Muscle Fatigue Lab Understanding Aerobic and Anaerobic Respiration and how it affects muscle performance

Select the position to exercise the muscles of the fingers and hand. Exercise will be intense and without breaks.

Data is usually presented in a table and Hold a clothes pin in the thumb and index finger of the dominant hand and open and close it while the other fingers of the hand are held out straight. The number of times the clothes pin opens to its maximum distance in 30 seconds is recorded on a data table. Students should attempt to squeeze quickly and completely, to get the maximum number of squeezes for each trial.   Repeat this process for nine more 30 second trials recording the result for each trial. Do not rest the fingers between trials. Conduct the same test using the non-dominant hand. Create a graph of the data collected. On the back of the graph, construct 3-5 statements which describe the outcome of the activity. Data is usually presented in a table and some type of graphic organizer.

Proper table includes column heading which include the units and a description. How is your data table different?

Graph depicts the number of clicks completed by for each 10 second trial completed by the right and the left hand. # squeezes Trial # Proper graphing includes a title, labeled x and y axis, an appropriate scale for each axis, a key and a description.

More Data to Analyze…

Understanding the science of the Investigation… Why… Did both hands decrease in strength? Did both hands experience increasing soreness as the number of trials increased? Did the muscles begin to experience a decrease in strength? Was there a decreasing number of squeezes as the number of trials increased? Was there a similar pattern for both the dominant and the non-dominant hand? Understanding the science of the Investigation…

Closer look at Cellular Respiration Glucose  Carbon dioxide + Water & 38 ATP +oxygen Glucose  Pyruvic Acid  Carbon dioxide + Water & 38 ATP Similarities: The top and bottom chemical reactions both have final products of carbon dioxide and water. Both will also make 38 ATP Both the top and bottom reactions start with glucose (stored energy) Difference: The bottom reaction has an extra step: glucose is changed into pyruvic acid. The top reaction just shows glucose changing into carbon dioxide.

Cellular Respiration has an anaerobic part and aerobic part. Parts 1 and 2 are needed to make ATP for muscle use. This is happening all the time. When oxygen is being supplied to meet the demands of the muscle, part 2 happens. What happens when oxygen becomes scarce?

Lactic Acid Fermentation: Occurs when the body does not have enough oxygen to meet the demands of the exercise, anything intense and constant. Making less ATP With less oxygen The arrow points to the chemical pathway: Pyruvic acid  Lactic Acid and 2ATP

Lactic Acid Production During very intense exercise, your circulatory system cannot keep up with your muscles' demand for oxygen. To maintain a steady supply of energy, muscles shift from aerobic metabolism, which requires oxygen, to anaerobic metabolism, which does not. Muscles can break down carbohydrates anaerobically to provide energy, resulting in a compound called pyruvate. When oxygen is available, pyruvate can be further broken down aerobically to provide more energy. But when sufficient oxygen is not available, pyruvate is converted into lactic acid. Click on the link: Muscle Fatigue Info Video

Lactic Acid and Fatigue Lactic acid is rapidly broken down into a compound called lactate, resulting in the release of hydrogen ions. Your body can clear lactate by metabolizing it for energy, but when lactate production exceeds the clearance rate, it accumulates in your muscles and bloodstream. While rising levels of lactate are associated with tired muscles, lactate does not actually cause fatigue. Rather, it is the increased acidity in your tissues, due to the buildup of hydrogen ions, that contributes to the sensation of fatigue. Muscle Fatigue & Soreness from Lactic Acid by JOE MILLER  Last Updated: Feb 05, 2014

Investigation Questions: What happened to your strength as you progressed through each trial? What physiological factor might cause one to get more squeezes to have less fatigue? Your muscles would probably recover enough after 10 minutes to operate at the original efficiency. Explain. Explain how the products of anaerobic respiration cause your cells to be less efficient? What is the relationship between the strength of your heart and aerobic respiration?

Heart pumps blood to muscles Heart pumps blood to muscles. Blood contains the protein hemoglobin which carries oxygen. Stronger heart muscle can eject a greater volume of blood than a less conditioned heart. Lactic acid builds up when oxygen demand cannot be met. Lactic acid changes intracellular pH which affects important chemical reactions (enzymes) and causes soreness. Some more science…

Reflection: Did the results turn out the way you would have expected given what you know about muscle fatigue? Explain. How does the data and graph help support the discussion about aerobic versus anaerobic respiration that we had at the beginning of the lab? What have you learned from this lab? What is something else concerning muscle fatigue that you would be interested in finding out the answer to?