Table 1.

Risk of bias assessment

Sport	References	Random sequence generator (selection bias)	Blinding of outcome assessment (detection bias)	Incomplete outcome data (attrition bias)	Selective reporting (reporting bias)	Other bias
Basketball	Szyman et al. [8]	High	Low	Low	Low	Low
	Arias [11]	Low	Low	Low	Low	Low
	Arias [12]	Low	Low	Low	Low	Low
	Arias et al. [13]	Low	Low	Low	Low	Low
	Arias et al. [14]	Low	Low	Low	Low	Low
	Arias et al. [15]	Low	Low	Low	Low	Low
	Arias et al. [16]	Low	Low	Low	Low	Low
	Regimball et al. [9]	Low	?	Low	Low	Low
	Chase et al. [17]	Low	Low	Low	Low	Low
	Satern et al. [18]	Low	?	Low	Low	Low
Cricket	Elliott et al. [19]	Low	?	Low	Low	Low
Fundamental skills
Throwing	Burton et al. [20]	Low	Low	Low	Low	Low
Catching	Isaacs [21]	Low	Low	Low	Low	Low
Multiple sports: bowling, basketball, throwing and baseball	Wright [22]	Low	Low	Low	Low	Low
Tennis	Timmerman et al. [23]	Low	Low	Low	Low	Low
	Buszard et al. [24]	Low	Low	Low	Low	Low
	Buszard et al. [25]	Low	Low	Low	Low	Low
	Kachel et al. [26]	Low	Low	Low	Low	Low
	Lee et al. [27]	Low	Low	Low	Low	Low
	Larson and Guggenheimer [28]	Low	Low	Low	Low	Low
	Farrow and Reid [29]	Low	Low	Low	Low	Low
	Hammond and Smith [7]	High	?	Low	Low	Low
	Gagen et al. [30]	Low	?	Low	Low	Low
	Elliott [31]	Low	Low	Low	Low	Low
Volleyball	Pellett et al. [10]	Low	Low	Low	High	High

High high risk of bias, low low risk of bias, ? unclear whether the risk of bias was low or high on the basis of the information provided in the article