Effect of 2 Types of Thoracholumbosacral Braces on Ankle and Knee Joint Co-contraction in Individuals with Kyphosis during Running

Using lumbar orthoses changes the running mechanics. An essential biomechanical factor in rehabilitation and injury prevention is the co-contraction of the knee and ankle joints. Therefore, this study aimed to investigate the effect of 2 types of thoracolumbosacral braces on ankle and knee joint co-contraction in people with kyphosis during running.

This quasi-experimental study was conducted on 15 men aged 18-25 years suffering from kyphosis greater than 40 degrees in the Biomechanics Laboratory of the University of Mohaghegh Ardabili Health Center during the summer of 2020. Each participant randomly performed 3 running tests in each condition: without a brace, with a sensor brace, and with a simple brace. The test consisted of electromyographic data of the selected lower limb muscles, which also recorded the contraction of the knee and ankle muscles in the right leg when running at a constant speed.

The results showed a reduction of the general knee co-contraction while using a sensory brace compared to without the brace by 6% during the loading phase (P<0.05). Additionally, using a simple brace compared to the condition without a brace, the ankle-directed contraction during the push-off phase decreased by 38% (P<0.05). Directed vastus medialis and lateralis co-contraction while using a sensory brace increased by about 49% compared to without the brace at the loading phase and increased by about 47% at the mid-stance phase without a brace condition compared to the simple brace condition (P<0.05).

General knee co-contraction after using a sensory brace was lower than when a simple brace was used.