Lab Exam #1 Flashcards
small motor units
fine muscle control
large motor units
high force
location of cell body of motor neuron
spinal cord
why do fast twitch motor units transport signal faster than slow twitch
because of thick myelinated axon
fast twitch motor neurons
large cell bodies
thick myelinated axon
require higher level of neural stimulation to depolarize
used during max. efforts
slow twitch motor neurons
smaller cell bodies
thinner less myelinated axons
require lower level of neural stimulatiion to depolarize
get first recruited
amplitute of a EMG
increases the higher the force is
what occurs before neural fatigue
local muscle fatigue
motor units recruited at a slow speed of motion
slow- and fast twitch
who will generate greater force at slow speed of motion; sprinter or endurance, why?
a sprinter will generate greater force, since he has more FT motor units - those have higher actin-myosin binding sites
what happens to force generated when speed increases
force decreases since less ST motor units get recruited as speed increases
endurance vs. sprinter force generation as speed increases
endurance athlete will produce less force since he has more ST motor units
sprinter will experience a smaller decrease in force production since he has more FT motor units
what is the speed a muscle can contract is usually based on
thickness of axon myelination
intramascular stores of myosin ATPase
between an endurance athlete and a sprinter who can generate greater force over time when fatigue occurs
endurance, since he has a higher ST muscle contribution
how do ST motor units generate greater force over time when fatigue occurs
greater capillarization
higher intramuscular concentration of myoglobin, mitochondria and oxidative enzymes
what is the max tension a muscle can generate based on
amount of actin and myosin binding
when we increase speed of a movement, which muscle types stop working first
ST motor units
formular for work (kgm)
force (kg) x distance (meters)
what does anaerobic power measure or reflect
the development of phosphagen metabolism
highest work performed in the first 5 sec
what does Anaerobic capacity meausre or reflect
the development of phospagen anaerobic glycolytic metabolism
total work performed in first 30 sec.
what does the fatigue index measure or reflect
oxidative capacity of a muscle
percent decline in work completed (first 5 sec. and compared to last 5 sec.)
high fatigue index
low oxidative capacity of muscle tissue
low fatigue index
high oxidative capacity of muscle tissue
what does body weight determine
optimal pedalin resistance