Many experts say there are lots of benefits in doing Tai Chi exercise. For example, Tai Chi can help older adults maintain balance and strength needed to prevent falls. But there are very few studies to examine the movements used in Tai Chi.
In this report, the results are presented from comparing the biomechanics of Tai Chi gait in healthy elders to young adults and to normal walking in older adults. Electromyography (EMG) of the leg muscles during Tai Chi was recorded for young and old Tai Chi practitioners.
Single-stance (standing on one leg), double stance (standing on two legs), and leg swing were analyzed. Amount of hip and knee flexion and time in each position were measured. Amount of muscle activation was also viewed in relation to the amount of time the person was in each position.
The author used a variety of tools to measure everything. Besides the EMG, a handheld dynamometer was used to measure knee extensor strength. Infrared sensitive cameras recorded movement. Two force plates in the walkway recorded ground reaction forces during regular walking and while doing Tai Chi movements in a forward direction.
The results showed quite a difference in biomechanics between a Tai Chi forward movement, Tai Chi gait, and normal walking between young and old. This is the first study to show age-related differences in movement during Tai Chi.
The main difference was noticed during the single-stance phase. The older group stayed on that leg less time with less hip and knee motion. Muscles of the leg were activated for less time.
These results are in agreement with other studies that show elders have trouble controlling trunk motion from side to side when standing on one leg. They tend to narrow their base of support, take small steps, and stay on each leg less time than younger adults.
With these changes in gait position, muscle activation patterns changed, too. This finding supports the idea that there is reduced muscle strength in older adults because of changes in muscle activation patterns, not the other way around. Slower pace and deeper knee flexion (lower center of gravity) are linked with change in muscle activation patterns. Weakness leading to falls may be the result of these changes.
Tai Chi has the capability of increasing strength and balance as a way to improve balance and prevent falls. A Tai Chi practice may also improve walking patterns among elders. The final result may be walking with more knee flexion, a lower center of gravity, and with greater efficiency and stability.
The author points out that only Tai Chi gait (walking movement) was analyzed in this study. Different results might be seen with Tai Chi motions that include trunk rotation, turns, kicking, and pushing down.