Table 1.

Selection criteria used in the meta-analysis.

Category	Inclusion criteria	Exclusion criteria
Population	Apparently healthy soccer players, with no restrictions on their playing level, sex, or age	Soccer players with health problems (e.g., injuries, recent surgery)
Intervention	A complex training programme, defined as a combination of heavy load strength exercise followed by a low load plyometric/power exercise, set by set	Exercise interventions not involving complex training or exercise interventions involving contrast training, where strength training exercises were conducted first and plyometric/power exercises at the end of the session (or during a different session)
Comparator	Active control group	Absence of active control group
Outcome	At least one measure of physical fitness (linear sprinting, jumping, and change of direction speed) before and after the training intervention	Lack of baseline and/or follow-up data
Study design	Controlled trials	Non-controlled trials