In society today we have a wide range of sports each requiring a variety of skills. Skill is an athlete's ability to choose and perform the right techniques at the right time, successfully, regularly and with a minimum of effort. Athletes use their skill to achieve athletic objectives e.g. sprinting a 10.0 second 100m. Techniques are the basic movements of any sport or event e.g. a the block start in a 100m race is a technique.
Ability is the make up of an athlete.
If you of average height, strong, good coordination and have an abundance of fast twitch fibres in your legs then you have the natural ability to be a sprinter. We inherit ability from our parents. Open skills are where you cannot control what happens next. An example of this is in football. Where you cannot control what happens next you use open skills.