HEALTHY YOU

Keep Moving to Fight Aging

The effects of immobilization on human tissue have been well discussed and described in the literature providing us an understanding of how the body responds to injury. In fact, immobilization can occur in many forms including casting, bracing, swelling following injury, hospitalization, walking with crutches or simply sustained sitting positions at work. Any deviation from complete activity can create motion loss surrounding an area or areas of the body thus producing an effect on connective tissue. The results of connective tissue change generally are similar to the aging process and therefore we can deduce that reduced activity accelerates the degeneration of normal, healthy tissue.

During development, four different types of tissue are differentiated: epithelial, connective, nervous and muscle tissue. Connective tissue is found throughout the body and plays a large role in supporting the other tissues (blood vessels, nerves, muscles) thus creating homeostasis to physical form. When movement is lost or altered, normal degradation and synthesis of connective tissue is dramatically changed. The effects directly alter the well being of primary tissues such as muscle, joints and bone.

Immobilization causes muscle atrophy by changing the contractile properties. It has been demonstrated that muscles with reduced activity, especially in a shorted position, convert in fiber type. The change (from slow twitch to fast twitch) weakens the postural muscles and leads to increased muscular fatigue. Cellular change within muscle tissue takes place as early as 10 hours post immobilization and causes damage in the muscle within 5 days. The longer normal activity is altered and mobility is limited, muscular tissue is replaced by connective tissue resulting in tissue stiffness and loss of range of motion.

Limited range of motion has a degenerative effect on weight bearing and non-weight bearing joints. Common synovial joints such as the knee, hip or shoulder undergo connective tissue changes in the synovial membrane and atricular cartilage. In one particular study, immobilization of dog knees for 11 weeks resulted in a 20% reduction in the protein concentration of the articular cartilage (Haapala et al, 1999). Even after the dogs were allowed to roam free for 50 weeks, their joints continued to show damage. More importantly, in human subjects, research has illustrated that individuals confined to wheelchairs for up to 14 months developed knee contractures primarily due to inflammation and proliferation of intra-articular connective tissue (Enneking, 1972).

Immobilization not only transforms the softer type tissue but also the bones. Osteoporosis is a common affliction amongst individuals with reduced mobility. Bone tissue requires mechanical loading for maintenance of normal bone mineral density. Supplemental calcium and certain hormones can assist bone metabolism but, it the absence of weight bearing loads, have not been shown to completely reverse demineralization. Some studies have compared bone mineral density recovery using treadmill exercise vs. regular activity and have determined that bone loss as a result of immobilization will recover with exercise (Kannus et al, 1996). These researchers also noticed that when exercise was stopped and subject became deconditioned, bone density again dropped below normal levels.

It is greatly important to keep yourself moving for the health of your tissues and the regulation of your physical form. Physical Therapists are highly qualified to assist you in the promotion of your mobility. Call to speak with your Physical Therapist should you have concerns about your mobility.

Life is motion… move well.

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