Final answer:
The technique used to observe postural distortion in association with muscle performance under testing is part of a neurological motor exam, including subtests like the Romberg test and assessments for muscle strength and tone.
Step-by-step explanation:
The technique that observes postural distortion and is associated with muscles that fail to meet demands of testing is part of a neurological motor exam. This exam assesses muscle strength and tone, plus sensory perception, such as proprioception, and involves different subtests. One subtest is assessing the rebound response of arms to determine cerebellar function. The Romberg test is another subtest, which focuses on the patient's sense of proprioception by having the patient stand with feet together and eyes closed to maintain balance. Tests to evaluate muscle strength include having the patient flex and extend the neck or shrug the shoulders against resistance, and checking gait and balance while the patient hops on one foot. If muscle tone is present, muscle strength is further tested by resistance and looking for lateral differences, which could indicate a deficit in the corticospinal tracts.