The Effect of Hamstring Stretching on Lumbar Muscle Activation in Officers

Prolonged periods of desk work and static postures in office workers lead to various musculoskeletal issues in both the lower and upper extremities. One such issue is hamstring muscle tightness observed in individuals. Tight hamstring muscles contribute to increased electromyographic muscle activity in the lumbar region, altered lumbopelvic rhythm, and changes in lumbar stabilization, leading to low back pain. The viscoelastic properties of the hamstring muscles play a crucial role in maintaining posture and stabilizing the lumbar region. Insufficient hamstring flexibility or viscoelastic properties can alter pelvic position and result in excessive stress in the lumbar region, thereby increasing the risk of low back pain.

It is anticipated that the activation, stabilization, and viscoelasticity of the muscles in the lumbar region will change through static active hamstring stretching exercises, which aim to restore the length-tension relationship in the hamstring muscles. This study aims to investigate the effect of active static hamstring stretching exercises on lumbar muscle activation, stabilization, and viscoelasticity in office workers.

Most office workers spend long hours working at a computer, leading to prolonged periods of sitting. As a result, low back pain is frequently observed among office workers due to extended sitting durations. Issues arising in the lumbar region significantly reduce individuals' quality of life and are the second leading cause of work absenteeism, thus increasing treatment costs.

The movement of the spine occurs through the coordinated functioning of muscles and nerves. While agonist muscles initiate and maintain movement, antagonist muscles control and modulate it. Healthy spinal movements are ensured by the optimal functioning of these muscles. To achieve this, individuals are provided with ergonomic training, core strengthening exercises, and stretching exercises.

The hamstring muscle contributes to the stabilization of the hip and pelvis joints, thereby aiding in the stabilization of the lumbar spine. The relationship between the viscoelastic properties of the hamstring muscle and the lumbar region encompasses a wide range of issues, including low back pain, postural disorders, and pelvic stability. Studies have reported that a minimum of 5-7 hours of sitting leads to hamstring muscle tightness. Hamstring tightness not only reduces the range of motion but also leads to various musculoskeletal problems. The tightness in the hamstring muscles can affect pelvic mobility and lumbopelvic rhythm. Additionally, research has shown a positive relationship between hamstring tightness and the severity of low back pain. Tight hamstring muscles can increase the tension in the muscles and ligaments of the lumbar region, resulting in significantly higher compression loads on the lumbar spine. Other postural changes associated with hamstring tightness may indirectly affect sacroiliac joint stability. Therefore, the flexibility of the hamstring muscles is extremely important for overall health and optimal physical fitness.

Participants will be divided into two groups: control and experimental. Participants will be randomized, stratified by gender, and a total of 50 individuals are planned to participate in the study. The study will last a total of 6 weeks. At the beginning of the study, both groups will receive briefings. The control group will receive training on spinal protection principles within the office. Additionally, participants in this group will receive short text messages on their phones containing information on maintaining proper posture throughout the day, sent on Mondays, Wednesdays, and Fridays for 6 weeks.

The experimental group, in addition to the spinal protection principles training, will perform active static hamstring stretching exercises in the office environment, consisting of 10 repetitions of 30-40 seconds of stretching and 30 seconds of rest, for a total of 10 minutes per session, 5 days a week. Participants in the experimental group will be supervised during the stretching exercises.

To ensure participants' eligibility according to the inclusion and exclusion criteria, the International Physical Activity Questionnaire-Short Form will be administered. The primary outcome measures of the study are electromyographic muscle activity, stabilization, and viscoelastic properties; the secondary outcome measures are myoton, sit-and-reach test, and photographic posture analysis. Assessments will be conducted on a single day and will be performed twice, at the beginning and at the end of the study, by the same researcher who is blinded to the treatment method.

Eligibility Criteria:
Inclusion Criteria:

* Individuals aged between 20 and 50 years
* Who are office workers
* Spending at least 5 hours daily sitting at a desk
* Willing to participate in the study
* And classified as physically inactive according to the International Physical Activity Short Form

Exclusion Criteria:

* Individuals with a history of lumbar spine and knee surgery within the last 6 months
* A history of any hamstring muscle injury within the last 6 months
* Presence of osteoporosis
* Concurrent mental, metabolic, rheumatologic, neuromuscular, cardiovascular, or pulmonary conditions
* Currently pregnant
* And individuals classified as obese (BMI \> 30 kg/m²)