Acute loading and aging effects on myostatin pathway biomarkers in human skeletal muscle after three sequential bouts of resistance exercise.

To determine the influence of age and resistance exercise on myostatin pathway-related genes, younger (n = 10; 28 ± 5 years) and older (n = 10; 68 ± 6 years) men underwent four testing conditions (T1-T4). A baseline (T1) muscle sample was obtained, whereas the second and third biopsies were obtained 48 hours following the first and second training sessions (T2, T3), and a final biopsy was taken 24 hours following T3. The training sessions consisted of 3 sets of 10 repetitions (80% of one repetition maximum) on leg press, hack squat, and leg extension exercises.

Megalin and androgen receptor gene expression in young and old human skeletal muscle before and after three sequential exercise bouts.

Androgen signaling occurs primarily via the androgen receptor. Megalin, a low-density lipoprotein endocytic receptor located in various mammalian tissues, has been recently shown to facilitate sex hormone–binding globulin (SHBG) steroid complexes across cell membranes. The purpose of this investigation is to determine if the megalin gene is expressed in human skeletal muscle and if present to determine how megalin and androgen receptor mRNA expression change in response to sequential exercise bouts with respect to aging.

The combined effects of exercise and ingestion of a meal replacement in conjunction with a weight loss supplement on body composition and fitness parameters in college-aged men and women.

This study was performed to evaluate the combined effect of a meal replacement and an alleged weight loss supplement (WLS) on body composition, fitness parameters, and clinical health in moderately overweight college-aged men and women. Body mass, bench press 1 repetition maximum (1RM), leg press 1RM, body composition, V(O2)max, fasting glucose (GLU), and lipid panels were evaluated before (T1) and after (T2) 8 weeks of combined resistance training (RT) and cardiovascular training (CVT). After T1, subjects were randomly assigned in a double-blind fashion to either the WLS (6 men, 7 women; 21 ± 5 years, 168 ± 8 cm, 75.

IGF-1 splice variant and IGF-1 peptide expression patterns in young and old human skeletal muscle prior to and following sequential exercise bouts.

Genes and proteins involved in insulin-like growth factor (IGF)-1 signaling are thought to be differentially expressed in older versus younger mammalian skeletal muscle following acute exercise. The purpose of this study was to examine how multiple bouts of conventional resistance training meant to elicit hypertrophy affect the mRNA expression of IGF-1EA and IGF-1EC (MGF) as well as the expression of total IGF-1 peptides in human skeletal muscle. Ten younger (18-25 years) and 10 older (60-75 years) males completed three sequential workouts (M, W, F) consisting of nine sets of lower body exercises with ten repetitions per set at an intensity of 80% of one repetition maximum.