Joint health

Approximately 50 percent of all the 50-year-olds are already suffering from some degree of change in their joints. Arthritis develops individually as the result of the environmental conditions, ergonomics, nutrition, weight, exercise routines and genes. Different factors of sitting and sitting position have a clear impact on the joints in four major areas: neck shoulders, back and lower limbs. Musculoskeletal Disorders (MSD) have a close link with the development of arthritis. For example, a joint once injured in an accident or playing sports is more prone to suffering from arthritis at some point.

Shoulders and mouse-hand

Shoulder joint problems are common in professions where the angle between the upper body and the upper arm is more than 30 degrees, for example, in dentistry. When using a saddle chair, the angle usually stays smaller than 30 degrees and helps to prevent shoulder joint problems.

The detrimental, sharp angle of the wrist, repetitious movements and muscle tensions, together with pinched nerves in the shoulder area, cause most mouse-hand problems. Relieving pressure from the neck and shoulder area, and finding the correct place for the shoulder while sitting in a good posture, also helps in getting rid of the mouse-hand problems. Good posture and good hand support with almost straight wrists prevents the problem.

Back and neck

Bad postures of the lower back cause uneven and increased compression pressure on the disks when the vertebrae are “ajar” and the facet joints cannot carry their part of the load (30 %). Sitting with the back rounded stretches the soft tissues around the vertebrae of the lower back, causing tension in the ligament tissues.

The neck vertebrae are in unnatural position to one another in traditional sitting, which generally causes arthritis in the neck vertebrae in the middle age. The muscles are tense and sore years before the actual joint problems appear.

These tensions dramatically weaken blood circulation in the area, consequentially reducing the oxygen and nutrient intake of the disks, ligaments and bones. Disks, vertebrae and ligaments have hardly any circulation of their own, so their nutrient and oxygen intake is vitally depending on the nearby tissues fed by active blood circulation.

Wrong and increased pressure and shortage of oxygen and nutrients are actually the two main factors damaging the lower back, and together they cause deterioration and osteoporosis. Sitting in a bad posture, with the neck and upper back in incorrect positions, increase the occurrence of arthritis in the upper back and cervical vertebrae.

The statements on the page are based on the following sources:
Michael Adams, Nikolai Bogduk, Kim Burton, Patricia Dolan: The Biomechanics of Back Pain
David A. Rubenstein, Wei Yin, Mary D. Frame: Biofluid Mechanics, an Introduction to Fluid Mechanics, Macrocirculation, and Microcirculation
Marcus J. Seibel, Simon P. Robins, John P. Bilezikian: Dynamics of Bone and Cartilage Metabolism, Principles and Clinical Applications