How to Size Forearm Crutches: Measure Your Hip, Not Your Height
Forearm crutches are fitted from the floor to your hip bone, not from your height. Here is how to take the measurement, and how to pick between the in-Motion Pro Short and Tall.
Most people size a crutch from their height because that is the number they know. It is the wrong number, and it is why a lot of crutches end up an inch off and uncomfortable in a way the owner never quite diagnoses.
The measurement that matters is the floor to the top of your hip bone. Two people who are both five foot eight can need different crutch sizes, because one carries more of that height in the legs and the other in the torso. Height averages over that difference. Hip height does not.
Take the measurement
Follow the steps above in order. The three that people get wrong, in the order they cost you accuracy:
Shoes. Measure in what you actually walk in. A pair of winter boots against bare feet is easily an inch, which on a crutch is the difference between a slight elbow bend and a locked arm.
The landmark. The top of the hip bone is the bony ridge of the pelvis, level with or slightly above where a low waistband sits. It is not your hip joint, which is lower and further out, and it is not your natural waist, which is higher.
Who holds the tape. If you measure yourself, you bend to read the number, and bending moves the landmark you are measuring to. Get someone else to read it, or stand against a wall, mark the height, and measure the mark afterwards.
Match it to a size
The in-Motion Pro comes in two, and both are adult:
| Size | Fits a hip height of | Handle positions |
|---|---|---|
| Short | 23.5” to 33.5” | 11 |
| Tall | 28.5” to 42.5” | 15 |
Note the overlap between 28.5” and 33.5”. That is intentional, not a mistake in the chart. If you land in it, both sizes will adjust to fit you, and the tie-breaker is where you sit within each range: choose the size that puts you nearer the middle rather than at the very end of the adjustment, so you have room to move the setting either way later.
The full chart, including the height ranges the store lists alongside these, is on the sizing page for the product.
One practical warning, because it catches people. On the product page the size selector opens on Tall. If you skim past it and add to cart, you have ordered Tall by default. Check it deliberately.
Set them up once they arrive
A correctly sized crutch that is badly adjusted feels the same as the wrong size, so this part matters as much as the purchase.
The handgrip
Stand upright with the crutch beside you, tip on the floor, and let your arm hang completely loose. The grip belongs level with the crease of your wrist. Set there, your elbow ends up bent about 15 to 30 degrees once you are actually bearing weight, which is what lets your arm absorb the step instead of transmitting it straight through a locked joint.
If your arm is straight and your shoulder rides up toward your ear when you take weight, the grip is too high. If you feel folded over the crutch and are looking at the ground, it is too low.
The cuff
The cuff sits on the forearm, one to two inches below the point of the elbow. It should hold you without gripping: you want to be able to let go of the handgrip to open a door and have the crutch stay hanging on your arm, and you want to get out of it without wrestling.
The in-Motion Pro ships with two cuff sizes for this reason. Forearms differ more than crutch manufacturers usually acknowledge, and a cuff that is right for one person rubs another. Try both before deciding the fit is wrong.
Give it a few days
The first setting is rarely the final one. Walk on them for a few days before you decide, then make one change at a time. The handle positions exist so you can move a single hole and feel the difference, rather than rebuilding the whole setup at once and not knowing which change did what.
If the size turns out to be wrong
Read the chart before you order rather than after, because a return crosses the border back to the United States and the return label comes out of the refund. You have 30 days. Measuring twice at the start is considerably cheaper than shipping a pair of crutches back to another country.