Ankylosing Spondylitis: Optimal Sitting Posture, Ergonomics, and Movement

What is the best position to sit with ankylosing spondylitis?

For individuals with ankylosing spondylitis (AS), the best sitting position is one that maintains the natural curves of the spine, particularly the lumbar lordosis, minimizes sustained spinal flexion, and encourages frequent movement to prevent stiffness and reduce spinal stress.

Understanding Ankylosing Spondylitis and Posture

Ankylosing spondylitis is a chronic inflammatory condition primarily affecting the axial skeleton, including the spine, sacroiliac joints, and sometimes peripheral joints. A hallmark of AS is the potential for new bone formation (syndesmophytes) and eventual spinal fusion, leading to a progressive loss of spinal mobility and often a characteristic stooped posture (thoracic kyphosis and loss of lumbar lordosis). Given this propensity for stiffness and deformity, maintaining optimal posture, especially during prolonged sitting, is paramount for managing symptoms, preserving function, and mitigating disease progression. Poor sitting posture can exacerbate pain, accelerate spinal fusion in unfavorable positions, and contribute to muscle imbalances.

Core Principles for Sitting with AS

The goal of proper sitting posture for someone with AS is to support the spine in its most neutral and functional alignment, minimizing stress on the inflamed joints and preventing the adoption of positions that encourage spinal flexion and stiffness.

• Maintain Neutral Spinal Curves: Focus on preserving the natural 'S' curve of the spine, particularly the inward curve of the lower back (lumbar lordosis) and the outward curve of the upper back (thoracic kyphosis).
• Avoid Prolonged Flexion: Slouching or rounding the back for extended periods can accelerate spinal stiffness in a flexed position, which is a common and debilitating outcome of AS.
• Ensure Adequate Support: The spine and pelvis require proper support to maintain alignment without excessive muscular effort.
• Distribute Weight Evenly: Avoid putting disproportionate pressure on one side of the body or one area of the spine.
• Prioritize Movement: No single static position is ideal for extended periods. Regular movement and changes in position are crucial.

The Ideal Sitting Posture for AS

When sitting, aim for the following alignment:

• Back Support: Sit with your back fully supported against the backrest of the chair. Your chair should ideally have a slight lumbar support to help maintain the natural inward curve of your lower back. If your chair lacks this, use a small rolled towel or a lumbar support pillow. Avoid slouching or leaning forward from the waist.
• Hips and Pelvis: Your hips should be positioned as far back in the chair as possible. Aim for your hips to be slightly higher than or level with your knees. This helps maintain a neutral pelvic tilt and prevents posterior pelvic tilt, which flattens the lumbar curve.
• Feet and Knees: Keep your feet flat on the floor or on a footrest if your feet don't reach. Your knees should be at approximately a 90-degree angle, or slightly greater than 90 degrees if your hips are elevated. Avoid crossing your legs, as this can rotate the pelvis and spine.
• Shoulders and Arms: Relax your shoulders down and back, avoiding rounding forward. Your elbows should be close to your body and bent at approximately a 90-degree angle when using a keyboard or desk, with forearms supported by armrests or the desk surface to reduce strain on the neck and shoulders.
• Head and Neck: Keep your head balanced directly over your shoulders, looking straight ahead, not jutting forward or tilted down. If using a computer, ensure your monitor is at eye level.

Ergonomic Considerations for AS

Optimizing your sitting environment is as important as your posture.

• Chair Selection: Invest in an ergonomic chair with good lumbar support, adjustable height, and armrests. A chair that allows for slight recline can also be beneficial, as it can reduce disc pressure compared to sitting upright at 90 degrees.
• Desk Height: Ensure your desk height allows you to sit with your forearms parallel to the floor and your shoulders relaxed.
• Monitor Placement: Position your computer monitor directly in front of you at arm's length, with the top of the screen at or slightly below eye level. This prevents neck flexion and strain.
• Keyboard and Mouse: Use an ergonomic keyboard and mouse that allow your wrists to remain in a neutral position.
• Footrest: If your feet do not comfortably reach the floor while maintaining proper hip and knee angles, use a footrest.

Postures to Avoid

Certain sitting habits can worsen AS symptoms and progression:

• Slouching or Rounding the Back: This promotes a kyphotic (forward-curved) posture and flattens the lumbar spine, which is detrimental for AS.
• Crossing Legs: This can rotate the pelvis and spine, leading to imbalances and increased stress on the sacroiliac joints.
• Leaning to One Side: Uneven weight distribution places undue stress on one side of the spine and pelvis.
• Sitting on Soft, Unsupportive Furniture: Sofas and soft chairs often encourage slouching and do not provide adequate spinal support.
• Prolonged Static Sitting: Remaining in any single position for too long, even an ideal one, can lead to stiffness and increased pain.

The Importance of Movement and Breaks

While optimal sitting posture is crucial, the single most important strategy for managing AS is to avoid prolonged static positions. The mantra "the next position is the best position" applies strongly to AS.

• Regular Micro-Breaks: Aim to stand up, stretch, and move around for 1-2 minutes every 20-30 minutes.
• Varying Positions: If possible, alternate between sitting, standing (with a standing desk), and even lying down for short periods throughout the day.
• Gentle Stretching: Incorporate gentle spinal mobility exercises and stretches during your breaks to counteract stiffness.

Beyond Sitting: Holistic Management

Proper sitting posture is one component of a comprehensive AS management plan. Other crucial elements include:

• Regular Exercise: A consistent exercise program focusing on spinal mobility, strengthening core and postural muscles, and cardiovascular fitness is essential.
• Stretching: Daily stretching routines, particularly for the spine, hips, and chest, are vital to maintain flexibility and combat stiffness.
• Physical Therapy: A physical therapist can provide personalized guidance on posture, exercise, and pain management techniques.
• Medication Adherence: Following your rheumatologist's prescribed medication regimen is critical for controlling inflammation and disease activity.
• Mind-Body Practices: Techniques like yoga or Pilates, adapted for AS, can improve body awareness, posture, and flexibility.

When to Consult a Professional

While these guidelines offer general best practices, individual needs vary. Consult your rheumatologist or a physical therapist if you experience:

• Worsening pain or stiffness despite adopting proper posture.
• Difficulty maintaining an upright posture.
• New or increasing spinal deformity.
• Need for personalized ergonomic assessments for your home or workplace.

Conclusion

For individuals managing ankylosing spondylitis, sitting is not merely a passive act but an active opportunity to support spinal health. The "best" sitting position is one that actively maintains the spine's natural curves, avoids prolonged flexion, and is frequently interrupted by movement. By understanding and implementing these principles, combined with a holistic approach to AS management, individuals can significantly improve comfort, reduce stiffness, and contribute positively to their long-term spinal health.