1. As you increase voltage to the muscle describe how it responds to the increased stimulus.
As the voltage was increased from threshold to maximum voltage, there was a greater force in the muscle contraction. Once the maximum voltage (2500 mv) was reached, even if there was an increase in voltage, the force of the muscle contraction remained the same.

2. What was the smallest voltage required to produce a contraction (the threshold voltage)? What proportion of the fibers in the muscle do you think were contracting to produce this small response?
0.2500V , a small contraction of all the muscle fibers

3. What was the smallest voltage required to produce the maximum (largest) contraction? What proportion of the fibers in the muscle do you think were contracting to produce this maximal response?
0.6500V, all muscle fibers contracted maximally.

4. What do you conclude happened to the number of fibers contracting as the voltage was raised from threshold to that required to produce a maximal contraction?
As the stimulus voltage is increased past the muscle’s threshold voltage, the amount of force in the entire muscle increases. Each time the voltage was increased the force generated from the muscle also increased. This occurs because, as the voltage increases, and is delivered to the whole muscle, more fibers are activated. This causes the total force produced by the muscle to increase.

5. In light of the all or none law of muscle contraction, how can you explain the graded response?
Although all of none determines how a single fiber reacts, the assessment of fibers in bulk depends upon the proportion of fibers stimulated. There is no reason to believe that there is a single threshold for fiber activation, but over a range, a greater proportion of fibers will be recruited. On the other hand, experimental modes can produce paradoxical responses.