Table 2. Methodological quality of included studies. Ardern et al. (2011b) Edwards et al. (2018) Hamrin Senorski et al. (2017) Langford et al. (2009) Lee et al. (2019) Müller et al. (2015) Nawasreh et al. (2018) Webster et al. (2019) Study participation High High High Moderate High High High High Study attrition Low Low High High High Low High High Prognostic factor measurement High Moderate High High High High High High Outcome measurement High High High High High High High High Study confounding High Moderate High Moderate High Low Moderate Moderate Statistical analysis and reporting Low High High Moderate High Moderate Low Moderate