Biology 1 HN Period 2
Title: The effect of hand dominance on anaerobic threshold
Background Information: After running a mile or two in gym class, you may feel “tired” and “sore”, but do you really know what that means? It means that you have been performing anaerobic cellular respiration because you have reached your anaerobic threshold and your muscles have become fatigued. When at rest and when oxygen is plentiful, a person performs aerobic cellular respiration and produces a lot (36) of usable energy called ATP. When depleted of oxygen, a person reaches their anaerobic threshold and performs anaerobic respiration (lactic acid fermentation), “an” meaning no and “aerobic” meaning oxygen. Only 2 ATP are produced during anaerobic respiration. During lactic acid fermentation, in addition to the 2 ATP being produced, lactic acid is also being produced. The lactic acid enables muscles to produce energy when oxygen is not available. The lack of energy being produced, the lack of oxygen available, and the production of lactic acid are all factors that contribute to the feeling of being tired and sore.
Experimental Design: The independent variable of this experiment is the hand that is used to pinch the clothes pin. The dependent variable is the number of pinches performed in the allotted 20 seconds. The type of clothes pin will remain the same throughout all of the trials as well as the time allotted for each trial and the fingers used to perform the exercises.
The purpose of this experiment is to demonstrate how muscle fatigue corresponds with the anaerobic threshold. Also, to take that one step further, this experiment tests whether a person’s dominant hand or non-dominant hand has a higher anaerobic threshold. I hypothesized that if a person’s dominant hand squeezes a clothes pin, then they will be able to perform more repetitions than with their non- dominant hand because the muscles in their dominant hand have a higher aerobic threshold due to the fact that the muscles in the dominant hand are stronger and used more frequently.
Methods: First obtain a clothes pin and make sure you have a firm grip between the index finger and thumb to make sure it won’t slip while performing the pinches. Then with your other hand, set a countdown timer for 20 seconds and begin the pinches as soon as the timer begins to count down. At the end of the 20 seconds, you need to stop only to record the number of pinches in your data table. Repeat this step for all 10 trials of the dominant hand and then again for all ten trials for the non-dominant hand.
Results and Conclusions: The data that was obtained from this experiment did correspond with my hypothesis. The data concluded that with the dominant hand, the person could perform an average of 56.6 pinches in 20 seconds. Whereas when a person used their non-dominant hand, only 55 pinches could be performed. When the independent variable being tested was a person's dominant hand, the dependent variable, number of pinches in 20 seconds, increased.
During the first couple of trials, the experiment seemed pointless because roughly the same amount of pinches were performed throughout the trials. However, at about the fifth trial, my fingers were beginning to lose strength. This happened because my finger's muscles had reached their anaerobic threshold. Once at the anaerobic threshold, my muscles began to produce lactic acid and only 2 ATP, compared to the regular 36 ATP, and caused that "sore" feeling. Although my fingers were performing the exercise, the soreness extended to my forearm because my fingers' muscles also extended to my forearms.
The results of the dominant hand versus the non- dominant hand had a very similar trend. Both trials began with a high number of pinches, then drastically declined, then increased slightly towards the end. Although the trials had similar trends, the dominant hand was able to