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