All or none principle and muscle tension factors

relaxation phase

follows contraction phase, lasts about 50 milliseconds

maximal stimuli

stimuli strong enough to produce action potentials in all motor units of a particular muscle

submaximal stimuli

stimuli that are strong enough to produce action potentials in additional motor units

threshold stimulus

stimulus is strong enough to produce action potential

What are the phases of a muscle fiber contraction/twitch

stimulus, latent period, contraction phase, relaxation phase

When would the number of muscle fibers being recruited increase

Activate neurons containing greater number of fibers, activate more motor neurons, or increase the frequency of motor unit activation

What is the all or none principle?

All of the muscle fibers in a motor neuron or none at all

sub threshold stimulus

Not strong enough to cause an action potential so it does not result in a contraction

Summation

Successive stimuli are provided before relaxation phase

latent period

brief period of a few milliseconds following a stimulus

contraction phase

muscle fiber begins shortening, lasts about 40 milliseconds

Treppe

occurs when multiple maximal stimuli are provided to rested muscle at a low frequency to allow complete relaxation between contractions (dead lift). Second is contraction provides more tension than the first, third provides more tension than the second, then every contraction afterwards produces same amount of tension

Tetanus

occurs when stimuli are provided at a high frequency so that no relaxation can occur between contractions

Characteristics of the consecutive stimulus in treppe

slight increase between first 3. After 3, equal tension is produced