Final answer:
The Trendelenburg Test is used to show proximal muscle weakness, specifically in the hip abductors. Other tests mentioned evaluate different musculoskeletal issues, while muscle strength testing against resistance can indicate lateralized or global motor system problems.
Step-by-step explanation:
The test that will show proximal muscle weakness is the Trendelenburg Test. This test is performed by having the patient stand on one leg while the examiner observes the pelvis level. If the pelvis drops on the side opposite to the stance leg, this indicates weakness of the hip abductor muscles on the stance leg side, which are important proximal muscles. This is in contrast to other tests listed, such as Load and Shift, FADIR (Flexion, ADduction, Internal Rotation), and the Compression Test, which are used for assessing other types of musculoskeletal conditions.
To assess overall muscle strength and potential motor system issues, muscle tone can be checked by having a patient contract muscles against resistance. A lateral difference in the ability to push against resistance may suggest a deficit in one corticospinal tract versus the other, whereas a general loss of strength might indicate a global motor system problem. Conditions such as cerebral palsy, multiple sclerosis (MS), or stroke can lead to Upper Motor Neuron (UMN) lesions. Pronator drift is a subtest for UMN lesions, where the patient extends both arms with palms up and eyes closed; a drifting arm may indicate motor system failure.