Kinesiology 4430F/G Lecture Notes - Lecture 6: Myosin, Caffeine, Sphygmomanometer
15 Jun 2016
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Brief (3-10s) high intensity (50-100%) tetanus, or voluntary contractions enhance the active state. Assessed by twitch potentiation of 150-200%, exponential decline with time for several minutes. 2 likely mechanisms (there could be others): ca2+ kinetics at the sr level (caffeine also works here, myosin light-chain phosphorylation during actin/myosin interaction. Weakness: inability to generate an initial force appropriate for the task. Fatigue begins almost immediately, but what part(s) of the system are failing: depends on the task, different parts of the system may fail under different tasks/situations. Possible sites of fatigue in the neuromuscular system. Fundamentally, fatigue works like this: percent of max capacity on the bottom, endurance/fatigue time on the left side. Dotted line: implies that you can go on forever if the percentage of work is low enough, probably not entirely true because people need to sleep. If you are using all of your strength, you will have a fast decline in endurance.
