Online Lab Muscle Function

I wanted to get an idea of how my muscles responded in certain situations. The situations tested were muscle contraction vs. relaxation, muscle reaction to cold, and muscle reaction to fatigue. The tools I used to conduct this experiment can be seen in the photo below.

A bowl of ice cold water, a strip of paper, a rubber ball, and a stop watch.

1. What are the three changes you observed in a muscle while it is working (contracted)?

The muscle became firm to the touch and slightly raised. The circumference of my arm also increased by about half an inch when I formed a fist.

2. What effect did the cold temperature have on the action of your hand muscles? Explain.

My muscle seem ed to get stiffer and slower to respond. I was able to form a fist far fewer times after the cold water. Are my blood vessels constricting to preserve heat and therefore depriving the muscles of needed oxygen?

Soaking my hand in the ice water.

3. In Figure 3, make a line graph of your results of the fatigue experiment. Be sure to fill in the values on the vertical axis.

My graphed results

4. What effect did fatigue have on the action of your hand muscles? Explain.

First of all my arm muscles began to ache. Second, they began to respond more slowly and did not feel as coordinated. The amount of squeezes every 20 seconds began to steadily decline.

Squeezing the ball during the fatigue experiment.

Illustration taken from www.rogers.k12.ar.us/.../musclenotes.html showing how a muscle contraction works.

I think the reason on the cellular level that my muscles responded the way they did to the cold has to do with cell respiration (maybe). Are the cells possibly not getting as much oxygen because my body is responding to the cold? I know that cells require oxygen in order to produce ATP unless they kick into anaerobic mode. I believe that that is the case with the fatigue exercise. After a certain amount of time my muscles kicked into anaerobic mode for energy which can only be sustained for short bursts.