Mexico 68, the triumph of physics in the high jump

This post is to cellebrate the 50 anniversary or Mexico 68 Olympic Games, fist Latin American country to be an olympic host.

Athletics has had several tests in the Olympic Games editions since Athens 1896. One of these tests is the high jump in which the athlete tries to exceed a horizontal bar that rests on two supports. From the point of view of physics, the jump movement can be understood with the concept of the center of mass which is a geometric point that represents the movement of the body.

By getting that the center of mass overcomes the bar so the body can also overcome it, a good height jump is achieved. Using the technique of scissors and other techniques, the center of mass must exceed by much the height of the bar to be able to jump it, but in the technique known as "the Fosbury flop", the center of mass is outside and below the body during the jump and for this reason, the body can overcome more easily.

But let's understand a little more about the center of mass of other objects. If we consider a soccer ball with its homogeneously distributed material, we can easily conclude that the geometric point just at its center is its center of mass. Taking other objects, this determination could be easy for some of them or complex for other ones. If you think of a donut, for example, you will be right if you say that its center of mass is in the center of the donut, which, in fact, does not belong to the donut!

For the human being, the center of mass depends on its position. When standing, you can say that your center of mass is at or near your belly button, approximately. But if you do many weight exercises for torso and arms, it is more possible that it is at a higher position. Or if you have a lot of mass in your hips, legs and thighs, the center of mass is at lower position, for sure. By assuming another position, you will also vary the position of your center of mass. If you arc the body to the front or backwards, your center of mass will be outside your body, as in the case of the donut.

The high jump appeared since Athens 1896 for men, while for women, it is included since Amsterdam 1928. During the first editions, the technique of scissors was used. In this technique, the jump is made, opening the legs in the form of a scissors, passing over the bar with one foot and then with the other. Based on this technique, there were variations that became popular as the western roll in which the body travels horizontally on its side just above the bar or the straddle technique where it travels upside down above the bar. The American male athlete Ellery Clark won the gold in high jump at Athens 1896 with a jump of 1.81 m and the Canadian female athlete Ethel Catherwood won the gold in this discipline in Amsterdam 1928 with a jump of 1.59 m, both using the technique of the scissors.

With more Olympic games, the heights increased until in 1968, the Olympic record was held by the Soviet Valeri Brúmel with 2.18 m height. In the Olympic Games of Mexico 68 the high jump was revolutionized with the American athlete Dick Fosbury who had been experimenting with a new jumping technique since he was 16 years old. This time, he placed his center of mass out of his body and passed over the bar on his back, which had not been done so far. Arcing his body, he achieved that his center of mass was below him so it was less difficult to overcome the height of the bar. He broke the Olympic record with a jump of 2.24 m.

Since Mexico 68, the technique of the "Fosbury jump" is the one that predominates in the high jump competitions. Nowadays, the Cuban Javier Sotomayor holds the men's high jump record with 2.45 m, while the Bulgarian Stefka Kostadinova has the women's high jump record with 2.09 m.

And of course, both the physics and the center of mass continue to play the leading role in the height increases of this fascinating sports discipline.