Manual Muscle Testing: Trunk Extension

"'original editor"'-Ruchi Desai

"'Top contributors"'-Lucinda hampton, Ruchi Desai and Kim Jackson

Introduction

Low levels of endurance of back muscles are reported as cause and effect of low back pain. Muscle strength testing is a validated tool for identifying low back pain problems. The involved muscles are: back extensor miuscles (intrinsic back muscles) aided by latissimus dorsi, quadratus lumborum, and trapezius.

When testing the thoracic and lumbar spine strength a few differences are noted:

• The Grades 5 and 4 tests for spine extension are different for the lumbar and thoracic spines. Beginning at Grade 3, the tests for both spinal levels are combined.
• Range of Motion are also different: Thoracic spine: 0° to 10°: Lumbar spine: 0° to 25°.

Lumbar Spine

Lumbar spine extension

Grade 5 (Normal) and Grade 4 (Good)

Technique

Position of Patient: Prone with hands clasped behind head.

Position of Therapist: Standing so as to stabilize the lower extremities just above the ankles if the patient has Grade 5 hip extensor strength. The weight of the head and arms essentially substitutes for manual resistance by therapist.

Test: Patient extends the lumbar spine until the entire trunk is raised from the table (clears umbilicus).

Instructions to Patient: “Raise your head, shoulders, and chest off the table. Come up as high as you can.”

Grading: Grade 5 (Normal) and Grade 4 (Good) The therapist distinguishes between Grade 5 and Grade 4 muscles by the nature of the response.

• The Grade 5 muscle holds like a lock. The patient with Grade 5 back extensor muscles can quickly come to the end position and hold that position without evidence of significant effort.
• Grade 4 muscle yields slightly because of an elastic quality at the end point. The patient with Grade 4 back extensors can come to the end position but may waver or display some signs of effort.

Alternate Instructions to Therapist:If the patient has hip extension weakness, stabilize the lower extremities by leaning firmly over the patient's body, placing both arms across the pelvis.

Alternative Grade 5: The Biering-Sorensen test or Sorensen test is a global measure of back extension endurance capacity. See link. Has a different starting position (prone with the trunk flexed off the end of the table at a level between the anterior superior iliac spine (ASIS) and umbilicus. The arms are folded across the chest. The pelvis, hips, and legs are stabilized on the table).

Thoracic Spine

Thoracic extension then going into lumbar extension, incorrect for pure thoracic testing.

Position of Therapist: Standing so as to stabilize the lower limbs at the ankle.

Test: Patient extends thoracic spine to the horizontal.

Instructions to Patient: “Raise your head, shoulders, and chest to table level.”

• Grade 5 (Normal): Patient is able to raise the upper trunk quickly from its forward flexed position to the horizontal (or beyond) with ease and no sign of exertion
• Grade 4 (Good): Patient is able to raise the trunk to the horizontal level but does it somewhat laboriously.
• Grade 3 (Fair): Patient completes the range of motion.
• Grade 2, Grade 1, and Grade 0: These tests are identical to the Grade 3 test except that the therapist must palpate the lumbar and thoracic spine extensor muscle masses adjacent to both sides of the spine. The individual muscles cannot be isolated.

This less than 3 minute video goes through the technique and scoring.