Ankle is statically and dynamically the most loaded joint in the human body. This is why it is not surprising that ankle sprain is among the most common daily and sports injuries. In sports 20–40 % of all injuries are ankle sprains.
Individual who suffered from an ankle sprain is more susceptible to recurrent ankle sprains and residual symptoms, which often leads to chronic ankle instability. It has been proven that 40 % of all ankle injuries have a potential to cause chronic problems. Chronic ankle instability is a condition defined as recurrent ankle sprains and a constant feeling of instability in ankle. This condition is often associated with a deficit in ankle muscles strength, poor balance and functional performance. Deficits in strength and proprioception create an environment where ankle relies on static stabilizers only. This is a good predisposition for repeated micro trauma on the joint cartilage, which may eventually lead to osteoarthritis. Improving the strength of ankle muscles creates more stable joint and reduces possibilities for chronic ankle instability. This can prevent recurrent trauma to the joint cartilage and occurrence of osteoarthritis.
In the master’s thesis, a cross-sectional study was performed in which we did measurements of strength of ankle muscles and stability indexes. We studied differences in these parameters among two groups of individuals. First group had an ankle sprain at least once before, the second group never suffered from this kind of injury. The results were also compared separately by gender, because in the cross-sectional analysis we found out that men have 2 times higher chance of an ankle sprain than women. The results of this study have shown that individuals with multiple ankle sprains have stronger plantar flexors than those without or with less than three ankle sprains. We did not find any other differences in muscle strength and stability indexes between injured and never injured group.