Assessment of Landing Parameters in Patients with Chronic Ankle Instability

<b>Background:</b> The aim of this study was a qualitative assessment and quantitative assessment, i.e., the assessment of time to stability (TTS) before and after fatigue test, of landing in patients with chronic ankle instability, referred to as "copers", in comparison to a control group of healthy persons. The indirect aim of the study was to develop a new method to assess more time precise measurement of TTS. <b>Methods:</b> The study involved 60 physically young active individuals aged 18 to 35 years. They were divided into three groups: the study population of 29 copers was divided into: I-14 persons with chronic one side ankle instability, study population II-15 persons with chronic bilateral ankle instability, and the control group included 31 persons without ankle instability. The study involved quantitative assessment of time to stability (TTS) after single-leg landing onto the HUR stabilometric platform from a 30 cm high platform before and after fatigue tests based on a modified Short-Term Fatigue Protocol. To conduct qualitative assessment of landing and to verify time to stability with video imaging, a video analysis was conducted. We used three cameras and two markers: on the malleolus lateralis of the fibula and on the malleolus medialis of the tibia. Each landing was subjectively assessed by a physiotherapist on a four-degree scale. A further biomechanic analysis was conducted only for the trials with a correct landing. The trials were repeated after a fatigue test. <b>Results:</b> There were significant differences before and after the fatigue test in qualitative landing analysis (<i>p</i> < 0.001) only for one jump for the right leg. In groups with unilateral and bilateral ankle instability, there was a higher percentage of landings with a considerable shift or unstable landings. The conducted dynamic test (TTS assessment) did not reveal significant differences between groups or after the fatigue test. <b>Conclusions:</b> Copers develop effective mechanisms of compensation, allowing them to participate in physical activities without symptoms of joint instability. Determining biomechanical differences between athletes who return to their sport and patients who develop chronic instability is important in the context of introducing adequate physiotherapy.