Table 2. GRADE analyses.

Certainty assessment							Certainty
Number of studies (and participants)	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations
Cardiovascular endurance (follow-up: range 4 weeks to 12 weeks)
14 (345 participants)	randomized trials	seriousa	seriousb	not serious	seriousc,d	publication bias strongly suspectede	⊕    ⃝    ⃝    ⃝ Very low
Power (follow-up: range 4 weeks to 8 weeks)
10 (280 participants)	randomized trials	seriousa	seriousb	not serious	seriousc,d	none	⊕    ⃝    ⃝    ⃝ Very low
Change of direction ability (follow-up: range 4 weeks to 8 weeks)
10 (269 participants)	randomized trials	seriousa	seriousb	not serious	seriousc,d	none	⊕    ⃝    ⃝    ⃝ Very low
Sprint (follow-up: range 4 weeks to 6 weeks)
11 (253 participants)	randomized trials	seriousa	seriousb	not serious	seriousc,d	none	⊕    ⃝    ⃝    ⃝ Very low
Muscular Strength (follow-up: mean 6 weeks)
1 (30 participants)	Randomized trials	seriousa	not serious	not serious	seriousc	none	⊕⊕    ⃝    ⃝ Low
Muscular Endurance (follow-up: mean 8 weeks)
1 (30 participants)	randomized trials	seriousa	not serious	not serious	seriousc	none	⊕⊕    ⃝    ⃝ Low
Basketball performance (follow-up: range 4 weeks to 8 weeks)
6 (163 participants)	randomized trials	seriousa	seriousb	not serious	seriousc,d	none	⊕    ⃝    ⃝    ⃝ Very low

a: Some included articles had some concerns of bias.b: There were different outcomes among studies.c: The sample size was not calculated by the appropriate method in some included studies.d: The total number of participants is below the optimal information size required to reliably detect a meaningful effect in some included studies.e: The results indicated a significant Egger's test (p < 0.05).