Strength, Endurance, Speed and Power
Athletic skill can be defined in terms of the ability to exert force (strength), to repeat an action for a long period of time (endurance) or to perform an action quickly (speed). Power is a combination of speed and strength -- it is the ability to perform an action against resistance with a sudden explosion of movement. Most sports make different demands on the athletes involved, emphasizing one of these skills more than the others and usually requiring a great deal of skill in two of these areas.
Power in Cyclic Sports
Cyclic sports such as long-distance running are defined primarily by endurance rather than power, but that doesn't mean that power is not a factor. Because power is a combined effect of highly-developed strength and speed, an endurance runner must have both these qualities in order to be faster than the competition. Rowing is another cyclic sport in which endurance is a major asset, but starting power (the ability to burst into action at the beginning of the race) is also important. In general, power is of secondary importance in cyclic sports but is still a significant factor.
Power in Acyclic Sports
Many popular sports are acyclic, meaning that they require complex actions and movements that do not repeat in a cycle. Basketball, football, hockey and martial arts are all acyclic sports. Different sports require different types of power. For instance, martial arts requires a strongly developed reactive power, which is the ability to land in a certain place and move explosively from that position into a new one without a pause. Hockey requires acceleration power, which is the skill of getting up to peak speed as quickly as possible. Football requires starting power, acceleration power and reactive power.
Acyclic Combined Sports
Sports that alternate cyclic and acyclic activities are referred to as "acyclic combined" sports. For example, when a high jumper runs up to the bar, the running is a cyclic activity, but it is immediately followed by the acyclic activity of the high jump itself. Several different types of power would be required for this, including starting power, acceleration power during the cyclic phase, and jumping power during the acyclic phase. No two sports require the exact same combination of types of power, whether the sport is cyclic, acyclic or acyclic combined.