The Effect Of Quadriceps Eccentric-concentric Contraction-induced Fatigue On Knee Proprioception

Objective: previous studies have found that the decrease of proprioception is accompanied by the increase of joint motion injury,and fatigue is one of the reasons for the decrease of proprioception.However,there is little information on how proprioception changes with the increase of muscle fatigue during exercise.In this paper,by analysing the experimental method of quadriceps were 90%,70% and 50%in three different fatigue before and after knee joint position related indicators,muscle force and find out the quadriceps fatigue affects the general rule of knee proprioception and discusses the reasons of this rule,training in after knee proprioception,resistance to fatigue and injury prevention training provide certain theoretical basis.In addition,this paper analyzes the correlation between proprioception and the quadriceps femoris muscle strength characteristics under different motion modes,and analyzes the correlation between the knee joint position perception and the muscle force perception before and after fatigue,so as to further explore the reasons for the changes of knee joint proprioception before and after quadriceps femoris fatigue.Methods: in this paper,the selection of tianjin sports college sports education professional athletics special healthy male 24,the German production ISOMED-2000 isokinetic muscle strength testing and training system in front of the fatigue and tiredness immediately to the participants after knee joint maximum isometric strength(MVIC),muscle force test,location,and the quadriceps not fatigue state centripetal and centrifugal condition under maximum peak force test.The fatigue plan adopts the centrifugal-centripetal mode(angular velocity is 90°/s,and the fatigue standard is:the peak moment appearing for 3 consecutive times is lower than 90%,70% and 50%of the maximum peak moment of the previous three times.The three fatigue degrees are tested separately,and each fatigue test interval is one week)?SPSS22.0 statistical software was used to analyze the test data.Results :(1)after quadriceps centrifugal-centripetal fatigue,the proprioceptionof the knee joint decreased compared with that before fatigue,and 90% of the muscle force perception relative deviation(RAEFS)and 30 degree position perception constant error(CEJPS)changed significantly after fatigue(P<0.05).After 70% fatigue,the relative constant errors of muscle force perception(RCEFS),60 degree position perception absolute errors(AEJPS),30 degree position perception constant errors(CEJPS)and absolute errors(AEJPS)changed significantly(P<0.05).After 50%fatigue,the relative constant error of muscle force perception(RCEFS),relative absolute error(RAEFS),60 degree position perception absolute error(AEJPS),variable error(VEJPS),30 degree position perception constant error(CEJPS),absolute error(AEJPS),variable error(VEJPS)all had statistical significance(P<0.05).(2)comparison of different fatigue degrees of quadriceps femoris: the relative variable error of muscle force perception(RVEFS)and absolute error of 30 degree position perception(AEJPS)were statistically significant when compared with 90%fatigue and 70% fatigue(P<0.05).When 70% fatigue was compared with 50% fatigue,the relative constant error(RCEFS),relative absolute error(RAEFS)and 30 degree position absolute error(AEJPS)of muscle force perception were statistically significant(P<0.05).When comparing 90% fatigue with 50% fatigue,the relative constant error of muscle force perception(RCEFS),constant error of 30 degree position perception(CEJPS)and absolute error(AEJPS)were statistically significant(P<0.05).(3)before,90% and 70% fatigue of quadriceps femoris,the variable error of the position perception of 60 degrees of knee extension was significantly greater than that of 30 degrees of knee flexion(P<0.05),but there was no significant difference in the position perception difference of the two angles when the quadriceps femoris was50% fatigued(P>0.05).(4)before and after quadriceps fatigue,there was only a moderate negative correlation between the muscle force perception of the knee joint and the position perception of the knees at 60 degrees(P<0.05,R<0),while there was no linear correlation between the muscle force perception and the position perception of theknees at 30 degrees(P>0.05).(5)of the knee joint muscle strength characteristics and correlation analysis of proprioception,the quadriceps muscle and just before fatigue,fatigue,70%,90%,relative peak torque of knee joint centripetal movement and muscle force of constant error(CEJPS),60 degrees position error between constant(CEJPS)there is a moderate negative correlation(P < 0.05,R < 0),there is no linear correlation between other indicators(P > 0.05).Conclusions :(1)the reliability of retest of constant error,absolute error and variable error used to measure the position perception of knee joint and muscle force perception is good.(2)after the quadriceps femoris centrifugal-centripetal contraction induced fatigue,the proprioceptive function of the knee joint decreased.After mild and severe fatigue of quadriceps femoris,the degree of reduction of muscle force perception was greater than that of moderate fatigue.The decreased sense of position increased with the increase of quadriceps fatigue.(3)compared with before fatigue,after quadriceps fatigue,the errors of each index of position perception of 30 degrees of knee extension after knee flexion were greater than 60 degrees of knee flexion.(4)the gap between the target Angle of the knee joint and the starting Angle has an effect on the position perception,that is,the greater the distance between the target Angle of the knee joint and the starting Angle,the greater the proprioception error will be generated by the subjects.This occurs in the quadriceps muscle before fatigue,mild fatigue,and moderate fatigue.However,this angular difference in knee position perception disappeared when the quadriceps reached severe fatigue.(5)before and after fatigue,there was no high correlation between knee joint position perception and muscle force perception.(6)before and after quadriceps fatigue,there is no linear correlation between muscle strength and 30 degree position sense of knee extension,and 60 degree degree of bending.