Award Date


Degree Type


Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Committee Member

Merrill Landers

Graduate Faculty Representative

E. Louie Puentedura

Number of Pages



Study Design

Randomized, blinded, cohort, within subjects design.

Background and Objective

The effects of different manual therapy (MT) techniques on lumbar multifidus (LM) thickness have been investigated in subjects with low back pain (LBP) but have not been investigated in asymptomatic subjects. The objective of this study was to examine the immediate effects of mobilization and manipulation on contraction thickness of LM in healthy individuals.

Methods and Measures

Forty-two healthy individuals participated in the study. Ultrasound imaging techniques were used to record LM thickness (L4-5 level) at rest, during an abdominal drawing in maneuver (ADIM), and during a prone upper extremity (PUEL) lifting task. Images were taken before and immediately following one of three randomly assigned MT techniques. Participants returned on two subsequent days to receive the remaining techniques, and data was compared to assess the effects of each technique.


A statistically significant interaction was found between treatment, contraction state and time for the PUEL task (p=0.019). Post hoc analysis revealed a statistically significant increase in resting muscle thickness following the supine anterior posterior thrust technique (p=0.005). No significant differences in muscle thickness were found with the other two techniques at rest or during the PUEL task (ps ≥ 0.887). This suggests that the supine AP thrust technique causes an increase in resting muscle thickness that does not occur with other MT techniques. For the ADIM data, no interaction among the three variables was found (p= 0.233). This suggests that no MT technique changed resting or contracted muscle thickness when the participants performed the ADIM.


Taken together, the findings from this study demonstrate that manual therapy had no effect on resting or contracted thickness in asymptomatic individuals. It may be that the changes in muscle thickness reported in the current body of literature are only observed in patients with LBP and may not occur in healthy individuals.


Asymptomatic individuals; Backache; Health and environmental sciences; Lumbar curve; Lumbar multifidus; Lumbar spine; Lumbosacral region; Manipulation (Therapeutics); Manual therapy; Physical therapy; Spinal adjustment; Ultrasonic imaging; Ultrasound imaging


Alternative and Complementary Medicine | Investigative Techniques | Physical Therapy | Therapeutics

File Format


Degree Grantor

University of Nevada, Las Vegas




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