Blog 11- Understanding Low Back Pain: The Impact of Poor Posture and Prolonged Sitting

Low back pain is a common complaint that affects millions of individuals worldwide. As a physiotherapist, I often encounter patients experiencing discomfort due to poor posture or prolonged sitting, particularly those with a rounded lumbar spine. In this blog, we will delve into the biomechanical changes that occur in the lumbar spine when it is flexed, explore the detrimental effects of prolonged sitting, and provide practical recommendations for posture modification and exercises to alleviate and prevent back pain. 

The Biomechanics of the Lumbar Spine in a Flexed Position 

The Lumbar Spine (Low Back)

The lumbar spine, composed of five vertebrae (L1-L5), is designed to maintain a natural curve known as lordosis. This curvature plays a crucial role in distributing mechanical stress during movement and maintaining spinal stability. However, when we adopt a flexed position, such as slumping or slouching, the natural lordotic curve flattens or reverses into kyphosis. This biomechanical change leads to several adverse effects: 

1. Increased Disc Pressure: Flexion of the lumbar spine increases the pressure on the intervertebral discs, particularly the anterior portion. Over time, this can contribute to disc degeneration, herniation, and chronic pain. 

2. Ligamentous Strain: The ligaments supporting the spine are stretched when the lumbar spine is in a flexed position, leading to potential ligamentous strain and instability. 

3. Muscular Imbalance: Prolonged flexion can cause certain muscles, such as the erector spinae, to weaken due to disuse, while others, like the hip flexors, may become overly tight and shortened. 

The Detriments of Prolonged Sitting 

Sitting for extended periods has become ubiquitous in modern lifestyles, whether at work, during commutes, or during leisure activities. Unfortunately, prolonged sitting is detrimental to overall health and can exacerbate low back pain. Here’s why: 

1. Reduced Blood Flow: Sitting for long durations restricts blood flow to the muscles and discs in the lower back, leading to stiffness and discomfort. 

2. Muscular Deconditioning: Lack of movement results in muscle deconditioning and weakening, particularly in the core and lower back muscles, which are essential for spinal support. 

3. Postural Strain: Most people tend to adopt poor postures while sitting, such as slouching or leaning forward, which exacerbates the negative biomechanical changes in the lumbar spine. 

Understanding Pain While Sitting 

Patients often ask, "Why does my back hurt even when I'm not moving?" The answer lies in the static nature of sitting, which places continuous strain on certain structures of the spine. Unlike standing or walking, which allows for regular muscle activity and movement, sitting imposes sustained pressure on the spinal discs and surrounding tissues. This continuous load can lead to muscle fatigue, ligamentous stress, and increased disc pressure, all contributing to persistent pain even in the absence of movement. 

Posture Modification Recommendations 

Improving posture is paramount in managing and preventing low back pain associated with prolonged sitting. Here are some recommendations: 

1. Ergonomic Chair: Invest in an ergonomic chair that supports the natural curvature of the lumbar spine. Ensure the chair height allows your feet to be flat on the floor, with knees at a 90-degree angle. 

2. Lumbar Support: Use a lumbar roll or cushion to maintain the natural lordotic curve while sitting. This helps distribute pressure evenly and reduces strain on the lower back. 

3. Regular Movement: Incorporate regular breaks into your sitting routine. Stand, stretch, or walk for at least 5-10 minutes every hour to alleviate pressure on the spine and promote blood flow. 

4. Proper Desk Setup: Adjust your desk and computer monitor height to avoid leaning forward. Your screen should be at eye level, and your elbows should be at a 90-degree angle when typing. 

Best Exercises for Managing Low Back Pain 

Focusing on exercises that encourage back extension is crucial for counteracting the negative effects of prolonged sitting and poor posture. Here are some effective back extension exercises: 

1. Prone Press-Ups: Lie face down on the floor with your hands placed under your shoulders. Press up with your hands, lifting your chest off the ground while keeping your hips in contact with the floor. Hold for a few seconds and then lower back down. Repeat 10-15 times. 

2. Standing Back Extensions: Stand with your feet shoulder-width apart. Place your hands on your lower back for support. Gently arch your back, pushing your hips forward and lifting your chest upwards. Hold for a few seconds and then return to the starting position. Repeat 10-15 times. 

Cobra Stretch

3. Cobra Stretch: Lie face down on the floor with your legs extended and the tops of your feet flat on the ground. Place your hands under your shoulders and gently lift your chest off the ground, extending your spine. Keep your elbows slightly bent and hold the position for 15-30 seconds. Repeat 3-5 times. 

By incorporating these back extension exercises into your routine, you can help alleviate low back pain, improve spinal alignment, and strengthen the muscles that support your lumbar spine. 

Conclusion 

Low back pain resulting from poor posture and prolonged sitting is a prevalent issue that can significantly impact quality of life. Understanding the biomechanical changes in the lumbar spine, recognizing the dangers of prolonged sitting, and implementing posture modifications are crucial steps in managing and preventing pain. Additionally, incorporating targeted exercises into your routine can strengthen the supporting muscles and alleviate discomfort. By adopting these strategies, you can take proactive steps towards a healthier, pain-free back and an overall improved quality of life. 

Marco Chiasson, Physiotherapist

Physika