Table 2.

Studies that investigated the effects of plyometric training programs on vertical jump performance.

Study	Sex	Age (Mean) and Competitive Level	n	Design	Training Protocol	Main Results
Martel, Harmer [42]	Women	Aquatic group: 14 yo Control group: 15 yo	19	Randomized controlled trial; 6-week period intervention	Aquatic plyometric training (APT): 2 × week; 45 min. Power skips, spike approaches, single- and double-leg bounding and squat jumps progressively increased from two times per session to five times per session. Bouts increased from 10 s to 30 s of maximal jump during the period. Depth jumps were performed involving three submerged boxes also progressively increasing the number of times session during the period. Control group (CG): a flexibility supervised program was conducted twice a week, consisting of three sets of 8–10 static stretches for 30 s each.	Meaningful increases in VJ were found after 4 weeks in both groups (3% in APT and 5% in CG). After 6 weeks, the APT improved 8% in comparison to the 4-week period, and no significant changes were found in control. Differences between groups revealed that players in APT jumped 1.5 cm higher than CG in baseline and 3.9 cm after the intervention period.
Lehnert, Lamrová [46]	Women	14.8 yo	11	Case reports; 8-week period intervention	2 × week The training program was divided into three cycles. The number of sets varied between 3 and 4, and the repetitions between 8 and 10. No information about the resting period was provided.	The standing VJ increased from 29.50 cm at the baseline to 30.45 cm after 4 weeks of the program and 33.54 cm at the sixth week after the completion of the program.
Milić, Nejić [52]	N.R.	16 yo	46	Case reports; 6-week period intervention	Plyometric training group: 2 to 3 times per week (15 sessions in total during the experimental period). Five exercises (hurdle jump, depth jump, box jump sideways, lunge jumps and vertical jumps) for explosive leg strength. The number of sets varied between 2 and 4, and the repetitions between 6 and 12 during the training period.	Meaningful improvements were found in the plyometric training group: The two-foot takeoff block jump improved 3.53 cm; the right foot takeoff block jump improved 3.44 cm; the left foot takeoff block jump improved 4.05 cm; the two-foot takeoff spike jump improved 5.22 cm; the right foot takeoff spike jump improved 4.34 cm; the left foot takeoff spike jump improved 5.39 cm; the standing depth jump improved 17.95 cm; and the triple standing jump improved 72 cm.
Vassil and Bazanovk [54]	Men and women	14.4 for women and 17.0 yo for men	21	Case reports; 16-week period intervention	Twice a week. Squat jumps, lateral box push-offs, overhead throws, split squats, power drop, depth jumps, lateral hurdle jumps, plyometric push-ups and single-leg lateral hops were implemented. Each session had six exercises repeated twice (two sets), varying the repetitions between 8 and 15.	VJ meaningfully improved in girls from 45.3 to 49.9 cm. Despite no significant changes being found, the jump’s height also increased in men from 62.1 to 67.2 cm.
Idrizovic, Gjinovci [56]	Women	16.6 yo	47	Randomized controlled trial; 12-week period intervention	Three groups: plyometric, skill-based and control. The plyometric and skill-based groups had two sessions per week in addition to their regular training. The plyometric training lasted 10–15 min/session, and the skill-based training lasted 20–30 min. The plyometric training consisted of upper and lower limb exercises. The sets of plyometrics per training varied between 5 and 6, and the repetitions between 1 and 5. Rest between sets varied between 2 and 5 min. The skill-based training consisted of volleyball drills, small-sided games and real-games drills.	The counter-movement jump improved 16.9% in the plyometrics group, 9% in the skill-based group, and 8.5% in the control group. Post hoc analysis revealed better effects of plyometrics in comparison with the other two training groups for counter-movement jump performance.
Myer, Ford [58]	Women	15.9 yo in plyometric group and 15.6 yo in balance group	18	Randomized controlled trial; 7-week period intervention	Two experimental groups: plyometric and balance. Both experimental groups participated in a common resistance training protocol. Eighteen experimental training sessions were completed. Plyometric training included (among other drills) wall jumps, squat jumps tuck jump, line jumps, lunge jumps, forward jumps and box drops. The time dedicated to each exercise varied between 10 and 20 s, and the repetitions between 3 and 10.	Plyometric training significantly increased knee flexion at the initial contact and the maximum angle in comparison to the control group during drop vertical jump tests. However, balance training increased maximum knee flexion during medial drop landing in comparison to plyometric. Both training protocols were effective in reducing lower extremity valgus measures at the hip and at the ankle and both reduced lower extremity valgus measures at the knee during a single-limb dynamic stabilization task.
Veličković, Bojić [60]	Women	14 to 16 yo	30	Case reports; 12-week period intervention	Experimental group had two sessions/week. No information about the training exercises or planification was provided.	Significant improvements in the experimental group were observed in the squat jump (+5.93 cm), counter-movement jump (+4.98 cm), drop jump (4.83 cm), and leg squat jump with preparation (+3.67 cm).
Turgut, Colakoglu [43]	Women	Weighted jump rope group: 15.0 yo; standard jump rope group 14.1 yo; control group: 14.4 yo	25	Randomized controlled trial; 12-week period intervention	Both training groups participated in three sessions/week. The control group did not participate in any training protocol. The weighted jump rope performed rope jumping with weighted ropes (600 g and 695 g). The standard jump rope consisted of a cable rope which weighed between 100 and 160 g. The training protocol for both groups varied between 30 and 60 s per repetition and between 1 and 3 sets.	The power during counter-movement jump tests was significantly improved by the weighted jump rope protocol in comparison to the control group (mean difference of 11.83 Watts). However, no meaningful differences were found between experimental groups.
Radu, Făgăraş [45]	Women	16 to 17 yo	15	Case reports; 10-week period intervention	Two plyometric sessions per week. The following exercises were included in the program: double leg and single-leg jumps; squat jumps; crossover jumps; increase and decrease jumps; broad jumps; box hop jumps; scissors jumps; single leg bounding; and power skipping.	Players meaningfully improved their overall performance at flight time, contact time, height, and power during the 15-s and 30-s jumping tests. No meaningful changes were found in stiffness.
Gjinovci, Idrizovic [48]	Women	21.9 yo	41	Randomized controlled trial; 12-week period intervention	Two experimental groups: plyometric and skill-based. Each group had two sessions per week. Plyometric training included lower-body exercises (leg hops, vertical jumps, tuck jumps, lateral/diagonal jumps, broad jumps, obstacle jumps, box jumps, and drop jumps) and upper body exercises (throwing exercises). The total of sets/week varied between 12 and 24 depending on the body part, and the repetitions between 40 and 58/week. Skill-based training consisted of volleyball drills, small-sided games, and game drills.	Both groups showed meaningful improvements in counter-movement jump performance. The plyometric group had an improvement of 27.6%, and the skill-based group had an improvement of 18%. Plyometric training was largely better than skill-based training considering the effects on counter-movement jump performance.
Hewett, Stroupe [44]	Women	15 yo	20	Case reports; 6-week period intervention	Experimental group had three sessions per week. The program followed three phases: Technique phase (2 first weeks), fundamentals phase (using a proper technique to build strength and power) and performance phase (focusing on achieving maximal jumping).	The plyometric group meaningfully improved vertical jump performance by 9.2%. Decreases in peak landing forces were observed.
Hrženjak, Trajković [47]	Women	Youth and junior plyometric group: 16.18 yo. Control group: 16.3 yo.	N = 60 Plyometric group (n = 31); control group (n = 29)	Randomized controlled trial; 6 -week period intervention	6 weeks; five training sessions per week (90 to 120 min). The number of training sessions was 15. The set model for development of explosive leg power consisted of five exercises, and exercises were done in the first part of the training session, after a 30-min warm-up.	Both the plyometric and the control group showed significant improvements (p < 0.05) in joint kinematics from pre- to post-training on most of the measures for linear velocity, except for the linear velocity in the hips during the eccentric phase (p = 0.669 for the plyometric group, p = 0.595 for the control group), where none of the group showed significant improvement.
Trajkovic, Kristicevic [49]	Women	17 yo	60	Case reports; 6-week period intervention	Twelve sessions were completed during the experimental period. The plyometric training program consisted of the following exercises: hurdle jumps, depth jumps, lateral jumps over box jumps, lunge jumps and vertical jumps. The number of sets per session varied between 2 and 4, and the repetitions between 6 and 12.	Meaningful within-plyometric group improvements were observed in right (+2.36 cm) and left (+2.48 cm) foot block jump, crossover jump (+2.64 cm) and sidestep block jump (+3.36 cm) performance. Changes were also significantly different from the control group.
Çankaya, Arabacı [51]	Women	16 yo	10	Case reports; 4-week period intervention	Six experimental sessions per week. Three sets of 30 jumps were added to the regular training session.	Meaningful increases in jumping height were found between the baseline (33.8 cm) and weeks 3 (36.0 cm) and 4 (36.4 cm).
Ramlan, Pitil [50]	Men and women	21 yo	12	Randomized controlled trial; 4-week period intervention	Two experimental groups: Plyometrics on grass and plyometrics on concrete surface. Both groups trained twice a week with the same number of sets, repetitions and resting time. The programs included the following exercises: drop from a platform, double leg jump over a hurdle, double leg drop jump and double leg drop jump over a hurdle. The number of repetitions varied between 3 and 6 sets of 12 and 7 repetitions, depending on the exercise.	Both groups improved their squat and counter-movement jumps after the training period. The plyometrics group on grass improved from 38.83 to 42.00 cm in the squat jump, and the plyometrics group on concrete from 39.33 to 41.50 cm. Moreover, the plyometrics group on grass improved their counter-movement jumps from 36.83 to 40.17 cm, and the plyometrics group on concrete from 35.33 to 39.00 cm. No significant differences between groups were found.

Yo: years old; VJ: vertical jump; N.R.: not reported.