Muscle Twitch and Energetics Quiz

Which phase of a muscle twitch is associated with the time delay between stimulation and contraction?

• Contraction phase

• Relaxation phase

• Latent period

• Recovery phase

What characterizes the latent period in a muscle twitch?

• Muscle fibers generate tension

• Calcium ions are released into the sarcoplasm

• Cross-bridges detach from actin

• Muscle fibers fully relax

Muscle tone refers to:

• The maximum force produced by a muscle

• The complete relaxation of a muscle

• A sustained partial contraction of a muscle

• The absolute refractory period of a muscle

Muscle tone is primarily important for:

• Maximizing force production

• Enhancing muscle relaxation

• Maintaining posture and readiness

• Increasing muscle size

Wave summation occurs when:

• Successive stimuli are delivered before a muscle can relax completely

• Muscle fibers contract in a coordinated manner

• Motor units alternate to sustain a contraction

• A muscle fully relaxes between stimuli

Temporal summation increases muscle contraction strength by:

• Increasing stimulus intensity

• Increasing stimulus frequency

• Increasing motor unit recruitment

• Increasing muscle relaxation time

The staircase effect, or treppe, is observed when:

• A muscle is continually stimulated at the same intensity

• A muscle shows increasing contractions with repeated, identical stimuli

• A muscle undergoes a tetanic contraction

• Muscle fatigue is reached

Which factor contributes to the treppe effect?

• Increase in calcium ions availability

• Decrease in ATP levels

• Increase in muscle relaxation time

• Decrease in temperature

Which of the following does NOT cause treppe?

• Elevated internal calcium levels

• Increasing stimulus frequency

• Muscle warming

• Accumulation of lactic acid

Incomplete tetanus is characterized by:

• A smooth, sustained muscle contraction

• A relaxation period between each contraction

• Complete relaxation of muscle between contractions

• No observable muscle contraction