Agerelated Muscle Changes

Agerelated Muscle Changes

AgeRelated Muscle Changes
One of​ the hallmark features of​ aging is the loss of​ muscular mass and ​ strength. ​
Much of​ this loss can be explained by changes to the neuromuscular system such as​ decreased number of​ motor neurons, decreased number of​ muscle fibers, and ​ decrease muscle fiber size. ​
But it​ is important to ask whether these changes are a​ consequence of​ aging or​ simply a​ result of​ an inactive lifestyle.
AgeRelated Changes to Muscle
The age related decline in muscle mass appears to occur in 2 phases. ​
The first or​ slow phase of​ muscle loss, in which 10% of​ muscle mass is lost, occurs between the ages of​ 25 and ​ 50. ​
The majority of​ muscle loss occurs thereafter where an additional 40% is lost from the ages of​ 50 to 85. ​
Overall, the human body loses 50% of​ its muscle mass by the age of​ 80. ​
This muscle atrophy can be explained by significant decreases in both the total number of​ muscle fibers, as​ well as​ in muscle fiber size.
It has been shown that aging results in a​ loss of​ the power and ​ speed producing fast twitch fibers particularly IIb and ​ an increase in the more aerobic slow twitch fibers. ​
This seems to make sense since movements that demand a​ high velocity of​ contraction such as​ jumping and ​ sprinting tend to be less in the older years. ​

Mechanisms of​ Strength Loss
The problems with decreasing strength can be seen in its contribution to osteoporotic decline in bone density, arthritic joint pain, and ​ an overall reduced functional capacity.
With the loss in muscle mass evidently comes a​ decrease in muscular strength. ​
However, as​ with muscle loss, most strength losses are not significant until the sixth decade. ​
as​ briefly mentioned, this loss in strength can be attributed to a​ decrease in the number of​ motor units nervemuscle fiber complex, the decreased number of​ muscle fibers and ​ the reduction in muscle fiber size. ​
it​ is also known that a​ decline in leg strength precedes upper extremity strength loss in the elderly. ​
This is important due to the fact that strength, rather than cardiovascular function, is considered to be the most physically limiting factor in the elderly. ​
This is apparent when considering strengthlimiting activities faced by many seniors such as​ getting up from a​ seated position or​ walking up stairs.
Encouraging is the finding that aging does not seem to effect eccentric strength. ​
This phase of​ contraction is an important consideration for the elderly due to the possible linkage 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 ​ counteract the effects of​ agerelated muscle and ​ strength loss. ​
Comparisons between active and ​ sedentary older adults suggest that much of​ the strength loss with aging is due lifestyle factors. ​
For example, individuals who continue to use certain muscles on a​ regular basis do not show the same agerelated decreases in strength. ​
In general, muscle atrophy, and ​ thus strength loss, will occur any time the muscles are not required to work against a​ given load. ​
The result will be a​ decrease in protein synthesis accompanied by an increase in protein breakdown. ​
Overall, the muscle atrophies and ​ loses much of​ its strength, characteristics commonly seen in astronauts during space flight. ​
Incorporating regular resistance training is the most effective means of​ attenuating this effect.
Encouraging Findings
Studies have consistently shown that regular exercise can improve muscular endurance and ​ strength in the elderly in a​ manner similar to that observed in young people. ​
One of​ the largest studies in this field was done at ​ McMaster University several years ago. ​
The researchers looked at ​ the effects of​ 2 years of​ twice/weekly strength training 8085% 1RM across 114 subjects between the ages of​ 6080 years. ​
The results indicated steady increases in strength in each of​ the muscle groups tested with no evidence of​ plateauing. ​
There were also significant increases in muscle mass accompanying the gains in strength and, perhaps more importantly, there was evidence that these strength gains translated into improved function as​ measured by walking and ​ stair climbing performance.
Although there are certain unavoidable changes that occur with aging, it​ is possible to delay or​ attenuate the losses muscle mass and ​ strength normally accompanying these changes. ​
Since so many daily living activities such as​ walking, climbing stairs, and ​ standing up from a​ chair are so dependent on strength it​ is imperative to minimize the agerelated loss in strength as​ much as​ possible. ​
The muscles in older adults maintain their ability to adapt; therefore, regular resistance training 23x/week should be implemented into the lifestyle of​ such individuals. ​
Moreover, a​ similar strength training protocol needs to be employed in younger adults as​ means of​ prevention and ​ staying healthy into the golden years!
Written by Yuri Elkaim, BPHE, CK. ​
Do not reprint without permission
Copyright 2018 Total Wellness Consulting.

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