Method of classifying

When classifying e.g., amputation, leg length difference and short stature, measurement of impairment alone is usually sufficient, because these impairments are not training responsive – for example, the residual limb of a unilateral lower-limb amputee does not increase in length in response to training. Because they are not training responsive, an athlete who has trained hard cannot alter their impairment measure and be placed into a less impaired class. Because there is no risk that an athlete’s class can be influenced by training there is no need for tests that provide an indication of how well-trained an athlete is.

However in many cases assessment of impairment alone is not sufficient, for one or both of the following reasons:

Evidence indicates that some of the impairments may be exacerbated by disuse, inactivity or poor training.
If impairment measures are training responsive, an athlete measured in an untrained state will have a more severe impairment measure than they would in a trained state, creating the possibility that they would be placed into a more impaired class when untrained, and a less impaired class when trained. If this occurred, it would defeat the purpose of classification, which aims to reward athletes for hard training;

Athletes do not have an impairment profile that fits exactly with a single class profile.
For example an athlete may have a combination of impairment types, such as impaired muscle power and impaired range of movement; or a topographical distribution of impairment that does not fit a class profile, such as often occurs with brain injury, incomplete spinal cord injury, spina bifida or polio.