You know your speed, but how FAST is your rope going?

By Mike and Becky Agostino

We’re always amazed how fast people can jump in speed.  This year, someone jumped an incredible 167 jumps in one minute!  This is how many right foot strikes in 60 seconds, but did you know that you can estimate the rope speed in miles per hour?  This is based on the basic path of the rope in individual speed—a circle.  Imagine that you had a single bead on your speed rope.  Seen from the side, this bead would travel around you in a circle. Not a perfect circle, but good enough to estimate your miles per hour using simple math.   

What’s my miles per hour? 

You need to estimate the height of the rope from the floor.  First ask someone to estimate how close the rope is to the top of your head (in inches) while doing speed—let’s call this the clearance.  Then get in your normal posture during speed and have someone measure your height in inches.  Add your clearance.  This total is the diameter of the circle.   

In this example, let’s say you average 136 right foot strikes per minute.  And your rope circle diameter is 62 inches.  According to the chart on our web page, your rope is moving a phenomenal 50 miles per hour! 

How is this calculated? 

Geometry tells us that the circumference of the rope circle is Pi (3.142...) multiplied by the diameter.  The circumference is how far the rope (or that imaginary bead) travels in one turn.  In a circle with a 62 inch diameter, the circumference is about 195 inches.  If you do 136 right foot strikes per minute, that’s 272 turns.  Multiply 195 inches times 272 turns per minute and you find that the rope has traveled over 53,000 inches or 4400 feet in that minute.  There are 5280 feet in a mile so the rope traveled 0.84 of a mile in one minute.  Multiply times 60 (minutes in an hour) and you find the miles per hour.  In this example, 50 miles per hour, almost highway speed!

 Who is the fastest in the country? 

We predict that the fastest rope speed is turned by someone tall and did not hit the highest counts this year. But their rope was traveling the fastest! 

 “See coach, I told you I was fast!”