Do you feel like your belt is always slightly tilted? Do you notice that one pant leg consistently frays at the heel while the other stays clean? Or perhaps you experience chronic lower back pain that only seems to strike on one side? How about hip, knee or ankle pain only on one side?
You might be dealing with a Limb Length Discrepancy (LLD). While many people have a slight difference in leg length, a discrepancy of more than 3mm to 10mm can lead to compensatory pain in the hips, knees, and spine. That’s were heel lift in your shoe may make a huge difference.
While a professional scan (like an X-ray or EOS scan) is the only way to get a definitive measurement, you can perform a preliminary check at home using these three simple methods.
Before You Start: Understanding “Functional” vs. “Structural”
Before grabbing your tape measure, it is important to know there are two types of LLD:
Structural: The actual bone (femur or tibia) is shorter.
Functional: The bones are equal, but a pelvic tilt or muscular imbalance makes one leg appear shorter.1
Method 1: The “Level Pelvis” Mirror Test
This is the easiest visual check and requires only a full-length mirror and a stiff, flat object (like a hardcover book or a clipboard).
Strip down to your underwear and stand in front of a mirror on a hard, level floor (no carpet).
Find your “hip bones” (the Anterior Superior Iliac Spine). These are the bony protrusions at the very front of your pelvis.
Place the book/level across both bones. If the book is perfectly horizontal, your legs are likely even. If the book tilts to one side, that side is likely the shorter limb.
The “Shim” Test: If you see a tilt, place thin magazines or floor tiles under the foot of the “short” side until the book becomes level. Measure the height of the magazines—this is a rough estimate of your discrepancy.
Method 2: The Tape Measure Technique
For this method, you will need a friend to help, as it’s nearly impossible to get an accurate reading while bending over.
Lie flat on your back on a firm surface.
Bridge up: Lift your hips off the ground, then set them back down. This “resets” the pelvis. Have your friend gently pull on both ankles to ensure you are straight.
Measure from Hip to Ankle: Have your friend measure from the bony point of your hip (the ASIS mentioned above) to the inner ankle bone (medial malleolus).
Compare: Write down the measurement for both sides. A difference of $1/4$ inch ($~6mm$) or more is usually considered clinically significant.
Method 3: The “Wear Pattern” Audit
Sometimes your gear tells the story your eyes miss. Lay out your most-worn items:
Shoes: Look at the outsoles. Does one shoe show significantly more wear on the heel or the outer edge than the other?
Jeans: Check the hems. Is one side tattered while the other is pristine?
The “Seam” Test: Put on a pair of leggings or trousers with a clear side seam. Stand straight and see if the seams line up evenly at the ankles.
Home measurements are excellent for identifying a potential problem, but they are prone to human error. If you find a discrepancy:
Do not immediately buy a large heel lift. Sudden corrections to the short leg can shock your spine.
Consult a professional. A medical professional can determine if the issue is structural (requiring a lift) or functional (requiring stretching and realigning).
Atlas Biomechanics is a USA based manufacturer of Heel Lifts. The most prescribed heel lift in the USA.
