Achilles tendon pathology is all too common in our running population. Orthotics have shown some promise, but their effect on Achilles kinetics is not entirely understood. Researchers at the University of Central Lancashire in the United Kingdom decided to investigate whether foot orthoses reduce the load experienced by the Achilles tendon during running. They included twelve male recreational runners who volunteered for the study, assessing each of their results with and without an orthotic.
The researchers found that there were no differences in ground reaction forces (GRFs) at peak moment between the orthotic and no-orthotic conditions. However, the results do show that peak Achilles tendon load (ATL) was significantly reduced in the orthotic condition compared to the no orthotic condition. The time to ATL was also significantly longer in the orthotic condition compared to the no orthotic condition. ATL loading rate was significantly lower in the orthotic condition as well when compared to the no orthotic condition.
It is hypothesized that running with increased midsole cushioning will result in the runner selecting an increased dorsiflexion angle at foot strike and throughout the stance phase. In turn, these mechanics reduce the load experienced by the Achilles tendon. Based on these findings, it is suggested that the risk of developing running related Achilles tendon injuries may decrease with the use of orthotics.
It is important to consult your physical therapist to discuss over the counter orthotic options if you are considering orthotic intervention. Happy running!
Sinclair, J., Isherwood, J., & Taylor, P. (2014). Effects of foot orthoses on Achilles tendon load in recreational runners. Clinical Biomechanics, 29(8), 956-958.
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