It’s estimated that about 40-70% of people have some degree of a leg length discrepancy. That simply means one leg is longer than the other. The difference is often so slight, it may not cause a problem.

However, if you’re an active runner, the condition may reveal itself in the form of low back pain and/or hip pain as the body attempts to compensate for the imbalance. 

Here’s what you need to know about the different causes of a leg length discrepancy, how it can be diagnosed, and how a heel lift can help keep your running on track.

Two types of leg length discrepancies

There are two different issues that can cause a difference in leg length: anatomical and functional.

An anatomical difference is when a bone in one leg is longer than the bone in the other leg. This can be diagnosed medical imaging such as X-ray or CT scans.

In a functional difference, the bones are equal in length, but a muscle imbalance, curvature of the spine, or even arthritis-related issues alters the alignment of the hips over time.

How to determine if you have a leg length discrepancy

While medical imaging is the only way to diagnose an anatomical difference, determining a functional difference can be more difficult. According to Runner’s World, there is a simple test you can try at home:

1. Lie barefoot on your back with your legs together. Ask a friend to place the palms of his hands on your hip bones—one hand on either hip.
2. Have your friend gently rock your hips side-to-side for about a minute. The goal is to allow your muscles to loosen up and relax.
3. Ask your friend to look at your feet to see if your ankle bones are even.

If your ankles don’t appear to be even, loosen up muscles further though simple stretches and repeat steps one through three.

If the at-home test reveals a possible imbalance, visit a healthcare professional for an official diagnosis.

How does a heel lift help with a leg length discrepancy?

Depending on your diagnosis, you may be prescribed a heel lift to wear in the shoe of your shorter leg. Heel lift therapy is a non-invasive, safe, and inexpensive way to help balance the discrepancy.

It’s important to follow the instructions of your healthcare provider. He or she may suggest you start using a lift for limited periods of time at first to allow your body to adjust gradually—especially when running.

An adjustable appliance such as the Adjust-A-Lift® Heel Lift will also make it easier to become accustomed to the change, as layers can be removed and added back to the lift as your needs progress. The lift’s three-layer construction of extra firm, open cell foam rubber also provides support with some flexibility, which can make it easier to adapt to in a running shoe.

Heel lifts for running issues

Heel lifts that fit inside the shoe are also often prescribed for other common overuse injuries related to running, including: 

Achilles Tendonitis. A heel lift in each shoe can help decrease stress exerted on the Achilles tendon and reduce heel pressure.

Plantar Fasciitis. Heel lifts work to take pressure off the plantar fascia fibrous tissue that runs along the bottom of your foot by shortening the length your calf must stretch during your stride.

Heel Spurs. For a heel spur that occurs at the back of the heel, a heel lift can potentially provide pain relief as it reduces stress on the Achilles tendon.

To determine whether heel lift therapy is the right treatment for a leg length deficiency or other overuse injury related to running, visit a healthcare provider. Should he or she suggest a heel insert, you’ll find the most versatile treatment option in the Adjust-A-Lift® Heel Lift.