Why Muscle Length Tests? MLTs are used to identify changes in Muscle extensibility that may be contribute to movement impairment and/or symptoms. Generally, positive Muscle length tests indicate a loss of extensibility of one or more muscles. This may imply release, mobilization and/or lengthening techniques are recommended. When used in conjunction with dynamic postural assessment, these tests may help to differentiate which muscles are affected by alterations in joint motion. For example, if a patient/client exhibits an anterior pelvic tilt (excessive lordosis) during an Overhead Squat Asesssment, it is implied by this type of test is that all hip flexors are potentially short/over-active. However, if followed by the Ely's Test, Ober's Test and Modified Thomas Test, it may be possible to determine whether maladaptive changes in flexibility have occurred in the rectus femoris, tensor fasciae latae and psoas/iliacus individually.