How to set up your first approach with actual dimensions.
Several Ways to Begin
There are several ways to begin when laying out your approach for the first time. These ways to begin all assume that you are using my general approach design.
Begin with setting your takeoff point by one of the following methods:
Choices 2 and 3 are supported by High Jump Coach 2010TM , but neither choice takes account of your actual flight distance. Thus, the generally require several adjustments early on to get the flight length and angle to the bar correct.
Then set the curve radius and the rest of your approach path by one of the following methods:
Choices 2, 3, and 4 are supported by High Jump Coach 2010, but all of these methods assume that your current approach shape is very close to the shape generated by the approach calculator. Thus they generally require several adjustments early on to get the run distance and curve radius to a good starting point.
From this point forward I am going to talk only about the preferred methods of establishing the first approach.
The method for establishing your first approach that I prefer gets you to a usable "first cut" in one pass. That "first cut" takes a bit more time, but it takes you directly to the first approach.
The other methods all rely on your current approach to be "reasonable"; generally a bad assumption. As such, they take some adjustments just to get you to started.
Get warmed up and take some jumps using your current approach. Have someone watch your takeoff point, and someone else watch your landing point. The takeoff point is the center of the footprint of your takeoff foot. The landing point is the position of your center of mass (CM) at the moment you contact the mat. Your CM is going to be a guess, just make the best guess you can. At the moment, close is good enough.
Now measure the horizontal distance between your takeoff point and your landing point and write it down.
Pick the angle that you want to have between the line of your flight across the ground and the bar. You don't have to think about this one, or even measure it, just use 25 degrees for now.
Make the best measurement you can of your total run distance. That includes the entire distance from your starting point to your takeoff point. You might have to put chalk on the soles of your shoes, run your approach, and then stretch the tape from chalk mark to chalk mark. Again, close is good enough for now. Write it down.
Pick the curve radius you want. This would be a bit tricky, because there are many variables involved in estimating the optimum curve radius for any jumper. Fortunately, I have done this enough to give you a formula for guessing the "first cut" curve radius:
R = 3Pr
Where R is your "first cut" radius and Pr is your personal record. So, if your best jump is 6'-6" then your "first cut" radius would be 19'-6" and if your best jump is 2.00 m then your "first cut" radius would be 6.00 m. Now figure out your radius and write it down.
Remember that this is a "first cut" at the radius. It is specifically intended that the "first cut" radius be somewhat bigger than optimum because I want to have your curve, lean angle at plant, and rotation about the bar all start out less than optimum. Then we can make adjustments to increase these parameters to yield optimum bar clearance.
Plug it in
The next step is to plug the measurements you have written down into High Jump Coach 2010. Once you have entered the measurements HJC 2010 will calculate approach measurements you can mark on the approach apron.
The Jump Test
All that is left now is for you to go out and learn to use the approach. Everything from here on depends on your ability to execute the approach and takeoff correctly. Once you can do that, you can begin the approach adjustment process. See Running it! to understand how the approach and takeoff should be executed for optimum bar clearance.