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J. Mens. Health 2022; 18(5): 116
https://doi.org/10.31083/j.jomh1805116
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
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Original Research
Correlation analysis of vertical jump variables in male track and field
athletes
Xiaoyang Kong1, Yongzhao Fan1, Hao Wu1,*
1School of Kinesiology and Health, Capital University of Physical Education and Sports, 100191 Beijing, China
*Correspondence: wuhao@cupes.edu.cn (Hao Wu)
Submitted: 10 September 2021 Accepted: 29 November 2021 Published: 18 May 2022
Abstract
Background: The purpose of this study is threefold: (1) compare differences in countermovement jump (CMJ) variables and squat
jump (SJ) variables in male track and field athletes; (2) explore the correlation of Fast Twitch Fibers (FT), Effect of Pre-stretch (EP)
and other variables during the CMJ in male track and field athletes; (3) explore the correlation of SJ variables in male track and field
athletes. Methods: 96 male university athletes (21.25 ±1.04 years; 71.96 ±8.58 kg; 180.05 ±5.66 cm) in track and field volunteered
to participate in this study. They are from Capital University of Physical Education and Sports, and all athletes are above the national
standard at the second level. Subjects sequentially completed 3 CMJs and 3 SJs on the force plate. Throughout the entire range of motion,
the CMJ and SJ were performed with both hands on the hips. In a laboratory, all of the individuals were assessed at the same time. SPSS
25.0 (Chicago, IL, USA) was used to run independent samples t-test and Pearson correlation analysis. Results: The vertical jump
displacement (VJD) (p<0.01), squat displacement (SD) (p<0.01), peak velocity (PV) (p<0.01), peak power (PP) (p<0.05), average
power (AP) (p<0.01) were significantly higher during the CMJ than during the SJ. The peak force (PF) (p<0.01) was significantly
smaller during the CMJ than during the SJ. The FT and EP during the CMJ were associated with low test-retest reliability (coefficient of
variation (CV): 9.73–8.86%). VJD, SD, PF, PP, and AP produced high test-retest reliability (CV: 2.29–4.48%) during both the CMJ and
SJ movements. The correlation results were as follows, the VJD during the CMJ was significantly related to SD, PF, PP, AP (r = 0.21, r
= 0.42, r = 0.8, r = 0.69, respectively). The PF during the CMJ was significantly related to PP and AP (r = 0.87, r = 0.72, respectively).
The PV during the CMJ was significantly related to PP and AP (r = 0.63, r = 0.79, respectively). During the CMJ, there were significant
connections between PP and AP (r = 0.94). Except for SD showed no significant relationships and the results for the correlation of other
variables were the same as CMJ during the SJ. Furthermore, the Fast Twitch Fibers (FT) during the CMJ was significantly related to PP
and AP (r = 0.49, r = 0.46, respectively). The Effect of Pre-stretch (EP) during the CMJ was significantly related to PV, PP, AP and FT
(r = 0.36, r = 0.24, r = 0.27, r = 0.22, respectively). Conclusions: Our results indicate that both FT and EP were highly significantly
correlated with PP in CMJ, and both FT and EP were significantly correlated with AP in CMJ. In addition, FT and EP data have good
reliability. It means that FT and EP may be important indicators of lower limb strength in male track and field athletes under certain
conditions. This will inform the training of male track and field athletes.
Keywords: Countermovement jump; Squat jump; Male; Fast Twitch Fibers; Effect of Pre-stretch; Track and field athletes
1. Introduction
Since ancient Greece, track and field have been one of
the most important and fascinating of all Olympic Games
competitions. With science and technology continue to ad-
vance, the level of athleticism increasing. Through continu-
ous summaries and analysis of various athletics disciplines,
it has been found that explosive power has a very impor-
tant impact on the results that can be achieved by athletes
in track and field. For example, in throwing, vertical jump,
and sprinting events, strong explosive power is necessary to
achieve excellent results [1]. The importance of impulsive
ability in the lower limbs cannot be overstated.
Vatical jump is one of the important means to evaluate
the impulsive ability of the lower limbs [2]. Vertical jumps
are frequently used in sporting fields, not only as a neces-
sary movement (e.g., basketball and volleyball), but also as
a functional test [3–6]. Many protocols exist in the literature
to prove or validate the proposed systems. Leaps with and
without countermovement [7–10], jumps with and without
arm swing [11,12], drop jumps [13–15], single and dou-
ble leg jumps [16], continuous jumps [17], squat jumps [7],
and loaded squat jumps [18] are among the various types of
jumps performed in those protocols. The height achieved
by the user can be measured with any of these types of
leaps, but the CMJ and SJ are the most widely utilized in
all related work. The CMJ and SJ are intriguing since they
are quick to complete, non-fatiguing, and need little famil-
iarization. Moreover, they can provide useful information
about an athlete’s neuromuscular and stretch-shortening cy-
cle (SSC) capacities [19–24].
The CMJ performance is determined by a complex
interaction among several factors, including the maximal
force developed by the musculature involved, the rate at
which force can be developed, and the neuromuscular co-
ordination [25]. The CMJ and SJ height have been widely
used by sports performance professionals as an alternative
to direct assessment of maximal force and power [26,27].
Recently. as a simple task where maximum performance is
dearly and objectively defined vertical jump has been ap-
plied to understanding human motor control of a multiar-
ticular movement. One major practical question, however,
remains the same: Which kinesiological factors are critical
for vertical jump performance (VJP)? Coaches and train-
ers have tended to focus on lower limb muscular strength
training as a means to improve VJP, but it seems that other
factors can affect vertical jump performance as well [28].
Further, many researchers have investigated the correlation
of variables in the lower limbs during CMJ and SJ. For in-
stance, the researchers analyzed the long jump test and dy-
namic balance correlations on amateur rugby players [8],
and Radhouane Haj Sassi et al. [29] examined the relation-
ship to the free countermovement jump (FCMJ) and the 10-
m straight sprint (10mSS). The main indicators involved are
jump height, peak force, peak power, rate of force devel-
opment, and reactive strength index [2–4,7,19,20]. How-
ever, the correlation between jump height, EP, and FT has
not been well investigated. Therefore, the purposes of this
study are (1) comparing differences in countermovement
jump (CMJ) variables and squat jump (SJ) variables in male
track and field athletes; (2) exploring the correlation of Fast
Twitch Fibers (FT), Effect of Pre-stretch (EP) and other
variables during the CMJ in male track and field athletes;
(3) exploring the correlation of SJ variables in male track
and field athletes. Thus, it provides a reference for the train-
ing of male track and field athletes.
2. Methods
2.1 Subjects
A total of 96 university male track and field athletes
(21.25 ±1.04 years; 71.96 ±8.58 kg; 180.05 ±5.66 cm)
volunteered to participate in this study. The events of spe-
cialization were short-distance (n = 27), middle-distance (n
= 16), hurdling (n = 13), jumping (n = 26), and throwing
(n = 14). All of these male athletes are above the national
standard at the second level, and they had not had a lower
limb injury in nearly three months.
Participants had been training regularly (three times
per week) for at least four years before the study. Vertical
jumps were a part of every athlete’s regular training routine.
They did not disclose any injuries or other conditions that
prevented them from training or influenced their maximum
physical performance in any way.
2.2 Testing protocol
The measurements were taken at China’s capital uni-
versity of physical education and sports’ Laboratory of
Sports Biomechanics. All participants were instructed to
refrain from rigorous exercise the day before the assess-
ments, as well as any additional resistance training in the 72
hours leading up to the tests. Participants were also asked to
refrain from exercising and drinking caffeinated beverages
for 24 hours before the testing sessions.
Under the supervision of the personnel, subjects en-
tered the Sports Science laboratory wearing comfortable
apparel and athletic shoes and were familiarized with the
vertical jumping movements and testing requirements. Be-
fore the tests, each participant was familiarized with the re-
search goals. After a 10-minute warm-up, the participants
performed three CMJs and three SJs on the force plate in or-
der. In a laboratory with an ambient temperature of 24 ◦C,
all athletes were examined at the same time of the week.
In the SJ test, subjects were asked to rest their hands on
their hips, as this test was designed to measure leg perfor-
mance rather than arm performance. Subjects squatted (pre-
ferred position) and held stationary for 1–2 seconds (Fig. 1),
then tried their hardest to jump up. Three jumps were con-
ducted at one-minute intervals, with the highest leap being
chosen for further investigation. Before take-off, subjects
were not allowed to perform any countermovement.
Fig. 1. Diagram of squat jump.
In the CMJ test, subjects were asked to rest their hands
on their hips, and the exam was designed to measure leg
performance rather than arm performance. Subjects began
in a fully erect standing position and were asked to make
a quick downward movement (preferred position) followed
by a quick upward movement (Fig. 2) before attempting to
jump up. Three jumps were conducted at one-minute inter-
vals, with the highest leap being chosen for further investi-
gation.
Fig. 2. Diagram of countermovement jump.
Vertical jumps were recorded at 500 Hz on a force plat-
form (Quattro Jump, 9286AA, Kistler, Switzerland). Par-
ticipants were required to keep their hands on their hips (to
control arm contribution) and jump with their trunks as erect
as possible in both SJ and CMJ to minimize or reduce en-
ergy gains related to trunk activity.
2
2.3 Data analysis
Excel (2019) and SPSS 25.0 (Chicago, IL, USA) were
used to collect and analyze all SJ and CMJ data. The verti-
cal jump displacement (VJD) was determined using previ-
ously established methods based on the projected flight du-
ration of the center of mass [30]. Squat displacement (SD)
was the lowest position of the athlete’s squat. Peak force
(PF) and peak velocity (PV) were measured directly by the
force plate. The maximal value of power during the propul-
sive phase of the CMJ and SJ was determined as peak power
(PP). Average power (AP) was average concentric power
from the time when v(t) becomes positive until takeoff. Fast
Twitch Fibers (FT) was the percentage of fast-twitch fibers
(estimate), indicating the percentage of fast muscle fibers
responsible for explosive force. A proprietary algorithm
based on hundreds of biopsies. Uses jump height of SJ and
CMJ (flight time method), sex, training type, and age. Ef-
fect of Pre-stretch (%) (EP) = (hf (CMJ)/hf (SJ) ×100%) –
100%.
Table 1. Characteristics of performance during the
countermovement jump (CMJ) and squat jump (SJ) (n = 96).
Variable CMJ SJ p t
Vertical jump displacement (cm) 50.03 ± 6.84** 45.68 ± 8.07 0.000 4.03
Squat displacement (cm) 33.85 ± 6.5** 24.89 ± 7.53 0.000 8.82
Peak force (% bw) 2.24 ± 0.18** 2.34 ± 0.22 0.001 –3.32
Peak velocity (m/s) 2.65 ± 0.27** 2.47 ± 0.24 0.000 4.88
Peak power (W/kg) 50.46 ± 8.06* 48 ± 7.35 0.029 2.2
Average power (W/kg) 29.94 ± 4.37** 24.44 ± 3.53 0.000 9.6
Fast Twitch Fibers (%) 49.15 ± 19.49 - - -
Effect of Pre-stretch (%) 26.86 ± 19.02 - - -
*p<0.05, ** p<0.01. Values are expressed in Mean ±SD.
2.4 Statistical analysis
The data are shown in descriptive statistics for mean
and standard deviation (SD). The Shapiro–Wilk test was
performed to verify the normality of the residual data.
The variables for the CMJ and SJ were analyzed using an
independent samples t-test and Pearson correlation anal-
ysis. Pearson’s product moment correlation coefficients
were used to determine the relationship of CMJ variables.
Within-subject variation and reliability for CMJ variables
and SJ variables was determined by calculating the coeffi-
cient of variation (CV), confidence limits (95%), and intra
class correlation coefficients (ICC) as described by Hopkins
[31]. Significant at p<0.05 and p<0.01 were recorded
separately and considered as significant. The analyses were
performed with the Statistical Package for Social Sciences
(SPSS 25.0, Chicago, IL, USA).
3. Results
The data follows a normal distribution. Table 1dis-
plays the mean (±SD) values for the CMJ and SJ. During
the CMJ, the VJD (p= 0.00), SD (p= 0.00), PV (p= 0.00),
PP (p= 0.029) and AP (p= 0.00) were significantly greater
than during the SJ. The PF (p= 0.001) was significantly
smaller during the CMJ than during the SJ.
Tables 2and 3show the calculated CV and ICC for
each of the force-time variables measured during the CMJ
and SJ, as well as the related 95% confidence limits. VJD,
SD, PF, PV, PP, and AP all had strong test-retest relia-
bility (CV range: 2.29–4.48%) and test-retest correlations
(ICC range: 0.88–0.98) for CMJ and SJ movements. Low
test-retest reliability (CV range: 9.73–8.86%) and high test-
retest correlations (ICC range: 0.96–0.98) were seen in the
FT and EP for the CMJ.
Table 2. During the CMJ, the coefficients of variation (CV),
intraclass correlation coefficients (ICC), and related 95%
confidence limits for variables (n = 96).
Variables CV (%) ICC (range)
VJD 2.93 0.97 (0.92–0.99)
SD 4.25 0.95 (0.89–0.98)
PF 3.52 0.88 (0.79–0.96)
PV 4.03 0.94 (0.86–0.98)
PP 2.29 0.90 (0.76–0.96)
AP 3.64 0.89 (0.77–0.98)
FT 9.73 0.96 (0.90–0.99)
EP 8.86 0.98 (0.86–0.99)
VJD, vertical jump displacement; SD, squat dis-
placement; PF, peak force; PV, peak velocity; PP,
peak power; AP, average power; FT, Fast Twitch
Fibers; EP, Effect of Pre-stretch.
Table 3. During the SJ, the coefficients of variation (CV),
intraclass correlation coefficients (ICC), and related 95%
confidence limits for variables (n = 96).
Variables CV (%) ICC (range)
VJD 2.43 0.98 (0.91–0.99)
SD 4.28 0.93 (0.90–0.95)
PF 4.09 0.89 (0.78–0.98)
PV 3.72 0.92 (0.85–0.99)
PP 2.93 0.94 (0.80–0.98)
AP 3.51 0.92 (0.81–0.99)
VJD, vertical jump displacement; SD, displacement
jump; PF, peak force; PV, peak velocity; PP, peak
power; AP, average power.
The interrelationship between variables for the CMJ
and SJ are presented in Tables 4and 5. SD, PF, PP, and AP
were all significantly connected to VJD during the CMJ.
3
Table 4. Results of intercorrelation of variables during CMJ tests (n = 96).
CMJ
VJD SD PF PV PP AP FT EP
CMJ
VJD 1.00
SD 0.21* 1.00
PF 0.42* 0.20 1.00
PV –0.02 0.01 –0.03 1.00
PP 0.8** –0.00 0.87** 0.63** 1.00
AP 0.69** 0.02 0.72** 0.79** 0.94** 1.00
FT –0.00 –0.02 –0.03 0.19 0.49** 0.46** 1.00
EP 0.02 –0.06 0.07 0.36* 0.24* 0.27* 0.22* 1.00
*p<0.05, ** p<0.01. CMJ, countermovement jump; VJD, vertical jump displacement;
SD, squat displacement; PF, peak force; PV, peak velocity; PP, peak power; AP, average
power; FT, Fast Twitch Fibers; EP, Effect of Pre-stretch.
The PF during the CMJ was tied to PP and AP in a signif-
icant way. PP and AP were both significantly connected
to PV during the CMJ. During the CMJ, there were signif-
icant correlations between PP and AP (Table 4). With the
exception of SD showed no significant relationships and the
results for the correlation of other variables are the same
as CMJ during the SJ (Tables 4and 5). Furthermore, PP
and AP were both significantly related to the FT during the
CMJ. PV, PP AP, and FT were all significantly connected
to EP during the CMJ.
Table 5. Results of intercorrelation of variables during SJ
tests (n = 96).
SJ
VJD SD PF PV PP AP
SJ
VJD 1
SD –0.15 1.00
PF 0.47* –0.13 1.00
PV –0.07 –0.05 –0.13 1.00
PP 0.75** 0.01 0.88** 0.31* 1.00
AP 0.71** –0.03 0.76** 0.67** 0.92** 1.00
*p<0.05, ** p<0.01. SJ, squat jump; VJD, vertical jump displace-
ment; SD, displacement jump; PF, peak force; PV, peak velocity; PP,
peak power; AP, average power.
4. Discussion
In the present study, there were significant relation-
ships between VJD and SD (r = 0.21; p= 0.046) during
the CMJ. The lower the squat position, the greater the ver-
tical jump performance under a certain condition. The cur-
rent findings are in line with previous findings. Rodrigo G.
Gheller et al. [32] discovered that jumping from a more
flexed knee posture seemed to be the greatest method for
achieving the best results [33]. This outcome is contrary to
that of Moran and Wallace et al. [34] who found that jumps
performed with 90 degrees of knee flexion had higher CMJ
height than jumps performed with 70 degrees of knee flex-
ion (0 indicates entire extension). Domire and Challis et
al. [35] reported that a deeper squat depth did not result in
larger jump heights, and they suggested that the results were
due to non-optimal coordination during the jumps. In ad-
dition to VJD, there was no significant correlation between
SD and others variables during the CMJ and SJ. The squat
height of the vertical jump was used as the preferred squat
height for the subjects in this study, and SD influenced the
intersegmental coordination of vertical leaps [33]. How-
ever, longer force exertion and thus higher jump perfor-
mance does not imply necessarily better impulsive ability
[36].
This study found a significant correlation of VJD and
PF during the CMJ (r = 0.42, p= 0.031) and SJ (r = 0.47,
p= 0.035). In contrast to earlier findings, this represents
a significant improvement. One hypothesis is that jump
height is mostly determined by coordination rather than just
by increased strength in triple extension [37,38]. Mean-
while, Maximum physical strength (as evaluated by a one-
rep maximum back squat) was found to be strongly linked
with VJD in college-aged athletes by Petersen et al. [39].
Changes in neural drive, which have a substantial influence
on force development throughout the early (0–50 ms) and
mid phase (50–200 ms) of rising muscular force, are most
likely to blame for variation in TPF within an individual
[40]. Moreover, despite having similar movement patterns,
SJ and CMJ have different properties [41]. Therefore, it is
suggested that the relevance of PF to VJD during the CMJ
might be the coordination of the lower limb joints.
According to Rodrigo G. Gheller et al. [32], when the
joints produced lower segmental angular velocity, the knee
and hip were more in phase, implying that the movement
pattern was more stable in this situation. However, in this
study, there were no significant relationships between PV
and VJD during the CMJ and SJ. The possible reasons are
that the subjects selected for the study included field and
track events in athletics, and they need more horizontal dis-
placement in training and competition, so this may be the
reason for the above results.
4
The current study’s findings reveal a clear and signif-
icant link between PP and VJD during the SJ and CMJ.
These findings are in line with others that have been pub-
lished. It was previously observed that peak power in a
40 kg traditional jump squat and CMJ height in a group
of Australian rules football players had a similar positive
link (r = 0.75) [42,43]. Furthermore, 5JT performance was
highly connected with vertical jump height and power fac-
tors, according to Chamari et al. [2]. Peak power (r = 0.8,
p<0.05 to r = 0.83, p<0.01) was likewise determined to
be the characteristic most associated with a vertical perfor-
mance by Ashley et al. [44]. One of the greatest indicators
of CMJ performance is the power reached during the con-
centric phase of the vertical leap. This should not be sur-
prising, power is a physical quantity that reflects how fast
or slow work is done. This outcome is contrary to that of
Morin J B, Jiménez-Reyes P et al. [45] who found verti-
cal jump height is a poor indicator of maximal power out-
put. The researchers suggested that the reasons for this re-
sult were individual push-off distance, optimal loading and
force-velocity profile. The relationship between SJ or CMI
height is clearly confounded by individual anthropometri-
cal and physiological factors inherent to each athlete tested.
Not taking these factors into account may lead to bias when
quantifying Pmax via single jump tests without additional
load. In addition to that, there was a significant relationship
between PP and FT during the CMJ, there is no literature on
this result until now, Possible reasons are that Fast-Twitch
Fibers increase peak power by increasing the velocity of
muscle contraction.
The present study showed that the EP during the CMJ
was significantly related to PV, PP, AP, and FT, respec-
tively. Previous studies have employed pre-stretch aug-
mentation percentage (PSAP) estimates to analyze an ath-
lete’s capacity to use the SSC to improve their vertical jump
height (JH) and peak power (PP) [24,46]. However, there
was no significant relationship between FT and VJD in the
present study, and this is different from the previous studies.
The possible reasons are that effect of pre-stretch is consid-
ered to be a measure of the ability to utilize the pre-stretch
of the muscles during a CMJ. To a certain extent, it does not
directly affect the vertical jump height, but the peak power
and peak velocity of the vertical jump.
In summary, the present data indicate that there is a
significant correlation between FT, EP, and PP during the
CMJ movement in male track and field athletes. The sig-
nificant correlation suggests that FT and EP can reflect the
countermovement jump performance to a certain extent.
Meanwhile, FT and EP data have good reliability, and EP
and PP may be used as a measure of CMJ performance when
testing male track and field athletes in lower limb explosive
exercise techniques. However, there are some limitations
to the article, as this study was conducted on track and field
athletes, while the applicability to other athletes (basketball,
volleyball, soccer, etc.) remains to be verified.
5. Conclusions
Our results indicate that both FT and EP were highly
significantly correlated with PP in CMJ, and both FT and
EP were significantly correlated with AP in CMJ. In addi-
tion, FT and EP data have good reliability. It means that FT
and EP may be important indicators of lower limb strength
in male track and field athletes under certain conditions.
This will inform the training of men’s track and field ath-
letes.
Abbreviations
CMJ, countermovement jump; SJ, squat jump; VJD,
vertical jump displacement; SD, squat displacement; PV,
peak velocity; PP, peak power; AP, average power; FT, Fast
Twitch Fibers; EP, Effect of Pre-stretch; CV, coefficient of
variation; ICC, intraclass correlation coefficients.
Author contributions
XK and YF designed the research study and performed
the research. HW provided help and advice on the vertical
jump experiments. XK analyzed the data. All authors con-
tributed to editorial changes in the manuscript. All authors
read and approved the final manuscript.
Ethics approval and consent to participate
All examinations were performed before the com-
mencement of the season, and this study was performed
with the approval of the Institutional Review Board of Cap-
ital University of Physical Education and Sports (Approval
number: 2018A06). In compliance with the Declaration of
Helsinki on human testing, all participants were told about
the procedures and completed an informed consent form.
Acknowledgment
Thank numerous individuals who participated in this
study.
Funding
We gratefully acknowledge the financial support by
State Key R&D Program (No. 2018YFF0300603).
Conflict of interest
The authors declare no conflict of interest.
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