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.
Fast-twitch muscles. Fast-twitch muscles use an 'anaerobic' metabolism to create fuel and need more oxygen, and they are much better at generating short bursts of strength or speed than slow muscles, such as a 100 metre sprint or weightlifting, but they tire more quickly.
The fast-twitch muscle fibers are those that have less endurance but have the most strength and power and grow the biggest. When you pick up a weight and do a biceps curl, the slow-twitch muscle fibers in the biceps are recruited first to contract and then lift the weight.