Kinematic effects of a low profile heel lift at the ankle and midfoot joints

Heel lifts are frequently utilized orthotic devices for the management of lower extremity conditions including Achilles tendinopathy, patellofemoral pain, and plantar fasciitis. However, the kinematic mechanisms by which heel lifts impose effects remain understudied, especially at the midfoot. Previous research has also focused primarily on devices larger than 10 mm which may introduce practical challenges.

To quantify the 3D kinematic effects of a low profile heel lift at the rearfoot and midfoot during overground walking in a healthy population.

This was a laboratory-based comparison study. Sixteen healthy females underwent three-dimensional gait analysis while wearing a modified minimalist shoe with and without a 6 mm heel lift. A validated multi-segment foot model was used to obtain kinematic data at the midfoot and rearfoot. The two orthotic conditions were randomly ordered and paired t-tests were conducted on the joint angle data using an alpha level of 0.05.

Significant effects of the low profile heel lift include increased ankle peak plantarflexion by 2.3° (p = .025) and abduction (p = .042) by 0.9° during stance for the rearfoot. Increased first (p = .012) and second peak dorsiflexion (p = .034) was observed at the midfoot by 0.9 and 0.6°, respectively.

These results suggest that low profile heel lifts exert significant but subtle kinematic effects at the rearfoot and midfoot, largely in the sagittal plane. These findings are novel, are relevant to clinical practice, and contribute to our understanding of the biomechanical implications of heel lift devices. Clinicians and researchers should be aware that low profile heel lifts exert subtle kinematic effects in healthy females, and care should be taken to extrapolate findings to symptomatic populations.