Effect of active static hamstring stretching exercises on lumbal region muscle activation in office workers

Introduction: It is suggested that tension in the hamstring muscles may influence lumbopelvic muscle activation patterns, thereby playing a role in postural control and spinal stability. Aim: This study aimed to investigate the effects of active static hamstring stretching exercises on lumbar muscle activation, stabilization, and postural parameters in office workers. Method: The study included individuals aged between 20 and 50 years, with at least two years of work experience, who worked at a desk for a minimum of five hours per day and were classified as "inactive" based on their physical activity level. Participants were randomly assigned to either an exercise group or a control group. The exercise group consisted of 12 women and 11 men, while the control group included 11 women and 12 men. In addition to spinal protection training, the exercise group performed supervised active static hamstring stretching exercises for ten minutes per day, five days a week. The control group received only spinal protection training and was sent posture-related informative messages three times per week. Muscle activation was measured using surface electromyography (sEMG), stabilization was assessed with the Stabilizer Biofeedback Pressure Unit, hamstring flexibility was evaluated using the Sit and Reach Test, and posture was analyzed with the Posture Screen Mobile application. Data were analyzed using SPSS version 24.0, with statistical significance set at p<0.05. Results: At the end of the 6-week program completed with 46 participants, significant changes in muscle activation were observed in the exercise group (n=23) for the rectus abdominis (RA), internal oblique (IO), external oblique (EO), and erector spinae (ES) muscles during maximal voluntary isometric contraction and during concentric, eccentric, and isometric phases of elevation (p<0.05). Additionally, significant improvements were observed in the sit and reach test (p=0.004), stabilization (p=0.005), and postural parameters (p<0.05). No significant changes were observed in the control group (n=23) (p>0.05). Conclusion: The findings indicate that active static hamstring stretching exercises lead to changes in lumbar muscle activation and improvements in postural alignment. Therefore, these exercises may represent an effective strategy to be integrated into spinal health support programs for office workers. Keywords: Lumbopelvic Stability, Electromyography, Flexibility, Thigh, Posture