A Biomechanical Study On The Four Crawling Movements Of Healthy Adult Men

As the promulgation and implementation of "healthy China 2030" planning outline,the national fitness craze is increasingly high,crawling movement as a new method of physical exercise is gradually accepted and loved by the public,and as a necessary project of army tactical training,how to effectively improve the efficiency of crawling,scientifically conduct the training,implements the civil-military integration national strategy is an important aspect of military functional physical training.In view of this,the objects of this study were four kinds of crawling movements with different height of center of gravity: low posture crawling high posture crawling,hand kneeling crawling and hand and foot crawling and the following is explored,the surface electromyography and kinematics characteristics of four kinds of crawling movements with different height of center of gravity of healthy adults;the movement intensity characteristics of healthy adults when crawling at different speeds.In this paper,four kinds of crawling movements with different height of center of gravity are defined by using literature method.As for the experimental method,eight healthy male subjects are asked to use the wireless surface electromyography test system,3d dynamic capture system and Polar Team Pro sports intensity monitoring system and collect the experimental dataare collected.After the later data processing,the following conclusions were drawn:(1)When healthy adult men adopt the hands and feet crawl,hand knees crawl,high position crawl and low position crawl these four different height of the center of gravity,in the support period,the lower the center of gravity is,the electromyographic amplitude of pectoralis major muscle,C4 paravertebral muscle is smaller,the electromyographic amplitude of rectus abdominis,external oblique,triceps brachii lateral head and biceps femoris long head is larger;In the swinging period,the lower the center of gravity is,the smaller the electromyographic amplitude of the anterior deltoid,lateral triceps brachii,rectus femoris,and the larger the electromyographic amplitude of the rectus abdominis and trapezius.For the crawling,the core muscles play a role in the energy transfer of the upper and lower limps,muscle amplitude is especially noticeable.(2)Different heights of gravity center will affect the work of healthy adult men' each muscle group,in a flat ground(the same crawl)under the condition of different heights of gravity center on healthy adult men,crawling has an impact on muscle strength and force model.When completing a certain action,the active(power)and the force mode of human body muscle group is different.If the working conditions of muscles are changed during the training,the crawling movement is changed from high center of gravity to low center of gravity or even lower center of gravity,not only the change of muscle force pattern should be considered,but also the change of the strength activity of each muscle involved in the movement should be paid attention to.Because changes in muscle strength patterns mark changes in the way muscles work,similarly,changes in muscle activity mark the level of muscle recruitment and arousal(strength).(3)There are differences in the muscle contribution rate of each muscle group in the crawling movement with different height of center of gravity,and the four-point support movement has a great correlation with the shoulder girdle muscle.The more difficult the four-point support movement is,the higher the requirement on the control stability of the shoulder blade and the core strengthening.(4)Under the condition of slow crawling,similar to the vertical walking,the time of supporting was significantly longer than the time of swing when adopting the four crawling positions.As the height of the center of gravity increases,the duration between the upper limbs swing and supporting tends to shorten,but from the total time,the higher the height of the center of gravity,the longer the period of the upper limbs and lower limbs;the range of the joint motion of low position crawing is larger than any other three crawing.As the height of the center of gravity increases,the range of motion of the hips and knees gradually decreases,although the range of motion of each crawling method is not the same,but the joint activity process seems similar.(5)The average heart rate ranged from 110 to 150 beats/min at different heights of gravity and speeds of crawling.The speed affects the heart rate of crawling.The faster the speed is,the higher the heart rate is.The heart rate of hand and knee crawling is the lowest in four crawling actions,Low posture crawling's heart rate is relatively higher.There was nospecific trend of heart rate between crawling with different height of center of gravity,and the intensity fluctuated between 50% and 89% of the maximum heart rate,which does have a great difference.In contrast,the low and high crawling positions commonly used in military fitness showed a higher heart rate range of 60-89%.