Muscle Length Tests (MLTs)
Research, Results and Practical Application
By Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, H/FS
Muscle Length Test (MLT) - "Muscle length testing involves elongating the muscle in the direction opposite of its action while assessing its resistance to passive lengthening (1)"
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.
The Difference Between a Good Assessment and a Bad Assessment:
Good tests, assessments and evaluations are valid, reliable and relevant -
Validity - Validity is a weakness of muscle length tests (MLTs) due to the number of potential structures that may restrict range of motion (ROM) at each joint. That is, the problem lies in defining these tests by a single muscle, rather than by all the structures that may limit joint motion.