Thursday, May 19, 2011

Tai Chi and Balance - Proprioception of the Knee and Ankle


study published by the British Journal of Sport Medicine shows that elderly people who regularly practice Tai Chi not only show better proprioception of the ankle and knee joints than sedentary people. Which would explain why Tai Chi improves balance in its practitioners.

Not only long term Tai Chi practitioners have better ankle and knee joint kinesthesis than sedentary controls but also their ankle joint kinesthesis is better than regular swimmers/runners. Furthermore, the latter did not perform any better in ankle and knee joint kinesthesis tests than their sedentary counterparts. 

 

The postural control system is the control circuit between the sensory sources, the central nervous system, and the musculoskeletal system. Proprioceptors and visual and vestibular (internal ear) centres contribute information to the central nervous system on body position and balance.

Other studies also showed that :
  • All age groups are more dependent on proprioception than on vision for the maintenance of balance.
  • Disruption of proprioceptive input was the most important determinant of quantitative balance performance in subjects older than 80 years.
  • Different kinds of exercise have different effects on balance. Comparison of the effects of proprioceptive exercise, bioenergetic physical activities (swimming, cycling, or jogging), and no exercise on postural control in elderly people shows that muscular strength was significantly increased in the bioenergetic exercise group, but proprioceptive exercise appeared to have the greatest effect on balance control.
Swimming and running are two of the most common exercises practiced by elderly people; they are excellent forms of aerobic exercise, and provide good training stimuli for cardiopulmonary function and muscle strength. Compared with Tai Chi, swimming and running involve cyclic repetitive actions. But awareness of joint position and movement is not emphasized during these exercise forms but highly in Tai Chi. This probably explains why the swimmers/runners did not have better scores for knee and ankle kinesthesis in this study.

It is interesting that the effects of Tai Chi on proprioception were different in the knee and ankle joints. An old Tai Chi proverb states, “In Tai Chi, the feet act as roots”. Also most Tai Chi forms are performed in a low position, which puts load on the muscles which stabilize hip, knee and ankle. The continuous changes of stances and steps cause more variations in ankle joint position, (toes or heels outward or inward, up or down). 

Moreover, while making a stride, feet moves are slow and deliberate. "Control your weight, don't let your weight control you".

These movements greatly improve and help to retain the sensitivity of proprioceptors located in the joint capsules, ligaments, tendons, and muscles.

Ankle proprioception is very important for the elderly to maintain proper postural control. When it comes to control of postural stability, the elderly rely more on hip movements, while young people rely on ankle movements. Therefore the impact of Tai Chi on ankle proprioception is of great benefit in improving and maintaining balance in old people.

The decline in proprioception with age is an important contributing factor to falls in the elderly. This study shows that, compared with other common activities, long term Tai Chi exercise is more valuable for maintaining balance control in the elderly. 


Practice, Slow... 
 

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