# The Role of Verbal Feedback in the Motor Learning of Gymnastic Skills: A Systematic Review
## 2 Materials and Methods
### Quality Assessment  
The quality of included studies was assessed using the Physiotherapy Evidence Database (PEDro) quality scale [34]. The PEDro scale consists of 11 criteria that assess the methodological quality of experimental studies. Each criterion can be rated from 0 to 1 point. For this review, criterion 1 was not included as it comprises the external validity, therefore a maximum possible score of 10 points could be reached. Points were awarded only when a given criterion was clearly satisfied (Table 1). All included studies were independently assessed by two raters ([PERSON], [PERSON]). The agreement between the reviewers was assessed with [PERSON]'s kappa. In case of any ambiguous issues regarding rating points, a final consensus was reached by discussion between the reviewers. Scores within the range of 8-10 were regarded as \"excellent\", 6-8 as \"good\", 4-5 as \"fair\", and \(\leq\)3 as \"poor\" quality.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Study**} & \multicolumn{8}{c}{**Criterion**} & \multirow{2}{*}{**PEDro Score**} \\ \cline{2-11}  & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** & **11** \\ \hline
**[PERSON]**[35] & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 2 \\
**[PERSON] and Busko**[36] & **0** & **1** & **0** & **0** & **0** & **0** & **1** & **0** & **1** & **1** & **4** \\
**[PERSON] et al.**[37] & 0 & 1 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 1 & 1 & 4 \\ \hline
**[PERSON] et al.**[38] & **0** & **1** & **0** & **1** & **0** & **0** & **0** & **0** & **1** & **1** & **4** \\
**[PERSON] and [PERSON]**[26] & 0 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 4 \\
**[PERSON] et al.**[39] & **0** & **1** & **0** & **1** & **0** & **0** & **0** & **0** & **1** & **1** & **4** \\
**[PERSON] et al.**[40] & 0 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 4 \\
**[PERSON] and [PERSON]**[9] & **0** & **1** & **0** & **0** & **0** & **0** & **0** & **0** & **1** & **0** & **2** \\ \hline
**[PERSON] and [PERSON]**[41] & 0 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 3 \\
**[PERSON] et al.**[42] & **0** & **0** & **0** & **1** & **0** & **0** & **0** & **0** & **0** & **1** & **1** & 3 \\
**[PERSON] et al.**[27] & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 3 \\
**[PERSON] et al.**[43] & **0** & **1** & **0** & **1** & **0** & **0** & **0** & **0** & **0** & **1** & **1** & **4** \\
**[PERSON] et al.**[44] & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 1 & 1 & 3 \\ \hline \hline \end{tabular}  
* PEDro rating criteria: (1) eligibility criteria were specified, (2) subjects were randomly allocated to groups, (3) allocation was concealed, (4) the groups were similar at baseline regarding the most important prognostic indicators, (5) there was blinding of all subjects, (6) there was blinding of all therapists who administered the therapy, (7) there was blinding of all assessors who measured at least one key outcome, (8) measures of at least one key outcome were obtained from more than 85% of the subjects initially allocated to groups, (9) all subjects for whom outcome measures were available received the treatment or control condition as allocated, (10) the results of between-group statistical comparisons are reported for at least one key outcome, (11) the study provides both point measures and measures of variability for at least one key outcome.  
\end{table}
Table 1: PEDro quality rating scores *.