Study On The Characteristics Of Different Scapular Dyskinesis Types And The Optimization Of Rehabilitation Movements By Surface Electromyography

Objectives: When individuals are rest,the abnormal position of scapular and(or)when individuals are active,the movement locus of scapula are unusual,these are performances of scapular dyskinesis.Scapular dyskinesis has three different types,in this study start with the classification of scapular dyskinesis,and for different types of scapular dyskinesis,we analysis muscle activation patterns of shoulder girdle muscles.Then according to the results,aiming at different types we make individualized rehabilitation plans.Methods: In this study,26 subjects,52 shoulders,who are athletes from Beijing Sport University,were evaluated and divided into 4 groups based on the golden standard of scapular dyskinesis: inferior scapular angle(21),medial scapular border(11),superior scapular border(4)and normal type(16).Participations' muscle activation patterns of shoulder girdle muscles(serratus anterior and trapezius),EMG data of the PNF(D1 and D2)and standard push-up plus were collected.Comparative analysis the date and conclude the characteristics of each type of shoulder girdle muscles.Results:(1)In overhead athletes,scapular dyskinesis occurred in a rate of 69.2%.The rate of inferior scapular angle type is 40.4%,normal type and medial scapular border type each takes 30.8% and 21.1%,the rest 7.7% is superior scapular border type.(2)Compared with normal type and inferior scapular angle type,the athletes in medial scapular border type have a significantly low LT activation levels in lifted phase of shoulder flexion(P<0.05),and UT/MT?UT/LT activation rates of medial scapular border type are significantly higher than those of normal type(P<0.05);other target muscles' activation patterns are have no differences in three types(P>0.05);In down phase of shoulder flexion,the sEMG of inferior scapular angle type are lower LT activation compared with another two types(P<0.05),and there are higher ratios of UT/LT?UT/SA than normal(P<0.05);Medial scapular border type has a lower activation level than normal(P<0.05),but higher ratio levels of UT/LT?UT/MT(P<0.05).(3)In the standard push-up Plus,the activity level of SA lower than normal type(P<0.05),but obviously lower ratio levels of UT/SA(P<0.05).And other sEMG are the same as normal type(P>0.05).(4)In PNF Upper limb D1 flexion movement,both inferior scapular angle type and medial scapular border type have a low UT activity level than normal type(P<0.05),and the UT/MT,UT/LT and UT/SA ratios are the same as normal type(P>0.05).But MT activated on a lower level than normal(P<0.05).(5)The activation of SA in normal type,the standard push-up Plus is higher than D1 flexion movements(P<0.05),But the standard push-up Plus has a obviously lower UT/SA ratio than D1 flexion movements(P<0.01).(6)In PNF upper limb D2 flexion pattern,the SA of medial scapular border is not only less activation than normal type(P>0.05),but significantly lower than the inferior scapular angle type(P<0.01).And the inferior scapular angle type have the same sEMG pattern as normal type(P>0.05);In PNF upper limb D2 extension pattern,MT of the inferior scapular angle type activated obviously below other two types(P<0.05);About medial scapular border type,UT activated significantly lower than normal type(P<0.01),as well as LT(P<0.05).Conclusions:(1)Even subjects with no symptoms of shoulder scapular dyskinesis still have chance of scapular dyskinesis,the rate of four types is inferior scapular angle(Type I)>normal type(Type II)> medial scapular border(Type III)> superior scapular border(Type IV);(2)Subjects with scapular dyskinesis do have changes of kinetics and activation patterns of shoulder girdle muscles in shoulder flexion: in inferior scapular angle type,the activation of LT is low and when compared activation of LT and SA with UT,UT' activation level is higher;Medial scapular border type's LT?MT are week,and the activation of UT is compensatory higher;(3)The standard push-up Plus is suitable for inferior scapular angle type subjects: lower activation of UT,higher activation of SA,and the ratios of UT and MT?LT?SA are normal;And PNF Upper limb D1 flexion movement is suitable for medial scapular border;(4)According to the target muscles' sEMG in PNF Upper limb pattern,we know that PNF can be used in late phase of scapular dyskinesis rehabilitation.