In this study, it is aimed to evaluate different ankle functions and postural control variables in university level volleyball players and students with stable ankles and to examine the results obtained. In this way, we aim to contribute to the physiotherapy and rehabilitation literature and clinical studies of physiotherapists who are interested in athlete health.

The hypothesis set in this study is:

H0: There is no difference between ankle functions and postural control variables of volleyball players and healthy controls.

H1: There is a difference between ankle functions and postural control variables of volleyball players and healthy controls.

There are studies proving that athletes with poor postural control have a higher risk of injury to the ankle and knee regions than those with normal. Balanced stance and effective postural control in activities involving ball contact during the game are the basic skills of volleyball. The ankle is a joint that needs to be evaluated frequently and its functions should be improved both in order to improve postural control ability and to prevent possible injuries. It has been proven in studies that the capacity shown in different functional parameters such as joint range of motion, strength and proprioception and balance both reduces the risk of injury and positively reflects on the performance parameters of the athlete. It will be useful to evaluate and examine the ankle functions and postural controls that change as a result of the training and exercises performed by the athletes, unlike healthy individuals who are not athletes, in order to understand the abilities developed specifically for the sport.

The study will be carried out in Yeditepe University Physiotherapy and Rehabilitation Graduate Laboratory. Female individuals aged 18-25 years, with stable ankles will be included in the study as a sample. The study will consist of two groups. The first group will include volleyball players playing in university teams, and healthy university students meeting the same criteria in the control group. The sample size of the study was calculated using the GPower program as type 1 error value= 0.05, power = 0.90, effect size (f value) calculated from the reference article and total of 40 subjects for the independent sample t-test.

The Cumberland Ankle Instability Tool will be used to select suitable participants for the study. Only ankles considered stable according to the questionnaire will be included in this study. First, static balance will be evaluated with the PK Prokin 252 system during the silent stand for postural control assessment. Then, different ankle functions of the people who will participate in the study will be evaluated. The measurement of the range of motion of the ankle will be evaluated with the help of a goniometer. Different degrees of position sense of the ankle joint will be evaluated with the aid of a goniometer and the sense of vibration will be evaluated with a tuning fork. Muscle strength will be measured with the help of a manual dynamometer during the movements of the muscles around the ankle. In addition, the participants who volunteered to participate in the study before the tests will be given a Voluntary Consent Form and a Demographic Information Form. Participants will be given rest periods between each test. Evaluation time will be 45 minutes for each participant. Participants will not be followed up after the assessments.

Inclusion Criteria:

• Female gender,
• Being between the ages of 18-25,
• Having a score of ≥24 on the Cumberland Ankle Instability Questionnaire,
• Volunteering for the study.

Exclusion Criteria:

• Presence of neuromuscular system disease,
• Presence of vestibular or visual problems,
• Presence of acute or chronic pain,
• An ankle injury in the last year,
• For the control group, regular participation in sports activities or physical activity for more than 150 minutes, 5 days a week.

The study was carried out with female individuals aged 18-25 who have stable ankles and have not had an ankle injury in the last 1 year. The study includes volleyball players playing in university teams and healthy university students who meet the same criteria.