| Tai chi as a traditional Chinese exercise has been existed more than 1200 years.Many studies found that regular Tai chi exercise can maintain or improve the balance control of body posture,and improve the function of musculoskeletal system,there for to prevent the elderly people from the risk of tumble.Objective: The reason of improvement of the elderly body balance control ability of Tai chi exercise may be related to the characteristics of this movement.Through the test of Tai chi classic action kinematic and dynamic data and the combination of lower limb muscles contraction in the Tai chi movement.The study revealed the characteristic,of Tai chi movement,discussed the reason of the improvement of Tai chi to muscle strength and the prevention of elderly falls.Methods: Our experiment recruited 15 subjects.The test content including normal walk and five Tai chi movements,each action tested five times,choose three effective experimental data from each action for statistical analysis.Compare the five Tai chi movements with normal walk movement parameters with Paired Sample T Test,The significance level set at 0.05.When P < 0.05,means the results have significant difference,when P < 0.01 means the results have highly significant difference.Results:1.compared with normal walking movement,the joint flexion and extension,adduction and abduction,articular internal rotation and outward turning range of the knee,ankle,and hip joint,was bigger during the process of Tai chi movement.Ankle flexion and extension in the five Tai chi classic movements have highly significant differences compared to the normal walking motion.Compared normal walking movement with Hug Knee Flexed Step,P value was 0.005;P value was less than 0.001 with Repulse Monkey;P value was less than 0.001 with LAN Finches' Tail;P value was 0.003 with Wave-hand in Cloud.In the knee joint flexion and extension,only Repulse Monkey(P <0.001)and Heel Kick(P=0.005)has a significant difference compared with normal walking movement.When doing all five Tai chi movements the knee varus and valgus and spiral outward turning angle range were greater than normal walking movement,and significantly different.On the hip kinematics index,only Wave-hand in Cloud had no difference in flexion,but on varus and eversion of hip flexion and extension,internal rotation and outward turning angle scope changes were greater than normal walking,and were significantly different in all other four Tai chi classic movement.2.Compared with normal walking,during doing Tai chi exercise,forward and backward,both left and right side,and the vertical displacement of the center of mass(COM)gravity displacement were all larger than normal walking.Definite indicators wereas following: During normal walking,the forward and backward displacement was 59.10 ±-35.40 mm,the left and right sides displacement was 733.82 ±-453.11 mm,vertical displacement was 53.08 ±-8.04 mm;When doing Hug Knee Flexed Step,the forward and backward displacement was 388.33 ±-85.64 mm,the left and right sides displacement was 1469.19 ±-427.03 mm,vertical displacement was 108.49 ±-23.12mm;When doing Repulse Monkey,the forward and backward displacement was 304.24±-79.89 mm,the left and right sides displacement was 1524.24 ±-325.72 mm,vertical displacement was 112.05 ±-23.31 mm;When doing Lan Finches Tail,the forward and backward displacement was 245.85 ±-132.20 mm,the left and right sides displacement was 946.46 ±-552.61 mm,vertical displacement was 120.97 ±-33.37 mm;Wave-hand in Cloud,the forward and backward displacement was 166.33 ±-133.70 mm,the left and right sides displacement was 929.02 ±-616.99 mm,the vertical displacement was60.30 ±-47.66 mm;and when doing Heel Kick,the forward and backward displacement was 228.68 ±-84.44 mm,the left and right sides displacement was 778.38±-467.69 mm,the vertical displacement was 230.61 ±-30.23 mm.3.Compared with normal walking,when doing Tai chi exercise,the subjects received smaller ground reaction force.The peak of the ground reaction force of all five kind of Tai chi classic movement were all lower than normal walking.The ground reaction has significant difference between normal walking and all five kinds of Tai chi classic movement.Compared with the normal walking,The P value of Hug Knee Flexed Step was 0.038;The P value of Repulse Monkey was 0.012;The P values of Wave-hand in cloud,LAN Finches Tail?Heel Kick were less than 0.001.4.Compared with normal walking,the forward,and left and right sides COP was greater when doing all five Tai chi movement,the lateral displacement of center of pressure travels(YCOP)was significantly greater in all five kinds of Tai chi classic movement than in normal walking;about the left and right sides displacement,compared with the normal walking,Hug knee flexed step flexed step was 54.34 ±-29.57 mm,P value was0.001;Repulse Monkey was 92.92 ±-28.99 mm,P value was less than 0.001;LAN Finches Tail was 56.07 ±-33.46 mm,P value was 0.001;Wave-hand in Cloud was90.82 ±-31.45 mm,P value was less than 0.001;Around the feet was 46.96 ±-20.36 mm,P value was less than 0.001.About forward and backward movement,however,only Hug Knee Flexed Step,Repulse Monkey,LAN Finches Tail had significant difference with normal walking,the P values were 0.001,0.002,0.010.Conclusion:1.Compared with normal walking,Tai chi classic actions have a unique time and space movement characters.We analyzed the gait of both Tai chi and normal walking,found that compared with normal walking,when doing Tai chi,the ankle and knee joint has a greater buckling range,wider joints buckling range has a great effect on improve the joints flexibility,therefor it is good to improve the balance control ability.A wide range dimension of lower limb joint activities can help improve the flexibility pace,reduce the risk of tumbling.2.Compared with normal walking,Tai chi requires the practitioners in crouch condition,it is slow,center of gravity moving in a three-dimensional space.Low center of gravity is conducive to increase muscle strength,at the meantime,muscle strength and joint stability of the knee and lower extremity ankle gets improving.3.Compared with normal walking,Tai chi classic action have larger pressure center displacement on forward and backward,and both left and right side.Larger range of Plantar pressure of Tai chi exercise can help increases lower limbs muscle contractionat a higher level,in order to improve the joints proprioception coordination,thus improve the balance control ability.4.Compared with normal walking,when doing Tai chi exercise there were a big proportion eccentric contraction of lower limb muscles,eccentric contraction is very effective om improving muscle fiber strength.lower limb muscles frequently change from centrifugal,centripetal and isometric contraction can conducive to the improve of muscle strength. |
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