During a neuromuscular lab experiment, a subject’s biceps br…
During a neuromuscular lab experiment, a subject’s biceps brachii muscle is stimulated electrically at increasing frequencies. Initially, isolated twitches are observed. As the frequency increases, the twitches begin to summate, and partial relaxation between contractions becomes shorter. Eventually, the electrical stimuli become so rapid that no relaxation is observed at all between contractions. The muscle enters a state of sustained contraction with no visible fluctuation in force output. Question: Which of the following best describes the muscle contraction observed when no relaxation occurs between stimuli and the muscle remains in a continuous, forceful contraction?