An observational study in Low Back Pain and Prolonged Standing, sponsored by University of Tehran. Active, not recruiting at 1 site in Iran. Open to participants aged 20 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by University of Tehran · Observational
The goal of this observational study is to learn whether a short screening test can identify healthy young adults who develop low back pain during prolonged standing ("pain developers"). The study includes university students aged 20 to 35 years with no history of clinical low back pain.
The main questions it aims to answer are:
Participants will attend two sessions on separate days:
Participants who report an increase of at least 10 mm on a 100 mm visual analog scale during the 2-hour standing session will be classified as pain developers. The screening results will be compared with this classification to calculate sensitivity, specificity, and overall accuracy.
2,923 studies on the registry are indexed under Low Back Pain; 579 are open to participants now.
This study's enrollment of 113 is above the median of 100 across 482 observational studies indexed under Low Back Pain.
Browse Low Back Pain studies →University of Tehran is the lead sponsor of 17 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Healthy university students aged 20 to 35 years living in University of Tehran dormitories, recruited through electronic and paper announcements in dormitories, the faculty, and dormitory online groups.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
University students aged 20-35 years without a history of clinical low back pain, assessed with the combined screening protocol and the 2-hour prolonged standing test.
Diagnostic Test: Combined Screening Protocol
Three clinical tests (self-reported active hip abduction, total hip internal rotation range of motion, single-leg squat) and 15-minute surface EMG of the left gluteus medius during standing.
Diagnostic Accuracy (Sensitivity and Specificity) of the Combined Screening Protocol
Sensitivity, specificity, and overall accuracy (with 95% confidence intervals) of the combined screening protocol (three clinical tests plus gluteus medius EMG gaps) for identifying pain developers, compared with the reference standard (an increase of at least 10 mm on a 100 mm visual analog scale from baseline at any 15-minute timepoint during 2 hours of standing).
Time frame: Index tests at Session 1 (Day 1) compared with the reference standard at Session 2 (within 2-28 days)
Pain Developer Status During a 2-Hour Prolonged Standing Test
Low back pain intensity is rated on a 100-mm Visual Analogue Scale (VAS; 0 = no pain, 100 = worst imaginable pain). Participants reporting an increase of ≥10 mm relative to baseline at any measurement point are classified as Pain Developers; all others are classified as Non-Pain Developers. This classification serves as the reference standard.
Time frame: Baseline (minute 0) and every 15 minutes up to 120 minutes during the 2-hour prolonged standing test (Session 2, 2 to 28 days after Session 1)
Folkins Three-Test Clinical Cluster Scores
Three clinical tests: (1) self-rated active hip abduction difficulty (0-5 per side, summed 0-10; positive if ≥4); (2) total bilateral passive hip internal rotation measured with a universal goniometer (degrees; positive if \>81.6°); (3) non-dominant single-leg squat, trunk score from video analysis (0, 5, 10, 15; positive if \>5).
Time frame: Session 1 (Day 1)
Number of Gluteus Medius EMG Gaps
Number of gaps in glutes medius surface EMG activity during 15 minutes of standing,A gap is defined as a period in which normalized EMG activity falls below 0.5% of maximum voluntary contraction for more than 0.2 seconds. The total number of gaps is reported, compared between pain developers and non-pain developers
Time frame: During a 15-minute standing EMG recording at Session 1 (Day 1)
Pain Catastrophizing Scale (PCS) Total Score
Correlation between Pain Catastrophizing Scale total score (range 0-52; higher scores indicate greater catastrophizing) and maximum VAS pain in an exploratory subgroup of participants reaching at least 20 mm VAS.
Time frame: Session 1 (Day 1)
Plan to share: No — individual participant data will not be shared publicly to protect participant confidentiality, as data sharing was not included in the informed consent. Aggregate results will be reported in publications.
No publications or documents are linked to this record.
Started Jul 2026 (actual). Primary completion is estimated for Nov 2026, 3 months after the start.
Of 176 non-industry observational studies under Low Back Pain, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 48. This study's planned 3 months is below that.
Counting every sponsor, half of 186 studies reached it within 24 months; a quarter within 10 and three quarters within 48.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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University of Tehran