Analysis of Balance and Functional Hop Tests in Athletes With Lower Extremity Injuries by Dual Task Study
Phase: NA
Conditions: Athletic Injuries, Knee Injuries, Ankle Injuries, Hip Injuries, Ankle Sprains, Reinjuries
Sponsor: Istanbul University

COVER PAGE 
TITLE: Analysis of Balance and Functional Hop Tests in Athletes with Lower 
Extremity Injuries by Dual Task Study 
NCT05484778 
Document Date: 03.06.2021 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1. Study Protocol 
1.1. Pre-measurement 
In this study, 19 athletes aged 16-30 years with a history of unilateral lower extremity injury 
and 20 athletes who have not had a lower extremity injury before were included. The MMSE 
(Mini Mental State Examination) score of each athlete was calculated. Before starting the 
measurements, the "Informed Consent Form" was signed by the participants. Before starting 
the performance measurements, the Mini Mental State Test was applied to the participants. 
For the cognitive task, the backward digit test of the Wechsler intelligence scale (WISC) was 
preferred. For the randomized number sequence to be used during dual task measurements 
to be of suitable difficulty for the cognitive level of the person, a 2-digit random number 
sequence was first told once, as one digit per second, and the person was asked to say the 
same number sequence in reverse. For each correct answer, the number of digits of the said 
number sequence is increased by one. The number of digits in which the person made a 
mistake was recorded and one more digit of this number was used during the measurements. 
1.2. Balance Measurement 
Biodex Balance System SD device was used for balance measurement. The device, which 
has a circular floor, four regions to represent 5° tilt in each region, and four quadrants to 
measure instability in anterior-posterior-medial-lateral directions, consists of 12 difficulty levels 
according to tilt formation resistance. The device, which can be used for both analysis and 
rehabilitation purposes, has different measurements and exercise modes. In calculating the 
instability level, mathematical formulas are used that consider the time spent by the person in 
the relevant regions and quadrants in each repetition. Athlete Single Leg Stability was 
preferred among the test modes included in the Biodex Balance System SD balance device. 
After the person's name, age and height information were entered into the database of the 
device, the screen of the device was adjusted to be at eye level according to the height of the 
athlete. The tests were applied to both legs in a randomized order twice, both as a single task 
and a dual task with cognitive task. The person took a position with his/her eyes open, the foot 
of the untested leg resting on the back of the ankle of the tested leg, his/her arms crossed on 
his/her chest, and the center of balance in the middle of the platform most comfortably. In this 
position, the coordination of the point where the heel touches the ground and the angle of the 
foot are recorded in the system. The content of the test was explained to athletes. The 
analysis protocol was applied at 5 difficulty levels, consisting of 20 seconds, 1 sample and 3 
test repetitions, with a 10 second rest between repetitions. In the dual task measurement, while 
the athlete is in the resting position on the platform, standing behind the athlete is the 
randomized number in the previously determined number of digits. The sequence was sung 
twice, approximately one digit per second, in a speaking voice. As soon as the second 
repetition was finished, the athlete took the test position, and the measurement was carried 
out. At the end of the measurement, the athlete was asked to say the said number sequence 
in reverse and the number sequence he said was recorded. A new number sequence is 
given after every 20 seconds of measurement. During the tests, the related test was 
canceled and repeated in cases such as opening the arms because of loss of balance, 
contacting the ground in the air, changing the coordinate of the foot on the ground. General 
stability index (OSI), anterior/posterior stability index (APSI), medial/lateral stability index 
(MLSI) were recorded. 
1.3. Functional Hop Test Measurement 
All the jump tests were applied to each leg separately. The test was repeated in cases where 
athlete touched the ground with his/her other foot, could not maintain his/her stability during 
the descent, and received support with his/her hand. For each jump, 1 sample and 2 
measurements were applied on each leg. Hops were measured twice as a single task and a 

dual task with cognitive task. During the dual task, while the athlete was in the ready position 
at the starting line, the random number sequence with the previously determined digits was 
repeated 2 times, standing behind the athlete, with a speaking voice, approximately one digit 
per second. After the second repetition, the athlete was asked to start jumping. At the end of 
the jump, the athlete was asked to say the said number sequence in reverse and the number 
sequence he/she said was recorded.