X, Y, and Z are the three measurements we use for forearm crutch sizing. X is the distance between the top of the cuff and the top of the grip. Y is the distance between the top of the grip and the bottom of the crutch tube or tip. Z is the circumference of your forearm at it's widest point. It is used to provide the correct cuff size.
Using a tape measure, measure from the top back surface of the hand grip to the top of the arm cuff. Measure along the bend of the crutch.
The higher up on the forearm your cuff is, the greater the mechanical advantage for you. However if it is too high up, the cuff will bite into your upper arm when you lean over. While we only need to know the distance from the hand grip, one method for determining where the cuff should be is to measure the distance from your elbow. The distance from your elbow to the top of the cuff should roughly be:
- 2" for 5'0" tall
- 3" for 5'8" tall
- 4" for 6'0" tall
This is only a guideline and your own comfort and usability will be the real final deciding factor. If your current outriggers are adjustable, try them at different heights.
Using a tape measure, hook the end to the bottom of the crutch tip or tube and measure to the top surface of the hand grip. Specify if Y was measured with or without a crutch tip. We will make sure the length is correct when we know what kind of tip you'll be using.
Using a tape measure or string, measure your forearm at it's widest point.
Do you often stub your crutch tips on the ground? It may mean your crutches are too long. Do you feel stoop shouldered? They may be too short. Try this test: Standing tall with your crutches at you side, allow your hand to drape over the grip. The deep crease between the palm of your hand and your wrist should line up with the top surface of your grip. If that crease falls above the top of the grip, there is a good chance your crutches are too short. If the crease is below the top of the grip, your crutches are probably too long.