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Tuesday, January 15, 2013

Age-Related Muscle Changes

One of the hallmarks of aging is the loss of muscle mass and strength. Much of this loss can be explained by changes in the neuromuscular system such as reducing the number of motor neurons, reduction in the number of muscle fibers, and to decrease the size of the muscle fibers. But it is important to ask whether these changes are a consequence of aging or simply due to an active lifestyle.

Age-related changes in muscle

The age-related reduction in muscle appears to occur in two phases. The first phase or "slow" muscle loss, which loses 10% of muscle mass occurs between the ages of 25 and 50. Most of the loss of muscle mass occurs as a result, which loses an additional 40% of the age of 50 to 85. In general, the body loses 50% of its muscle mass at age 80. This muscular atrophy can be explained by a significant decrease in either the total number of muscle fibers as well as the size of the muscle fiber.

E 'has been demonstrated that aging results in a loss of power output and speed of fast-twitch fibers (IIB in particular) and increased more aerobic slow twitch fibers. This seems to make sense that movements requiring high speed of contraction (eg, jump and run) tend to be less age.

The mechanisms of loss of strength

The problems with decreasing strength can be seen in its contribution to decreased bone density osteoporosis, arthritis, joint pain, and total functional capacity.

With the loss of muscle mass is obviously a decrease in muscle strength. However, as for the loss of muscle the majority of the power loss is not significant until the sixth decade. As mentioned briefly, this loss of strength may be attributed to a decrease in the number of motor units (muscle and nerve fiber complex), reduction in the number of muscle fibers and the reduction in the size of muscle fibers. It is also known that a decrease in strength of the leg precedes the loss of strength of the upper extremities in the elderly. This is important for the fact that the strength, rather than cardiovascular function, is considered the most limiting factor in the elderly physically. This is evident when you consider the activities-force limiters facing many seniors, such as rising from a sitting position or climbing stairs.

Promotion is the finding that aging does not seem to eccentric strength. This phase of contraction is an important consideration for the elderly because of the possible link between poor eccentric strength and the incidence of falls in the elderly.

The Importance of Active Living

Regular exercise is the most effective way to slow and reverse the effects of muscle loss associated with aging and strength. The comparison between the active and sedentary older adults suggest that most of the loss of strength with aging is due lifestyle. For example, people continue to use certain muscles regularly not show the same age related decrease in strength. Low overall loss, muscle atrophy, and therefore occurs when the muscles do not have to work against a given load. The result will be a decrease in protein synthesis, accompanied by an increase in protein catabolism. In general, the muscle atrophies and loses much of its strength, characteristics commonly seen in astronauts during spaceflight. The integration of the formation of normal strength is the most effective way to mitigate this effect.


Encouraging Findings

Numerous studies have shown that regular exercise can improve endurance and muscle strength in the elderly in a manner similar to that observed in the young. One of the largest studies in this field was conducted at McMaster University for several years. The researchers examined the effects of two years of strength training twice / week (80-85% 1RM) of 114 subjects aged 60-80 years. Results indicated an increase in the force constant of each of the muscle groups tested without evidence of stagnation. There was also a significant increase in muscle mass that accompany strength gains and, perhaps most importantly, there was no evidence that these gains strength function resulted in better (in terms of performance and walking up stairs).

Although there are some inevitable changes that occur with aging, you can delay or attenuate the loss of muscle mass and strength normally associated with these changes. Given that many everyday activities such as walking, climbing stairs and rising from a chair are so dependent on the strength is essential to minimize the age-related loss of force as much as possible. The muscles of older people to remain adaptable, therefore regular endurance training (2-3x/week) should be implemented in the lifestyle of these people. On the other hand, a strength training protocol for use in young adults as a means of prevention and staying healthy in the golden years!

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