The SEMG Properties Of The Right Side Of The Body Of Backward Cross-kicking Under The Condition Of Air Hammer On Taekwondo

Objective:To analyze the characteristics of force in backward cross-kicking movements through analysingmuscle electrophysiology of taekwondo athletes in backward cross-kicking movements.Methods:The experiment objects were divided into the low level group and high level group, each6.Low level group of Taekwondo majors Shenyang Sport University Sports Training Institute, nooccupation training experience. The high level group of Shenyang Sport University AffiliatedSchool of sports Taekwondo athletes, including2master class2,4one class.The thesis analysesthe integrated electromyography (iEMG), onset time of EMG, mean duration of EMG onset,contribution rate of muscles, and force by combining the16-channnel myo-equipment(megawin6000－16)(sampling rate:1000Hz) and two videos(SonyDCR－48E)(sampling rate:50Hz) to record the muscle activity and movements.Results:1. From preparatory posture to toes off ground, subjects in the high level and low level groupsshow significant differences in mean onset time of biceps femoris, anterior tibial, andgastrocnemius muscles (p <0.01), in mean duration of contractions of anterior tibial andgastrocnemius muscles (p <0.01). And anterior tibial muscle has an important role in this phase(high level group:23.23±13.76, low level group:27.88±15.18).2. From toes off ground to raising knee to vertex, it is shown the activation time of obliquusexternus abdominis muscle is later in the low level group than in the high level group （in thehigh level group：0.03±0.01，in the low level group：0.05±0.02，P＜0.01）.The iEMG in thehigh level group （11.43uVs-65.08uVs）is greater than that in the low level group （8.36uVs-106.79uVs）.The EMG activity of biceps femoris is maximal in both the high level and lowlevel groups（in the high level group：31.64±7.18, in the low level group:27.94±5.22）.3. From raising knee to vertex to maximal force, it is shown that mean duration of EMG onsetof the rectus femoris is longer in the low level group than in the high level group（in the highlevel group：0.04±0.02，in the low level group：0.08±0.05，P＜0.01); EMG activity of theobliquus externus abdominis muscle is maximal in both iEMG (in the high level group：261.23±42.74，in the low level group：173.92±33.48，P＜0.01）and contribution of rate （in the highlevel group：28.94±2.81, in the low level group：26.38±3.61）.4. From the maximal force to the withdraw of leg, all investigated muscles are activated;however，the activation time of all muscles in the low level group is uneven compared with thehigh level group. The obliquus externus abdominis muscle is maximal in iEMG（in the high level group：672.92±194.37, in the low level group:405.93±177.58，P＜0.01）, contributionrate (in the high level group:37.59±7.62, in the low level group:31.42±8.73), and force（inthe high level group：37.02±10.19, in the low level group:28.04±12.70）. The exertion isshown the feature of quickly closing force by the athletes in the low level group and theexertion is sustained by the athletes in the high level group.5. During the restoration of movement, offset of all muscle activation is shown consistent inboth the high and low level groups. For the duration of activation, anterior tibial muscle islongest in both the high and low level groups （in the high level group：0.58±0.12，in the lowlevel group:0.28±0.01，P＜0.01）. Biceps femoris is maximal in iEMG（in the high levelgroup：409.26±148.26，in the low level group：246.01±130.88，P＜0.01）and contributionrate（in the high level group：21.75±5.27, in the low level group:19.68±2.93）. The exertionis shown the feature of relaxation by the athletes in the low level group and the exertion issustained by the athletes in the high level group.Conclusions:1. High level group of lower level group stage technology movement order, stability;2. High level group of each stage of low level group of muscle force is bigger, last longer;3. In different5phases, regardless of levels, the maximum is anterior tibial, biceps femoris,anterior tibial, obliquus externus abdominis, and anterior tibial muscles. However, othermuscles show larger in the high group level than in the low group level.Suggestions:1. In the following study, it is expected that more muscles are involved.2. In the training of backward cross-kicking in taekwondo, movements should be studiedaccording to various phases.3. In the training of strength, the muscle should be exercised according to each technicalcharacteristic stage by stage.