Family characteristics have limited ability to predict weight status of young children.

The ability of (a) family characteristics (marital status, income, race, and education), (b) parental control over child's food intake, and (c) parental belief in causes of overweight to predict weight status of children was assessed. Parents/caretakers of elementary school-aged children were surveyed to determine attitudes related to childhood nutrition and overweight. Anthropometric measurements were obtained from children to determine weight status (n=169 matched surveys and measurements).

Effect of a 10-week strength training program and recovery drink on body composition, muscular strength and endurance, and anaerobic power and capacity.

Objective: We investigated whether postexercise consumption of a supplement containing whey protein, amino acids, creatine, and carbohydrate combined with a strength training program promotes greater gains in fat-free mass (FFM), muscle strength and endurance, and anaerobic performance compared with an isocaloric, carbohydrate-only control drink combined with strength training.

Methods: The study was double blind and randomized, and the experimental supplement was compared with a carbohydrate-only control. Forty-one males (n = 20 in control group, n = 21 in the supplement group; mean age, 22.

Resistance training exercises acutely reduce intraocular pressure in physically active men and women.

Our purpose was to examine the effect of the chest press and leg press exercises on intraocular pressure (IOP) in physically active, college-aged students. Fifteen healthy males and 15 females performed 3 sets of 10 repetitions of the chest press or leg press with 70% 1 repetition maximum (1RM). IOP was measured using applanation tonometry with a Tono-PenXL prior to exercise, following each set and 5 minutes after the third set.

The effect of beta-hydroxy beta-methylbutyrate on muscular strength and body composition in collegiate football players.

This study assesses the effects of daily beta-hydroxy beta-methylbutyrate (HMB) supplementation on muscular strength (bench press, squats, and power cleans) and body composition (body weight and body fat) among collegiate football players undergoing a strenuous exercise program. Subjects were collegiate football players (n = 35) training under the supervision of certified strength coaches averaging 20 hours of weekly exercise. In the first supplementation period, 16 of the 35 subjects were supplemented with 3 g of HMB per day for 4 weeks; the other 19 received a placebo followed by a 1-week washout period and then a second supplementation period in a randomized double-blind crossover, placebo design.

Use of amino acids as growth hormone-releasing agents by athletes.

Specific amino acids, such as arginine, lysine and ornithine, can stimulate growth hormone (GH) release when infused intravenously or administered orally. Many individuals consume amino acids before strength training workouts, believing this practice accentuates the exercise-induced GH release, thereby promoting greater gains in muscle mass and strength. The GH response to amino acid administration has a high degree of interindividual variability and may be altered by training status, sex, age, and diet.

Growth hormone administration and exercise effects on muscle fiber type and diameter in moderately frail older people.

Objective: Reduced muscle mass and strength are characteristic findings of growth hormone deficiency (GHD) and aging. We evaluated measures of muscle strength, muscle fiber type, and cross sectional area in response to treatment with recombinant human growth hormone (rhGH) with or without a structured resistance exercise program in frail older subjects.

Design: Placebo-controlled, randomized, double blind trial.

Space travel directly induces skeletal muscle atrophy.

Space travel causes rapid and pronounced skeletal muscle wasting in humans that reduces their long-term flight capabilities. To develop effective countermeasures, the basis of this atrophy needs to be better understood. Space travel may cause muscle atrophy indirectly by altering circulating levels of factors such as growth hormone, glucocorticoids, and anabolic steroids and/or by a direct effect on the muscle fibers themselves.

Organogenesis of skeletal muscle in tissue culture.

Skeletal muscle structure is regulated by many factors, including nutrition, hormones, electrical activity, and tension. The muscle cells are subjected to both passive and active mechanical forces at all stages of development, and these forces play important but poorly understood roles in regulating muscle organogenesis and growth. For example, during embryogenesis, the rapidly growing skeleton places large passive mechanical forces on the attached muscle tissue.

Attenuation of skeletal muscle wasting with recombinant human growth hormone secreted from a tissue-engineered bioartificial muscle.

Skeletal muscle wasting is a significant problem in elderly and debilitated patients. Growth hormone (GH) is an anabolic growth factor for skeletal muscle but is difficult to deliver in a therapeutic manner by injection owing to its in vivo instability. A novel method is presented for the sustained secretion of recombinant human GH (rhGH) from genetically modified skeletal muscle implants, which reduces host muscle wasting.

Bioreactor perfusion system for the long-term maintenance of tissue-engineered skeletal muscle organoids.

Three-dimensional skeletal muscle organ-like structures (organoids) formed in tissue culture by fusion of proliferating myoblasts into parallel networks of long, unbranched myofibers provide an in vivo-like model for examining the effects of growth factors, tension, and space flight on muscle cell growth and metabolism. To determine the feasibility of maintaining either avian or mammalian muscle organoids in a commercial perfusion bioreactor system, we measured metabolism, protein turnover. and autocrine/paracrine growth factor release rates.

Increase in percutaneous muscle biopsy yield with a suction-enhancement technique.

The percutaneous muscle biopsy technique is used in clinical practice and biomedical research. We developed a new enhanced-suction technique [suction-enhancing nipples (SEN)] and compared it with techniques currently in practice by assessing biopsy yields on anesthetized pigs. We applied the enhanced-suction technique to human subjects participating in a clinical trial.

Mechanical stimulation of skeletal muscle increases prostaglandin F2 alpha production, cyclooxygenase activity, and cell growth by a pertussis toxin sensitive mechanism.

Repetitive mechanical stimulation of differentiated skeletal muscle in tissue culture increased the long-term production of prostaglandin F2 alpha, an anabolic stimulator of myofiber growth. Within 4 h of initiating mechanical stimulation, the enzymatic activity of cyclooxygenase (prostaglandin GH synthase [PGHS]), a regulatory enzyme in prostaglandin synthesis, was increased 82% (P < .005), and this increase was maintained for at least 24 h.

Growth and development of bovine fetuses and neonates representing three genotypes.

Growth was examined in bovine fetuses and neonates that typically differ in mature size and postnatal developmental pattern. Pregnancies were established from matings expected to produce early (E), late (L), and intermediate (I) maturing postnatal growth patterns. Tissues were collected at 100 and 200 d of gestation and 30 d postnatal.

Mechanical stimulation of skeletal muscle cells mitigates glucocorticoid-induced decreases in prostaglandin production and prostaglandin synthase activity.

The glucocorticoid dexamethasone (Dex) induces a decline in protein synthesis and protein content in tissue cultured, avian skeletal muscle cells, and this atrophy is attenuated by repetitive mechanical stretch. Since the prostaglandin synthesis inhibitor indomethacin mitigated this stretch attenuation of muscle atrophy, the effects of Dex and mechanical stretch on prostaglandin production and prostaglandin H synthase (PGHS) activity were examined. In static cultures, 10(-8) M Dex reduced PGF2 alpha production 55-65% and PGE2 production 84-90% after 24-72 h of incubation.

Glucocorticoid-induced skeletal muscle atrophy in vitro is attenuated by mechanical stimulation.

Glucocorticoids induce rapid atrophy of fast skeletal myofibers in vivo, and either weight lifting or endurance exercise reduces this atrophy by unknown mechanisms. We examined the effects of the synthetic glucocorticoid dexamethasone (Dex) on protein turnover in tissue-cultured avian fast skeletal myofibers and determined whether repetitive mechanical stretch altered the myofiber response to Dex. In static cultures after 3-5 days, 10(-8) M Dex decreased total protein content 42-74%, total protein synthesis rates 38-56%, mean myofiber diameter 35%, myosin heavy chain (MHC) content 86%, MHC synthesis rate 44%, and fibronectin synthesis rate 29%.

L6 myoblast proliferation in response to muscle-derived extracts and serum from exercise-trained rats.

Serum and skeletal muscle-derived extracts (MDE) were bioassayed for their ability to promote [3H]thymidine incorporation in L6 myoblasts to determine if exercise-training increases mitogenic growth factor activity. Rats were trained by climbing a 60 cm vertical grid with progressively greater weight for 7 and 28 days. Serum from 7 day trained rats and vastus MDE from 7 and 28 day trained rats, but not rectus femoris MDE, had increased mitogenic activity compared to serum and MDE from untrained rats.

Effect of the beta-agonist cimaterol on growth and composition of neonatal rats selected for large and small body size.

The effect of subcutaneous injection of the beta-agonist cimaterol on growth and body composition of neonatal rats differing in growth potential was examined. Rats that represented substrain populations of Charles River CD rats selected for either large or small body size were used. Cimaterol administration resulted in a greater reduction in body weight gain in the Large strain rats.

Heart Rate and Lactate Levels During Weight-Training Exercise in Trained and Untrained Men.

In brief: The effects of squatting exercise on heart rate and blood lactate levels were studied in five trained and five untrained men between the ages of 22 and 37. The subjects performed squats (sets of ten repetitions until exhaustion), resting for 2 1/2 minutes between sets. Total positive work was estimated with the following formula: (bar mass + body mass) X vertical displacement X repetitions.