1. Name and describe the methods by which the muscle system contributes to homeostasis and quality of life.
(1) movement - get goods, avoid harm
(2) support - so parts can work properly (e.g.,
bones, eyes, viscera)
(3) heat production - replace lost heat - for fast
chemical reactions
2. Describe the effects of aging on four of the following parameters for muscle cells and describe practical effects on maintaining homeostasis and quality of life from these age changes.
a. ability to be stimulated = slower
starting and stopping of contraction
- decr. efficiency
of motor end plate (smoother) + changes in action potentials (APs) (weaker,
slower, irregular) -> slower starting and stopping of contraction (incr.
refractory period)
b. storing and generating energy for
contraction = decr. energy storage and supply
- decr. storage
of ATP, C-P, and glycogen + decr. oxidative enzymes and mitochondria -
> decr. endurance from decr. energy storage and supply
c. ability to be stretched = decr. ability
to be stretched -> decr. range of motion
- decr.
# of sarcomeres -> decr. strength at stretched condition + decr. range
of motion
d. cell thickness
- little age
change BUT decr. exercise -> decr. thickness -> decr. strength, appearance
e. cell number
- decr. # of
muscle cells -> decr. thickness and decr. strength unless exercise hypertrophies
remaining cells
- more rapid
loss of Type II (fast twitch) muscle cells than Type I (slow twitch) muscle
cells -> decreased speed and strength of motions
f. ability to repair when injured
- no age change
-> retain ability to benefit from strength training
g. ability to thicken when exercised
- no age change
-> retain ability to benefit from strength training though slower hypertrophy
of muscle cells
h. proportions of different fiber types
- great
decr. in Type II fibers -> decr. speed and strength
3. Describe the effects of age changes in motor neurons and action potentials on muscle performance.
(1) decr. strength (from decr. # of motor neurons
-> incr. muscle cells are "orphaned")
(2) decr. precision of control (from motor
neuron "adoption" of abandoned muscle fibers -> incr. size of motor units)
(3) slower peak power, lower peak power, and
prolonged contractions (from slower and more varied motor neuron APs)
- effects = decr.
strength, decr. precision and accuracy of movement, decr. speed of starting
motion, decr. speed at repetitive motions
4. Describe the effects of age changes in neurons other than motor neurons (i.e., sensory, CNS) on muscle performance.
- decr. # and functioning - decr. speed, decr. strength, decr. accuracy, and decr. coordination
5. Describe the effects of age changes and disease changes in the circulatory system on muscle functioning.
- decr. maximum rate of work (from capillaries
- decr. #, thicker, narrower, more irregular, decr. # of pores -> decr.
exchange; From smaller arteries - decr. adaptability)
- atherosclerosis - decr. supply -> great
decr. maximum rate of work, great decr. functioning, great decr. thickness,
great decr. strength
6. Describe the effects of aging on muscle mass and name six effects from these changes.
- gradual decr. in mass, especially after
age 50, and especially with decr. exercise (from decr. # of muscle cells
and decr. thickness of muscle cells)
- effects =
(1) decr. strength
(2) decr. speed
(3) decr. coordination
(4) altered
posture
(5) altered
appearance and body proportions
(6) need for
decr. calories and diet modification
(7) need to
adjust medications due to altered % body fat vs % lean body mass
- NOTE: great variability
among people and among different muscles in a person because of variable
decr. in exercise
7. Describe the effects of age changes in the muscle system on (1) reaction time, (2) speed of motion, and (3) skill.
(1) incr. reaction time -> slower starting
an action
(2) decr. speed of motion -> decr. speed to
complete and action
(3) little change in skill for practiced motions,
but decr. ability for new skills
8. Describe the effects of aging on the four aspects of stamina; i.e., performing extended vigorous activity.
(1) decr. maximum rate of extended work ->
must "pace" slower
(2) decr. endurance for extended hard work
-> must "quit" sooner
(3) incr. recovery time (e.g., removal of
lactic acid)
(4) incr. stiffness and soreness after exercise
(from incr. lactic acid build-up)
9. Describe the effects of aging and changes in exercise on VO2 max and describe the effects from these changes.
- VO2 max = O2 used /
kg body weight / minute
- variable rate but gradual decline beginning
at age 20 for men and age 35 for women
- rate of decline related mostly to rate of
decline in exercise
- much of decline due to increase in body
fat and decrease in muscle mass
- little decline in VO2 max / kg
muscle / minute
- possible to slow or temporarily reverse
decline with increased exercise
- many reasons for decr. VO2 max
- normal
- incr.
body fat, decr. muscle mass, decr. cardiac efficiency, decr. speed
of cardiac and respiratory adaptability, decr. cardiac sensitivity to catecholamines,
decr. maximum minute volume, decr. respiratory efficiency (incr. residual
volumes, incr. work of breathing), decr. skeletal efficiency (respiration,
joints), decr. muscle extraction of O2 from blood, decr. capillary exchange
(thicker capillary walls, decr. capillary pores)
- abnormal
- atherosclerosis, heart disease, respiratory disease, skeletal diseases
(arthritis)
- effects from decr. VO2 max
(1) decr. maximum
rate of work
(2) faster onset
of fatigue
(3) with great
decr. VO2 max, limitations in ADLs and other ordinary activities
(4) social,
psychological, economic effects from reduced maximum work capacity and,
with great decr. VO2 max, limitations in activities
NOTE: effects amplified by decr. efficiency
of working (decr. efficiency of O2 use by heart, respiration,
joint stiffness), decr. coordination, altered movement patterns. Therefore,
a given decr. in VO2 max has greater effect in an older person
than in a younger person.
- effects of exercise
- decr. exercise
-> decr. VO2 max
- incr. exercise
-> slower decr. in VO2 max or temporary incr. VO2
max followed by slow decr. VO2 max
-
most incr. VO2 max from exercise from incr. O2 extraction
by muscles (other factors from above also improve)
10. Describe effects on the muscle system and three other systems - circulatory system, skeletal system, endocrine system; on quality of life; on diseases; and on life expectancy from staying physically active - i.e., maintaining high level of exercise.
muscle system
(1) slows decline
in stamina (maximum rate of work, endurance, post-activity soreness and
stiffness, recovery time
- due to (1) slower decr. in energy storage (ATP, C-P, glycogen), (2) slower
decline in oxidative enzymes, (3) slower decrease in muscle perfusion
(2) slows decline
in muscle mass
(3) slows decline
in strength
(4) slows decline
in insulin sensitivity
- # 2-4 due
to (1) slower decr. in muscle cell thickness, (2) slower loss of muscle
cells (especially Type II fast fatiguable fibers), (3) slower incr. in
muscle fat
(5) slower decline
ability for fast movements
- from (1) slower increase in reaction time and (2) slower decline in speed
of motion
circulatory system
- decr. risk of atherosclerosis
- decr. BP or slower rise in BP
- decr. LDLs, decr. cholesterol, incr. HDLs
skeletal system
- slows decline in
minerals, maintains joint mobility
endocrine system
- slows decline in
insulin sensitivity, maintains GH levels
quality of life
- retain physical
ability plus non-biological benefits derived therefrom
diseases
- decr. risk of developing
some diseases - e.g., atherosclerosis, heart disease, strokes, diabetes,
osteoporosis
- decr. severity of
diseases
life expectancy
- little increase
in life expectancy currently demonstrated, though increase is expected
11. Describe the effects from reducing levels of physical activity.
- no "bank account" from exercise
- "use it or lose it"
12. Describe effects on the muscle system and three other systems -
circulatory system, respiratory, nervous, skeletal, endocrine system; on
quality of life; on diseases; and on life expectancy from increasing activity
when older.
muscle
(1) incr. muscle mass
(2) incr. strength
(3) incr. speed of motion
(4) incr. stamina - all four parts including
VO2 max
- NOTE: same proportion of improvement
as in young person
-due mostly
to incr. cell thickness
circulatory
(1) incr. cardiac
output, incr. cardiac efficiency, incr. HDL/LDL ratio, incr. vessel diameter,
decr. BP, decr. arrhythmias
(2) incr. organ perfusion
(3) probably decr.
risk of atherosclerosis
respiratory
(1) slows decline
in respiratory functioning
(2) helps reduce effects
from COPD (incr. mucous clearance, incr. respiratory muscle function, decr.
airway collapse, decr. smoking)
nervous
(1) incr. speed of
CNS impulse processing
(2) incr. short term
memory
(3) improves sleep
(4) improves motor
neuron functioning -> incr. speed and strength
skeletal
(1) slows bone demineralization
(2) reduces risk of
osteoporosis
(3) improves joint
function = easier movement, incr. ROM
endocrine
(1) incr. insulin
sensitivity
- incr. glucose tolerance. decr. risk and severity of NIDDM
(2) slows decline
in growth hormone
- slows decline in organ size and function
quality of life, diseases, life expectancy
(as above)
miscellaneous
(1) weight regulation,
incr. nutrition by incr. amount and variety of foods eaten
(2) incr. independence
(3) improves, psychology
- e.g., incr. mood, incr. well-being, decr. boredom, decr. anxiety, decr.
stress
(4) incr. social contacts
(5) improves economic
status
13. Explain why exercise programs for older people must be individualized.
- increased heterogeneity as age increases
14. Name six important steps or considerations in planning an exercise program for elders.
- set goals
- evaluate participants before beginning and
after participation in the program for a while (e.g., several weeks)
- individualize the program for each participant
- adjust the program according to the
progress of the participants
- include modifications in nutrition in the
program to accommodate for the increase in physical activity and altered
metabolism
- take steps to minimize injuries and risks
from possible abnormalities or diseases present in the participants
- alter the nature of the exercises to avoid
boredom and maintain interest
- provide positive feedback to maintain interest
and motivation
- consider implementing "alternative practical"
exercises such as activities of daily living (ADLs), hobbies, etc.
15. Describe effects of age changes and abnormal changes on ability to drive motor vehicles.
- slower and weaker responses
- increasing difficulty solving complicated
or novel problems
- declining vision
- declining hearing
- decreasing ability to stay mentally focused
on tasks
16. Explain why driving a motor vehicle is important to many elderly.
- important for quality of life, psychological health, social well being, economic efficiency, access to needed services
17. List ways by which adequate transportation can be retained longer in spite of age changes.
- ongoing education, training, and evaluation
of motor vehicle driving skills
- providing alternate sources of transportation
for non-driving elders
© Copyright 1999 - Augustine G. DiGiovanna - All rights reserved.
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PERSPECTIVES by Augustine G. DiGiovanna, The McGraw-Hill Companies, New
York, 1994 or 2000; (2) If prior written permission is obtained
from Augustine G. DiGiovanna.