This skill is the ability to perform all kinds of sports (including acrobatics)
Since the activity to gain any skill in this requires hours of training. You can extend your time of strenous activity with succesful skill rolls. Each time your time limit of activity is reached you can perform a skill check with a cumalative modifier of -1 per time repeated. To get another timeperiod of what your constitution normally allows.

In case of falling a succesfull roll lets you avoid the damage of a 5 yard fall. Or reduces the damage you take like you would have fallen 5 yard less.
For jumping you can add your result-10 to your str score to calculate heights or widths.
For every full 5 pounds of weight over 100 subtract 1" from your jumping height
(So a person with a weight of 200 lbs and a strength of 6 would have a base jump height of 4' 4" ) If you have a running start, add half your speed in mph to the width you jump.
For a pole jump, substitute the height you can jump because of strength against the length of the pole(but still add the extra height for skill).
It is possible to specialise in swinging on the lines from grappling hook or the like.
If you roll succesfully you can travel at twice your run speed. If you want to travel even faster, you can use your swinging skill in combination with fake quality to simulate enhanced movement