Motion Analysis Between Standard Push Up And Unstable Push Up

Objective:This paper aims to analyze motion differences between standard push up and unstable push up practiced using a unstable push up trainer. By using the surface EMG signal analysis we obtained properties of unstable push up trainer. It can provide us with much deeper understanding of push up motion and more effective methods to practice muscles’ instability and strength through comparison activation levels of muscles when using a unstable push up trainer with different grip distances.Methods:Six male of Shanghai university of sports participated in this experiment whose fitness experience is at least two years. Subjects practiced standard push up and unstable push up motion under the condition that their grip distance between two palms are 50%、100%、150%、200% of their shoulder width respectively, total eight groups. We used Trigno lab wireless surface EMG testing instrument and analyze SEMG signals by using EMGWorks 4.0 analysis software, obtaining EMGRMS and IEMG.The experimental data is represented by the average and standard deviation using SPSS 19.0 statistical software,significant difference in P <0.05.Results:EMGRMSchanges in different palm distance when practicing standard stable push up motion, the EMG of brachioradialis is minimal in 200% group, the EMG of biceps brachii is minimal in 100% group and maximal in 200% group, the EMG of triceps is maximal in 50% group, the EMG of trapezius in 150% and 200% groups is far less than those in 50% and 100% groups, the RMS of EMG of deltoid anterior bundle is maximal in 50% group, the EMG of abdominis changes small between first three groups and is maximal in 200% groups, the EMG of largest erector spinae is maximal in 50% group.EMGRMS of muscles changes because of different palm distance in unstable push up motion. With the increase of palm distance, EMG activity of biceps brachii increased,triceps’ and trapezius’ activity both decreased, the EMG of pectoralis in 200% group increased, the EMG of erector spinae in 50% group is maximal among them.Two different push up motions under the same condition of palm distance: the EMG of trapezius、pectoralis major beam and rectus abdominis in 50% groups had significant difference(P<0.05); the EMG of trapezius and rectus abdominis in 100%group had significant difference(P<0.05); the EMG of biceps brachii and trapezius in150% group had significant difference(P<0.05); the EMG of brachioradialis and biceps in 200% group had significant difference(P<0.05).The training effects to triceps, ectopectoralis, deltoid and erector spinae is greater when practicing standard push up with small palm distance, the training effects to biceps, ectopectorallis and erector spinae is greater with bigger palm distance.The training effects to triceps brachii, trapezius, deltoid and erector spinae is greater when practicing unstable push up with small palm distance, the effects of training on brachial radial, biceps brachii and ectopectoralis is greater with bigger palm distance.Conclutions:There is difference between two types of push up, especially under the condition of double shoulder width, as upper limb is much more unstable when using unstable push up trainer, and this situation can be a important stimuli for upper body muscles and body core muscles controlling stability of whole body.