There are many tests that evaluate fall and balance. As a clinical test, the Four Square Step Test (FSST)Test is reliable, valid, easy to score, quick to administer, requires little space, and needs no special equipment. It is unique in that it involves stepping over low objects (2.5cm) and movement in 4 directions. FSST was developed in 2002 to measure the rapid stepping that is often required when changing direction and avoiding obstacles while walking. The FSST requires a stopwatch and four single point sticks. Using the sticks resting flat on the floor to form a cross, the subject starts in one square and steps in one direction into each of the four squares and then reverses direction back to the start. The FSST is unique in that it challenges motor planning, sequencing and recall, whilst simultaneously providing clinicians with the opportunity to measure and observe a person's clearance of low obstacles at speed. The ability to clear the trail leg when stepping over an obstacle has been shown to be reduced in healthy populations. Dual task is simultaneous performance of two tasks that can be performed independently, measured separately and with different goals. Individuals have difficulties in performing two tasks together. When two tasks are performed at the same time, deterioration in performance of one or both is called dual task interference. This occurs when task requirements exceed the capacity. Age, walking speed, lower extremity muscle strength and cognitive status are factors that contribute to the dual task. In addition, prioritizing the motor or cognitive task in a dual task affects the dual task performance. Knowing these factors and improving some of them can help to create training programs designed to improve the dual task performance of individuals. There are several studies investigating factors contributing to dual task performance that focus on balance in the elderly. However, the studies including middle age group are limited. There are no studies evaluating the factors contributing to the single and dual task performance of FSST in the literature. In this study, it is aimed to explain the factors related to motor and cognitive functions to the single and dual task performance of FSST.

Participants: Healthy middle age group (50-65 years) Method: Demographic information of all participants (age, gender, body mass index), educational level (primary, undergraduate, graduate), history of falling (at least in 6 months), comorbidities (hypertension, diabetes, kidney diseases, etc.), drug using (how many per day, which one) to be examined by questionnaire and also visual impairment, the use of glasses will be recorded. Motor skills of participants; muscle strength, range of motion (ROM), gait speed (14m), Functional Reach Test will be evaluated. The Mini Mental Test and the Stroop test will be used to evaluate cognitive skills. Single and dual task performance will be evaluated by FSST.

The participants performed the FSST;

1. FSST single: This test is consist of only FSST.
2. FSST motor: FSST is combined with a motor task (carrying a cup of water)
3. FSST cognitive: FSST is combined with a cognitive task (auditory N-back test) As prioritization affects dual task performance, in this study the prioritization will be used in dual task's evaluation. Therefore the dual task will be perform as;

1-With no prioritization 2-With prioritization (focus on balance task) 3-With prioritization (focus on cognitive task) 4-With prioritization (focus on motor task) Note: Balance task is FSST. Cognitive task is auditory N-back test. Motor task is carrying a cup of water.

Statistical Analyses:

The data will be analyzed with Statistical Package for the Social Sciences (SPSS) 21.0 package program. Descriptive statistical information will be given as mean (X) ± standard deviation (X ± SD) and minimum (min), maximum (max) frequency (f) and percentage (%). The variables will be tested for normality using the Kolmogorov-Smirnov test. When the parametrical test assumptions are obtained, the correlation between the FSST single, FSST motor and FSST cognitive is evaluated by Pearson Correlation Analysis, if the parametrical test assumptions are not obtained, Spearman Correlation Analysis will be used. Multiple linear regression analysis will be applied to determine which potential factor is effective in performance in each FSST test. As a result of the power analysis using the effect size value in the reference study for the study, it was calculated that 85% power could be obtained at 95% confidence level when at least 60 people.

Inclusion Criteria:

• At least to graduate from primary school or ability to read and write
• Mini mental test score> 24
• Functional reach test score≥15 cm
• Ability to walking independently in the community

Exclusion Criteria:

• Living in nursing home
• Presence of central nervous system disease (dementia, Parkinson's disease, stroke, etc.)
• Polypharmacy (more than 6 medications per day)
• Presence of hearing impairment that cannot be resolved by hearing devices and presence visual impairment that cannot be resolved by hearing aids.
• Presence of musculoskeletal injuries or impairments (NEH limitation, muscle weakness, etc.), which may affect the performance in physical tests

Sixty healthy active (joining social activities, sports and artistic activities etc.) participants (men and women) between the ages of 50-65 will be included in the study.