An observational study in Hamstring Tightness, Lumbar Lordosis and Sedentary Behavior, sponsored by Cairo University. Not yet recruiting at 1 site in Egypt. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-06.
Sponsored by Cairo University · Observational
The goal of this observational study is to learn about the relationship between hamstring tightness and the lumbar lordosis angle in sedentary adults across different sitting postures. The main question it aims to answer is:
Is hamstring tightness related to the lumbar lordosis angle across three functional sitting postures (upright, slumped, and forward-leaning)? It also asks whether hamstring tightness differs between men and women, whether it differs between the dominant and non-dominant leg, and whether the lumbar lordosis angle differs between men and women across the three postures.
Participants will have their hamstring tightness measured with the Active Knee Extension test and their lumbar lordosis angle measured with a bubble inclinometer while sitting in each of the three postures.
Prolonged sitting is a defining feature of contemporary sedentary lifestyles and an established risk factor for musculoskeletal disorders of the lumbar spine. During sustained sitting, the hip is held in flexion and the hamstring muscle-tendon unit is maintained in a shortened position, which over time is associated with reduced hamstring extensibility (hamstring tightness). Because the hamstrings originate from the ischial tuberosity, a loss of hamstring extensibility exerts a posteriorly directed pull on the pelvis, promoting posterior pelvic tilt. Through regional spinopelvic coupling, this change in pelvic orientation alters the sacral slope and, consequently, the lumbar lordosis angle.
Although the relationship between hamstring tightness and lumbar lordosis has been described previously, most existing studies have evaluated it in the standing position. Sedentary individuals, however, spend the majority of their day seated, where the line of gravity, baseline muscle activity, and passive tissue demands placed on the spine differ substantially from those in standing. Evidence is therefore limited regarding how hamstring tightness relates to the lumbar lordosis angle across the functional sitting postures encountered in daily life, and regarding how this relationship may vary by sex and between the dominant and non-dominant lower limb.
This cross-sectional observational study will be conducted on 110 sedentary adults (55 male and 55 female), aged 18 to 45 years, recruited according to predefined eligibility criteria. The sample size was determined using G*Power based on a bivariate-normal correlation model. Eligible participants will be sedentary (more than six hours of sitting per day and a physical-activity level below 600 MET-minutes/week on the International Physical Activity Questionnaire), with a body mass index below 30 kg/m², bilateral hamstring tightness, and no current low back pain or other exclusionary conditions.
Following screening and informed consent, each participant's demographic and anthropometric data will be recorded, and lower-limb dominance will be determined using a three-task behavioral battery. Hamstring tightness will be assessed bilaterally using the Active Knee Extension (AKE) test, recorded with a digital goniometer, with the mean of three trials used for analysis. The lumbar lordosis angle (T12-S2) will be measured using a double bubble inclinometer in three randomized functional sitting postures-upright, slumped, and forward-leaning-with the mean of three trials per posture used for analysis.
The primary aim is to examine the correlation between hamstring tightness and the lumbar lordosis angle in each of the three sitting postures. The secondary aims are to compare hamstring tightness between male and female participants, to compare hamstring tightness between the dominant and non-dominant lower limb, and to compare the lumbar lordosis angle between male and female participants across the three postures. Data will be analyzed using Pearson correlation coefficients, independent- and paired-samples t-tests, and a mixed-design analysis of variance, with the significance level set at p \< 0.05.
30 studies on the registry are indexed under Lordosis; 5 are open to participants now.
This study's planned enrollment of 110 is above the median of 59 across 14 observational studies indexed under Lordosis.
Browse Lordosis studies →Cairo University is the lead sponsor of 4,941 studies on the registry; 1,458 are open to participants now.
Of its 37 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
Counted across the registry records on this site, refreshed daily.
Sedentary adults of both sexes, aged 18 to 45 years, recruited from the Nasser institute hospital, and the surrounding community. Eligible participants are healthy individuals with a sedentary lifestyle (more than six hours of sitting per day and a physical-activity level below 600 MET-minutes per week on the International Physical Activity Questionnaire), a body mass index below 30 kg/m², and bilateral hamstring tightness, with no current low back pain or other excluding musculoskeletal, neurological, or spinal conditions
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.
Sedentary adults aged 18-45 years (55 male, 55 female) with bilateral hamstring tightness and no current low back pain, assessed for hamstring tightness (Active Knee Extension test) and lumbar lordosis angle (bubble inclinometer) across three functional sitting postures (upright, slumped, and forward-leaning).
Other: Hamstring tightness and lumbar lordosis assessment
Hamstring tightness measured bilaterally with the Active Knee Extension test (digital goniometer) and lumbar lordosis angle (T12-S2) measured with a bubble inclinometer across three functional sitting postures. No therapeutic intervention is administered; these are observational measurements only.
Correlation between hamstring tightness and lumbar lordosis angle across three functional sitting postures
Hamstring tightness is measured as the Active Knee Extension (AKE) deficit in degrees (mean of three trials per limb, using a digital goniometer). The lumbar lordosis angle is measured in degrees using a bubble inclinometer (T12-S2, mean of three trials per posture) in three functional sitting postures: upright, slumped, and forward-leaning. The association between hamstring tightness and the lumbar lordosis angle is assessed for each posture using the Pearson correlation coefficient.
Time frame: At a single assessment session (cross-sectional; Day 1).
Difference in hamstring tightness between males and females
Hamstring tightness (bilateral mean Active Knee Extension deficit, in degrees) compared between male and female participants.
Time frame: At a single assessment session (cross-sectional; Day 1).
Difference in hamstring tightness between the dominant and non-dominant lower limb
Hamstring tightness (Active Knee Extension deficit, in degrees) compared between the dominant and non-dominant limb. Limb dominance is determined using a three-task behavioral battery.
Time frame: At a single assessment session (cross-sectional; Day 1).
Difference in lumbar lordosis angle between males and females across the three sitting postures
Lumbar lordosis angle (degrees, bubble inclinometer, T12-S2) compared between male and female participants in each of the three functional sitting postures (upright, slumped, forward-leaning).
Time frame: At a single assessment session (cross-sectional; Day 1).
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Aug 2026; primary completion for Oct 2026, 2 months later.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.