Muscle Mature Girl
Skeletal muscle contractility and myosin function decline following ovariectomy in mature female mice. In the present study we tested the hypothesis that estradiol replacement can reverse those declines. Four-month-old female C57BL/6 mice (n = 69) were ovariectomized (OVX) or sham operated. Some mice were treated immediately with placebo or 17beta-estradiol (OVX + E(2)) while other mice were treated 30 days postsurgery. Thirty or sixty days postsurgery, soleus muscles were assessed in vitro for contractile function and susceptibility to eccentric contraction-induced injury. Myosin structural dynamics was analyzed in extensor digitorum longus (EDL) muscles by electron paramagnetic resonance spectroscopy. Maximal isometric tetanic force was affected by estradiol status (P or= 0.401) but did restore ovariectomy-induced increases in muscle wet mass caused by fluid accumulation. Collectively, estradiol had a beneficial effect on female mouse skeletal muscle.
muscle mature girl
We conducted a 12-wk resistance training program in elderly women [mean age 69 +/- 1.0 (SE) yr] to determine whether increases in muscle strength are associated with changes in cross-sectional fiber area of the vastus lateralis muscle. Twenty-seven healthy women were randomly assigned to either a control or exercise group. The program was satisfactorily completed and adequate biopsy material obtained from 6 controls and 13 exercisers. After initial testing of baseline maximal strength, exercisers began a training regimen consisting of seven exercises that stressed primary muscle groups of the lower extremities. No active intervention was prescribed for the controls. Increases in muscle strength of the exercising subjects were significant compared with baseline values (28-115%) in all muscle groups. No significant strength changes were observed in the controls. Cross-sectional area of type II muscle fibers significantly increased in the exercisers (20.1 +/- 6.8%, P = 0.02) compared with baseline. In contrast, no significant change in type II fiber area was observed in the controls. No significant changes in type I fiber area were found in either group. We conclude that a program of resistance exercise can be safely carried out by elderly women, such a program significantly increases muscle strength, and such gains are due, at least in part, to muscle hypertrophy.
NIA-supported researchers have been studying the effects of strength training for more than 40 years and have identified multiple ways it can benefit older adults, including maintaining muscle mass, improving mobility, and increasing the healthy years of life. Learn more below about these findings from NIA-supported researchers, along with their tips for maintaining strength or becoming stronger as we age.
Some people have a hard time gaining muscle no matter how much they lift, while others have a hard time losing weight even when focusing on aerobic activity. This variability from person to person is another area of current research both at NIA and the institutions it supports.
Derived from the Greek root words sarx (flesh) and penia (loss), sarcopenia is defined as a decline in muscle mass, strength, and function. It is often associated with older adults, but some forms of sarcopenia can also affect middle-aged people. Sarcopenia has been connected to weakness; fatigue; lower energy levels; and difficulty standing, walking, and climbing stairs. Sarcopenia is more likely to occur in people with chronic diseases and may contribute to risk of falls, fractures, other serious injuries, and premature mortality. Poor nutrition and lack of exercise can increase the odds of developing sarcopenia. If you or a family member is feeling general weakness, talk with a doctor. It could be related to sarcopenia or another medical condition.
NIA-supported scientist Roger A. Fielding, Ph.D., associate director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University outside Boston, is a strong proponent of continuing to push our muscles as we age. He leads multiple studies aimed at better understanding age-related changes in muscle structure and function and how adding resistance training can prevent frailty and improve mobility and independence.
Strength training (also known as resistance training) is different than aerobic exercises such as running, cycling, or walking. Weightlifting, either with machines or free weights, is one type of resistance training. Other types include using medicine balls or resistance bands, or body weight-bearing exercises such as pushups, squats, or yoga. Resistance training requires our muscles to contract to lift a heavy object against the pull of gravity.
The more weight we contract against, the faster our bodies burn through reserves of adenosine triphosphate (ATP), a molecule that carries energy to cells. As we lift weights or do other demanding exercises, our ATP reserves are replenished through a complex, coordinated metabolic and chemical response that cascades through the entire body, including sparking short-term chemical changes in the DNA of muscle tissue that make them more tuned to specific proteins supporting sugar and fat metabolism.
One of the big rewards for Villareal and his team is observing participants who make positive changes and stick with them. Some volunteers have even exceeded the 10% body weight loss target, losing as much as 20% of their body weight. The weight losses combined with building muscle mean they feel better and become more independent and mobile.
Move mindfully. Beavers points out that low bone density and muscle strength are associated with increased falls and fractures. Exercises that incorporate mindfulness with balance and movement, such as tai chi and yoga, can improve strength in these areas and help prevent falls and fall-related fractures.
Women over age 65 have a harder time preserving muscle than men of the same age, which probably affects their ability to stay strong and fit, according to research conducted at Washington University School of Medicine in St. Louis and the University of Nottingham in the United Kingdom.
In a paper published March 26 in the journal Public Library of Science (PLoS) One, Mittendorfer and her colleagues in the Division of Geriatrics and Nutritional Science at Washington University and at the University of Nottingham found that post-menopausal women are less able to use protein from their diets in order to build muscle mass. Men of the same age were able to store more dietary protein in muscle, they report.
The researchers studied 13 men and 16 women ages 65 to 80 who fasted overnight. The next day, investigators took muscle biopsies from each of the subjects, then gave them a protein drink and an intravenous infusion of amino acids labeled with tracer molecules that could easily be detected in muscle. Three hours later, the researchers took another muscle biopsy.
She says the hormone estrogen is necessary to help maintain bone mass both in women and men, and it also may play a role in preserving muscle mass. Beginning at age 50, people lose up to 0.4 percent of their muscle mass every year, making them less mobile, more prone to fractures and at risk for potentially life-threatening falls.
Rather than eating more food, Rennie and Mittendorfer say older people should focus on eating a higher proportion of protein in their everyday diet. In conjunction with resistance exercise, that could help to reduce the loss of muscle over time. They say there also may be a case for taking hormone replacement therapy in some form to help build muscle mass, but that must be balanced against other risks associated with such treatment, including heart disease.
Falls can be especially challenging for older people who are obese and who also have sarcopenia (the medical term for a loss of muscle strength as we age). Currently, 5 percent to 13 percent of adults older than 60 have sarcopenia. Those rates may be as high as 50 percent in people 80-years-old and older.
A team of researchers writing for the Journal of the American Geriatrics Society suggested that it is important to identify people at risk for falls related to obesity and muscle weakness so that healthcare providers can offer appropriate solutions.
Onset for DM2 ranges from the second to the seventh decade of life, often presenting with myotonia, weakness, or cataracts. In general, DM2 is a less severe disease than classic DM1. In most cases, weakness predominantly involves the proximal muscles, particularly the hip girdle muscles.2
Research suggests that, in DM1, there may be abnormalities in the parts of the brain that determine the rhythm of sleeping and waking, making excessive daytime sleepiness a barrier to full participation in work, school, or social life for many adults with the disorder. In some people, there is a kind of overall "apathy" that may be due to changes in the brain related to DM1. Also, in patients with DM1, cognitive skills are diminished, and the IQ has been shown to be lower with younger age of onset. In both classic DM1 and DM2, frontal lobe cognitive impairment (attention deficit) worsens over time but does not extend to other areas of cognition. Thus, cognitive problems do not show the same degree of deterioration over time that is typical of muscle dysfunction in DM1. 041b061a72