Heel lifts are wedge-shaped inserts placed inside or on the bottom of a shoe to elevate the heel. They’re used to manage a range of musculoskeletal conditions, from leg length differences to Achilles tendon pain to growing pains in children’s heels. Most are simple, inexpensive devices made from rubber, cork, silicone, or foam, and they work by changing the angle of your ankle joint, which shifts how forces travel up through your leg.
How Heel Lifts Work
When you add height under the heel, it tips your foot into a slightly more downward-pointing position at the ankle. This reduces how far your ankle bends upward during walking and running. A 15 mm lift, for example, meaningfully decreases the peak upward bend of the ankle during a running stride. That single change ripples through the chain: it alters the tension on the Achilles tendon, changes how your knee and hip absorb force, and can level out a pelvis that’s been sitting unevenly due to one leg being shorter than the other.
Heel lifts come in two forms. Internal lifts sit inside the shoe, under your heel or under an existing insole. External lifts are built onto the outsole of the shoe itself by a cobbler or orthotist. The practical limit for an internal lift is about 10 mm (roughly three-eighths of an inch). Beyond that, most shoes can’t hold both the lift and your foot without the heel slipping out. If you need more correction, the lift goes on the outside of the shoe.
Correcting Leg Length Differences
The most common medical reason for a heel lift is a leg length discrepancy, where one leg is measurably shorter than the other. Small differences are extremely common and often cause no symptoms at all, but larger gaps can lead to an uneven gait, pelvic tilt, and pain in the lower back, hip, or knee over time.
Measuring the difference accurately matters. A pelvic X-ray taken while standing is considered the gold standard for quantifying how much one leg falls short. Clinical measurements taken with a tape measure, whether you’re lying down or standing, have been shown to be sufficiently accurate compared to the X-ray, so your provider may use either method. The size of the lift is then tailored to the discrepancy, though clinicians don’t always correct the full difference at once. A partial correction is sometimes used first to let your body adapt.
Achilles Tendon Pain
Heel lifts are widely recommended for Achilles tendinopathy, the chronic, nagging pain in the tendon connecting your calf to your heel bone. The logic is straightforward: elevating the heel shortens the distance the tendon has to stretch, reducing the load on an irritated structure. A systematic review confirmed that heel lifts do reduce the stretch on the calf muscle and Achilles tendon during walking, and they decrease ankle motion during running.
However, a recent randomized controlled trial published in the Journal of Orthopaedic & Sports Physical Therapy found that the actual biomechanical changes from heel lifts were minimal. During running, the lifts reduced ankle motion by only about 2 to 3 degrees. The researchers concluded that these small changes “undermine the clinical rationale” for using heel lifts specifically to reduce Achilles tendon load. This doesn’t mean heel lifts never help with tendon pain, but it does suggest the benefit may not come from the mechanism most clinicians assume.
Sever’s Disease in Children
Sever’s disease is heel pain caused by inflammation at the growth plate of the heel bone, common in active kids between ages 8 and 14. Heel lifts are one of the most widely prescribed treatments. They work by lifting the heel on an inclined plane, which reduces the pull of the calf muscle on the back of the heel bone where the growth plate sits.
In a randomized trial of nearly 200 children, heel lifts produced a meaningful improvement. About 20 to 30 percent of children using standard heel lifts saw significant pain relief, with pain scores dropping by roughly 19 percent on average. Custom-made foot orthotics performed considerably better in the same trial (70 to 90 percent improvement rates), but heel lifts are far cheaper and more accessible, making them a reasonable first step for many families.
What Types Are Available
You’ll find heel lifts in three general categories:
- Off-the-shelf cushion lifts: Soft silicone or gel wedges sold at pharmacies and online. These provide a small elevation (typically 5 to 10 mm) and some shock absorption. They’re the easiest to try and the least expensive.
- Firm orthotic lifts: Made from cork, hard rubber, or layered materials, often prescribed by a podiatrist or physical therapist. These provide a more precise height correction and hold their shape longer under body weight.
- External shoe modifications: For corrections above 10 mm, a shoe repair specialist or orthotist adds material to the outsole. This is the only practical option for larger leg length differences and allows for much greater height adjustment without compromising fit.
Potential Downsides to Watch For
Heel lifts are simple devices, but they do change your biomechanics in ways that aren’t always predictable. Research on gait symmetry found that while a heel lift improved some asymmetries, it introduced new ones. Specifically, it increased side-to-side asymmetry at the hip and raised the inward-bending force at the knee. Increased frontal plane hip asymmetry has been associated with a higher risk of hip and knee osteoarthritis, though it remains unclear whether temporary use creates enough stress to cause problems.
The knee finding is particularly relevant if you have existing knee issues. The added inward force at the knee (called a varus moment) is something clinicians flag for patients with knee arthritis or prior knee injuries. Similarly, changes in hip loading may matter for anyone with a history of hip impingement or a hip replacement.
More practically, an internal lift that’s too tall will push your heel up and out of the shoe, reducing stability and potentially causing blisters. Starting with a thinner lift and gradually increasing the height gives your body time to adjust and helps you find the point where the benefit outweighs any awkwardness in fit. If the lift shifts around inside your shoe, securing it under the insole or using an adhesive-backed version keeps it in place.