The Effect Of Different Load Squat On The Co-activation Of Leg And Core Muscles On The Unstable Surface

Objective: By comparing barbell back squatting on stable and unstable surface,this paper explores the characteristics of muscle co-activation during barbell back squat and the relationship between load change and muscle co-activation.Methods: Sixteen male students in physical class of Beijing Sports University in 2014 and 2015 were squatting on the balance mat with barbell.The loads were 30% 1RM,50% 1RM and 70% 1RM,respectively.Motion Analysis Raptor-4(200Hz)and DELSYS TRIGNO Mobile(2000Hz)were used to obtain the kinematics and surface EMG parameters of barbell back squat.Results: There was no significant difference in muscle activation between knee joint and core area(p > 0.05)by comparing barbell back squatting under different planes;there was significant difference between muscle activation and load in barbell back squatting(2)There was no significant difference between barbell squat,co-activation ratio of knee joint and core area and load on unstable plane and stable plane(p > 0.05).However,in the unstable plane,the co-activation ratio showed an upward trend over 30% 1RM.The co-activation ratio reached the maximum at 70% 1RM,and the angle fluctuation of knee joint was also small.Conclusions: In this study:1.the muscle activation degree of barbell squatting on unstable plane was the same as that on stable plane.With the increase of load,the muscle activation increased,but there was no significant difference between the two planes.2.On the unstable plane or the stable plane,the co-activation of knee and core area will not increase significantly with the increase of load.3.On the unstable plane,the joint angle did not fluctuate significantly with the increase of load.