Chapter2 Flashcards
Four results of muscle impairment
Muscle weakness
Slowness of movement
Loss of muscle power
Early muscle fatigue
By age 80 what percent of muscle strength is gone
40 -50 percent, also alpha motor neurons, and muscle cells
Motor unit changes in the elderly
Denervation of fibers, followed by reinervation by surrounding motor units resulting in larger motor units
Larger motor units cause what
Increased contraction and duration with decreased fine motor control and decreased speed of relaxation affecting coordination
Sarcopenia
Loss of muscle mass in elderly
Percentage of strength decline
8% per decade from 30-40 on ( Schiller 2000)
Therapy is not on.y to regain strength but also
Increase functional reserve
4 age related muscle changes
Decreased muscle mass
Increase fatigue
Increase fat in muscle
Increase connective tissue in muscle
Age related muscle changes can be altered by what 3 things
Exercise
Nutrition
Hormonal supplements
Muscle weakness is due to what 3 things
Decreased ability to activate muscle mass
Decreased quantity of muscle tissue(cross bridges)
Decrease force generated by cross bridges
3 changes in neural mechanisms
Undefined changes
Delay in conduction velocity
Delay in transmission
In Vivo muscle twitch is
Max velocity of a single muscle fiber
Characteristics of elderly in Vivo muscle contraction
Prolonged contraction with 50%delay in muscle relaxation impairing alternating movements and protective reactions during falls
5 Muscle changes that cause decreased endurance
Decreased blood supply and capillary density
Impairment of glucose transport
Lower mitochondrial density
Decreased activity of oxidative enzymes
Decreased rate of phosphor eating repletion
Muscle protein synthesis does what with age
Declines
Which protein is most important in skeletal muscle
MyHC
What happens to MyHC with age
Decreased production
Increased cytokines levels or inflammation cause what
Decreased IGF-1 an important modulator of muscle mass
A cytokine causes what
Inflammation
IL-6 is a cytokine which does what
Increase inflammation
Predicts level of disability in adults
Blocks Ifg-1 production
Low IFG-1 results in what
Poor knee ext strength
Slower walk speeds
Decreased mobility
