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©Journal of Sports Science and Medicine (2020) 19, 347-357
http://www.jssm.org
Received: 01 November 2019 / Accepted: 20 February 2020 / Published (online): 01 June 2020
`
The Effects of Assisted and Resisted Plyometric Training Programs on Vertical
Jump Performance in Adults: A Systematic Review and Meta-Analysis
Hubert Makaruk 1, Marcin Starzak 2, Bogusz Suchecki 3, Maciej Czaplicki 3 and Nenad Stojiljković 4
1 Department of Physical Education and Sport and 2 Department of Sports for All, Jozef Pilsudski University of Physical
Education in Warsaw, Faculty of Physical Education and Health, Poland; 3 Jozef Pilsudski University of Physical Educa-
tion in Warsaw, Faculty of Physical Education and Health, Poland; 4 University of Niš, Faculty of Sport and Physical
Education, Serbia
Abstract
Traditional, assisted and resisted plyometrics are considered to be
effective training methods for improving vertical jump perfor-
mance. The purpose of this systematic review and meta-analysis
was to compare effectiveness of traditional, assisted and resisted
plyometric methods on vertical jumping ability in adults. Availa-
ble literature was searched using MEDLINE (via EBSCO),
SPORTDiscus (via EBSCO), Scopus and Web of Science data-
bases. The methodological quality of studies was assessed using
the PEDro scale. Peer-reviewed studies were accepted only if they
met all eligibility criteria: (a) healthy adults mean age > 18 years
(b) training program based on plyometric exercises (c) the study
reported on vertical jump height for the countermovement jump
or drop jump performance. Of the 5092 articles identified, 17
studies were included in the qualitative and quantitative analyses.
Both funnel plot analysis and Egger's test (p = 0.04) indi-
cated publication bias for the comparison of resisted plyometrics
and control condition. No publication bias was found for the other
meta-analyses (p > 0.05). The effects of the traditional and as-
sisted plyometric methods, when compared with the control con-
dition (a non-plyometric condition), on jump height were moder-
ate (SMD = 0.68, 95% CI 0.37 to 0.99, p < 0.0001; SMD = 0.70,
95% CI 0.20 to 1.20, p = 0.006, respectively). The effects of the
resisted plyometric methods, when compared with the control
condition, on a jump height was small (SMD = 0.48, 95% CI 0.17
to 0.79, p = 0.002). There were no significant differences between
the training effects of the assisted and traditional plyometric in-
terventions on jump height (SMD = 0.62, 95% CI -1.66 to 2.91,
p = 0.59), nor between the resisted and traditional plyometric
training programs (SMD = 0.2, 95% CI -0.19 to 0.23, p = 0.86).
Traditional, assisted and resisted plyometric methods are effec-
tive training modalities for augmenting vertical jump perfor-
mance in healthy adults. Resisted and assisted plyometric meth-
ods are equally effective as the traditional plyometric method in
improving vertical jumping ability in healthy adults.
Key words: Plyometric exercise, human physical conditioning,
resistance training, lower limb, stretch-shortening cycle, vertical
jump.
Introduction
Jumping ability has been considered as fundamental for
successful performance in many sports (Sheppard et al.,
2008). Depending on the sport, the importance of jumping
ability can be affected by the direction of the jump. Con-
sidering the tactical nature of jumping activities in team
sports like basketball, football (soccer) and volleyball, a
vertical jump height is often considered to be critical
performance outcome (Sattler et al., 2012). For example, a
greater jump height achieved during a jump in basketball
produces more favourable condition for shots and re-
bounds. In volleyball, the achievement of a greater jump
height provides a clear advantage in the attack and block
actions. Also, several studies have shown a positive asso-
ciation between jumping ability and other motor abilities
(Wisløff et al., 2004; Maulder and Cronin, 2005).
The countermovement jump (CMJ) and drop jump
(DJ) are reliable and valid for the evaluation of jumping
performance (Arteaga et al., 2000; de Villarreal et al.,
2009). At this point it is worth noting that both tasks rep-
resent different muscle action patterns (Flanagan and
Comyns, 2008). The CMJ is classified as slow SSC move-
ments and DJ as fast due to shorter contraction time and a
smaller range of motion when compared to CMJ.
Plyometric exercises are widely believed to contrib-
ute to positive neuromuscular adaptations to high eccentric
forces and corresponding improvements in vertical jump-
ing ability (Markovic 2007; de Villarreal et al., 2009;
Stojanović et al., 2017). This training approach is effective
due to increase fibre force and contraction velocity (Mali-
soux et al. 2006). The main mechanism explaining the ef-
fects of plyometric exercises is related to a specific muscle
performance in the stretch-shortening cycle (SSC). This se-
quence of concentric (shortening) contraction preceded by
the intense eccentric action (stretch) increased force and
velocity compared to concentric action alone (Bobbert et
al. 1996). The effect of the SSC is due to the storage and
utilization of the elastic energy, the stretch reflex and ten-
don reflex (Bosco et al., 1982; Kawakami et al., 2002). A
typical plyometric training includes jumps in place, stand-
ing jumps, multiple hops and jumps, bounds and drop
jumps (Baechle and Earle, 2008). Jumps in place involve
jumping and landing in the same spot. Standing jumps like
vertical jumps, jumps over barriers are performed with
maximal effort. Multiple hops and jumps involve repeated
movements. Bounds are performed in a horizontal direc-
tion. Drop jumps consist of jumping off a box, a two-leg-
ged landing, and jump upward or to another box immedi-
ately after landing.
Assisted and resisted training methods have been
adapted from sprint training (Rumpf et al., 2016) as a novel
solution in the plyometric regime. Assisted plyometrics
usually involve mainly countermovement jumps and drop
jumps with the aid of elastic bands or tubing fixed between
the body harness and point (e.g. the ceiling of a training
Review article
Assisted and resisted plyometrics
348
hall) above the body. This system pulls on an individual
upward (Makaruk et al., 2014; Sheppard et al., 2011).
There are several types of resisted plyometric exercises that
are performed under varied external conditions like water,
sand and additional external loads. The most common
among them are aquatic plyometrics (Robinson et al.,
2004) and plyometric exercises with a weight vest (Khlifa
et al., 2010), elastic bands (pulling downward) (Argus et
al., 2011) and dumbbells (Markovic et al., 2011). The
ground contact time (CT) during a jump is a basic parame-
ter differentiating assisted and resisted methods. Assisted
plyometrics provides shorter CT (Tufano et al., 2018),
while resisted plyometrics results in longer CT
(Dell'Antonio et al., 2016; Makaruk et al., 2010) as com-
pared to the traditional plyometrics.
The conception of assisted and resisted methods in
a plyometric intervention is based on two general training
principles, i.e. specificity and overload (Baechle and Earle,
2008). Specificity aims to produce a high transfer of train-
ing exercises to sports performance by emphasizing similar
movement patterns, muscle action and contraction velocity
to those during sports competition. This idea was used by
Makaruk et al. (2010), who found that drop jump training
showed a positive tendency for changes in force at peak
power during the CMJ test. Therefore, the authors claimed
that plyometric training with a weight vest (resisted plyom-
etrics) could be a specific and effective stimulus for ath-
letes who require power production against large re-
sistance, e.g. in shot put. In turn, the overload principle
states that disturbance of the homeostasis of the body, in-
cluding cells, tissues, and organs, is required for effective
training adaptation. According to Sheppard et al. (2011),
assisted plyometrics could be a novel ‘overloading’ stimu-
lus for the athletes in jumping sports who have a narrow
window of adaptation for jumping performance develop-
ment. This type of plyometric exercises promote an im-
provement in jumping ability by decreasing an effective
mass of a jumper and an increasing peak acceleration dur-
ing jump due to unloaded condition (Sheppard et al. 2011).
Following this observation, they found that a 5-week as-
sisted jumping training allowed young elite male volleyball
players to increase jump height for CMJ, while traditional
jump training did not provide significant enhancement in
jump height. Reducing impact landing forces is the other
reason why assisted or resisted plyometric exercises are
implemented into the training programs (Argus et al., 2011;
Donoghue et al., 2011). Some studies have demonstrated
that the aquatic environment (Robinson et al., 2004) or
sand (Impellizzeri et al., 2008; Miyama and Nosaka, 2004)
induced less muscle damage in comparison to a solid sur-
face. Moreover, research revealed that aquatic- and land-
based plyometric training programs provided similar gains
in athletic performance (Arazi et al., 2012; Robinson et al.,
2004).
Although traditional plyometric training programs
have been shown to improve jumping ability in athletes
who already achieved of jumping ability (de Villarreal et
al., 2009; Stojanović et al., 2017), the use of traditional
plyometric training methods may be insufficient for the
improvement of jump height (Argus et al. 2011). Several
original studies provided evidence that incorporation of the
assisted and resisted plyometric methods using non-stand-
ard devices (e.g. rubber bands) or environment (e.g., water)
during plyometric training programs may pose a more ef-
fective approach to enhance jumping ability as compared
to the traditional plyometrics in athletes (Argus et al. 2011;
Sheppard et al., 2011) and non-athletes (Kibele et al.,
2015). Conversely, other studies found greater jumping ef-
fects for traditional plyometric method relative to resisted
plyometrics in recreationally trained students (McClenton
et al., 2008). To our knowledge, no systematic review has
been conducted to determine and compare the effects of
different plyometric training methods on vertical jumping
ability in adults. Clarifying the influence of plyometric
training interventions on jump performance in adults ap-
pears to be important for three reasons: (i) to determine the
effects of traditional, assisted and resisted plyometric train-
ing methods as compared to control group (no plyometric
training), (ii) to identify if assisted and resisted plyometric
methods are more effective than traditional plyometrics
and (iii) to provide sport coaches with a critical evaluation
of the current plyometric methods concerning sport level.
The objective of this systematic review and meta-analysis
was to compare the effects of traditional, assisted and re-
sisted plyometric methods on vertical jumping ability in
healthy adults.
Methods
Search strategy
This systematic review with meta-analysis was conducted
according to the criteria of the Preferred Reporting Items
for Systematic Reviews and Meta-Analysis Statement
(PRISMA). A literature search was performed using the
MEDLINE (via EBSCO), SPORTDiscus (via EBSCO),
Scopus and Web of Science Core Collection databases,
with no restriction of dates until June 1, 2019 (with an up-
date until February 11, 2020), for peer-reviewed articles
published in the English language. The following groups
of keyword combined with Boolean operators were used as
search terms: (“plyometric*” OR “jump* exercise*” OR
“plyometric* training” OR “jump* training” OR “ballis-
tic* training” OR “ballistic* exercise*” OR “power train-
ing” OR “explosive training”) AND (“power” OR “reac-
tive strength index” OR “rate of force development” OR
“jump* height” OR “countermovement jump” OR “drop
jump” OR “depth jump” OR “vertical jump*” OR “center
of body mass” OR “flight time” OR “contact time” OR
“vertical velocity”). The electronic data search and screen-
ing based on titles and abstracts were conducted inde-
pendently by three authors (MS, MC, and BS). The dupli-
cate articles were rejected. The scanned articles were dis-
cussed during the meeting of all the authors and selected
for further eligibility assessment.
Inclusion criteria
The inclusion criteria were: (a) healthy adults mean age >
18 years (b) training program based on plyometric exer-
cises, i.e. modalities which utilize the stretch-shortening
cycle (e.g., CMJs, DJs, hurdle jumps) (c) the study required
Makaruk et al.
349
to report vertical jump height for the CMJ or DJ perfor-
mance.
Exclusion criteria
The exclusion criteria were as follows: (a) studies with no
randomized design (b) plyometric training program with
duration < 4 weeks (c) the study program design based on
upper body plyometric exercises (d) studies providing no
comparison between traditional plyometrics vs. assisted
plyometrics, nor traditional plyometrics vs. resisted plyom-
etrics (e) studies using within-subject design.
Data extraction
The data extraction was undertaken independently by two
authors (MC and BS) while the third author (HM) checked
the extracted data and made the final study inclusion. Any
disagreement was resolved with discussion among review-
ers. The following data from the included publications
were provided: population (sports level, age and gender),
characteristics of plyometric training (sample size, dura-
tion, days a week and total jumps) and reported outcomes
(CMJ, DJ and muscle damage). Data from graphs were ex-
tracted with Meazure® software (version 2.0.1, C Thing
software, USA).
Quality assessment
The quality of each study included in this review was as-
sessed using the PEDro (Physiotherapy Evidence Data-
base) quality scale (Moher et al., 2009). The PEDro scale
consists of 11 criteria assessing methodological quality of
the experimental studies. Each criterion can be rated from
0 to 1 point. For this review, criterion 1 was not included
as it comprises external validity. Therefore, a total of 10
po ints w ere scored. Point s were award ed onl y when a give n
criterion was clearly satisfied (Table 1). Ambiguous issues
regarding rating points were discussed between the review-
ers (HM, MS). Studies with scoring points range 8-10 were
considered of “excellent”, 6-8 of “good”, 4-5 of “fair”, and
<3 of “poor” quality.
Statistical analysis
Meta-analyses were conducted in Review Manager
(RevMan5.3, Copenhagen: The Nordic Cochrane Centre,
The Cochrane Collaboration, 2014). The agreement be-
tween reviewers was tested using the Kappa correlation co-
efficients (Altman, 1991). Coefficients of 0.81–1.00 are
generally interpreted as very good, 0.61–0.80 as good,
0.41–0.60 as moderate, 0.21–0.40 as fair and <0.20 as poor
(Altman, 1991). In meta-analysis with at least ten studies,
a funnel plot and Egger’s regression test for funnel plot
asymmetry were used to assess publication bias (Egger et
al., 1997), which was considered if the p < 0.05. Random
effects meta-analyses were conducted to determine and
compare the effects of traditional, assisted, and resisted
plyometrics on jump height. The standard mean difference
values (SMD) with a 95% confidence interval (CI) were
used to estimate the magnitude of training intervention.
The SMD was calculated using the difference between raw
mean changes (post minus pre values) in the compared
groups that was divided by the post-pooled standard devi-
ation (SDpost-pooled). Hedges' adjusted g was applied to give
a better estimate in cases of smaller sample sizes (Hedges
and Olkin, 2014), using formula 1:
(1)
where N= the sum of sample sizes, SDpost-pooled was calculated using
the formula 2:
(2)
where SD = standard deviation, n = sample size of groups.
Table 1. PEDro quality rating of included studies.*
Study Criterion PEDro score
1 2 3 4 5 6 7 8 9 10 11
Arazi et al., 2012 0 1 0 1 0 0 0 1 1 1 0 5
Arazi et al., 2014 0 1 0 1 0 0 0 1 1 1 1 6
Argus et al., 2011 0 1 0 1 0 0 0 1 1 1 0 5
Impellizzeri et al., 2008 0 1 0 1 0 0 0 1 1 1 1 6
Jurado-Lavanant et al., 2015 0 1 0 1 0 0 0 1 1 1 1 6
Jurado-Lavanant et al., 2017 0 1 0 1 0 0 0 1 1 1 1 6
Khlifa et al., 2010 0 1 0 1 0 0 1 1 1 1 1 7
Kibele et al., 2015 0 1 0 1 0 0 0 0 1 1 1 5
Kobak et al., 2015 1 1 0 1 0 0 0 1 1 1 1 6
Makaruk et al., 2010 0 1 0 1 0 0 0 1 1 1 1 6
Makaruk et al., 2014 0 1 0 1 0 0 0 1 1 1 1 6
Markovic et al., 2011 0 1 0 1 0 0 0 1 1 1 1 6
Markovic et al., 2013 0 1 0 1 0 0 0 1 1 1 1 6
McClenton et al., 2008 0 1 0 1 0 0 0 1 1 1 1 6
Ploeg et al., 2010 0 1 0 1 0 0 0 1 1 1 1 6
Robinson et al., 2004 1 1 0 1 0 0 0 1 1 1 1 6
Stemm and Jacobson, 2007 0 1 0 0 0 0 0 1 1 1 1 5
* PEDro rating criteria (1) eligibility criteria were specified, (2) subjects were randomly allocated to groups, (3) allocation was concealed, (4) the
groups were similar at baseline regarding the most important prognostic indicators, (5) there was blinding of all subjects, (6) there was blinding of all
therapists who administered the therapy, (7) there was blinding of all assessors who measured at least one key outcome, (8) measures of at least one
key outcome were obtained from more than 85 % of the subjects initially allocated to groups, (9) all subjects for whom outcome measures were available
received the treatment or control condition as allocated, (10) the results of between-group statistical comparisons are reported for at least one key
outcome, (11) the study provides both point measures and measures of variability for at least one key outcome
SMDRawmeanchange
1
Raw mean change
2
SD
𝑝
𝑜𝑠𝑡
𝑝
𝑜𝑜𝑙𝑒𝑑
1 3
4N 9
SD
𝑝𝑜𝑠𝑡𝑝𝑜𝑜𝑙𝑒𝑑
n
1
1SD
1
2
n
2
1SD
2
2
n
1
n
2
2
Assisted and resisted plyometrics
350
Figure 1. The flow chart of the study selection process. VJH – vertical jump height.
Subgroup analysis was carried out to evaluate the
effects of training status on vertical jump performance
when plyometric methods were compared. The plyometric
training effects on jump performance were interpreted us-
ing the following thresholds: trivial (<0.20), small (0.21-
0.60), moderate (0.61-1.20) and large (>1.20) (Hopkins et
al., 2009). A chi-squared statistic was used to calculate the
level of heterogeneity. The I2 measure was used to describe
the percentage of variation across studies. The value of
25%, 50% and 75% were classified as low, moderate and
high statistical heterogeneity, respectively (Higgins et al.,
2003).
Results
Study selection
A total of 5092 articles were identified in the initial search.
Following the exclusion of duplicates and the screening
process based on titles and abstracts, 58 studies remained.
After the full-text review of remaining studies, 17 articles
were met final inclusion criteria. Details of study identifi-
cation are presented in Figure 1.
Methodological quality
The quality analysis found that all studies were either of
good or fair methodological quality (grades 5-7). The mean
overall rating was 5.8±0.5. The most common missing cri-
teria were blinding procedures. All included studies scored
negative for blinding of the subjects and therapists. Except
for one study (Khlifa et al. 2010) they did not specify that
the assessors were blinded to group allocation. With one
exception (Kibele et al., 2015), all studies fulfil the criteria
of the obtained outcome data for at least 85% of subjects
initially allocated to groups. Two studies (Arazi et al.,
2012; Argus et al., 2011) did not report both point measures
and measures of variability for vertical jump performance.
In all papers the study groups were similar in the values of
the baseline measurements. The rate of agreement between
the assessments performed by two reviewers was classified
as very high since the Kappa correlation coefficient was
0.92.
Study characteristics
The pooled sample size of 17 studies was 458 subjects (Ta-
ble 2). The number of participants ranged from 6 to 20
Makaruk et al.
351
individuals per group. Two studies involved high-level ath-
letes, 3 studies referred to medium-level athletes, while 12
studies involved physically active or untrained individuals.
The duration of training programs was as follows: 4 weeks
(n = 2 studies), 5 weeks (n = 1 study), 6 weeks (n = 5 stud-
ies), 7 weeks (n = 2 studies), 8 weeks (n = 4 studies), 10
weeks (n = 3 studies). The number of training days per
week ranged from 2 to 3. Four studies involved the
traditional and assisted plyometric methods. Other
programs consisted of the traditional and resisted plyom-
etrics, including aquatic (n = 7), sand (n = 2), weight vest
(n = 3), dumbbells (n= 1), resistance of elastic bands (n =
3), unstable surface (n=1). The types of plyometric exer-
cises mainly included vertical jumps like countermove-
ment jumps, drop or depth jumps, squat jumps, hops, hur-
dle jumps, tuck jumps as well as bounds, broad jumps, sin-
gle-leg jumps, and lunge jumps. The total number of jumps
across training programs varied from 144 to 6500 jumps
Table 2. Systematic review and characteristic of included studies.
Study
Population Plyometric training Outcomes (pre-post change)
Sports level
Age
(mean ± SD
in years)
Gender Sample
size (n)
Duration
(weeks)
Days
a week
(duration
of session)
Type of
exercises
(jumps in
total)
CMJ (%) DJ (%)
Muscle
damage or
muscle
soreness
Arazi et al.,
2012
Semi-
professional
basketball
players
TP: 18.0 ± 1.4
RP#: 18.0 ± 0.6
C:20.4 ± 0.6
M
TP: 6
RP#: 6
C: 6
8 3
(40 min)
AJs, SJs,
SDs (3564)
TP: 29.3% ↑
RP#: 30.4% ↑
C: -1.1%
Arazi et al.,
2014
Healthy men,
experienced
in
plyometrics
TP: 20.5 ± 0.3
RP$: 20.7 ± 0.5 M TP: 7
RP$: 7 6 2
(35 min)
DJs
(1200)
TP: 9.1% ↑
RP$: 8.6% ↑
Argus,
2011
Professional
rugby
players
TP: 24 ± 2
RP‡: 23 ± 2
AP: 25 ± 2
M
TP: 8
RP‡: 9
AP: 11
4 2 CMJs
(144)
TP: 1.1%**∆
RP‡:
3.7%**▲
AP: 6.2%**▲
Impellizzeri
et al., 2008
Amateur
soccer
players
25 ± 4 M TP: 18
RP$: 19 4
3
(15 min
warm-up)
VJs, BJs,
BRJs, DJs
(4500)
TP: 14.6% ↑
RP$: 6.5% ↑
Likert scale (0-
6max)
TP>RP$
Jurado-
Lavanant
et al., 2015
Healthy and
physically
active men
21.2 ± 2.9 M
TP: 20
RP#: 20
C: 25
10 2
(35 min)
VJs
(6500)
30 cm (box)
TP: 7.3% ↑
RP#: 4.8%
C: 2.4%
50 cm (box)
TP: 13.4% ↑
RP#: 3.6%
C: 1.6%
CK
TP>RP#
Jurado-
Lavanant
et al., 2017
Physical
education
students
TP: 20.8 ± 3.1
RP#: 21.8 ± 3.4
C: 20.1 ± 2.2
M
TP: 20
RP#: 20
C: 25
10 2
(35 min)
VJs
(6500)
TP: 13.1% ↑
RP#: 14.6% ↑
C: -0.3%
Khlifa et
al., 2010
Elite
basketball
players
TP: 23.6 ± 0.3
RP^: 23.1 ± 0.3
C: 24.2 ± 0.2
M
TP: 9
RP^: 9
C: 9
10
2-3
(90 min)
VJs, BJs,
BRJs, DJs
(11930)
TP: 7.0% ↑
RP^: 12.2% ↑
C: 1.8%
Kibele et
al., 2015
Physically
active
students
TP: 24.1 ± 4.6
RP†: 24.1 ±
3.4
M TP: 13
RP†: 20 7 2
(40 min)
CMJs, DJs,
HJs (1050)
TP: 5.3%
RP†: 13.6% ↑
Kobak et
al., 2015
Students
22.5 ± 1.41 M: 21
F: 13
TP: 11
RP#: 12
C: 11
8 2
(60 min)
DJs, SJs,
CPs, LJs,
TJs, DJs,
SLJ (4196)
TP: 10.7%
RP#: 13.0% ↑
C: 8.9%
Makaruk et
al., 2010
Students
experienced
in drop
jumps
21.2 ± 1.3 M
TP: 14
RP^: 14
C: 14
6 3 (40-45
min)
DJs
(660)
TP&: 11.6% ↑
RP^&: 6.1% ↑
C: 2.0%
30 cm (box)
TP&: 8.7%↑£
RP^&: 2.0%£
C: 0.8%
AP-assisted plyometrics, RP-resisted plyometrics, TP-traditional plyometrics, C-control group (without intervention), #-aquatic, ⁑- dumbbells, $-sand, ^-weight
vest, , ‡- resistance of the elastic cords, †-unstable surface, BJs-bounds, BRJs-broad jumps, CJs-contrast jumps, CMJs-countermovement jumps, CPs- calf pops,
DJs- drop or depth jumps, HJs-hurdle jumps, HPs-hops, JBs-jumps to box, Js-jumps, LJs-lunge jumps, QQJs- quarter quick jumps, Sds- skipping drills, SJs-
squat jumps, SLJs-single leg jumps, STLJs-standing long jumps, TJs-tuck jumps, VJs-vertical jumps. **-lack of data regarding significance, &-unpublished data,
£-form of resisted plyometrics included in meta-analysis, ↑-indicates significant increase, ▲-small effect size, ∆-trivial effect size
Assisted and resisted plyometrics
352
Table 2. Continue….
Study
Population Plyometric training Outcomes (pre-post change)
Sports level
Age
(mean ± SD
in years)
Gender Sample
size (n)
Duration
(weeks)
Days
a week
(duration
of session)
Type of
exercises
(jumps in
total)
CMJ (%) DJ (%)
Muscle
damage or
muscle
soreness
Makaruk et
al., 2014
Collegiate
basketball
and
volleyball
players,
track and
field athletes
TP: 21.7 ± 2.2
AP: 21.3 ± 1.9
C: 20.9 ± 1.8
M
TP: 11
AP: 11
C: 11
5 3 DJs
(588)
30 cm (box)
TP: 9.0% ↑
AP: 8.4% ↑
C: 0.8%
60 cm (box)
TP: 6.0% ↑
AP: 8.5% ↑
C: -0.5%
Markovic
et al., 2011
Physical
education
students
22 ± 3 M
RP⁑: 12
AP: 10
C: 10
7 3
CMJs
(420)
RP⁑: 3.4% ↑
AP: 8.6% ↑
C: 0.6%
Markovic
et al., 2013
Physical
education
students
23.7 ± 1.7 M
TP: 12
RP^: 11
RP‡: 12
AP: 12
C: 13
8 3
CMJs
(1404)
TP: 11.6%↑
RP^: 7.5% ↑
RP‡: 7.2% ↑£
AP: 8.4% ↑
C: 1.0%
(McClento
n et al.,
2008)
Recreationall
y trained
students
TP: 21.3 ± 2.0
RP‡: 22.2 ±
2.5
C: 21.5 ± 1.7
M: 14
F: 7
TP: 11
RP‡: 10
C: 10
6 2
DJs, SJs,
QQJs, CJs
(274-278)
TP: 10.5% ↑
RP‡: 5.3%
C: 1.3%
(Ploeg et
al., 2010)
Untrained
individuals
M: 21.8 ± 2.3
F: 22.4 ± 3.5
M: 16
F: 23
TP: 8
RP#: 10
C: 10
6 2
HPs, VJs,
STLJs,
HJs, SLJs,
BJs, TJs,
JBs
(1460)
TP: -2.6%
RP#: 0.7%
C: 5.9%
(Robinson
et al., 2004)
Physically
active
women
TP: 20.6 ± 0.6
RP#: 19.8 ± 0.3 F TP: 15
RP#: 16 8 3
(65 min)
BJs, HPs,
Js
(3–5 sets o
f
10–20 reps
of 10 drills
per
training)
TP: 32.5% ↑
RP#: 33.5% ↑
Muscle
soreness
TP>RP#
(Stemm
and
Jacobson,
2007)
Physically
active men 24 ± 2.5 M
TP: 8
RP#: 7
C: 9
6 2
SJs, HJ,
TJs
(1620)
TP: 7.8% ↑
RP#: 6.5% ↑
C: 1.5%
AP-assisted plyometrics, RP-resisted plyometrics, TP-traditional plyometrics, C-control group (without intervention), #-aquatic, ⁑- dumbbells, $-sand, ^-weight
vest, , ‡- resistance of the elastic cords, †-unstable surface, BJs-bounds, BRJs-broad jumps, CJs-contrast jumps, CMJs-countermovement jumps, CPs- calf pops,
DJs- drop or depth jumps, HJs-hurdle jumps, HPs-hops, JBs-jumps to box, Js-jumps, LJs-lunge jumps, QQJs- quarter quick jumps, Sds- skipping drills, SJs-
squat jumps, SLJs-single leg jumps, STLJs-standing long jumps, TJs-tuck jumps, VJs-vertical jumps. **-lack of data regarding significance, &-unpublished data,
£-form of resisted plyometrics included in meta-analysis, ↑-indicates significant increase, ▲-small effect size, ∆-trivial effect size
Study outcomes
The funnel plot analysis and Egger's regression test indi-
cated publication bias for the comparison of resisted
plyometrics and control condition (p < 0.05). No publica-
tion bias was found for the other meta-analyses (p >
0.05). The effects of the traditional and assisted plyometric
methods, when compared with the non-plyometric control
condition, on jump height were moderate (SMD = 0.68,
95% CI 0.37 to 0.99, p < 0.0001; SMD = 0.70, 95% CI 0.20
to 1.20, p = 0.006, respectively) (Figure 2-3). The effect of
the resisted plyometric methods, when compared with the
control condition, on jump height was small (SMD = 0.48,
95% CI 0.17 to 0.79, p = 0.002) (Figure 4). Heterogeneity
of the effect of the traditional and resisted methods was
moderate (I2 = 31-33%) and low for assisted methods (I2 =
0%).
We did not find any significant difference between
the training effects of the assisted and traditional plyome-
tric interventions on a jump height (SMD = 0.62, 95% CI -
1.66 to 2.91, p = 0.59) (Figure 5). There were also no sig-
nificant difference between resisted and traditional plyom-
etric training programs (SMD = 0.20, 95% CI -0.19 to 0.23,
p = 0.86) (Figure 6). The subgroup analysis for training sta-
tus showed similar non-significant differences (p = 0.89)
between the training effects of the resisted and traditional
methods for athletes and non-athletes (SMD = -0.03, 95%
CI -0.57 to 0.52, p = 0.92; SMD = 0.02, 95% CI -0.23 to
0.29, p = 0.90, respectively). Heterogeneity for the com-
parisons of the resisted versus traditional plyometric meth-
ods and the assisted versus traditional methods was very
low (I2 = 0%). Heterogeneity in the subgroup analysis of
athletes was moderate (I2 = 33%).
Makaruk et al.
353
Figure 2. Forest plot summarizing the effects of traditional plyometrics vs. control on vertical jump height. Data reflects
standardized mean differences. CI - confidence intervals.
Figure 3. Forest plot summarizing the effects of assisted plyometrics vs. control on vertical jump height. Data reflects stand-
ardized mean differences. CI - confidence intervals.
Figure 4. Forest plot summarizing the effects of resisted plyometrics vs. control on vertical jump height. Data reflects stand-
ardized mean differences. CI - confidence intervals.
Figure 5. Forest plot summarizing the effects of traditional vs. assisted plyometrics on vertical jump height. Data reflects
standardized mean differences. CI - confidence intervals.
Assisted and resisted plyometrics
354
Figure 6. Forest plot summarizing the effects of traditional vs. resisted plyometrics on vertical jump height, including train-
ing status (subgroup analysis). Data reflects standardized mean differences. CI - confidence intervals.
Discussion
The empirical evidence presented in this systematic review
and meta-analysis confirmed the effectiveness of tradi-
tional, assisted and resisted plyometric training methods on
vertical jumping ability when compared with the no plyom-
etric control condition. The results of the systematic review
and meta-analysis showed that assisted and resisted plyom-
etric methods are equally effective as traditional plyome-
tric method in improving vertical jumping ability in adults.
The subgroup analysis pointed to similar and statistically
non-significant training effects for athletes and non-ath-
letes comparing resisted and traditional plyometrics. Over-
all, this review suggests there is a need for further explora-
tion of factors influencing the effects of plyometric training
methods in increasing jumping performance.
The findings of this systematic review extended
those of previous reviews (Markovic 2007, de Villarreal et
al., 2009; Stojanović et al., 2017) regarding the effects of
plyometric training methods on jumping ability and pro-
vided preliminary evidence that the assisted and resisted
plyometrics are an effective method for vertical jumping
ability improvement in healthy young adults. The plyome-
tric training effects were moderate for the traditional and
assisted (SMD = 0.68 and SMD = 0.70, respectively)
plyometrics and small for the resisted plyometrics (SMD =
0.48) when compared with no plyometric training condi-
tion. It is in congruent with the findings of Markovic
(2007) and of de Villarreal et al. (2009) who also revealed
moderate effects of plyometric intervention. Interestingly,
the meta-analysis by Stojanovic et al. (2017) including
only female athletes demonstrated moderate, large and
very large effects (range SMD = 1.09-3.59) for jump height
depending on the type of vertical jump measured. We
found very low heterogeneity of the effects for the assisted
plyometrics, and a moderate heterogeneity for traditional
and resisted methods when compared with control condi-
tions. This may suggest that sources of variability exist in
plyometric training of the included studies. It also needs to
be highlighted that the heterogeneity of the effects of as-
sisted or resisted vs. traditional plyometrics was very low.
The comparison of training effects of the assisted
vs. traditional and resisted vs. traditional plyometric meth-
ods revealed similar jumping gains. These findings pro-
duce several interesting implications for the theory and
practice in plyometric training. First, traditional plyometric
method guarantees significant jumping enhancement with-
out using additional equipment (e.g., weight vest, elastic
cords) or specific environments (e.g., swimming-pool,
sand). Second, the fact that a comparable increase in jump-
ing ability were induced by methods using different under-
lying mechanisms implies broader spectrum of plyometric
exercises in sports training. Based on the previous studies
(Makaruk et al., 2010, Makaruk et al., 2014), it was ex-
pected that contact time would increase after resisted
plyometric training and decrease after assisted training.
Accordingly, resisted plyometric methods may be used
where ability to generate maximal force for jumping ability
enhancement is important (e.g., beach volleyball), while
assisted plyometric methods may be included in training
when time to produce maximal force for increasing jump
height is limited (e.g., defence actions in team sports). Fur-
ther research is required to test these contentions due to
lack of experimental studies addressing this issue directly.
Third, a plyometric training is associated with high ground
reaction forces during landing (Makaruk and Sacewicz,
2011), potentially resulting in exercise induced muscle
damage (Marginson et al., 2005). Thus, to reduce the im-
pact of landing force, non-specific conditions for plyom-
etrics are applied. For example, an aquatic environment
produces buoyancy that reduces weight-bearing stress on
muscles and joints. Three studies investigating muscle
Makaruk et al.
355
damage or muscle soreness, researchers (Impellizzeri et al.,
2008; Jurado-Lavanant et al., 2018; Robinson et al., 2004)
found that resisted plyometric methods (two aquatic and
one sand plyometrics) had a greater preventive effect than
a traditional one. It needs to be highlighted that both meth-
ods provided similar jumping performance enhancement.
Considering previous research demonstrating that
sport level influenced the effects of plyometric training (de
Villarreal et al., 2009), this issue was analysed in the pre-
sent review. A subgroup analysis of training status showed
that athletes and non-athletes had similar responses for re-
sisted plyometrics relative to traditional plyometrics. How-
ever, heterogeneity in the athletes group was moderate,
while in non-athletes was very low. Moderate level of het-
erogeneity in athletes may be caused by plying different
sports (basketball, rugby, soccer), baseline jump perfor-
mance and sports experience. Since only two studies
(Khlifa et al. 2010, Argus et al., 2011) investigated training
effects on the elite athletes and two on semi-professional
(Arazi et al., 2012) or amateur athletes performance (Im-
pellizzeri et al., 2008). A moderator analysis for high- and
low-level athletes was not performed. Also note that only
one study investigated the long-term effects of the assisted
and traditional plyometrics on jump height in professional
athletes, and one in collegiate athletes.
The results of this review should be interpreted with
some limitations. First, a small number of studies limited
the ability to draw definite conclusions. Second, some in-
cluded studies involved relatively small groups in the ex-
periments. Third, meta-analyses conducted in this review
used non-plyometric training groups (control) not differing
physically active subjects (e.g. controls participating in
their regular training program) from non-active subjects
(e.g. controls completing only pre- and post-testing).
Fourth, the analysed plyometric methods involved differ-
ent types of equipment and environment. Fifth, 14 of 17
studies lasted less than 10 weeks, while the study
(Stojanović et al., 2017) reported that the advantages of
plyometric training in jumping performance are greater for
interventions of 10 weeks or more. In addition, different
plyometric jumps, total number of jumps and the intensity
of exercises differ across studies.
Conclusion
This review demonstrates that the traditional, assisted and
resisted plyometric methods can be recommended as effec-
tive training modalities for augmenting vertical jump per-
formance. To sum up, the assisted and resisted plyometrics
are as effective as traditional plyometrics. Therefore, there
is no robust evidence to suggest that the traditional plyom-
etric method should be substituted by the assisted and re-
sisted methods in the jump training of adults. Further re-
search with greater sample sizes of athletes is required to
examine the effects of assisted and resisted plyometric
methods on jumping performance in sports training.
Acknowledgements
The experiments comply with the current laws of the country in which
they were performed. The authors have no conflict of interest to declare.
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Key points
Traditional, assisted and resisted plyometric methods
can be recommended as effective training modalities
for augmenting vertical jump performance in healthy
adults.
Resisted and assisted plyometric methods are equally
effective as traditional plyometric method in improv-
ing vertical jumping ability in healthy adults.
It is suggested that long-term effects of assisted and
resisted plyometrics on high-level athletes should be
investigated.
AUTHOR BIOGRAPHY
Hubert MAKARUK
Employment
Ass. Prof. at Jozef Pilsudski University
of Physical Education in Warsaw, Fac-
ulty of Physical Education and Health,
Poland
Degree
PhD
Research interest
Plyometrics, strength and conditioning,
athletic performance, motor learning
E-mail: hubert.makaruk@awf-bp.edu.pl
Marcin STARZAK
Employment
Ass. at Jozef Pilsudski University of
Physical Education in Warsaw, Faculty
of Physical Education and Health, Po-
land
Degree
MSc
Research interest
Sports science, strength and condition-
ing, athletic performance
E-mail: marcin.starzak@awf-bp.edu.pl
Bogusz SUCHECKI
Employment
Masters student at Jozef Pilsudski Univ.
of Physical Education in Warsaw, Fac-
ulty of Physical Education and Health,
Poland
Degree
Bachelor of Physical Education
Research interest
Coaching science, soccer training, injury
prevention
Maciej CZAPLICKI
Employment
Personal Trainer student at Jozef
Pilsudski University of Physical Educa-
tion in Warsaw, Faculty of Physical Ed-
ucation and Health, Poland
Degree
MSc
Research interest
Sports training, basketball training, ex-
ercise physiology
Makaruk et al.
357
Nenad STOJILJKOVIĆ
Employment
Ass. Prof. at University of Niš, Faculty
of Sport and Physical Education, Serbia
Degree
PhD
Research interest
Physical education, methodology of sci-
entific research, plyometrics
E-mail: snesadif@yahoo.com
Hubert Makaruk
Department of Physical Education and Sport, Jozef Pilsudski
University of Physical Education in Warsaw, Faculty of Physical
Education and Health, Poland
