3+ 4/2002 - Společnost pro pojivové tkáně

Secondly, we immobilised young healthy
subjects by strict bed-rest over 90 days
(Long Term Bed Rest = LTBR study). In both
groups, the muscle-bone relationship was
investigated by peripheral computed
tomography of the lower leg, and jumping
force and power was measured on a ground
reaction force plate.
As expected, immobilisation led to
areduction of muscle mass, muscle force
and muscle power, and subsequently to
losses of bone mineral content in the leg.
Moreover,balance control was affected.The
subjects recovered from these changes
within different time ranges, depending on
their physical efforts. Recovery appeared to
be complete.
In the veteran athletes, muscle force
and power turned out to be significantly
and substantially greater than in age
matched controls, but not if compared to
younger subjects.
In conclusion, the effects of immobilisation
are apparently completely reversible,
whereas the physiological process of aging
is irreversible and can at best only be slowed
down, even by extensive exercise.
The LTBR study is sponsored by ESA
and carried out by MEDES / Toulouse. This
contribution has been supported by the
DLR (50 WB 0156)
IMPACT OF SARCOPENIA ON AGING
D. D. Thompson
Pfizer Global Research and Development Pfizer, Inc.,
Groton, Connecticut 06340, USA
Age-related loss of muscle (sarcopenia)
in the elderly has a significant impact on
morbidity, mortality and healthcare costs.
This reduction of muscle mass in the elderly
results in reduced strength and performance
and compromises the quality of life.
98
LOCOMOTOR SYSTEM vol. 9, 2002, No. 3+4
One serious consequence of sarcopenia in
the elderly is an enhanced propensity to fall
and suffer injuries from the fall. It has been
reported that approximately 30 % of individuals
> than 65 years of age and 50 % of
individuals > than 80 years fall each year.
Also, 10 % of these falls result in serious
injury and about 4 – 6 % result in skeletal
fractures. In the U.S., the average cost of
hospitalization due to falls among the elderly
is about $12,000. Approximately onethird
of all admissions to long-term institutional
care of the elderly is directly due to
loss of physical performance resulting from
poor muscle strength. With the 65 year old
plus segment of the population growing at
the highest rate, the impact this changing
demographic profile will have on healthcare
systems throughout the world will be
substantial. In 1900, the percentage of the
world's population that was 65 + yrs of age
was less than 1 %. In 1992 this increased to
about 6.2 %. In 2050,the percentage of individuals
in the population is expected to increase
to greater than 20 %. Thus, it will
become an important healthcare imperative
to develop strategies that will improve
physical strength and performance in the
elderly to prevent falls leading to loss of
independence, quality of life and high
healthcare costs.
STRENGTH AND FATIGUE IN AGEING
HUMAN MUSCLE
S.D.R. Harridge
Department of Physiology, Royal Free & University College
Medical School, Rowland Hill Street, London NW3
2PF, UK
Muscle strength, defined as the amount
of force a muscle may produce during
a maximum voluntary isometric contraction,
declines with increasing age. Cross-