MEAUREMENT OF THRESOLD STIMULUS

LABORATORY REPORT Activity 2 Twitch Contractions and Summation Name Instructor Date PREDICTIONS Effect of Muscle Fiber Length on Contraction 1. As muscle fiber length increases Effect of Stimulation Frequency on Contraction 2. As the frequency of stimulation increases, the force of contraction MATERIALS AND METHODS Measurement of Threshold Stimulus 1. Dependent Variable 2. Independent Variable 3. Controlled Variables Effect of Muscle Length on Contraction 1. Dependent Variable 2. Independent Variable 3. Controlled Variables Effect of Stimulation Frequency on Contraction 1. Dependent Variable 2. Independent Variable 3. Controlled Variables 4. What structure was stimulated to cause a muscle contraction 5. Explain why the temperature of the water bath was 35C (95 F). 6. At a stimulation frequency of 15 Hz how many stimuli were there per second RESULTS See Table 4 Measurement of Threshold Stimulus See Graph Effect of Stimulation Value on Twitch Contraction Force 1. What is the threshold stimulus 2. What is the maximum force generated at the threshold stimulus 3. How does increasing voltage above threshold stimulus affect force development See Table 5 Muscle Length and Contraction Force See Graph Effect of Muscle Fiber Length on Contraction Force 4. What was the force of contraction at a muscle length of 7.0 mm 5. What was the optimal muscle length (muscle length that generated the maximum force) 6. What was the maximum force generated at optimal length 7. How does increasing muscle fiber length affect force of muscle contraction See Table 6 Stimulation Frequency and Contraction Force See Graph Effect of Stimulation Frequency on Contraction Force 8. What was the force of contraction at a stimulation frequency of 22.5 9. At what frequency of stimulation was the maximum force generated 10. What was the maximum force generated in this experiment 11. How does increasing stimulation frequency affect force production DISCUSSION 1. Explain why muscle contraction