Office Program Effects on Pain, Posture, Muscle Physiology, Stress, Ergonomics, and Quality of Life in LBP Workers

Pain intensity will be assessed using the Numeric Rating Scale (NRS), an 11-point scale from 0 (no pain) to 10 (worst possible pain). Participants will rate their average low back pain at baseline and after the 12-week intervention. Changes in NRS scores will be compared across groups.

Lumbar posture will be assessed using the Flexible Curve method, which measures lumbar curvature by molding a flexible ruler along the participant's lumbar spine. Measurements will be taken in the prone position to assess lumbar extension and in the sitting position to assess lumbar flexion. The molded curve will then be traced onto paper to calculate the lumbar lordosis angle and curvature index. Changes in lumbar curvature values will be compared between groups to determine the effects of the interventions on spinal alignment. The unit of measurement will be degrees.

Core stability will be assessed using a sphygmomanometer pressure biofeedback test. Participants will be positioned sitting, with the cuff placed behind the lumbar region and inflated to a baseline pressure of 40 mmHg. Changes in pressure during controlled abdominal drawing-in maneuvers will be recorded. Smaller pressure deviations indicate better core muscle activation and stability. Core stability scores will be compared between groups to evaluate the effectiveness of each intervention. The unit of measurement will be millimeters of mercury (mmHg).

Quality of life will be assessed using the Short Form-36 (SF-36) questionnaire, which measures eight health domains: physical functioning, role limitations due to physical health, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health. Each domain is scored from 0 to 100, with higher scores indicating better health status. Changes in SF-36 scores will be compared between groups to determine the impact of the interventions on overall quality of life.

Stress levels will be assessed using the Perceived Stress Scale (PSS), a validated self-report questionnaire that measures the degree to which situations in a participant's life are appraised as stressful. Participants complete the 10-item PSS, with each item scored on a 0-4 scale. Higher total scores indicate higher perceived stress. Changes in PSS scores will be compared between the three study groups to evaluate the effect of the interventions on stress reduction.

Ergonomic risk will be evaluated using the Rapid Office Strain Assessment (ROSA), a validated observational tool designed to assess risk factors associated with office workstation setup. The ROSA score is calculated based on chair design, monitor height, keyboard/mouse position, posture, and duration of exposure to each risk factor. Higher scores indicate greater ergonomic risk. Changes in ROSA scores will be compared between groups to determine whether the interventions improve workstation ergonomics and reduce musculoskeletal risk factors.

Lumbar trunk muscle endurance will be assessed using three standardized endurance tests, the unit of measurement per item will be second:

• Kraus-Weber Test (Trunk Flexor Endurance): Participants maintain a supported trunk flexion position while time to fatigue is recorded.
• Sorensen Test (Trunk Extensor Endurance): Participants maintain a horizontal torso position while the pelvis is secured, with hold time recorded.
• Shirado Test (Abdominal and Lumbar Endurance): Participants perform an isometric abdominal and lumbar hold, and duration until fatigue is measured.

Longer hold times indicate better muscle endurance. Changes in endurance times will be compared between groups to determine the effectiveness of the interventions.

Muscle fatigue will be assessed using surface electromyography (sEMG) recorded from the lumbar extensor muscles during a standardized isometric contraction task. sEMG signals will be analyzed for median frequency (MF) and root mean square (RMS) changes. A decrease in MF and an increase in RMS over time indicate greater muscle fatigue. Differences in sEMG-derived fatigue indicators will be compared between intervention groups to determine the effect of the programs on lumbar muscle fatigue. The unit of measurement will be microvolts (µV).

Flexibility will be assessed using the Sit-and-Reach Test, which measures hamstring and lower back flexibility. Participants sit on the floor with legs extended and reach forward along a standardized measurement box. The distance reached (in centimeters) is recorded, with greater reach indicating better flexibility. Changes in Sit-and-Reach scores will be compared between groups to evaluate the effects of the interventions on flexibility. The unit of measurement will be centimeters.