Clinicians use a variety of in-shoe heel lifts to treat a range of musculoskeletal conditions. The mechanics of how these orthotic devices work, however, is unclear. So a group from LaTrobe University in Australia put together a study that asked this question: Do heel lifts affect lower limb biomechanics and muscle function during walking and running?
“There is currently a lack of evidence for the effectiveness of heel lifts and the mechanism by which they exert their therapeutic effect,” said lead author Chantel Rabusin, a director at Melbourne Podiatry Group and a PhD candidate at LaTrobe University, in an email to LER. “Our review synthesized reported findings and summarized the effects of heel lifts on lower limb biomechanics and muscle function.”
In their systematic review, the group started with 1,483 citations, assessed 801 articles for inclusion and ultimately examined 23 studies with a total of 377 participants. The studies looked at the effects of heel lifts on the following parameters: temporospatial, kinematic, kinetic, muscle function, and plantar pressures during walking and running in both asymptomatic and symptomatic participants. One key challenge was the wide range of protocols used by the various studies to examine walking speed.
While a large number of parameters were assessed across the numerous studies, few findings were statistically significant. Findings with significance include:
- In asymptomatic participants
o heel lifts of 10mm decreased duration of swing phase (standardized mean difference [SMD] = –1.3)
o heel lifts of at least 5cm decreased velocity (SMD = –0.93) during walking
o heel lifts of 15mm decreased maximum ankle dorsiflexion angle (SMD = –1.5)
o heel lifts of 12mm and 18mm decreased gastrocnemius muscle tendon unit length (SMD = –0.96) during running
- In participants with restricted ankle joint dorsiflexion, heel lifts of 6mm and 9mm increased medial gastrocnemius electromyography amplitude (SMD between 0.68 and 0.98) during walking
- In participants with hemophilia, heel lifts of 9mm increased ankle joint maximum range of motion (SMD = 1.6) during walking
Overall, the group found that heel lifts affect specific lower limb biomechanical and muscle function parameters during walking and running. See the Figure for a graphic summary of their findings.
“These parameters may be favorable in the management of disorders of the posterior lower limb,” said Rabusin. “This information is clinically relevant and will assist in clinical reasoning for the use of heel lifts in the prevention and management of lower limb musculoskeletal conditions.”
Source: Rabusin CL, Menz HB, McClelland JA, et al. Effects of heel lifts on lower limb biomechanics and muscle function: A systematic review. Gait Posture. 2019;69:224-234.