(Circle cards have been added here, please check out the today's headlines client)
Maybe many freestyle swim friends have never considered this problem. In fact, whether the freestyle arms are coordinated and coordinated is an important condition for the uniformity of forward speed. There are usually three ways to fit two arms.
Taking the above picture as an example, we take the athlete's right hand (that is, the hand exposed outside the water surface) as the reference hand, and set that the arm is in the water state at this time (that is, the moment when the arm is moved in the air, that is, the moment it enters the water).
At this point, if the athlete's left hand (the hand that is ready to start paddling underwater) is within an angle of 30° to the horizontal plane, we call it a front crossing;
Within 30°-60°, it is called a mid-crossing;
After 60 °, it is called posterior crossover;
It's actually that simple, do you understand?
Let's talk about the characteristics of each of the three technologies:
Front crossing: refers to the fact that one arm is in the downlining stage when the other arm enters the water, which is a technique with a sliding stage.
1. Anterior crossover (Park someone's technique):
1, the best effect of paddling (the time limit often mentioned in the commentary), that is, each stroke provides a lot of forward momentum
2, the body is in a very stretched state, which is convenient for the body to exert force
3. The rhythm of movement is slow, so as not to overload the athlete's heart and lungs.
4, the body is stable, the resistance is small, so long-distance athletes generally use this technique.
You can look at the video of Park Tae-hwan at the Guangzhou Asian Games 400 and Shanghai World Championships 400 since to see how dashing Park Tae-hwan's front cross is (the stability of the body is his killer skill, pay attention to the mixed cross he uses when sprinting)
This is the Incheon Asian Games video
Middle cross: Refers to the middle part of the paddling stage when one arm enters the water and the other arm has entered the paddling stage.
2. Middle Cross (Phelps, Rochte):
This technology will generally be used with the front cross, the combined product is called mixed cross, that is, while using the front cross, while using the middle cross, the characteristics of this technology is that the athlete's body is obviously up and down during the swim, but it is such an ups and downs, the athlete can take advantage of the momentum very well, suitable for European and American athletes Phelps is a mixed cross jumping tour
Posterior crossover: Refers to the second half of the paddling phase when one arm enters the water and the other arm has entered the paddling phase.
3. Posterior crossover (Popov):
Because the frequency of this action two-arm paddling is very high, it requires a strong explosive force, so short-distance athletes use this technique, this technology can instantly burst out the athlete's physical strength, which belongs to the most violent swimming method, you can go to see the 50m freestyle... This method of swimming is also the most physically demanding, as one of the two arms is always paddling.
The front cross is relatively easy to learn and master, and the general beginners are using the front cross with the tour, which is more suitable for beginners to use. However, due to the forward cross due to the air movement of one arm and into the water, the paddling arm has not yet entered the most effective paddling stage, in this gap where neither arm produces propulsion force, the swimming speed will decrease, affecting the uniformity of the speed.
The mid-cross can continuously generate propulsion and can keep the body moving at an even speed.
The back crossing will also have a short deceleration, which has a certain impact on the swimming speed, so the propulsion effect is not as good as the "front crossing".
The biggest advantage of the mid-front crossover technique is that it can keep the body in an elongated streamlined posture, effectively reducing resistance.
This feature of the two-arm movement applies to the middle and long distances, but should be different for the short distances. When racing short distances, the outstretch time should not be too long, and when one arm is crossed, the other arm should start to stroke down.
The significance of this cooperation is that when one arm stops paddling, the other arm can almost immediately complete the water grab action and begin to gain thrust. This will make the body's streamlined posture worse when drawing upwards, but by shortening the slowing period between the movements of the arms, the speed of swimming can also be accelerated. However, such cooperation will increase energy consumption.
This is why some athletes would rather sacrifice their swimming speed in longer distances than extend their outstretched arms to minimize energy consumption.
Beginners are suitable for both front and front crossing
The advantage of the front crossing is that the 2 arms are separated, easy to learn, basically it is an alternating one-handed freestyle, and it is also easy to inhale with one hand reaching out in front.
But people who learn to freestyle in this way usually have incoherent movements, the torso is not full, the arm force component is too large, the two arms cannot be linked, and the good front cross technology is actually a back cross of the rotation center forward, but this step of evolution is difficult to practice. Inhale is the same, the inhalation of the front cross is early, most people turn their heads during the paddling process, this is a very bad habit, the body has not yet turned, the head will turn first, the range of the head is usually too large, the time is too long, and the continuity of the action has a great impact. It is also super difficult to change the lift arm to inhale after the action is fixed to the same as the backcross.