KPE161H1 Lecture Notes - Lecture 4: Myocyte, Endurance Training, Motor Unit
9 Mar 2019
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Document Summary
If 70% st and 30% ft chance at doing marathons. Inactivity fibres shift back to fast twitch: aging may result in changes in percentage of ft and st fibres, decreased recovery decreased amount of possible training. Effect isn"t that big: bigger problem inactivity, body gets rid of ft fibres (aren"t used) % of ft fibres decrease over time. All-or-none response: all muscle fibres in one motor unit have the same characteristics. Recruitment patterns: brain uses feedback during movement from receptors to determine amount of fibres needed (especially if it is an unfamiliar object, beginning of action brain recruits st only, proprioceptors tell brain if the muscle is moving. St motor units generally produce small amounts of force good for smaller and more precise movements, typically day-to-day stuff. Ft for high speed/force movements: slow twitch utilize more oxygen. More efficient means of releasing energy from food (uses fat: graph, use isometric contractions to measure max force production.
