Discrete Motor Skills
A Discrete Motor Skill is one which has a clear start and end point. An example of this is flicking a light switch, it is either on or off, from the picture on the right, you can see that in order to turn the switch on, you need to position your hand on/underneath the switch and apply pressure in an upwards motion, once the switch has flicked, the movement is over and the goal of the skill is achieved. The start and end points of the movement are easily definable and don't need to be repeated.
Serial Motor Skills
A serial motor skill is one which comprises of the execution of multiple discrete skills in sequence. An example of which is changing gears in a manual car. In order to change from 1st to 2nd gear, you are required to make the movement from notch 1 to notch neutral, this is the first discrete skill, however the action is not complete as the gear stick is in neutral not the position of 2nd gear, which is what the goal is. Therefore a second discrete skill must be executed in order to move the stick from the neutral notch of the gear box, towards the notch for 2nd gear.
Continuous Motor Skill
A Continuous Motor skill is a skill which is repeated continuously, therefore they are repetative and the start and end points are hard to distinguish. An example of this is walking