Isolateral exercise is a technique that is used in strength and fitness training to work one particular side of the body at a time rather than trying to train both sides at once. For instance, if you are used to doing traditional push-ups then a more isolative based movement would be to execute a one-arm push-up. This is a great way to maximize the strength on that one side of the body.
So why do people do isolateral-based movements? Well to start, when considering developing a highly effective strength and conditioning program one must include isolative based movements in their program to optimally develop symmetry and equal total-body strength. There are basically 2 benefits to executing this type of movement. The first is that you allow the working side of the body to lift the weight or resistance on its own without any assistance or compensation from the other side. This allows for a greater increase in strength independently on each side of the body.
The second benefit includes a transfer of strength, or cross transfer, from the working side of the body over to the side that is not executing the lift at that particular time. This is why it is still beneficial to train the body, if possible, even during an injury. Your body can still benefit from exercise even if you are not training a particular body-part. An example here would be that if a person broke their right arm and that arm is in a sling, then it can not perform any tasks. However, the left arm can. Doing something as common as arm curls with the left arm can cross transfer strength over to the injured right arm.
So now you know what isolative exercise is and how it works. You are beginning to learn the secrets of strength and exercise!