Isometric Stability vs. Isotonic Mobility for Chronic LBP (LBP)

An RCT of Isometric Stability Versus Isotonic Mobility for LBP Rehabilitation

Background: Low back pain (LBP) is a leading cause of disability, often requiring primary care management.

Objective: To compare the effectiveness of isometric versus isotonic exercise programs for LBP.

Methods: Sixty adults with LBP were randomly assigned to two groups. Group A (n=30) performed isometric exercises, infrared therapy, and TENS. Group B (n=30) performed isotonic exercises with the same adjunct therapies. Pain (VAS), disability (MODI), and abdominal endurance were measured pre- and post-intervention.

Keywords: Exercise therapy; low back pain; disability evaluation

Study Overview

• Status: Completed
• Conditions: LBP
• Intervention / Treatment: Other: Isometric exercises; Other: Isotonic exercises

Detailed Description

Group-Specific Exercise Protocols:

• Isometric Exercise Group (IEG): This group performed a circuit of three core-stabilizing isometric exercises, each held for 10 seconds with brief rest intervals, for 5 complete repetitions. The exercises included: (a) Isometric Curl-Up, (b) Side Bridge, and (c) Bird Dog. The total dedicated exercise time was approximately 20 minutes per session.
• Isotonic Exercise Group (ITG): This group performed a circuit of three dynamic, strength-oriented isotonic exercises, each completed for 10 repetitions. The exercises included: (a) Bent Knee Sit-Up, (b) Cross Curl-Up, and (c) Prone Back Extension. The total dedicated exercise time was also approximately 20 minutes per session. All exercises were selected and adapted from previously published rehabilitation protocols for CLBP [13].

Adjunctive Therapies (Common to Both Groups):

1. Infrared (IR) Therapy: A standard therapeutic infrared lamp was positioned 50 cm from the participant's lumbar spine at a 90-degree angle. Heat was applied for 15 minutes per session to promote muscle relaxation and local blood flow.
2. Transcutaneous Electrical Nerve Stimulation (TENS): Electrodes were placed over the painful lumbar area. A low-frequency (<10 Hz) TENS unit was applied for 20 minutes per session. The analgesic mechanism of TENS is well-documented, involving the modulation of pain pathways via opioid and noradrenergic receptors in the central nervous system [16].

Both groups received a standardized four-week intervention program, consisting of three supervised sessions per week, totaling 12 sessions. Each 55-minute session included adjunctive therapies common to both groups, followed by the specific exercise protocol.

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Palestinian Territories
  • West Bank
    • Bethlehem, West Bank, Palestinian Territories, 3600700
      • Palestine Ahliya University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 18 and 60 years;
• Diagnosis of non-specific CLBP, defined as pain localized between the lower rib margin and the gluteal folds persisting for more than three months;
• Self-reported pain intensity score between 40 mm and 80 mm on a 100-mm Visual Analogue Scale (VAS), indicating moderate to severe pain;
• Pain experienced on at least three days in the month preceding enrollment, with documented interference in daily activities;
• A formal referral for physiotherapy management.

Exclusion Criteria:

• The presence of "red flag" pathologies (e.g., spinal tumor, infection, fracture); - Neurological signs or symptoms suggestive of radiculopathy or myelopathy;
• a history of spinal surgery or epidural steroid injections within the previous 12 months;
• Systemic inflammatory diseases (e.g., rheumatoid arthritis) or major neurological disorders;
• Pregnancy;
• Receipt of physiotherapy for low back pain within the last six months;
• Current use of non-steroidal anti-inflammatory drugs (NSAIDs) or inability to refrain from their use during the study period;
• Any diagnosed psychiatric condition.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: arm 1- Group A : Isometric Exercises; • Isometric Exercise Group (IEG): This group performed a circuit of three core-stabilizing isometric exercises, each held for 10 seconds with brief rest intervals, for 5 complete repetitions. The exercises included: (a) Isometric Curl-Up, (b) Side Bridge, and (c) Bird Dog. The total dedicated exercise time was approximately 20 minutes per session.	Other: Isometric exercises; • Isometric Exercise Group (IEG): This group performed a circuit of three core-stabilizing isometric exercises, each held for 10 seconds with brief rest intervals, for 5 complete repetitions. The exercises included: (a) Isometric Curl-Up, (b) Side Bridge, and (c) Bird Dog. The total dedicated exercise time was approximately 20 minutes per session.
Experimental: arm2- Group B: Isotonic Exercises; Isotonic Exercise Group (ITG): This group performed a circuit of three dynamic, strength-oriented isotonic exercises, each completed for 10 repetitions. The exercises included: (a) Bent Knee Sit-Up, (b) Cross Curl-Up, and (c) Prone Back Extension. The total dedicated exercise time was also approximately 20 minutes per session. All exercises were selected and adapted from previously published rehabilitation protocols for CLBP	Other: Isotonic exercises; • Isotonic Exercise Group (ITG): This group performed a circuit of three dynamic, strength-oriented isotonic exercises, each completed for 10 repetitions. The exercises included: (a) Bent Knee Sit-Up, (b) Cross Curl-Up, and (c) Prone Back Extension. The total dedicated exercise time was also approximately 20 minutes per session. All exercises were selected and adapted from previously published rehabilitation protocols for CLBP [13].

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VAS	Measured using a 100-mm Visual Analogue Scale , where 0 mm represents "no pain" and 100 mm represents "the worst pain imaginable." Participants marked a point on the line corresponding to their current pain level. The Arabic version of the VAS has been validated as a reliable and responsive tool for pain assessment in clinical populations [17].	4 WEEKS

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MODI	This self-administered questionnaire contains 10 items addressing various aspects of daily life (e.g., pain intensity, personal care, lifting, walking). Each item is scored from 0 to 5, with the total sum converted to a percentage (0-100%); higher scores indicate greater disability. The MODI is a gold-standard tool with demonstrated high reliability, validity, and sensitivity to clinical change in patients with low back pain [18].	4WEEKS
Muscular Endurance	Assessed via a standardized Abdominal Endurance Test. Participants were instructed to hold a partial curl-up position (trunk elevated at 30° from the plinth) for as long as possible while maintaining proper form. The time in seconds until failure was recorded. This test is a validated and reliable measure of core muscular endurance, a key component of lumbar stability [19].	4WWEKS

Collaborators and Investigators

• Sponsor: Palestine Ahliya University

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2025
• Primary Completion (Actual): June 1, 2025
• Study Completion (Actual): August 1, 2025

Study Registration Dates

• First Submitted: January 25, 2026
• First Submitted That Met QC Criteria: January 25, 2026
• First Posted (Actual): February 2, 2026

Study Record Updates

• Last Update Posted (Actual): February 2, 2026
• Last Update Submitted That Met QC Criteria: January 25, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Disability; LBP; Exercise therapy
• Additional Relevant MeSH Terms: Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise
• Other Study ID Numbers: PAUB

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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