Question

Experiment Sd 2. Use the data in Table 1 to calculate the percent change in amplitude (Am ) activity that occurs between the 0-20 sand 60-80 intervals. Do the same for What accounts for the difference in the percent change observed in grip streng the two time intervals? change in amplitude (AmV) in electrical intervals. Do the same for grip strength. age observed in grip strength and Am V for 3. Compare mean grip strengths and Am V for the 0-20 s and 80-100 s in Table 1. Do your findings support or refute the practice of "coaching from the sidelines" at sporting events 4. Use the graphs and your data from Table 1 to explain how our neuromuscular systems attempt to overcome fatigue during heavy work or exercise. How might fatigue increase me risk of musculoskeletal injury? 5. Compare the data in Tables 1 and 2. Explain any differences seen in the 80-100 s time intervals between the two tables. What does this tell you about the brain's role in fatigue? 6. The mean grip strength is much less for repetitive gripping (Table 3) because repetitive relaxation of the hand is averaged into the calculation. (a) Compare your mean grip strength during the 0-20 s and 80-100 s time intervals in Tables 1 and 3. Was there a difference in your ability to recover strength with coaching during continuous vs. repetitive gripping? (b) Calculate the percent change in mean grip strength between the 1-20 s and 60-80 s time intervals in Tables 1 and 3. Do your answers support brief relaxation of muscles to delay fatigue?

Answer 1

Answering the physiological aspect of this question

How neuromuscular junction(NMJ) overcome fatigue in heavy exercise = NMJ overcome fatigue by receiving extra oxygen from the haemoglobin(Hb) , as Hb has total four oxygen molecule attached to it and usually in normal routine work it release only one or two oxygen molecule but in cases of heavy exercise Hb release it 3rd oxygen molecule even helping muscle undergoing heavy exercise to perform aerobic respiration (otherwise they would have been performing anaerobic glycolysis which would release lactic acidosis causing fatigue)

Fatigue is a protective mechanism as well to prevent the muscle from undergoing heavy work load and muscular sprain or muscular tear but if you continue doing heavy exercise inspite of excessive pain it could lead to muscular tear,sprain,tendinitis etc

Brain has a following role in fatigue

1. As in case of heavy exercise carbon dioxide level of the body increases and oxygen demand also increases so brain stimulate the respiratory centre to increase the breathing rate to wash out carbon dioxide and increase oxygen saturation of the blood

2. Cerebral perfusion decreases in heavy exercise as in this case it send all the blood the muscle undergoing strenuous work ,so brain send the signals to heart to increase the heart rate and stroke volume

Thank You!