Table 4.
Type of limitations of the selected investigations.
| Investigation | Type of limitations |
|---|---|
| Gutiérrez Porlán and Serrano Sánchez (2016) | Formulation of the aims and objectives of the research, self-reported data. |
| Jiménez-Cortés, Vico-Bosch & Rebollo-Catalán (2016) | Not mentioned |
| Mengual-Andrés et al. (2016) | Implementation of the data collection method, sample size. |
| Cote and Milliner (2017). | Implementation of the data collection method, sample size. |
| Cabezas González et al. (2017) | Not mentioned |
| García-Esteban (2017) | Not mentioned |
| Guzmán-Simón, García-Jiménez, and López-Cobo (2017) | Implementation of the data collection method, sample size. |
| He and Zhu (2017) | Implementation of the data collection method, sample size. |
| Blayone, Mykhailenko, Kavtaradze, Kokhan, and Barber (2018) | Implementation of the data collection method, lack of data, formulation of the aims and objectives of the research, self-reported data. |
| Byungura et al. (2018) | Implementation of the data collection method, research time. |
| Bond et al. (2018) | Sample size. |
| Guillén-Gáme, Mayorga-Fernández & Álvarez-García (2018) | Lack of data, sample size, formulation of the aims and objectives of the research. |
| He et al. (2018) | Implementation of the data collection method, Lack of data. |
| Kim et al. (2018) | Lack of data, sample size, self-reported data, lack of previous research studies on the subject. |
| Madsen et al. (2018) | Implementation of the data collection method, lack of previous research studies on the subject. |
| Esteve-Mon et al. (2019) | Sample size. |
| Gallego Arrufat et al. (2019) | Implementation of the data collection method, sample size. |
| He and Li (2019) | Implementation of the data collection method, lack of data, formulation of the aims and objectives of the research. |
| Kim et al. (2019) | Lack of data. |
| López-Belmonte et al. (2019) | Lack of data. |
| McGuinness and Fulton (2019) | Not mentioned |
| Cabero-Almenara et al. (2020) | Not mentioned. |
| Guillén-Gámez and Mayorga-Fernández (2020a) | Self-reported data. |
| Guillén-Gámez and Mayorga-Fernández (2020b) | Not mentioned. |
| Guillen-Gamez, Mayorga-Fernández, and Del Moral (2020). | Sample size. |
| Grande-de-Prado et al. (2020) | Implementation of the data collection method, self-reported data |
| Romero-Tena et al. (2020) | Sample size. |
| Llorent-Vaquero et al. (2020) | Not mentioned. |
| Martzoukou et al. (2020) | Self-reported data; sample size. |
| Ortega-Sánchez et al. (2020) | Implementation of the data collection method. |
| Romero-García et al. (2020) | Not mentioned. |
| Ryhtä et al. (2020) | Implementation of the data collection method, research time, lack of data. |
| Sales et al. (2020). | Implementation of the data collection method. |