Immediate Effect of Lumbar Mobilization on Paraspinal Muscle Stiffness

Immediate Effect of Maitland Grade III++ Central Posteroanterior Mobilization on Erector Spinae and Multifidus Muscle Stiffness in Healthy Adults: A Randomized Crossover Trial

This randomized controlled crossover study will investigate the immediate effect of central posteroanterior lumbar mobilization on the intrinsic stiffness of the erector spinae and multifidus muscles in healthy adults without low back pain. Twenty-four participants will complete two experimental visits in randomized order. During one visit, participants will receive Maitland Grade III++ central posteroanterior mobilization at the L4 vertebral level, while during the other visit they will receive a sham mobilization condition involving gentle rhythmic pressure. Muscle stiffness will be assessed using shear wave elastography immediately before and after each intervention.

Study Overview

• Status: Recruiting
• Conditions: Muscle Stiffness
• Intervention / Treatment: Procedure: Maitland Grade III++ Central Posteroanterior Mobilization; Procedure: Sham Lumbar Mobilization

Detailed Description

The study will be designed as a randomized controlled crossover trial to investigate the immediate effects of manual spinal mobilization on lumbar paraspinal muscle stiffness in healthy adults without low back pain. Each participant will attend two separate study visits and will receive both experimental conditions in a randomized order.

In the experimental condition, Maitland Grade III++ central posteroanterior mobilization will be applied over the spinous process of L4. The intervention will consist of three 60-second sets of passive rhythmic oscillatory pressures performed at approximately 2 Hz, with 30-second rest periods between sets. In the control condition, participants will receive a sham mobilization presented as a Grade I mobilization technique. The sham intervention will follow the same timing structure but will consist of gentle rhythmic pressure over the L4 spinous process.

Intrinsic muscle stiffness of the right erector spinae and multifidus muscles will be assessed using shear wave elastography. Three measurements will be obtained immediately before and after each intervention, and the mean value will be expressed in kilopascals. Measurements will be performed in a standardized prone position at the L4-L5 level.

• Study Type: Interventional
• Enrollment (Estimated): 25
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Žiga Kozinc, PhD; Phone Number: +386 040161503; Email: ziga.kozinc@s2p.si

Study Locations

• Slovenia
  • Izola, Slovenia, 6310
    • Recruiting
    • University of Primorska, Faculty of Health Sciences, Izola
    • Contact: Žiga Kozinc, PhD; Phone Number: +386 040161503; Email: ziga.kozinc@s2p.si

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Men and women aged 21 to 38 years.
• Resident of the Republic of Slovenia.
• No current low back pain.
• No contraindications to lumbar manual mobilization.
• Ability to assume and maintain the required prone testing position.
• Provision of written informed consent.

Exclusion Criteria:

• Current low back pain.
• Spondylolisthesis.
• Severe osteoporosis.
• Spinal stenosis.
• Lumboischialgia or other significant structural spinal deformity.
• Fibromyalgia.
• Recent spinal surgery or lumbar spinal fixation.
• Cauda equina syndrome.
• Nerve root compression associated with neurological deficits.
• Malignancy.
• Recent relevant trauma.
• Joint instability.
• Active rheumatoid arthritis.
• Acute local or systemic infection.
• Long-term local corticosteroid use.
• Inability to assume or maintain the required testing position.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Mobilization-Sham Sequence; Participants receive Maitland Grade III++ central posteroanterior mobilization during the first study visit and sham mobilization during the second study visit.	Procedure: Maitland Grade III++ Central Posteroanterior Mobilization; Central posteroanterior mobilization is applied over the L4 spinous process with the participant in a prone position. The intervention consists of three 60-second sets of passive rhythmic oscillatory pressures performed at approximately 2 Hz, with 30-second rest periods between sets, resulting in approximately 360 oscillatory pressures in total.; Procedure: Sham Lumbar Mobilization; Sham mobilization is applied over the L4 spinous process with the participant in a prone position. The procedure consists of three 60-second sets of gentle rhythmic pressures with 30-second rest periods between sets. The timing and therapist contact are matched to the experimental condition, while substantial mobilization pressure is avoided.
Active Comparator: Sham-Mobilization Sequence; Participants receive sham mobilization during the first study visit and Maitland Grade III++ central posteroanterior mobilization during the second study visit.	Procedure: Maitland Grade III++ Central Posteroanterior Mobilization; Central posteroanterior mobilization is applied over the L4 spinous process with the participant in a prone position. The intervention consists of three 60-second sets of passive rhythmic oscillatory pressures performed at approximately 2 Hz, with 30-second rest periods between sets, resulting in approximately 360 oscillatory pressures in total.; Procedure: Sham Lumbar Mobilization; Sham mobilization is applied over the L4 spinous process with the participant in a prone position. The procedure consists of three 60-second sets of gentle rhythmic pressures with 30-second rest periods between sets. The timing and therapist contact are matched to the experimental condition, while substantial mobilization pressure is avoided.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Erector Spinae Muscle Stiffness	Intrinsic stiffness of the right erector spinae muscle is assessed using shear wave elastography and expressed as shear modulus in kilopascals (kPa). Three measurements are obtained at each time point and averaged. The outcome is the change from the pre-intervention to the immediate post-intervention measurement.	Immediately before and immediately after each intervention session
Change in Multifidus Muscle Stiffness	Intrinsic stiffness of the right multifidus muscle is assessed using shear wave elastography and expressed as shear modulus in kilopascals (kPa). Three measurements are obtained at each time point and averaged. The outcome is the change from the pre-intervention to the immediate post-intervention measurement.	Immediately before and immediately after each intervention session

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Erector Spinae Muscle Stiffness Assessed by Myotonometry	Myotonometry will be used to assess mechanical muscle stiffness at the same measurement location used for the erector spinae shear wave elastography assessment. Measurements will be performed immediately before and after each intervention condition. The outcome will be the change in muscle stiffness from pre-intervention to immediate post-intervention.	Immediately before and immediately after each intervention session
Change in Multifidus Muscle Stiffness Assessed by Myotonometry	Myotonometry will be used to assess mechanical muscle stiffness at the same measurement location used for the multifidus shear wave elastography assessment. Measurements will be performed immediately before and after each intervention condition. The outcome will be the change in muscle stiffness from pre-intervention to immediate post-intervention.	Immediately before and immediately after each intervention session

Collaborators and Investigators

• Sponsor: University of Primorska

Study record dates

Study Major Dates

• Study Start (Estimated): September 30, 2026
• Primary Completion (Estimated): November 26, 2026
• Study Completion (Estimated): November 30, 2026

Study Registration Dates

• First Submitted: September 11, 2026
• First Submitted That Met QC Criteria: September 11, 2026
• First Posted (Actual): September 17, 2026

Study Record Updates

• Last Update Posted (Actual): September 17, 2026
• Last Update Submitted That Met QC Criteria: September 11, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Manual Therapy; Shear Wave Elastography; Muscle Stiffness; Spinal Mobilization; Maitland Mobilization; Posteroanterior Mobilization
• Other Study ID Numbers: UP-FHS-PA-SWE-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data underlying the results reported in subsequent publications may be made available upon reasonable request to the study investigators. Data will be shared for scientifically justified purposes following approval by the investigators and, where appropriate, completion of a data-sharing agreement.
• IPD Sharing Time Frame: Data will be available following publication of the main study results and will remain available for at least 5 years.
• IPD Sharing Access Criteria: Researchers with a scientifically justified proposal may request access. Requests will be reviewed by the study investigators and data will be shared in de-identified form subject to applicable ethical and data-protection requirements.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No