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.
The fast-twitch muscle fibers are known as the white muscle, while the slow-twitch muscles fibers are known as red muscle. These two types of muscle fibers are engaged differently depending on what type of activity you are doing.lite sprinters may have up to 80% more white muscle fibers than red since their performance relies on this type of tissue. White muscle fibers fatigue at a much faster rate than their red counterparts because of a buildup of lactic acid, so they are only good for short bursts of speed.