| Backgrounds:With the rapid development of the economy and the improvement of people's living standards,the number of jobs based on sedentary,transportation,watching TV and using computers have continued to increase steadily,and people's physical activities have been greatly reduced.The waist and back of the human body is constantly overloaded every day,causing more and more people to suffer from low back diseases.As a simple periodic motion,the rotation activity has high safety and strong operability.It is suitable for all ages and is easy to complete.As a necessary community sports equipment for most communities,it plays an indispensable role in the mass fitness and daily fitness of the community population.However,the manufacturers of waist twisting apparatus are numerous and complicated,and the production of waist twisting apparatus in different regions is different,and the waist twisting apparatus has a low utilization rate and a poor fitness effect.To this end,this study uses the common waist twisting apparatus in community to compare with the self-made apparatus,and explores the biomechanical characteristics on body movement and related muscles of different waist twisting activities to better achieve the exercise of waist and back muscles,to reduce the risk of lower back and other diseases,and hopes to provide a basis for the research and production of the community apparatus.Methods:Kinematics and EMG data of 11 male college students in Shanghai University of Sport are collected synchronously by Vicon three-dimensional infrared motion capture system and Delsys wireless sEMG acquisition system.In this study,nine muscles of superior lateral consisting of the erector spinae,the obliquus externus abdominis muscle,the rectus abdominis muscle,the gluteus medius muscle,the rectus femoris,the biceps femoris,the tibialis anterior muscle,the gastrocnemius lateral head and the gastrocnemius medial head are selected the sEMG.Paired sample T test is performed on all processed data using SPSS 20.0 statistical software.P<0.05 is considered as significant difference.Results:(1)The torsion angles of trunk,thigh and shank:When twisting right,the shank torsion angle of the community apparatus is significantly larger than that of the self-made apparatus(P<0.05).When turning left,the shank torsion angle of the self-made apparatus is significantly larger than that of the community(P<0.05).Compared with the same twisting device,the shank torsion angle of the self-made apparatus is greater than the right turn when turning left,which has a significant difference(P<0.05).The trunk and shank torsion angle of the community apparatus are significantly larger than the left turn(P<0.05).(2)The maximum rotation range of shoulder,hip and itself:Whenever turning right or left,the maximum rotation range of the shoulder is that the self-made apparatus is larger than the community apparatus,which has a significant difference(P<0.05).The maximum ranges of rotation of the hip and itself are that the community apparatus are larger than the self-made,which have significant differences(P<0.05).(3)EMG RMS values:In a complete periodic motion,the RMS values of the erector spinae,the obliques externus abdominis,the gluteus medius,the rectus femoris,the tibialis anterior and the gastrocnemius lateral head and the gastrocnemius medial head muscle of the self-made apparatus are significantly greater than that of the community apparatus(P<0.05).When right turn,the RMS values of the erector spinae,the obliquus externus abdominis,the gastrocnemius lateral head muscle of the self-made apparatus are significantly greater than that of the community(P<0.05).When turning left,the erector spinae,gluteus medius,rectus femoris,biceps femoris,tibialis anterior muscle,medial head of gastrocnemius and lateral head of gastrocnemius have significant differences compared with the community apparatus(P<0.05).Compared with the same apparatus,the biceps femoris of the self-made is greater than the right turn when left,with significant difference(P<0.05),the gastrocnemius lateral head is greater than that of the left turn when there is a right turn(P<0.05).There is a significant difference(P<0.05)when the RMS value of the gluteus medius is greater than that of the left turn when the community apparatus turn right.(4)EMG contribution rates:In a complete periodic motion,the electromyographic contribution rates of the erector spine,oblique externus abdominis and rectus abdominis muscles of the community apparatus are higher than those of the self-made apparatus,with significant differences(P<0.05).The EMG contribution rates of lower limb muscles the rectus femoris,tibialis anterior and medial head of gastrocnemius muscle of the self-made apparatus are higher than that of the community,with significant differences(P<0.05).When turning right,only the contribution rate of lateral head of gastrocnemius muscle of the self-made apparatus is greater than that of the community,with significant difference(P<0.05).When turning left,the electromyographic contribution rate of the medial head of gastrocnemius muscle of the self-made apparatus is higher than that of the community,with significant difference(P<0.05).The contribution rates of erector spinae and extra-abdominal oblique muscles are in the first two places during the rotation of the waist twisting apparatuses.Conclusion:(1)Compared with the self-made waist twisting apparatus,the community waist twisting apparatus has a larger range of motion in the torsion angle of the trunk,the maximum rotation range of the hip and itself.(2)The activation of self-made waist twisting apparatus related muscles is greater than that of the community one.The recruitment and mobilization of motor fibers are more,and the muscle strength is greater while the range of motion is smaller.(3)Compared with the self-made waist twisting apparatus,the community waist twisting apparatus have a higher proportion of the waist and back muscles in its own rotation,but the two types of waist and back muscles(except the rectus abdominis muscle)are the main force muscles. |
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