First, start the kettle bell.
At this time, the latissimus dorsi is involved in linking the arm and the body, swinging the kettle bell back with the shoulder as the axis. At this time, it is necessary to keep the spine in the middle, so as to keep the spine naturally bent and protect our backs.
The above posture is so important because the elastic tissue in the middle and back of the trunk can reduce the impulse of muscles, thus reducing the burden on the spine; At the same time, this "burden reduction" effect can be further assisted by swinging arms; The muscle chain of the trunk will transfer the swing force of the arm to the hip joint drive. During the whole process, our trunk stores enough energy. In order to make the trunk have more energy, we need to help tighten the abdominal muscles, grab the ground with our toes and so on.
Second, start swinging.
1, we need to keep the abdomen tight and the core hard. Only in this way can we ensure the stability of the back and not be injured by sports.
2. Pay attention to our bodies and realize that all activities occur in the hips and shoulders, especially our spinal joints should avoid exercise at this time.
Third, the whereabouts of the kettle bell.
When the kettle bell falls and bends your hips, you should also pay attention to avoid hurting your back. Stand up straight until your forearm almost touches your stomach before relaxing your gluteal muscles. At the last moment, the hip joint hinges your gluteal muscles to avoid the kettle ringing.
I choose to bend my hips at this time, not earlier. Mainly to avoid shearing force when heavy objects are far away from the body. Because shear force and pressure are perpendicular to each other, they will cause joints to rub against each other. This is an unstable activity. As shown in the figure, the farther the weight is from the body, the greater the shear force.
Reference book:
Lumbar repairman
Hu Bell-Minimalist &; extreme
Walking into the kettle bell
An unarmed soldier