Let's begin with the sports photographs.
Quite often the photographer of a sport such as football, soccer or even competitive bicycling will have a single subject - the athlete.
Additionally, this athlete is usually in motion and heading towards a goal or finish line.
While watching this as it happens can be exciting, a photograph of an athlete doing their job can actually be dull.
How many times do we see images of a runner sprinting towards the end zone? These are not necessarily compelling images, but they could be if the photographer had only added an element of space to the photograph.
How is this done? For sports or motion images the old rule of thirds is bent a bit.
Instead of having the subject taking up the middle third of the scene, they are balanced at one end or the other.
For example, that runner would have the space in front of him to give the image a sense of his goal and some energy.
This same principle can apply to something like wildlife photography as well.
While a dog running across the lawn is an interesting thing to record with your camera, such a scene loses its impact if it is just a portrait of a dog in the center of the frame.
Instead, the photographer could pan on the dog and leave a trail of space behind him to give a sense of his speed and excitement.
Where portraiture is concerned the same idea of additional space can bring a great deal of interest to what might otherwise be a somewhat plain image.
For instance, a smiling child looking directly into the lens is always going to be a nice photograph, but if that child is smiling at something or someone "off camera" it adds vibrancy and remarkable depth.
Quite often a portrait with the subject's attention directed back into the same space as the viewer can give a significant effect.
It is important to remember that if the subject is looking directly to their right or left, the portrait must be balanced to accommodate this.
This means that the individual should be bumped to an alternate side of the frame from that direction which they are facing.