Muscle Fatigue
Muscle contractions are essential for muscles to function properly. The inability of a muscle to maintain tension is muscle fatigue. Failure to contract may occur because of the accumulation of lactic acid, a lack of ATP, or decreased blood flow. In this exercise, you will investigate the correlation between repeated movements and muscle fatigue.
| Materials
Rubber Band |
Stopwatch |
Note: If you suffer from a medical condition that does not permit you to perform this activity, please ask a partner to volunteer for you.
Procedure
1. Hypothesize how many times you can stretch a rubber band between your thumb and pinky finger in 20 seconds. Record your predictions in the table below.
2. Using your dominant hand, count the number of times you can completely stretch a rubber band between the thumb and pinky finger in 20 seconds. Be sure to stretch the rubber band as far as possible each time and do not take a break in between trials.
3. Record your count for each trial in Table 1.
| Table 1: Experimental Counts | |||||
| Trial 1 | Trial 2 | Trial 3 | Trial 4 | Trial 5 | |
| Predicted Value | |||||
| Actual Value |
Post-Lab Questions
1. How did the predicted results compare to the actual results?
2. Did you notice any changes in the number of repetitions you could perform, or how your hand felt after each of the trials?
3. Explain the actions that were occurring at the cellular level to produce this movement. Include sources of energy and any possible effect of muscle fatigue.
4. Hypothesize what would happen if blood flow was restricted to the hand when this experiment is performed.