| Research purposesThis article will study the difference of left and right middle whipping legs effect of Sanda athletes of different levels through the method of sports biomechanics.The difference of kinematics and dynamics between left and right middle whipping legs;The relationship between different movement characteristics of left and right middle whipping legs and striking effect;The relationship between different movement characteristics of left and right middle whipping legs and tactical intention;Problems in the movement characteristics of left and right middle whipping legs.Research methods:Subjects: 15 athletes from Shanghai Institute of Physical Education and 15 athletes from Grade I and Grade II of competitive affiliated schools.Experimental instruments: VICON motion analysis system,Kistler three-dimensional force measuring platform and multifunctional force measuring target.Experimental Scheme: In this experiment,VICON,three-dimensional force measuring table and force measuring target are synchronously tested for male athletes' left and right middle whipping legs.In the experiment,the subjects are required to stand on one force measuring table with their left foot in front,right foot behind and left and right feet respectively.The left and right middle whipping legs are effectively struck three times respectively and the one with the best striking effect is selected for data collection and calculation.Finally,the collected and calculated data are statistically analyzed.Data collection: collect striking force through force measuring target and reaction force through force measuring tableData calculation: according to the data collected by VICON system,calculate the action time,displacement distance of support foot,rotation angle and angular velocity of support foot,knee flexion angle of support leg,knee flexion angle and angular velocity of whipping leg,hip flexion and rotation angle of whipping leg and torso rotation angle.Research results:1?The right middle whip leg of the excellent group's striking power(BW)was greater than the left middle whip leg,and there was a significant difference(P<0.05);the left middle whip leg of the excellent group's movement time(s)was shorter than the right middle whip leg,and there was a significant difference(P<0.05).The general group's left and right middle whip legs were close to each other in terms of strike power and time of movement trends,and there was no significant difference.2?The right middle whip leg of the excellent group was larger than that of the ordinary group with a significant difference(P<0.01);the right middle whip leg of the ordinary group was shorter than that of the excellent group with a significant difference(P<0.05);the time of action(s).The left middle whip leg had a close association between the excellent group and the normal group in terms of strike power and movement time,with no significant differences.3?The torso rotation angle(°)of the right middle whip leg was greater than that of the excellent group,and there was a significant difference(P<0.05);the ground reaction force of the left and right middle whip legs of the excellent group was smaller than that of the ordinary group,and there was a significant difference(P<0.05);the displacement distance of the supporting leg of the left and right middle whip legs of the excellent group was greater than that of the ordinary group,and there was a significant difference(P<0.05);the maximum extension angle of the striking leg knee joint of the left and right middle whip legs of the excellent group was greater than that of the ordinary group,and there was a significant difference(P<0.05).4?In the excellent group,the rotation angle of the supporting leg in the start-up phase,the rotation angle of the supporting leg in the whipping phase,and the rotation angle speed of the supporting leg in the whipping phase were all greater than that of the right whip leg with significant difference(P<0.05),and the trend of other indicators was similar;in the ordinary group,the rotation angle of the supporting leg in the start-up phase of the left middle whip leg was greater than that of the right middle whip leg with significant difference(P<0.05).5.When the right middle whipping leg is struck,the striking force has a significant correlation with the action time(p = 0.034 < 0.05 and r =-0.589);There was a significant correlation between start-up phase time and action time(p = 0.000 < 0.05 and r = 0.946).The reaction force has a significant correlation with the action time(p = 0.004 < 0.05 and r=0.732).6.When the left middle whipping leg is struck,the striking force has a significant correlation with the rotation angle of the supporting leg at the starting stage(p = 0.017 < 0.05 and r = 0.624);The rotation angular velocity of the supporting foot has a significant correlation with the action time in the starting phase(p = 0.047 < 0.05 and r =-0.539);The rotation angle of the supporting foot and the flexion angle of the hip joint have significant correlation with the action time,and the P values are(0.042)and(0.019)respectively.Conclusion:1.In terms of striking effect,the left middle whip leg in the excellent group has shorter action time than the right middle whipping leg,and the right middle whip leg has greater striking force than the left middle whipping leg;The striking force and action time of left and right middle whipping legs in the common group are not significantly different.The action time of right middle whipping leg is shorter in the normal group than in the excellent group.2.In terms of kinematics and dynamics,the rotation angular velocity of the supporting foot can shorten the action time when the left and right middle whipping legs are struck;In the excellent group,the rotation angle of the supporting leg in the whipping stage is smaller than that of the left middle whipping leg which is favorable for the hitting leg to fall back.In the normal group,the right middle whipping leg trunk rotates excessively which affects the striking force.3.In the correlation analysis between the striking effect of left and right middle whipping legs and kinematic and dynamic characteristics,short action time and small ground reaction force in the starting phase of right middle whipping legs can effectively improve striking force and shorten action time;The short start-up period(stepping landing time)of the left middle whipping leg support leg,the large rotation angle(stepping landing angle)of the support leg in the start-up period,the small rotation angle of the support leg in the whipping period and the small flexion angle of the hitting leg hip joint can all improve the hitting force and shorten the action time. |
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