Table 1.
Proposed checklist for the quality assessment of internal validity, statistical validity, and external validity: Reproduced and modified with permission from J. Taborri et al., Feasibility of Muscle Synergy Outcomes in Clinics, Robotics, and Sports: A Systematic Review; published by Hindawi, 2018.
| Item | Index | Score | ||
|---|---|---|---|---|
| Aim of the work | ||||
| 1 | Description of a specific, clearly stated purpose (IV) | Y | N | Maybe |
| 2 | The research question is scientifically relevant (EV) | Y | N | Maybe |
| Inclusion criteria (selection bias) | ||||
| 3 | Description of inclusion and/or exclusion criteria (IV-EV) | Y | N | Maybe |
| Data collection & processing (performance bias) | ||||
| 4 | Data collection is clearly described and reliable (IV-EV) | Y | N | Maybe |
| 5 | Same data collection method used for all subjects (IV) | Y | N | Maybe |
| 6 | Data processing is clearly described and reliable (IV-EV) | Y | N | Maybe |
| Data loss (attrition bias) | ||||
| 7 | Data loss <20% (EV) | Y | N | Maybe |
| Outcomes (detection bias) | ||||
| 8 | Outcomes are topic relevant (EV) | Y | N | Maybe |
| 9 | Outcomes are the same for all the subjects (IV) | Y | N | Maybe |
| 10 | The work answers the scientific question stated in the aim (IV) | Y | N | Maybe |
| Presentation of the results | ||||
| 11 | Presentation of the results is sufficient to assess the adequacy of the analysis (IV) | Y | N | Maybe |
| Statistical approach | ||||
| 12 | Appropriate statistical analysis techniques (SV) | Y | N | Maybe |
| 13 | Clearly states the statistical test used (SV) | Y | N | Maybe |
| 14 | States and references the analytical software used (SV) | Y | N | Maybe |
| 15 | Sufficient number of subjects (SV) | Y | N | Maybe |
EV: External Validity; IV: Internal Validity; SV: Statistical Validity.