There was a time in my life I thought all of this stuff was common knowledge but after working with many people I realized it wasn't including my father.
This is why I am putting up pictures and trying to help anyone that is interested.
Here is a pictuer of two swing like things I think they are self explanatory.
The one on the right shows a regular A frame with the weight in the middle hanging straight down.
All of the energy is directed down.
In the same picture you will see the swinging weight on the outside of the frame.
Now some of the energy is directed outside the frame.
Due to leverage the leg closest to the weight is directed down but the leg farthest away it is directed up.
Once you get outside the frame you end up in the critical area and all of this force is reversed so to speak on the right leg.
There is also another thing at play the angle of the support legs.
Not only do they play a role in the critical zone of the swing they also play a role in leverage and center of gravity.
The second picture shows how you can overcome this with an imaginary line due to the fact you have put your frame at a 60 degree angle but installed two boards at the bottom increasing the angle and changing the center of gravity.
Levers gears pulleys inclined plains and yes even a swing works on this same principle.
You can speed things up change direction or slow things down in each case sacrificing one for the other.
Worth
Swing 1.jpg