Table 1 Selection criteria used in the meta-analysis
Category | Inclusion criteria | Exclusion criteria |
|---|---|---|
Population | Youth* participants aged < 18 years (i.e., group mean value), with no restrictions on their physical fitness or sport-specific performance level, sport practiced, competitive level, or sex | Participants with health problems (e.g., injuries, recent surgery), precluding participation in a plyometric-jump training program |
Intervention | A plyometric-jump training program lasting ≥ 2 weeks with ≥ 6 total training sessions, which included unilateral and/or bilateral jumps, loaded or unloaded exercises, with repeated (cyclical) or non-repeated (non-cyclical) jumps, which commonly utilize long (countermovement jump) or short (drop jump) stretch shortening cycle | Exercise interventions not involving plyometric-jump training (e.g., upper-body plyometrics only training interventions) or exercise interventions involving plyometric-jump training programs representing less than 50% of the total dedicated-intervention training load (i.e., lower-limbs number of exercises) when delivered in conjunction with other training interventions (e.g., high-load resistance training) |
Comparator | Studies comparing groups of different maturity status with or without active or passive control groups. According to standardised methods, comparisons included well-defined maturation groups (e.g., Tanner stages; estimation of age at peak height velocity; x-ray methods [e.g., Fels method]) | Absence of a well-matched maturation-age comparator group (i.e., studies including different maturation-age groups that also differ in other relevant moderators [e.g., physical fitness or sport-specific performance level; sex]) Studies comparing different maturation-age groups but exposed to different plyometric-jump training interventions |
Outcome | At least one measure related to physical fitness (e.g., jump height) or sport-specific performance (e.g., soccer ball kicking velocity) before and after the training intervention | Lack of baseline and/or follow-up data |
Study design | Experimental design with a control group, and two or more maturity groups exposed to the same plyometric jump-training stimulus (e.g., type of exercises, intensity, volume, frequency) | Single-group interventions |