Effects Of Towing Resistance On Lower Extremity Kinetics In Maximum Velocity Phase Of Sprint

ObjectiveThe purpose of this study is to understand the biomechanical mechanism of dashrunning support leg joint and changes in applying different leg joint biomechanicsmechanism supporting players drag resistance load, using the inverse dynamic method ofdrag resistance, applying different negative biomechanical characteristics of loadsupporting leg hip, knee, athletes three ankle joint.MethodThis study selected8Shanghai Institute of Physical Education sports trainingprofessional two male athletes as the research object.Multifunctional resistance/useof independent research and development of power traction training device forathletes applying progressive resistance load:0N,50N,80N,110N.Kinematic datausing MotionPro X high-speed video camera running, ground reaction force data3-D force platform to collect running support phase using KISTLER, carries onprocessing to the kinematic data using SBCAS software, the kinetic data and the useof inverse dynamics method to calculate the supporting leg.Data were analyzed bySPSS19.0software, analysis of repeated measurement method (Repeated MeasureANOVA). Post hoc (post hoc test) using the method of BONFERRONI, significantdifference level is set to P<0.05, P<0.01to have a very significant difference.Result1） Step drag resistance run can cause runners process significantly decreased (P<0.05),supporting time is significantly increased (P<0.01).2） Drag resistance can cause athletes run way running instant support leg three jointangles of the significant changes (P<0.05).3） With resistance load increases, the ground support vertical and horizontal componentforce shows decreasing trend, with resistance load increases, buffer and stretch ratiodecreases, the proportion of buffer period decreases, stretching stage the proportionincrease.4） With the increasing resistance load, power athletes ankle centripetal contraction ofthe maximum value was decreased, but the decrease was not obvious; maximum powerof centrifugal contraction is not very clear.5） Applying the resistance load, peak power of athletes leg knee concentric contractiondecreases, which reduces the knee concentric contraction of peak power of80Nresistance when the load amplitude maximum, when the resistance load exceeds80N,the knee joint in the ground after not buffer, but directly to the push-off phase.6） Resisting load has been increasing, flexion peak torque athletes leg hip extensorpeak torque was decreased,80N decreased the amplitude of the maximum resistanceload. Power peak hip centrifugal contraction was decreased, the80N pressure overloadcentrifugal contraction reduces the maximum peak power.Conclusions1) Drag resistance training athletes supporting leg moment hip angle decreases, isconducive to the runners attitude to corrective action, to prevent excessive back.2) Drag drag run, increase with the increase of load, the knee joint are no longer presentbuffer phenomenon, eccentric contraction ability so that resistance training method is not suitable for the development of knee extensor.3) Drag resistance training of sprint runners all joints of the lower extremity of the torqueand power can not enhance the role play, there is a direct relationship between thedecreased level of speed and resistance conditions.4) Drag resistance training should pay attention to in practice, haul distance is not toolarge, it should be combined with other training methods.