Border Collies originated in the region near the border between England and Scotland, and many believe that is how they got their name. These wonderful dogs were needed to help with herding livestock such as sheep and cattle.
In order to be able to do this, they needed to be highly intelligent and have great physical attributes to be able to keep the animals confined to a certain area, or to move them to a new grazing area. With careful breeding over a long period of time, we got today's version of what many would call the world's smartest dog.
Border Collies needed to be able to run very fast and turn on a dime to keep up with and overtake the sheep they were assigned to. Indeed they can do these things very well, and with a top speed of about 35 MPH they are not the fastest dog in the world, but they can outrun most other dogs and domestic livestock.Here is a list of the top 15 fastest dogs https://waggingmongrel.com/the-15-fastest-dog-breeds/ However, if you are using a Border Collie for their intended purpose of herding sheep, you need to be aware that Coyotes are quite a bit faster than your dog with top speeds nearing 45 MPH.
Why is it that Border Collies can jump so high? It is probably because all the muscles that they need for running fast and being agile are also beneficial for jumping. I don't think they need to be able to jump almost 6 feet high when they are keeping sheep in line. Maybe they just developed the ability to jump high when they are bored and have no work to do. They love to play and jumping is a very big part of catching a Frisbee or chasing a bouncing ball.
Here is a video of my Border Collie jumping high in the air to catch some snow.