Archimedes once said, "Just give me a fulcrum and a lever long enough, and I can pry up the whole earth!" " "This shows the powerful function of leverage. Lever principle is widely used in life and plays an important role in sports practice. From a mechanical point of view, muscle work completely follows the lever principle.
In the sports system, bones are the lever of sports, joints are the hub of sports, and skeletal muscles are the driving force of sports. Skeletal muscle, under the control of nervous system, pulls the bone lever around the joint for various movements by changing its length. In-depth study on the application of lever principle in sports practice can help athletes choose materials and exercise their physical fitness.
Different sports events provide scientific theoretical basis, increase the effectiveness of exercise and improve sports performance. Bone lever consists of three points: fulcrum (O), force point (F) and resistance point (R), two acting forces of force and resistance, and two arms of force and resistance. The product of power and arm constitutes the dynamic moment, and the product of resistance and arm constitutes the resistance moment.
1. Balance bar: the fulcrum is located between the force point and the resistance point, and the dynamic moment is equal to the resistance moment.
2. Labor-saving lever: the resistance point is located between the fulcrum and the stress point, and the dynamic moment is less than the resistance moment. Since the power arm is larger than the resistance arm, if the power moment is smaller than the resistance moment, then the power must be smaller than the resistance, which saves labor.
3. Effort lever (speed lever): the force point is located between the fulcrum and the resistance point, and the dynamic moment is greater than the resistance moment. Because the resistance arm is greater than the power arm, if the power moment is greater than the resistance moment, then the power must be greater than the resistance, so it is very laborious.
When the lever rotates around the shaft, each point on the lever moves in an arc, and the speed of each point is proportional to the distance from the shaft, that is, the farther away from the shaft, the faster the rotation speed of each point of the lever, also known as speed lever.
Part of the competitive ability of excellent athletes is obviously changed through training, that is, training; The other part is mainly determined by genetic characteristics, which is called congenital. The selection of athletes is to select talents with superior congenital conditions and suitable for a certain sport from an early age, and conduct systematic and purposeful training to achieve excellent sports results.
Whether an athlete can climb the peak of sports is composed of many factors, but its internal factors are the most basic and important, and the internal factors, including shape, function, psychology, physical quality and health status, can be described and measured by certain standards.
The application of lever principle in athlete selection mainly focuses on the measurement of body shape and the proportional relationship between innate factors.