Which of the following is a common footwear modification used by pedorthists?

Heel lifts are a common footwear modification used by pedorthists primarily to address leg-length discrepancies, improve posture, and alleviate discomfort related to certain conditions or injuries. When a patient has one leg that is shorter than the other, a heel lift can help balance the body and promote more effective weight distribution during walking or standing. This modification can also alleviate stress on the lower back, hips, and knees by aligning the body's biomechanics.

Additionally, heel lifts can be beneficial for patients with specific conditions such as Achilles tendonitis or plantar fasciitis, as they reduce strain on affected areas while providing the necessary support to facilitate healing.

Other choices involve modifications that serve different purposes. Arch supports, for example, primarily provide additional support for the arch of the foot, which is vital for individuals with flat feet or certain types of foot pain. Leather insoles might enhance comfort or control moisture, but they do not specifically address biomechanical issues. Lace types can affect fit and comfort but are not considered a formal modification for specific foot or gait problems. This systemic understanding of heel lifts underscores their practical application and significance in pedorthic practice.