Muscle Fatigue Lab - lab PDF

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Muscle fatigue lab Honors 10 Biology Shoptime

Introduction This Lab experiment is based on Muscle Fatigue which is a state of exhaustion or loss

of strength and/or muscle endurance following strenuous activity associated with the accumulation of lactic acid in muscles. While we are exercising our muscles we create lactic acid. Lactic Acid is a waste product of anaerobic respiration that accumulates in muscles during exercise. This accumulation of Lactic acid happens because of the process called fermentation. This process allows cells to release energy in the absence of oxygen, so we have more energy to continue on working out. While we are working out our body, the different body parts need to work together to be the most effective and efficient. An important part of this is our skeletal muscle. Your skeletal muscles are usually attached to bones, as they aid in the movement of the skeleton. Movements are voluntary and has a striated or striped appearance. Smooth muscles also aids us through this process. These cells appear smooth under the microscope, and movements are involuntary. This includes moving food through the digestive tract, or the flow of blood through the circulatory system. Muscles are made up of fibers and those fiber create a muscle fiber structure, skeletal muscle fibers are filled with tightly-packed filament bundles called microfibrils. Each myofibril contains thick filaments of a protein called myosin, thin filaments of a protein called actin. The actin filaments are bound together in the areas called z lines. Two z lines and the filaments between them make up a unit called a sarcomere.In between each bone there is a neuromuscular junction, which is the point of contact between a motor neuron and a skeletal muscle cell. Within the neuromuscular junction there is acetylcholine. The motor neuron releases a neurotransmitter which causes a muscle fiber to contract.Tendons join skeletal muscles to bones. They pull on the bones and make them work like levers.Opposing pairs is a system in which one muscle contracts while the other relaxes. There are two different muscle fibers in the human body. There are red muscle fibers, which slow twitch muscle that contains many mitochondria. Red muscle is useful for endurance activities like long distance running. Then there are white muscle fibers, in which fast twitch muscle that contracts more rapidly and generates more force than red muscle. Contains less mitochondria and tires more quickly than red muscle. Useful for activities that require great strength or quick bursts of speed like sprinting. After reading an article about the process of fermentation and its effects on athletes I learned that “In the absence of oxygen, ATP is derived from the breakdown of glucose and glycogen but by a different metabolic process. When the amount of ATP needed cannot be derived quickly enough with traditional oxygen intake and conversion to energy, the body then relies on the anaerobic energy system, which creates as a byproduct lactic acid.” I noticed during the experiment that a burning sensation occurs when this process begins. I also read that “The production of lactate is a beneficial process because it regenerates important coenzymes used up in the oxidation of glucose; regenerating them is important for energy metabolism and so ultimately for exercise to continue. But increased blood lactate from strenuous anaerobic exercise causes a lowering of pH...” This shows that Lactic acid that is produced and accumulated in your body during exercise is what allows you to continue and help your body recuperate after strenuous activity. The main

Purpose of this experiment is to explore how rapidly your muscles fatigue after exercise and recover after rest. My Hypothesis for this experiment is that I think I will only be able to complete the reps in my dominant arm for about one minute, but less reps in my weaker arm. Overtime my bicep, and triceps muscles will become more, and more tired from lifting the weight causing me to go slower and complete less reps than I could in the beginning. I know that this is an exercise that uses white muscle fibers that generates more force than red muscle fibers, but they tire quickly. Procedure 1. Choose one person (between you and your lab partner) to perform the experiment first. 2. Grab an 8 pound weight from the rack and put it in your dominant hand. 3. At your partners signal, begin your reps. Make sure your arm is straight and bends properly. 4. Continue with the weights until you can no longer do so. When you can no longer can pick up the weight, signal your partner who will stop timing. Record the time and the number of reps in table 1. 5. Rest for 1 minute 6. Repeat steps 3-4, but with the opposite hand. Record the new time and number of reps in table 1. 7. Repeat this entire procedure for your partner. 8. Repeat this entire procedure again for both partners so there is two sets of data and an average can be determined. Materials 1. Stopwatch 2. Muscle fatigue lab Sheet 3. Pencil 4. Enough space to perform the exercise (Weight Room at diman) 5. 8 pound weight

Data and observations Table 1. Amount of Exercise that Causes Muscle Fatigue. 1st Exercise period

2nd Exercise period

Names:

Time ~sec # of Reps

Time ~sec # of Reps

Qualitative Data (sight, smell, taste, hear, feel)

Cheyenne Alves (Right arm)

49 Secs

20 Reps

50 Secs

23 Reps

While the time went by I became more fatigued and felt a burning sensation in my muscles.

Cheyenne Alves (Left Arm)

25 secs

9 Reps

54 Secs

24 Reps

I felt like I had more strength the second time in my left arm.

Alexys Bosse (Right Arm)

58 Secs

25 Reps

55 Secs

26 Reps

The first time around I felt that I could go faster, but I felt my arms got warm and my hands turned red. I could feel my muscle get shaky, and I also felt pain in my wrist.

Alexys Bosse (Left Arm)

1 Minute

31 Reps

1 Minute

34 Reps

I realized I had more strength in my left arm from always liting my heavy backpack with this arm but I also felt like I went slower in this arm so it allowed me to concentrate on the quality of the rep and the number of reps I completed.

Analysis and Conclusions 1. Explain in terms of aerobic respiration, oxygen consumption and anaerobic respiration (Specifically, lactic acid fermentation ~ch.9 of your textbook) what is happening in the muscles in the above experiment? In the experiment we conducted, we worked out our bicep and tricep muscles in our

upper right and left arm. While we work these muscles out, a few processes occur. These processes include aerobic respiration, oxygen consumption, and anaerobic respirations. Aerobic respiration is when a form of incomplete intracellular breakdown of sugar or other organic compounds in the absence of oxygen that releases energy; cellular respiration in the absence of oxygen.This happens as we work out because we breath heavily and inhale great amounts of oxygen in a short time, so our body tries to make as much it can to allow us to breath. Oxygen consumption is the rate at which oxygen is used by tissues, usually given in microliters of oxygen consumed in 1 hour by 1 milligram dry weight of tissue. Lastly, Anaerobic respiration is a form of incomplete intracellular breakdown of sugar or other organic compounds in the absence of oxygen that releases energy; cellular respiration in the absence of oxygen. 2. Why do your muscles fatigue? Respond in terms of ATP production. Our muscles fatigue because we use up all of our stored ATP or as some people like to refer to it as energy. Without the ATP being created in our bodies we wouldn't have energy to do anything nevermind lifting 8 pound weights. 3. Do your muscles completely recover from fatigue after 1 minute? 2 minutes? Why do you think this is or is not? In my opinion I believe that our muscles recover from fatigue in a minute or two. After cheyennes first session of reps, her arms were a little sore, but when she started session two of the reps she was able to complete more reps than she did the first time around. I observed that she got stronger as my muscles recovered from the fatigue. When I was completing the first round of reps my hands go very red and warm, and I could not continue for as long as my second set of reps. Therefore the production of Lactic acid during exercise is absolutely important and beneficial to an athlete who is working out or physically active for long periods of time.

Sources ❖ "Muscle fatigue." Medical Dictionary for the Health Professions and Nursing. 2012. Farlex 20 Feb. 2015 http://medicaldictionary.thefreedictionary.com/muscle+fatigue ❖ Diman biology 10 student textbook ❖ Biology 9 notes from mrs. parents class

❖ Biology 10 notes from this years class...