Effectiveness of a Workplace-Based Core Stability Exercise Program in Reducing Occupational Low Back Pain Among Hospital Nurses: A Quasi-Experimental Study

The study is a quasi-experimental investigation conducted at a tertiary care hospital in Islamabad, Pakistan, aimed at evaluating the effectiveness of a structured, workplace-based core stability exercise program in reducing occupational low back pain (OLBP) among hospital nurses. A total of 146 registered nurses experiencing OLBP were enrolled and allocated into two equal groups: an intervention group (n = 73) and a control group (n = 73). Allocation was based on departmental feasibility and work schedules rather than randomization to maintain clinical workflow, reflecting a pragmatic design.

Participants in the intervention group engaged in a supervised core stability exercise program three times per week over four consecutive weeks, totaling 12 sessions. Each session lasted approximately 30-40 minutes and included three phases: a 5-10 minute warm-up with low-intensity mobility and stretching exercises targeting the lumbar spine and lower extremities; a 20-25 minute core stability training phase focusing on neuromuscular activation and strengthening of deep trunk stabilizing muscles (transversus abdominis, lumbar multifidus, pelvic floor, diaphragm, obliques, and trunk extensors) through progressive static and dynamic exercises such as abdominal drawing-in maneuvers, pelvic tilting, bridging, bird-dog, side bridge, and plank variations; and a 5-minute cool-down with gentle stretching to promote recovery. Exercise intensity was progressively increased by modifying duration, repetitions, and complexity while maintaining correct technique under physiotherapist supervision. The control group continued routine occupational activities without structured exercise.

The primary outcome was pain intensity measured by the Numeric Pain Rating Scale (NPRS), a validated 11-point scale ranging from 0 (no pain) to 10 (worst pain imaginable). Pain was assessed at baseline and immediately post-intervention. Baseline characteristics of participants, including demographic and occupational variables, were comparable between groups except for a significant difference in workplace department distribution, which was controlled for in sensitivity analyses.

Statistical analyses employed non-parametric tests due to non-normal distribution of NPRS scores. Within-group changes were analyzed using the Wilcoxon signed-rank test, and between-group differences post-intervention were evaluated using the Mann-Whitney U test. Effect sizes (r) were calculated to quantify the magnitude of changes. A sensitivity analysis using ANCOVA adjusted for baseline pain intensity and workplace department to address potential confounding from the non-randomized design.

The study's rationale is based on Panjabi's spinal stability model, which describes spinal stability as a function of the passive (vertebrae, discs, ligaments), active (muscles, tendons), and neural control subsystems. Occupational activities of nurses, including manual patient handling and prolonged static postures, impose repetitive biomechanical loading on the lumbar spine, risking tissue fatigue and injury. Core stability exercises target the active and neural subsystems by enhancing deep trunk muscle activation and neuromuscular coordination, improving spinal stiffness, load sharing, and movement efficiency, thereby reducing mechanical stress on passive structures and alleviating pain.

Strengths of the study include standardized, supervised intervention delivery, 100% participant retention, validated pain measurement, and comprehensive statistical analysis with effect size reporting and sensitivity adjustment. Limitations include the quasi-experimental non-randomized design with potential selection bias, imbalance in workplace department distribution, short intervention duration limiting assessment of long-term effects, and reliance solely on self-reported pain without functional or biomechanical outcome measures.

The study was approved by the Institutional Review Board and Ethics Committee of Shifa International Hospitals, Islamabad, Pakistan, and conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants. No external funding was received, and the authors declared no conflicts of interest.