Increase In Lean Tissue Mass Research Articles

Changes In Parameters Of Bone And Body Composition In Females Undergoing U.S. Army Basic Training

U.S. Army initial entry training (IET) requires soldiers to undergo a vigorous nine week basic training course designed to enhance physical strength, endurance and function to prepare them for combat operations. However, there is little known about the effect of this type of training on bone parameters. PURPOSE To observe the response of bone and lean tissue mass (LM) to strenuous physical training in a cohort of IET soldiers, and to explore the association between LM and bone area (BA), bone mineral content (BMC), and bone mineral density (BMD). METHODS 151 female soldiers (age 21.4 ± 3.4 years) underwent dual x-ray absorptiometry scanning before and after nine weeks of basic training. A total body scan provided BA, BMC, BMD and LM measures for the total body (TB), the upper extremities (UE), and the lower extremities (LE). Data were analyzed using paired sample t-tests and Pearson's correlation coefficients. RESULTS Total body BMD decreased from 1.20 ± 0.08 to 1.19 ± 0.08 g/cm2 (p<0.001). Total body LM increased from 39.38 ± 4.30 to 41.84 ± 4.42 kg (p<0.001), and was not significantly correlated with parameters of bone. Total body BMC and BA did not change significantly. Extremity data are presented in the following table:TableThe observed changes in LM were positively correlated with changes in BA for the UE (r=.52) and LE (r=.32) (both p<0.001). CONCLUSION This study provides evidence for the influence of physical training on bone acquisition in the skeletally mature female. Lower extremity bone area increases in response to short term, strenuous, weight bearing activity without a concomitant increase in BMD or BMC. Increases in bone area in the extremities are positively associated with increases in lean tissue mass. At this time it is unknown if significant changes in soft tissue composition result in artifactual variability in measures of bone.

Effect of Creatine Ingestion after Exercise on Muscle Thickness in Males and Females

Muscles exercised before creatine (Cr) supplementation have a greater elevation of intramuscular Cr than nonexercised muscles. To determine whether preferential increase of muscle thickness could be achieved by ingesting Cr immediately after exercise of specific muscles over 6 wk. Another purpose was to determine if the increase in lean tissue mass (LTM) with Cr supplementation is greater in males than females. Subjects randomly assigned to Cr (six males, five females, 0.2 g Cr x kg(-1)) and placebo (PL; five males, five females) performed single-limb training with one side of the body two times per week and with the opposite limbs two times per week. Cr was consumed after training of one side of the body and PL after training the opposite side. Subjects on PL always consumed PL after exercise. Elbow flexors and knee extensors muscle thickness, LTM, fat, and bone mass, and single-limb bench and leg press one-repetition maximum (1-RM) were assessed before and after 6 wk. Within the Cr group, elbow flexors muscle thickness increased more in the limbs trained on days Cr was supplemented compared with limbs trained on days PL was supplemented (P < 0.02). All other measures changed to a similar extent between limbs. Males on Cr had the greatest increase in LTM (P < 0.05) with no difference between females on Cr and PL. Bench press 1-RM increased more in Cr than PL groups (P < 0.01). All other measures changed to a similar extent between groups. Males increased bone mass (P < 0.01) with no effect of Cr supplementation. Supplementing with Cr after training of the arms resulted in greater increase in muscle thickness of the arms. Males have a greater increase in LTM with Cr supplementation than females.

In-Season Creatine Supplementation by Rugby Union Football Players

2303 Rugby union football is a sport that relies on muscular strength and endurance, as well as aerobic endurance. Simultaneous training for strength and aerobic endurance is challenging because one type of training can interfere with the other (i.e. heavy aerobic training can compromise muscle mass and strength development; whereas heavy strength training can compromise aerobic endurance due to muscle hypertrophy). PURPOSE: To determine if creatine supplementation during a season of rugby union football can preserve lean tissue mass and muscular performance, without negatively affecting aerobic endurance. METHODS: Rugby union football players were randomized to receive 0.1 g/kg/d creatine monohydrate (n = 9) or placebo (n = 9) during 8 weeks of the rugby season. Players practiced (mainly aerobic training) twice per week for approximately 2 hours per session and played one 80 minute game per week. Before and after the 8 weeks players were measured for body composition (air displacement plethysmography), muscular performance (number of repetitions at approximately 75% 1-RM for bench press and leg press), and aerobic endurance (Leger shuttle-run test with 1 minute stages of progressively increasing speed). RESULTS: There were time main effects for loss of body mass (−0.7 kg; p = 0.05), loss of fat mass (−1.9 kg; p<0.05) and a trend for an increase in lean tissue mass (+1.2 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 to the placebo group (+5.8 repetitions vs. +0.9 repetitions; p<0.05). There were no changes in either group for aerobic endurance. CONCLUSION: Creatine supplementation during a rugby union football season is effective for increasing muscular performance, but has no effect on body composition or aerobic endurance. Supported by NutraSense Co.

The effects of gymnastics training on bone mineral density

The purpose of this study was to examine the effect of 27 wk of gymnastics training on bone mineral density (BMD), body composition, insulin-like growth factor I (IGF-I), and osteocalcin. Subjects were 11 female intercollegiate gymnasts and 11 controls. Dual energy x-ray absorptiometry (Lunar DPX) was used to determine BMD (L2-L4 and femur) and to assess body composition. The gymnasts were significantly lower in weight (53.9 and 60.8 kg) and % body fat (22.6 and 30.6) compared with controls. After training, body weights of gymnasts remained the same but there was a significant increase in lean tissue mass of 2.9 kg (6.7%, P < 0.05). No changes in body composition were observed in the controls. The gymnasts had significantly higher mean lumbar (1.321 vs 1.225), and femoral neck (1.163 vs 1.079) BMD (g.cm-2) than the controls. Lumbar BMD increased significantly (1.3%) in gymnasts following training but femoral neck BMD did not increase. No BMD changes occurred in the control group. Regarding serum IGF-I, no differences were seen between the groups or across time. Serum osteocalcin values were significantly higher in the gymnasts than the controls, but no differences were found across time. In conclusion, gymnasts had significantly higher BMDs than controls, and a significant increase in lumbar BMD was seen in the gymnasts following 27 wk of training.

Changes in body composition and bone density after discontinuation of growth hormone therapy in adolescence: an interim report

Growth hormone deficiency (GHD) in adults and children is associated with decreased lean tissue mass (LTM), increased fat mass and reduced bone mineral density (BMD). The changes in BMD and body composition, 6 and 12 months after ceasing GH treatment, were assessed using dual-energy X-ray absorptiometry in eight patients with GHD (age range, 13.8-17.5 years). Seven age-matched normal subjects who had completed growth were assessed at 0 and 12 months. Total body BMD was low at baseline (p < 0.05) in patients with GHD compared with the predicted values based on sex-specific regression equations, with height, weight and age taken into account. Total body, lumbar spine and femoral neck BMD increased in the patients and controls at 12 months. LTM decreased significantly by a mean of 1.37 kg in the patients with GHD at 12 months whereas there was a non-significant increase in LTM in the control group. The percentage of body fat increased in all patients with GHD at 6 and 12 months, from 27.2 +/- 11% (mean +/- SD) at baseline to 32 +/- 9.9% at 12 months (p = 0.009). There was no significant increase in mean percentage body fat in the control group. The ratio of android (trunk):gynoid (legs) fat was calculated using default settings of dual-energy X-ray absorptiometry. The mean android:gynoid fat ratio increased, though non-significantly, in patients with GHD at 12 months, with 6 of 7 showing an increase; no change was observed in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in body composition with danazol therapy

Whole body lean and fat mass measurements by dual energy x-ray absorptiometry were performed in 14 premenopausal women undergoing danazol treatment for endometriosis. After 6 months, there was a significant increase in lean tissue mass. Body fat decreased but this was significantly less in the android (upper body segment) region than in the gynoid (lower body segment) region. Danazol thus has both anabolic and androgenic effects on body composition. Dual energy x-ray absorptiometry provides a new, noninvasive, and rapid means of studying body composition.