The study was approved by the ethical committee of Faculty of Physical Therapy, Cairo University (REG.N. 012/003402). Before beginning the testing procedures, parents of all participants were interviewed and provided a written consent to agree about the participation of their children in the study. Any exclusion criteria that might exist were examined. Demographic data as age and gender were documented for all children before starting the evaluation procedures. Also, anthropometric data as height, weight, and body mass index (BMI) were measured before starting the evaluation procedures. The investigator made sure that children are not tired or hungry during testing to maintain alertness and concentration.
Gross motor function classification system—expanded and revised
The GMFCS-E&R is valid and reliable when applied by medical personnel or caregivers . According to Palisano et al. , the researcher asked the child to do functional tasks from each level of the user’s manual to determine which level the child fits in according to age band. Subjects classified in categories 1 or 2 only were included.
Timed up and down stairs test
The researcher then begins to illustrate and demonstrate TUDS test procedures before any trials are conducted. Participants were advised to face forward when ascending and descending the stairs. The child was not required to return to the starting mark. Handrails were available on one side only. The participants were allowed to wear shoes, but no orthotics were allowed. Limited number of demonstrations and trials was permitted to all participants.
According to Corral et al. , participants were asked to stand 30 cm from the bottom of one set of stairs (10 steps, each 16 cm in height and 31.5 cm in depth). The subjects started the trial on the count of 3 to go up the stairs as quickly as possible while maintaining caution, turn around on the highest step, and descend again until both feet are on the bottom step. The researcher walked along beside the participant to ensure safety and to provide verbal encouragement as needed.
The child was not allowed to run, jump, or skip steps; otherwise, any pattern of climbing was acceptable (such as step to or step over strategy, facing forward or sideway, not holding rails, or holding with 1 or both hands).
The time required to ascend and descend stairs was measured in seconds from the count of 3 until both feet returned to the bottom step. Shorter times indicate better functional ability.
All children were filmed during performance of the test. To determine test-retest reliability, each participant performed the test on 2 sessions, and the rest interval between both testing sessions was 20 min. Participants were instructed to complete two trials of the test in each session, with an optional 1-min break in between. The better of the two trials was employed in the analysis.
The main investigator scored all children at real time using a stopwatch and then rescored them later from the video to determine intra-rater reliability. Another research team member scored all children from the video to determine inter-rater reliability. Each investigator did not have any knowledge of the scores of other trials during scoring.
Descriptive statistics of mean ± standard deviation (SD) and frequency was carried out to calculate the measured variables. Test-retest, intra-rater, and inter-rater reliability were expressed as intra-class correlation coefficients, ICC (2, 1). Repeated measurements by the same rater on real-time measurement (T1-T2) of TUDS test were used to calculate test-retest reliability. Repeated measurements by the same rater on real-time and video recording measurement were used to calculate intra-rater reliability. Measurements by different raters on video recording measurements were used to calculate inter-rater reliability. The level of significance for all statistical tests was set at p < 0.05. Statistical analysis was conducted through the Statistical Package for Social Studies (SPSS) version 25 for windows (IBM SPSS, Chicago, IL, USA).