Physiology And Injuries In Sports — Physical Education STD 12 Commerce — Question
CBSE BoardEnglish MediumSTD 12 CommercePhysical EducationPhysiology And Injuries In Sports5 Marks
Question
Discuss any three physiological factors determining speed.
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Answer
Physiological Factors Determining Speed:
Mobility of the Nervous System: Our muscles contract and relax at the maximum possible speed as seen in sprinting events. This rapid contraction and relaxation of muscles is made possible by rapid excitation and inhibition of the concerned motor centres. This is called the mobility of the nervous system. The nervous system can maintain this rapid excitation and inhibition only for a few seconds after which the excitation spreads to the neighbouring centres causing tension in the entire body. This results in decrease in speed. The mobility of the nervous system can be trained but only to a limited extent. In fact, speed is determined to a great extent by genetic factors.
Muscle Composition: Muscle with greater percentage of fast twitch fibres contract with more speed in comparison to muscles with lower percentage of fast twitch fibres. In fact, the muscle composition is genetically determined and cannot be changed by training. Different muscles of the body have different percentages of fast twitch fibres. So, different parts of the body have different speed performances.
Explosive Strength: For every quick and explosive movement, explosive strength is indispensable. For example, a quick punch in boxing cannot be delivered if the boxer lacks explosive strength. Explosive strength further depends on muscle composition, muscle size and muscle coordination. It also depends on the metabolic process. Except muscle composition, the remaining factors can be improved through training which in turn will improve the speed to a limited extent. The relative proportion of fast twitch fibres and slow twitch fibres determines, to a large extent, the maximum possible speed with which a muscle can contract. This proportion of fibres is genetically determined. This implies that top sprinters have more percentage of fast twitch fibres, whereas, endurance athletes have more percentage of slow twitch fibres (red fibres).
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