Nonspecific low back pain is a common musculoskeletal problem that also affects many young adults, including university students. It can negatively impact academic performance, daily life, and overall well-being. Research shows that stabilization exercises targeting the lumbar multifidus muscle play an important role in rehabilitation, but it is unclear whether modified versions of these exercises may provide additional benefits.

This study will investigate a simple modification of the traditional "bird-dog" exercise, called the "Multifidus Lift Exercise." In this version, participants maintain the contralateral knee about 10 cm above the ground while in a four-point kneeling position. This adjustment is expected to increase multifidus activation and improve back endurance.

University students aged 18-25 with nonspecific low back pain will participate in a 6-week supervised program, performing the exercise twice weekly. A healthy control group without low back pain will also be included. The main outcome will be back extensor muscle endurance (Biering-Sørensen Test). In participants with back pain, pain intensity (Visual Analog Scale) and functional disability (Oswestry Disability Index) will also be measured.

The study aims to determine whether this low-cost, practical, and time-efficient exercise can improve muscle endurance, reduce pain, and decrease disability in young adults with low back pain. Results may provide evidence for an effective and accessible preventive and therapeutic approach in student populations.

Background and Rationale. Nonspecific low back pain (NSLBP) is highly prevalent in young adults and is associated with decreased academic performance, daily activity limitations, and reduced well-being. Stabilization exercises targeting segmental control-particularly the lumbar multifidus-are widely supported in rehabilitation literature. Conventional four-point kneeling ("bird-dog") activates multifidus and erector spinae; however, whether targeted modifications can yield greater multifidus activation remains insufficiently studied. This study evaluates a simple, low-cost modification termed the "Multifidus Lift Exercise" (MLE): in quadruped, the contralateral knee is maintained ~10 cm off the ground to bias multifidus recruitment. We hypothesize that MLE will improve lumbar extensor endurance and, in participants with NSLBP, reduce pain and disability.

Objectives and Research Questions. Primary objective: determine the effect of a 6-week supervised MLE program (2 sessions/week) on lumbar extensor endurance (Biering-Sørensen test). Secondary objectives (NSLBP group): assess changes in pain (10-cm VAS) and functional disability (Oswestry Disability Index, Turkish validated version). Key research questions test whether MLE increases endurance and reduces pain/disability in NSLBP, and whether endurance differs between NSLBP and healthy students.

Design and Setting. Single-center, interventional, non-randomized, parallel-group, pre-post design conducted at the Physiotherapy & Rehabilitation Exercise Hall, Selçuk University (Konya, Türkiye). Two cohorts will be observed under the same intervention protocol: (1) university students (18-25 y) with NSLBP and (2) healthy controls without recent low back pain. Allocation is based on current status (no randomization). Masking is not feasible (exercise behavior). Primary purpose: treatment/rehabilitation.

Intervention (Exercise Protocol). All participants receive an initial brief training on isolated multifidus activation and motor control principles. Each supervised session includes standardized warm-up (5 min brisk walk; mobilization; hamstring stretch), the MLE performed slowly and with breath control, and cool-down (static stretches). Repetition progression: weeks 1-2: 8-10 reps; weeks 3-4: 10-12; weeks 5-6: 12-15, emphasizing form and endurance. A 3-week pilot (2 sessions/week) mirrors the 6-week protocol in compressed form (wk1→8-10; wk2→10-12; wk3→12-15) to estimate effect size for main-study sample size planning.

Outcomes and Assessments. Primary outcome is Biering-Sørensen endurance time (seconds) in both groups. Secondary outcomes in NSLBP include VAS pain and ODI (%). Measurements occur at baseline and post-intervention. Adverse symptoms prompting immediate pause (e.g., dizziness, undue fatigue) are recorded session-wise.

See "Outcome Measures" and "Time Frame" modules for exact definitions and schedules.

Participants and Eligibility. Target population: Selçuk University students aged 18-25. Two cohorts (NSLBP vs healthy) are defined by clinical status and physician clearance for exercise. Inclusion/exclusion criteria address red flags, recent surgery or neurological deficits, pregnancy, regular analgesic use, high-load sports, and recent structured exercise that could confound endurance.

Complete criteria are provided in the "Eligibility" module.

Sample Size and Pilot-Informed Planning. The pilot (n≈20; 10 NSLBP/10 healthy) will provide effect size estimates (Cohen's d) to power the main study via G*Power. The anticipated main-study enrollment will be balanced across cohorts per power analysis.

Statistical Analysis (Summary). Analyses will use two-tailed α=0.05 with 95% CIs (IBM SPSS). Descriptives will summarize baseline characteristics. Normality will guide test selection. Between-group comparisons for endurance (NSLBP vs healthy) will use t-test or Mann-Whitney U. Within-group pre-post changes (endurance for both groups; VAS/ODI for NSLBP) will use paired t-tests or Wilcoxon signed-rank. Where appropriate, repeated-measures ANOVA (with Greenhouse-Geisser adjustment) will model time effects; ANCOVA may adjust for baseline imbalances. Exploratory Pearson/Spearman correlations will assess relationships among endurance, pain, and disability; multiple linear regression may evaluate predictors of disability change.

Safety and Monitoring. This is a low-risk, behavioral exercise intervention. Sessions are supervised by study staff; standardized stop rules (e.g., onset of dizziness, dyspnea, undue fatigue, new pain flare) are applied. A formal Data Monitoring Committee is not planned; safety is monitored by the investigative team at each session. Adverse events and withdrawals are documented.

Ethics and Oversight. Ethics approval was granted by the Selçuk University Faculty of Health Sciences Ethics Committee for Non-Interventional Clinical Investigations (Decision/Approval No: 2025/674; Meeting No: 05; Ref: 2025/05; Date: 30/04/2025). Participation is voluntary with written informed consent. Data are handled under the Declaration of Helsinki and applicable regulations (including Turkish KVKK). De-identified, aggregate results will be disseminated.

Data Handling and Dissemination. De-identified data will be analyzed and reported in aggregate. Individual participant data sharing is not planned. Findings will be prepared for peer-reviewed publication and scientific meetings, and may inform practical, community-oriented exercise programs for student populations.

Inclusion Criteria:

• Age between 18 and 25 years

Currently enrolled as a university student at Selçuk University

Willing to participate voluntarily and sign informed consent form

Medically suitable for exercise participation

For NSCLBP group:

History of nonspecific chronic low back pain within the past 3 months

Physician confirmation of nonspecific low back pain

Oswestry Disability Index (ODI) ≥ 21% (moderate disability)

Visual Analog Scale (VAS) score ≥ 3.5

For Healthy control group:

No history of low back pain within the past 3 months

Physician confirmation of no contraindications for exercise

Exclusion Criteria:

• Presence of radicular pain or nerve root compression symptoms

History of spinal surgery

Neurological deficits within the past 3 months (e.g., muscle weakness, reflex loss, paresthesia)

Systemic infection or systemic disease affecting participation

Cardiovascular or pulmonary disease contraindicating exercise

Clinical "red flag" symptoms (e.g., saddle anesthesia, bowel/bladder incontinence, fever, known cancer)

Pregnancy

Regular use of analgesics, muscle relaxants, or anti-inflammatory medications

Participation in regular exercise programs in the past 3 months

Active involvement in sports directly affecting lumbar muscles (e.g., fitness, pilates, yoga, swimming)

Inability to comply with exercise sessions or study protocol

The decision on IPD sharing will be made after study completion and in accordance with institutional and ethical guidelines

No masking will be implemented. Both participants and investigators are aware of the intervention assignment.