There is no such position as Mayor of the United States (US). A  Mayor is typically a political position for cities and towns. The  United States is led by a president. Curr â¦ ently, the president is  Barack Obama.
Slow twitch muscle fibres are good for endurance activities like long distance running or cycling. They can work for a long time without getting tired. Fast twitch muscles are good for rapid movements like jumping to catch a ball or sprinting for the bus.
â¢ A fast muscle like an eye muscle will have more fast-twitch motor units than slow ones â¢ A support muscle in the back will have more slow-twitch units â¢ A leg muscle that can be involved in both support and spurts of fast activity generally has a fairly equal mix of both.