Anatomy

Everyone is built differently with different proportions. This will change the look of your technique. This does not mean that you are necessarily wrong if your movement looks different. For this reason, it is important to refer to the fundamentals of movement and the intention of a joint as part of a system. This is important to understand and recognize in dealing with athletes of different proportions. The most common example will be Short Limb Vs Long Limb athletes. A short limb athlete will have a much more upright position in a squat; while long limb athlete may fold forward. 

Our body is a complicated system that uses everything to perform a task. We can not 100% isolate a muscle such that only one muscle operates at a time. A better term than isolation will be target. Rather than thinking of an exercise in terms of body parts we view it as a movement. We look to see if each part of the system is operating properly. Movements can have a main mover which is often thought of as the body part an exercise works. This can give us a priority of where to look first. Just like in assessment, we look for the biggest return on investment first.