As Good As It Gets: Muscles in Octogenarian Women
Dont Get Stronger With Exercise
Study says women need to start exercising earlier
to build strength that will last
Ellen Prouty, 80, participates in a
strength-building study conducted by Dain LaRoche. See box below for
more on this earlier study.
March 31, 2009 - Octogenarian women were unable to
increase muscle mass after a 3-month weight lifting program targeted at
strengthening the thigh muscle, according to a new study from the
Journal of Applied Physiology. The researchers say the results are
surprising because previous studies have found resistance training
capable of increasing muscle mass, even for people who are into their
70s. A study reported last October in SeniorJournal.com found, however,
that older women could build strength but not sustained muscle power.
An increase in muscle size translates to an
increase in strength, according to this new study. (See reference to
earlier story in box on this page.)
Still, the Ball State University study contained
some good news: The octogenarians were able to lift more weight after
the training program, likely because the nervous system became more
efficient at activating and synchronizing muscles.
The American Physiological Society published the
study, Improvements in whole muscle and myocellular function are
limited with high-intensity resistance training in octogenarian women.
The researchers are Ulrika Raue, Dustin Slivka, Kiril Minchev and Scott
Trappe.
Key to muscle power for seniors is to maintain it
over the lifespan rather than try to develop it later in life
Oct. 23, 2008 - Elderly women can increase muscle
strength as much as young women, a new study from the University of
New Hampshire finds, indicating that decline in muscle function is less
a natural part of the aging process than due to a decline in physical
activity. But, the senior citizens did not build power.
Read more...
The experiment involved six women, all in their
80s, all of whom lived independently and came to the laboratory three
times a week for three months. The women exercised on a machine designed
to strengthen the thigh (quadriceps) muscle. They did three sets of 10
lifts, with a 2-minute rest period between sets.
The researchers measured the size of the womens
thigh muscle using an MRI, before the exercise program began and after
it ended. They also took biopsies from the thigh muscles, which they
used to track muscle changes at the cellular level.
The biopsies included both fast-twitch and
slow-twitch muscle fibers. Fast-twitch muscles are high powered and
explosive and are associated with anaerobic exercise. Slow-twitch are
associated with aerobic tasks, including endurance exercise such as
marathons.
Fast-twitch muscles are important in posture and
balance and so may be of particular importance for the elderly, who are
more prone to falls. When people do not use their muscles during a
period of convalescence or with a sedentary lifestyle, the fast twitch
muscles lose functionality and atrophy more quickly than slow-twitch.
From the muscle biopsies, the researchers isolated
single muscle strands, both fast-twitch and slow-twitch. They measured
the strength, speed and power of each fiber and examined the genetic
profile of these strands.
No change in muscle strength
As a result of the exercise program, the
octogenarians were able to increase the amount they could lift with
their quadriceps by 26%. That was the good news. The bad news was that
the pre- and post-training MRIs showed that the training did not change
their muscle size. This was surprising because an earlier study had
found that 70-year-old women gained 5% muscle mass with resistance
training.
The biopsy results confirmed the MRI results: there
was no change in the size of the individual muscle strands, pre-training
versus post-training. This confirms that the increase in the amount the
women could lift with the quadriceps was unrelated to improvement in
muscle strength. Instead, the results were probably due to improvements
in how efficiently the nervous system was able to activate and
synchronize the muscles.
In an earlier study, the researchers found that the
muscles of octogenarian men also failed to gain strength with the
exercise program. Together, the studies show that the muscles of
octogenarian men and women are far less responsive to improving with
exercise, even compared to people only 10 years younger.
The message of the study is that exercise is good
for octogenarians, just not as good as we thought it would be, Dr.
Trappe said. The study also suggests that it is better to build as much
muscle mass as possible earlier in life to ensure more muscle strength
in later life. We should do all we can to educate people to build up
the muscle before 80, he said.
Next steps
Muscle atrophy relates not only to aging, but to
people whose muscles are immobilized for a period and even for
astronauts who spend long periods of time in space. Dr. Trappe, who also
does research on astronauts, next wants to begin to uncover the
physiological basis for why the muscles of octogenarians do not gain
strength with resistance exercise.
His team may be able to build on two intriguing
findings from the current study:
● while the octogenarian women had many fewer
muscle fibers, the fibers they did have were large and healthy looking
● the genes involved in muscle growth are
present in the resting muscle of the octogenarians at much higher levels
compared to young people.
These results suggest that the octogenarian muscle
is already operating at peak capacity and may not have the potential for
better performance, Dr. Trappe said. If these mechanisms can be
understood, it may be possible to find ways to strengthen older muscles.
Physiology is the study of how molecules, cells,
tissues and organs function to create health or disease. The American
Physiological Society (APS) has been an integral part of this scientific
discovery process since it was established in 1887.
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