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.
Your skeletal muscle contains two types of muscle fibers: fast-twitch and slow-twitch. Your fast-twitch and slow-twitch muscle fibers are separated into three distinct types.Slow-twitch fibers contain type 1 muscle fibers, while your fast twitch fibers contain both type 2a and type 2b.our fast-twitch and slow-twitch muscle fibers are separated into three distinct types. Slow-twitch fibers contain type 1 muscle fibers, while your fast twitch fibers contain both type 2a and type 2b.