during the experimental period between the two groups. We conclude that exogenous GH reduces body fat in obese women in the apparent absence of significant kilocaloric restriction. The effect appears to be unrelated to endogenous GH secretion or body composition.

An introduction to body composition models used in nutritional studies.

Chemical analysis of cadavers has led to the definition of 'reference' man but diseases may result in significant changes in body composition. By measuring body composition in patient groups the nature of disease progression can be followed and management regimens evaluated. Various techniques are available which attempt to measure body composition in vivo. Several models of body composition have evolved with the introduction of new measurement techniques. A description of these models is presented. The limitations of the models and the techniques adopted for their measurement are discussed.