Learn More
Reduced lower extremity strength has been associated with reduction in gait speed, balance, stair-climbing ability, and getting up from a seated position. The relationship of lower extremity strength and the ability to accomplish selected functional activities was examined in 16 healthy but frail older adults ranging in age from 75 to 88 years (mean = 80.9(More)
Peak absolute force, specific tension (peak absolute force per cross-sectional area), cross-sectional area, maximal unloaded shortening velocity (Vo; determined by the slack test), and myosin heavy chain (MHC) isoform compositions were determined in 124 single skeletal fibers from the soleus muscle of 12-, 24-, 30-, 36-, and 37-mo-old Fischer 344 Brown(More)
The effects of ageing and of exercise on muscle mass, fiber cross-sectional area, and fiber type composition of a weight-bearing muscle, the soleus and a non-weight-bearing muscle, the extensor digitorum longus (EDL) were investigated in female Long-Evans rats. The animals were exercised by means of voluntary wheel running beginning at 4 months. Runners and(More)
Age-related changes in skeletal muscle mass, fiber area, and contractile function were examined in pathogen-free rats at 6, 12, 28 and 36 mos of age. The intent of this study was to clarify age-related decline, particularly in contractile force, and to determine if the decline in contractile tension with age is due to alterations at the neuromuscular(More)
Both estrogen and testosterone are present in males and females. Both hormones contribute to the well being of skeletal muscle and bone in men and women, and there is evidence that the loss of sex hormones is associated with the age-related decline in bone and skeletal muscle mass. Hormonal supplementation of older adults to restore estrogen and(More)
The recovery of atrophied muscle mass in animals is thought to be dependent on a number of factors including hormones, cytokines, and/or growth factor expression. The Akt/mammalian target of rapamycin (mTOR) signaling pathway is believed to be activated by these various factors, resulting in skeletal muscle growth through the initiation of protein(More)
Null mutation of titin-cap (TCAP) causes limb-girdle muscular dystrophy type 2G (LGMD2G). LGMD2G patients develop muscle atrophy, and lose the ability to walk by their third decade. Previous findings suggest that TCAP regulates myostatin, a key regulator of muscle growth. We tested the hypothesis that TCAP knockdown with RNA interference will lead to(More)
We examined effects of 4 wk of food restriction on ovariectomy-related changes in muscle, bone, and plasma insulin-like growth factor I (IGF-I). Female Sprague-Dawley rats (7 mo old) were assigned to freely eating groups: sham-operated (Sham), ovariectomized (Ovx-AL), and estrogen (estradiol)-replaced Ovx (Ovx+E(2)). Ovx rats were also pair fed with Sham(More)
Female rats (7-8 mo old, n = 40) were randomly placed into the intact control (Int) and ovariectomized control (Ovx) groups. Two weeks after ovariectomy, animals were further divided into intact 2-wk hindlimb unloaded (Int-HU) and ovariectomized hindlimb unloaded (Ovx-HU). We hypothesized that there would be greater hindlimb unloading-related atrophy in Ovx(More)
Changes in passive muscle stiffness with age and disuse were assessed in male Fischer-344 and Brown Norway rats. Three groups of rats were studied: young (approximately 7 months old), old (approximately 33 months old), and old that had undergone 2 weeks of hindlimb unweighting, a model of reduced muscle use. Four hindlimb muscles were examined: the soleus(More)