9.7: Activity 6

Hypothesis

If muscle fatigue is induced in the dominant hand, then the number of beans moved within 60 seconds will decrease compared to the number moved before fatigue, demonstrating that muscle fatigue negatively affects fine motor skills.

Variables

• Independent Variable: Muscle fatigue (before and after inducing fatigue).
• Dependent Variable: Number of beans moved in 60 seconds.

Materials

• Beans (any small type, such as kidney or pinto beans)
• Beaker, cup, or mug (with an opening smaller than a fist)
• Stopwatch or timer

Procedure

• Part A Fine Motor Skills Before Muscle Fatigue:
  • The subject will move beans from a tabletop into the cup using only the thumb (1st digit) and ring finger (4th digit) of their dominant hand.
  • When the timekeeper says "go," the subject will start moving the beans one at a time for 60 seconds.
  • Record the number of beans moved in Trial 1 in the data table.
• Part B Fine Motor Skills After Muscle Fatigue:
  • To induce fatigue, the subject will make a tight fist and hold it for 3-5 minutes until they feel fatigued.
  • After the fatigue is produced, the subject will move beans again using the same method as in Part A, for another 60 seconds.
  • Record the results for Trial 1 in the “after fatigue” column.
• Repeat Trials:
  • Repeat the steps of Parts A and B for Trials 2 and 3, ensuring to record the number of beans moved in each trial.

Reflection Questions

1. What conclusions can you make about the effect of muscle fatigue on fine motor skills for your subject?
2. Did the subject’s performance improve after fatigue? If so, why do you think this could have happened?
3. Select (circle) the type of muscle fibers (slow-twitch or fast-twitch) and their characteristics in the muscles of the hand. Why? Justify your selection based on your understanding of muscle physiology.