Motor Control and Recruitment Flashcards
what is a twitch?
a single electrical signal from the brain to the muscle
What can change in the action potential signals?
strength CANNOT change, but frequency CAN change
what happens when multiple impulses are sent?
twitch summation (wave summation)
- we are going to get more force of contraction
what is a complete tetanus?
when the force of the muscles involved are at their maximum output
What is the length of our sarcomere going to impact?
the amount of tension that can be developed
equation for total muscle tension
active + passive tension
active tension: tension generated via muscle contraction
passive tension: tension generated through stretch caused by external force (ex. dumbbell)
what is the length-tension relationship?
- the amount of force produced also depends on the starting position (resting length) of the sarcomere
- too stretched: reduced capacity for crossbridge formation
- too much overlap between actin filaments: crossbridges interfere with each other
- the optimal length is 80-120% of our resting muscle length
what is a motor unit?
a single motor neuron and all the fibers that it innervates
what are the two main types of muscle fibers?
type I and type II
- all muscle fibers innervated by the same motor neuron are the same type of fiber
what happens if we need more force?
we recruit more motor units
- principle of orderly recruitment: states that motor units are always recruited (“fired”) in the same order
what does strength training do for orderly recruitment?
- it increases the number of motor units recruited
- improves the efficiency and speed of recruitment
what are the two ways we can produce more force?
- frequency of electrical impulse / twitch summation
- recruitment of motor units
what is affected based on the type of activity that is being done?
- different muscle fibers
- different energy systems
what is the type I muscle fiber?
- oxidative
- slow twitch
what is the type IIb (x) muscle fiber?
- glycolytic
- fast twitch
