Parallel motion linkages or push/pull linkages use two fixed pivots to make the input and output travel in the same direction, through a link arm. Each fixed pivot has a moving pivot on either ...

Watch this video of a birthday party. There's a tug of war over a present and it shows how the push and pull forces work. Read this scenario and have a think about what may happen. The twins are ...

What is the pull-up hack ... from under the bar limits your range of motion as you move upward. Instead, she recommends performing a slight push on the bar before you initiate the move.