To be FIT means basicaly to be in great shape and physical condition. In this article we have Heike Breuer explaining what the main forms of physical conditions are:
Main Forms of Motor Exertion/Physical Condition
Sport consists of various components that have different levels of involvement in particular forms of movement.
Strength: In sport, strength does not (only) acts as a physical characteristic (F=m x a), but as a motor characteristic. Strength in sport is the capacity to use muscle activity to overcome or counteract resistance. Important performance-limiting factors stem, in particular, from the muscles themselves. One sport in which strength is particularly dominant is weight lifting.
Endurance: Endurance is the organic ability to withstand fatigue in a prolonged workout and the subsequent rapid ability to recover.The most important performance limiting factors are to be found in the organ system, particularly the cardiovascular and respiratory system. Sports for which endurance is the dominant principal form of exertion include marathon running, triathlon and cycle racing.
Speed: Speed is the ability of the nervous muscular system to react as quickly as possible to a signal(reaction speed) and to perform movements with the greatest alacrity(speed of movement) Key performance-limiting factors are nerve conduction velocity and muscle contraction velocity. The best example of a sport in which speed is the dominant factor is the 100m sprint.
Flexibility: Flexibility is the capacity to perform voluntary large-amplitude movements in particular joints. lt depends on joint mobility and elasticity of muscles and connective tissue. Key performance-limiting factors are anatomical and biomechanical conditions, the elasticity of muscles and sinews and muscle resting tension.An example of a sport in which flexibility is extremely important is gymnastics.
Coordination: Coordination refers to the interaction of the central nervous system and the skeletal muscles in a purposeful sequence of movements.Coordination is a very important and performance-limiting factor in all sports.
These five different main forms of motor exertion can each be subdivided into different types and occur in hybrid forms(eg, strength endurance, speed endurance, speed strength, etc). Physical condition is therefore determined by development of the five motor characteristics. Good general fitness is characterized by an optimally high and even level of development of all motor characteristics. A high level of physical condition is characterized by a high level of training of the motor characteristics that determine performance in a particular sport.