Detailed Description:

The procedures of the current study will be explained to the children and their parents then parents read and sign an informed consent form. Spirometry (spirOx plus, MEDITECH, China) will be used in the current study; Hand-held lung function test equipment uses infrared signal acquisition methods to measure the forced vital capacity-related items. It has a compact design, is lightweight and is convenient to carry and use; also, it uses low power consumption and can store up to 200 test cases. It can measure forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), peak expiratory flow (PEF) and PEF in 25%, 50%, and 75% also the device may provide percentages like FEV1/FVC, and FEP25/75. This device has proven to be valid and reliable to measure spirometry functions. Phyphox application will be used(physical phone experiment, version 1.1.7), a free program with at least 30 functions for proceeding with physics experiments. The application is named phyphox (an acronym for physical phone experiments) and bosom on Google's Play Store and Apple's App Store in September 2016. To buttress users about the world, an accompanying website was created at http://phyphox.org, which offers itemized instructions, demonstration videos and technical information in English and German. The app itself is presently being translated into additional languages by volunteers from all around the world. The application can use the remote access option to transfer the screen to another monitor wirelessly; also, the app can measure acceleration, gyroscope, linear acceleration, and magnetometer readings. Also exporting the results is available on the wireless screen. This application is proven to be valid and reliable to measure the sensor's readings. After obtaining the consent form, some demographic data like gender, age, weight, height and BMI were collected then each child was asked to take a deep breath and then expire for 6 sec at the spirometer. The mobile application will be opened, and a new experiment will be created with the following criteria: sensors are acceleration, gyroscope, linear acceleration and magnetometer, the sampling rate is 800 Hz, the Experiment time is 30 sec with a 3-sec delay, then the remote access option will be enabled so that the screen appears on laptop screen wirelessly. Abdominal support will be modified so it contains a pocket in its centre so the mobile can fit onto it. Then the mobile phone with the application opened on its screen will be fitted in the pocket in the modified belt, so when the belt is attached the mobile sensors will be very close to the centre of gravity of the participant. After wrapping the belt, participants will be asked to conduct a mini-SITCIB test. For each condition, they will be asked to stand as the condition states for 30 sec and start counting when the application starts recording the sensors data, the conditions are as follows: opened eye with the fixed surface, the closed eye with the fixed surface, opened eye with movable surface and closed eye with the movable surface. Finally, the data will be extracted and stored anonymously on the hard drive as CSV files. The condition test is over when (a) the participant opens his/her eyes in an eyes-closed condition, (b) raises arms from sides, (c) loses balance and requires manual assistance to prevent a fall.}}