Muscle Tension Lab Report

The more stimuli per second, the greater the force generated by the muscle due to a

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The results in Figure 2. show that increasing the stimulus strength (V) from 0 to o.40V will result in an increase of Active Muscle force generated by the gastrocnemius muscle in the Buffo Marinus, confirming the hypothesis. The force generated plateaus when the stimulus is beyond o.40V.

Next with a stimulation duration of 50us, the stimulus amplitude should be set to the maximal tolerable stimulus intensity. With stimulus frequency of 2Hz, observe and record the leg movement, increase it by 5Hz but should not exceed 50Hz. With the electrodes connected to the analogy output channel and ground of the DAQ board. With the corresponding LabVIEW program, the frequency and amplitude (voltage) of the stimulation supplied to the leg can be controlled. With this the “sweet spot” of the lowest amplitude and best frequency to cause evoked movement can be found and recorded. Now the stimulation frequency should be set to 10Hz and the duration of stimulation pulse to 5ms or less. The range if leg movement changes can be observed as amplitude changes. Electrical stimulation in increments of 0.01V should be delivered and the minimal voltage required to generate muscle twitch should be recorded. The pulse duration should then be increased by durations of 10ms and the minimum voltage should be recorded this should be repeated for a variety of pulse

Statistics uses math to determine whether or not an experiment happened by chance. In other words, it determines the probability of your results being by chance or if it is factual data. The mathematical ways of determining probably include looking at mean, standard deviation, mode, and median. This experiment will use statistics to test the probability.

Introduction: Exercise is a physical activity or particular movement that is used in order to become healthier and stronger. (1) Exercise, in all of its forms, has various effects on the different systems in the human body. One of the main benefits is cardiovascular health, including circulation and heart health. Exercise uses a lot of energy, which the cells derive from oxidising glucose. Meaning that the heart has to work harder to pump more blood throughout the body and the heart has to beat faster in order to achieve a high effort. (2) The heart benefits from exercise include being able to pump more blood through the body and continue working at a higher level with less strain. (3)

The EMG signal that is observed through the placement of electrodes on the skin is closely coupled with the generation of muscle force. In normal conditions, the force-EMG relationship is either linear or the increase in EMG at low force levels is less than proportional (Semmler 2014). However, a different force-EMG relationship was observed following eccentric exercise,

Review Sheet Results 1. Describe how increasing the stimulus frequency affected the force developed by the isolated whole skeletal muscle in this activity. How well did the results compare with your prediction? Your answer: When the stimulus frequency was at the lowest the force was at its lowest level out of all of the experiments. As the stimulus frequency was increased to 130, s/s the force increased slightly but fused tetanus developed at the higher frequency. When the stimulus frequency was increased to the amounts of 146-150 s/s, the force reached a plateau and maximal tetanic tension occurred, where no further increases in force occur from additional stimulus frequency. 2. Indicate what type of force was developed by the isolated skeletal muscle in this activity at the following stimulus frequencies: at 50 stimuli/sec, at 140 stimuli/sec, and above 146 stimuli/sec. Your answer: At 50- Unfused

Two fishermen, Steven and George, headed out to fish along the Bale River, in Westport Wisconsin around 10:30a.m. After sitting for hours with no sight of fish, Steven felt a tight pull on his fishing rod. He immediately jumped and started to reel in his catch. But as his catch got closer, Steven caught a glimpse of what looked like an arm. As he reeled in more, he was shocked and frightened. George came by him and saw that this was not a fish. It was a human humerus covered in algae. George called the police immediately and soon enough the entire river was under investigation. The police, in addition, discovered a skull and a pelvis by a nearby sewer system. The femur of the skeleton was found by a nearby ditch. The four body parts were taken back to the lab for further analyzing.

higher the hertz, the more cycles the sound wave goes through a second. The higher the

From \cite{aus} and \cite{childers2012measurement} the biomechanics of the hip is studied. When we walk, during the initial contact the hip moves towards extension. However once the heel contacts the ground range of extension reduces. With short stump it stays in flexion.

ions across the membrane of the mitochondria during oxidative phosphorylation. Muscle buffering capacity is also improved. One acute response to hypoxia is hyperventilation; this increased rate of respiration occurs to maintain the alveolar partial pressure of oxygen. Hyperventilation leads to increased removal of carbon dioxide through the lungs and a state of respiratory alkalosis. This state of respiratory alkalosis can lower the pH of the blood and result in additional bicarbonate being excreted by the kidneys. This is the mechanism by which we increase muscle buffering capacity. Something to note about muscle buffering capacity and the lactate threshold is that there is a phenomenon that is called the “lactate paradox.” The lactate paradox

3. How can you explain the increase in force that you observe? the increase is how many volts went into the muscle.

Muscle cells rely on cellular respiration for energy. During normal physical activity the cells are supplied with oxygen to convert glucose to ATP, CO2 and water. During prolonged intense physical activity the muscles are not supplied with enough oxygen to produce ATP for energy. Therefor the muscles rely on cellular fermentation to break down glucose. This method yields less ATP and builds up lactic acid which makes muscles burn. In this lab students will use prolonged repetitions of squeezing a clothespin to analyze the effects of cellular fermentation on the muscles ability to do work.

Post-lab Quiz Results You scored 50% by answering 2 out of 4 questions correctly. 1. Which of the following is not one of the ways that the body can increase the force produced by a skeletal muscle? Your answer: b. application of high-frequency stimulation by a motor neuron Correct answer: d. application of higher voltages to the whole muscle 2. When a muscle receives a stimulus frequency that causes non-overlapping twitches to follow each other closely in time such that the peak tension of each twitch rises in a stepwise fashion up to a plateau value, the result is known as You correctly answered: c. treppe. 3. In this experiment the isolated skeletal muscle was repetitively stimulated such that individual twitches overlapped with each other and resulted in a stronger muscle contraction than a standalone twitch. This phenomenon is known as You correctly answered: c. wave summation. 4. Wave summation is achieved by Your answer: c. summating action potentials so that their depolarizing magnitude is greater. Correct answer: a. increasing the rate of stimulus delivery (frequency)