The Kinematics Analysis Of V2 Sliding Technique For China's Young Elite Cross-country Skiers

Research purpose: To obtain the kinematic parameters of the excellent cross-country skier V2 technology,find out the technical rules and analyze the relationship between these parameters and speed,so that the athletes and coaches have a better understanding of the structure and technology of movement.It also provides beneficial assistance for the improvement of athletes' own movements,and helps coaches to carry out targeted technical optimization training.Research method: Through SIMI 3D motion three-dimensional motion capture system,three-dimensional motion image shooting of V2 technical movements of eight female cross-country skiers.The image analysis system is used for kinematics analysis.The human model uses Hanavan human model for data processing and digital low-pass filtering for data smoothing.The center of gravity,time,displacement,speed,joint angle,and angular velocity of eight athletes are obtained Kinematic parameters,analyzing the laws of cross-country skiing V2 technology.The Spearman correlation analysis method was used to find out the kinematic factors affecting the gliding speed.Research results:(1)The average speed of athletes is between 4.04 m / s and4.72 m / s;the maximum value of speed is generated before and after T5,and the maximum is between 4.68 m / s and 5.85 m / s.(2)The elbow and shoulder joint angles change away from each other;the changes in the angular velocity of the hip and knee joints decrease(minimum)-increase-decrease-increase-decrease.(3)The law of change of the angular velocity of the elbow joint is increasing-decreasing-increasing-decreasing;the law of changing the angular velocity of the shoulder joint is increasing-decreasing-increasing;The change curve of hip joint angular velocity is similar,and the change of hip joint angular velocity is slightly larger than that of knee joint.(4)During the subject's action period,the average speed of the X axis and the maximum speed showed a very significant correlation(P <0.01,r = 0.970);the average speed of the X axis and the average speed in each stage showed a very significant positive Correlation(P <0.01,r = 0.904).The X-axis average speed wassignificantly correlated with the maximum speed on the Y-axis(P <0.05,r = 0.831).The average speed of the X-axis in the subject's action period was significantly positively related to the relative value of the highest point of the center of gravity during the pole period(P <0.05,r = 0.802).(5)The average speed was significantly correlated with the cycle rate(P <0.05,r = 0.799).(6)The average speed of the athletes was significantly positively related to the maximum angle during the snow contact of the knee joint(P <0.01,r = 0.855).The average speed during the athlete's action cycle was significantly related to the angular velocity of the shoulder joint(P<0.05,r = 0.795),and significantly related to the angular velocity of the hip joint(P<0.05,r = 0.723).(6)The mobility of the joints of the upper limbs(including the pole angle)is significantly related to the maximum of the joints of the upper limbs at the pole stage(P <0.05);while the mobility of the joints of the lower limbs is significantly related to the minimum of the joints of the lower limbs during the kicking stage.Correlation(P <0.05).Research conclusions:(1)The higher the maximum speed value,the larger the average speed of each stage,the higher the average speed,the better the athlete's performance.(2)Within a certain range,when the value of the maximum swing speed of the athlete is larger,the faster the athlete is,the better the performance is.(3)Within a certain range,when the height of the athlete's center of gravity is relatively high,the faster the athlete's gliding speed,the better the performance.(4)The larger the cycle rate is,the faster the athlete is.In training and competition,athletes and coaches should pay attention to increasing the cycle rate.(5)The angle of the knee joint during sliding is very important.The full expansion of the knee joint angle is conducive to the exertion of the surrounding muscles and exerts the greatest effect,which will affect the athlete's performance.(6)The angular velocity of the shoulder and hip joints is very important during the gliding process.The larger the angular velocity of the shoulder and hip joints is,the greater the muscle strength around the joint is and the stronger the explosive force is.The greater the angular velocity during stretching,the faster the speed during training and competition,and the better the results.