Why can't I do pull-ups?

Many female friends want to lose weight through exercise, but some exercises are not suitable for female friends. For example, many female friends cannot do pull-ups. This is mainly because our arms are not as strong as those of men, so they cannot support their bodies at all. In this case, there is no way to do pull-ups. If you force yourself to do it, it will cause muscle strain.

1. The pull-up has a narrower base of support. The projection of the bar covered by the line connecting the outsides of your hands on the ground is the area of ​​your base of support. Apparently it was small, just a narrow strip. The area of ​​your base of support for a pull-down is the area covered by the projection of your hips and feet on the ground. Apparently, it's huge.

2. At the bottom of the pull-up, your body is directly under the bar. At the top, your body is to the side of the bar. This means that during the pull-up process, the body rotates around the bar. At the lowest point, your center of gravity is directly underneath the bar, and if you pull straight down, it's easy. (Here we are only referring to the concept of force, excluding other variables. If you really pull straight down with force, you will find that this movement is not easy, but that is another issue. The reason lies in the position of the muscles. Since the back muscles are located at the back of the human body, it is not easy to exert force when you pull straight down.) If you want to rotate your body, you are doing a pulling and pushing movement, which is very difficult. In this movement, the pushing muscles are also involved, and the angle of this movement is not very convenient for the pushing muscles to exert force.

3. The moment arm for a pull-up is long, and the moment arm for a pull-down is short.

As for the movement of the body in space, this is a description of a superficial phenomenon and cannot be considered a scientific statement.

As for which one is more difficult, closed-chain or open-chain, they cannot be compared because there is no one-to-one correspondence between them. You could roughly say that pull-ups correspond to pull-downs and push-ups correspond to bench presses.

Although the movement is relatively simple when doing pull-ups, you do need to know some techniques. If you don't know the techniques, it will be difficult to do it successfully. Because pull-ups require a lot of arm strength to complete, you must train your arm strength well, otherwise you will not be able to complete this movement.