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Background and Study Aim: Judo is categorized among events which develop apart from technical aspects many physical abilities such as explosive strength, speed and co-ordination. One representative task which involves the above mentioned abilities when performed from any athlete is the vertical jump. Purpose of this paper is to answer the question: if there are differences between untrained young males and advanced level Greek judo athletes in jumping ability in four different vertical jumping tasks. Material/Methods: Twenty male [(10 untrained/10 advanced ones), mean age: 19.4±1.6 years/ 17.3±1.2 years respectively] performed squat jumps, countermovement jumps and drop jumps from 20 and 40 cm height (DJ20 and DJ40, respectively). Kinetic data for further analysis were collected by a ground mounted 40×60 cm force plate. Results: Advanced young judokas presented higher scores in all examined jumping tasks compared to untrained ones, revealed shorter duration of examined contact times of all tasks and as a result better utilisation of stretch-shortening cycle mechanism. Total neuromuscular activation that adopt judokas reveals a more mature and skill dependent strategy compared to untrained ones. Conclusions: Vertical jump does not characterizes from a technical point of view a judo athlete but it seems that performance in vertical jumping tasks is affected by the participation and years habituation to ballistic and explosive strength training. Judo specific training in advanced-level judokas improves and induces specific neuromuscular alterations as well as performance in various jumping tasks.
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Differences in vertical jumping performance between
untrained males and advanced Greek judokas
Georgios Zaggelidis1ABE, Savvas N. Lazaridis1BCD, Alexandros Malkogiorgos2BC,
Fotios Mavrovouniotis3E
1 Laboratory of Coaching and Sport Performance, Department of Physical Education and Sport Sciences, Aristotle University
of Thessaloniki, Thessaloniki, Greece
Laboratory of Physical Exercise and Leisure, Department of Physical Education and Sport Sciences, Aristotle University
of Thessaloniki, Thessaloniki, Greece
3 Laboratory of Exercise and Physical Health, Department of Physical Education and Sport Sciences, Aristotle University
of Thessaloniki, Thessaloniki, Greece
Source of support: Department of Physical Education & Sport Sciences of Aristotle University of Thessaloniki, Thessaloniki, Greece
Received: 29 October 2011; Accepted: 8 May 2012; Published online: 21 May 2012
Judo is categorized among events which develop apart from technical aspects many physical abilities such as ex-
plosive strength, speed and co-ordination. One representative task which involves the above mentioned abilities
when performed from any athlete is the vertical jump. Purpose of this paper is to answer the question: if there are
differences between untrained young males and advanced level Greek judo athletes in jumping ability in four dif-
ferent vertical jumping tasks.
Twenty male [(10 untrained/10 advanced ones), mean age: 19.4±1.6 years/ 17.3±1.2 years respectively] performed
squat jumps, countermovement jumps and drop jumps from 20 and 40 cm height (DJ20 and DJ40, respectively).
Kinetic data for further analysis were collected by a ground mounted 40×60 cm force plate.
Advanced young judokas presented higher scores in all examined jumping tasks compared to untrained ones, re-
vealed shorter duration of examined contact times of all tasks and as a result better utilisation of stretch-shorten-
ing cycle mechanism. Total neuromuscular activation that adopt judokas reveals a more mature and skill depen-
dent strategy compared to untrained ones.
Vertical jump does not characterizes from a technical point of view a judo athlete but it seems that performance
in vertical jumping tasks is affected by the participation and years habituation to ballistic and explosive strength
training. Judo specific training in advanced-level judokas improves and induces specific neuromuscular alterations
as well as performance in various jumping tasks.
Key words:
judo • jump • stretch-shortening cycle • martial arts • combat sports
Author’s address:
Lazaridis Savvas, Giannakopoulou16, 5612; Department of Physical Education and Sport Sciences, Aristotle
University of Thessaloniki, Thessaloniki, Greece; e-mail:
Maximizing jumping performance during a task involves
a complex movement sequence, which requires an opti-
mal interlimb coordination of lower limbs. This actually
indicates an efficient energy transfer across the involved
joints during the jumping [1–5]. Throw techniques are
a dominant factor in the complex fighting movements
of judo. The effective development of throw techniques
is an important technical factor and marks a significant
part of judo training and performance. Competitive judo
is described as a multi-joint and of high intensity task in
which the specific throwing techniques during a match
require good physical fitness [6–8]. Explosiveness and
and Study Aim:
Authors’ Contribution:
A Study Design
B Data Collection
C Statistical Analysis
D Manuscript Preparation
E Funds Collection
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power-endurance capacities have a central importance
among the fitness capacities governing judo training and
competition [9,10]. Power-endurance capacities are dis-
tinguished by their intensity and near maximal exertion
over a certain period (e.g., movement sequences of 10
to 20 seconds), and by the ability to repeat this maxi-
mal performance several times during a bout [11]. In
addition to this, judo is a martial art classified among
those specialties requiring high technical skills along
with execution of main technical actions as fast as pos-
sible [8,12]. So, it would be interesting to study second-
ary ballistic and explosive movements such as vertical
jumping tasks from a neuromuscular point of view and
to give information about the potential different neu-
romuscular activity patterns adopted as a result of dif-
ferent training level and status.
Material and Methods
Twenty male (10 untrained, 10 advanced level Greek
Judokas) participated in this study. Young untrained
were 17–21 years old (age 19.4±1.6 years, body mass
72.9±9.6 kg, body height 1.77±0.04 m) and judokas
were 16–18 years old (age 17.3±1.2 years, body mass
81.5±1.4 kg, body height 1.76±0.05 m). Judo ath-
letes participated in this study had at least 3 years of
national competition experience and in addition to this
had international one (participation to Greek National
Team). Before testing, all participants read and signed
a written informed consent statement. This study met
the standards of the local ethics committee on human
research in accordance with the Declaration of Helsinki.
Initially, the investigator who assessed all evaluations
collected the anthropometric data that are required for
ground reaction force normalization. After collecting the
anthropometric data the participants were warmed-up
for 15 minutes (walking/running on treadmill, hopping/
jumping, and performed various warm-up exercises for
the trunk and lower limbs. We avoided doing more famil-
iarization because that would alter the original jumping
strategy, as reported recently [13]. Then participants per-
formed four types of bilateral maximal vertical jumping
tasks (squat jump, countermovement jump, drop jump
from 20 and 40 cm., SJ, CMJ, DJ20 and DJ40 respec-
tively). Three maximal efforts at each jumping condi-
tion with random order and 2-min rest interval in be-
tween were performed (Figures 1, 2). Participants were
instructed to jump upwards as high as possible, keeping
their hands placed on the hips. For the SJ test, subjects
were positioned on the force plate with the knee angle
set at 90°. The starting knee angle was recorded using a
standard goniometer. For the CMJ, subjects stood erect,
and counter-moved until the knee was flexed approxi-
mately to 90°, before jumping. Finally, the DJ test in-
cluded DJs from 20 and 40 cm height. Subjects landed
on both feet on the force plate, which was approximate-
ly 8 cm in front of the jumping platform edge. During
the test no verbal motivation or any kind of feedback
about their performance was provided. Trials were fur-
ther processed as judged from kinematic data and with
the typical shape of force – time curve [14]. For kinet-
ics, only the vertical ground reaction forces Fz were cal-
culated. Ground reaction forces (for the estimation of
jumping height and contact periods) were recorded with
Figure 1. A representative judo athlete during the
execution of SJ task.
Figure 2. A representative judo athlete during the
execution of SJ task.
Judo – an educational
system established by
Kano which in fact means
the “gentle way”, but for
the purposes of article is
referring to the competitive
martial art event called Judo.
Jump – A multi-joint
movement of lower
extremities mainly task,
which raises the centre
of gravity and in fact the
whole body from the level
of surface, vertically or
Stretch-shortening cycle
– A mechanism involving
an eccentric contraction of
muscles before the concentric
Martial arts – Systems
including physical practises
and elements from ancient
combats created for self-
defending purposes and in
nowadays for competitive
Combat sports
Competitive sports between
two participants who
fight one each other with
restricted rules or even
without ones and with the
aim of winning a match or
Original Article
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a ground mounted 40×60 cm force plate (Bertec Type
4060, Bertec Corporation, Columbus, OH, USA). The
sampling frequency for ground reaction force signals
was set at 100 Hz.
Data were further processed online using scripts of Matlab
6.1 (The MathWorks Inc.). Jump height and contact
times were estimated taking into account the impulse
which was recorded from the vertical ground reaction
force (vGRF) – time curve. Only the best trial was fur-
ther analysed. Lastly, the stretch shortening cycle perfor-
mance gain as a percentage was calculated using the below
equation: SSC performance (%) = [(CMJ-SJ)/ SJ] ×100.
Statistics were performed with the SPSS/PC 19.0 (SPSS
Inc.) statistical package. Mean, standard deviation of the
mean was assessed for all dependent variables. Two way
ANOVA with repeated measures (2×4) has been used to
identify significant differences between the groups and
the four examined jumping tasks. The significance level
was set to 0.05 with Bonferroni correction and significant
difference between boys and men (p<0.05, p<0.01, and
p<0.001) were depicted as *, ** and *** respectively.
Regarding jumping tasks, advanced judokas presented
higher jumping performance in all examined tasks (SJ,
CMJ DJ20 and DJ40) compared to untrained young
males (p<0.05, Figure 3). Their better performance
scored during CMJ task, and this occurred due to the
better utilisation of the stretch shortening cycle (11.4
vs. 7.2%, p<0.05) and its’ gain as shorter total contact
times revealed as well (Figures 4, 5).
During the selected jumping tasks, young judokas pre-
sented higher jumping performance, better recoil utili-
zation of the SSC, and shorter contact times at each ex-
amined phase. It seems that experienced athletes develop
a technique for more optimal storage and reuse of elas-
tic energy and therefore muscle output is higher during
the propulsive phase [1,2,15]. Vertical jumping perfor-
mance is not largely described in the literature concern-
ing judo athletes. However, from the obtained results it
seems that this performance is a discriminatory com-
ponent between the two groups with large differences
[16,17]. Young judokas showed superior ballistic per-
formance, indicated by their better jumping score and
higher percent of SSC utilization. This finding comes
in accordance with previous that refer to martial arts
sports and probably comes from neural and muscular
adaptations due to their training [9,18,19]. In a similar
study [20], relevant kinetic factors such as application
of vertical ground reactions forces (VGRF) revealed that,
in hip throwing techniques these forces may be the ma-
jor factor which distinguishes an expert from a novice
judoka player and concluded that experts, in a specific
throwing technique, generated higher values of vertical
impulse compared to novice ones. As well as that, in a
recent study and in other combat sport (taekwon-do), it
*** ** **
Jumping performance (cm) of untraine and judo
athletes during SJ, CMJ, DJ20 and DJ40 tasks
DJ20 DJ40
Figure 3. Jumping performance (cm) in all selected jumping
tasks in untrained males and advanced level
judokas (n=10/10).
Stretch shortening cycle utilization (%)
Figure 5. Stretch-shortening cycle utilization (%) in
untrained males and advanced level judokas
** ** **
Contact times (ms) of untrained and judo athletes
during SJ, CMJ, DJ20 and DJ40 tasks
DJ20 DJ40
Figure 4. Contact times (total, in ms) in all selected jumping
tasks in untrained males and advanced level
judokas (n=10/10).
Zaggelidis G et al – Differences in vertical jumping per formance…
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was suggested that in a specific natural technique of this
combat sport which included the vertical jump task, bet-
ter biomechanical parameters were developed compared
to a traditional one technique [21]. In the same man-
ner, natural and simple vertical jump tasks used in our
study can be applied to young judokas from their com-
petent coaches in order to maximize and optimize their
training process through these biomechanical benefits.
In conclusion, superiority of athletes in jumping perfor-
mance in all selected jumping tasks could be partially
attributed to the immature technique of untrained par-
ticipants which also is verified with differences in acti-
vation of their neuromuscular system. Participation and
years of habituation to ballistic and explosive strength
training and particularly in judo specific training in ad-
vanced-level judokas, may be the major factor which in-
duced specific neuromuscular alterations as previous
studies in martial arts sports suggested. Technique of
this combat sport is prevail during a match, but definite-
ly these neuromuscular adaptations cannot be omitted.
Variables such as better utilization of recoil energy and
better jumping performance are not directly connected
to the better performance and do not predict this during
a judo event. However, the gain in CMJ task which was
shown more in athletes was occurred due to the better
storage and reuse of elastic energy in their muscle-tendon
unit [4]. This in turn can be advantageous in force pro-
duction [22]. In practice, this can provide a judo player
indirectly with an advantage in maximizing its perfor-
mance and lead him to high level categories by exploiting
the biomechanical efficiency that vertical jumps develop
and embody this efficiency in his throwing techniques.
To our knowledge, this is the first study which record-
ed and analysed different types of vertical jumps from a
kinetic point of view in advanced level judokas and not
only, in order to clarify potential neuromuscular adap-
tations arose from training in these jumping tasks and
to better give an optimal training control.
The authors would like to thank Professor Kotzamanidis
C., PhD, Department of Physical Education and Sports
Science for his assistance in providing us the laborato-
ry of coaching and sport performance on a daily basis
for the execution of the measurements.
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Original Article
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... Judo is a high-intensity intermittent activity, in which some actions performed by lower limbs involve the stretch-shortening cycle (SSC), such as several throwing techniques (Detanico et al., 2012;Torres-Luque et al., 2015;Zaggelidis et al., 2012). Optimisation of the SSC seems to improve through judo-specific training, as better utilisation of the SSC was observed in advanced judo athletes compared to untrained males (Zaggelidis et al., 2012), as well as better performance in countermovement jump (CMJ) (representation of SSC) observed in advanced judo athletes compared to novices (Detanico et al., 2016). ...
... Judo is a high-intensity intermittent activity, in which some actions performed by lower limbs involve the stretch-shortening cycle (SSC), such as several throwing techniques (Detanico et al., 2012;Torres-Luque et al., 2015;Zaggelidis et al., 2012). Optimisation of the SSC seems to improve through judo-specific training, as better utilisation of the SSC was observed in advanced judo athletes compared to untrained males (Zaggelidis et al., 2012), as well as better performance in countermovement jump (CMJ) (representation of SSC) observed in advanced judo athletes compared to novices (Detanico et al., 2016). Moreover, CMJ performance was positively correlated with the number of throws in a judo-specific test (Special Judo Fitness Test-SJFT) (Detanico et al., 2012) and with effective combat time in female team athletes during an official judo competition (Kons et al., 2018). ...
... Previous studies used the same SSC protocol in healthy men (age 25.3 years) and found a decrease of 15% in power output (Lazaridis et al., 2018), higher than in our participants. These findings suggest higher tolerance to fatigue or a lesser performance decrement in CMJ power output within Judo athletes, possibly due to the neuromuscular adaptations from specific training involving SSC (Zaggelidis et al., 2012). It has been documented that prolonged and intense eccentric exercise, mainly involving SSC, induces immediate and prolonged reductions in several muscle functions, such as stretch-reflex sensitivity, joint stiffness regulation, and jump performance (Horita et al., 1999;Nicol et al., 2006). ...
This study aimed to analyse unilateral countermovement jumps (CMJ) performance and muscle soreness in lower limbs, as well as to compare lower limb asymmetry over 48 h after a stretch-shortening cycle (SSC) fatigue protocol. Fourteen judo athletes performed unilateral CMJ on each leg before, and after the 5th and 10th sets over 24 h and 48 h of an SSC-fatigue protocol. The SSC protocol reduced CMJ performance after the 5th set and 10th sets, especially in the weaker limb (p < 0.05), but returned to the baseline values after 24 h. Asymmetry increased for peak force, peak power, and mean power after the 5th set compared to the baseline (p < 0.05) and remained higher for peak force after the 10th set (p = 0.019), returning to the baseline values after 24 h (p < 0.05). Soreness increased for the lower body at post, 24 h, and 48 h compared to the 25 baseline (p < 0.05). In conclusion, a fatiguing SSC protocol can result in increased bilateral asymmetries in judo athletes, but after 24 h and 48 h of the protocol the bilateral asymmetry returned to the baseline values, with only muscle soreness still elevated
... Thus, higher levels of muscle power in the lower limbs of the post-menarche girls may help to explain their higher performance in SJFT. In addition, the greater time of formal training in post-menarche girls most likely contributed to increased muscle power, as Zaggelidis et al. [32] verified that judo training enhances vertical jump performance, mainly due to improvements in the stretch-shortening cycle (SSC). ...
... Another interesting finding was that the number of years of formal training was positively associated with SLJ performance, showing improvements in muscle power of the lower limbs in post-menarche girls with judo training experience. A previous investigation found that vertical jump performance discriminated adult judo athletes with different training experience levels (advanced vs. novice) [40], likely due to SSC enhancements [32]. Moreover, muscle power of the lower limbs is an important parameter related to technicaltactical performance during judo matches in senior female athletes [41]. ...
Full-text available
Purpose: To compare body size measurements and physical performance among female youth judo athletes with differing menarcheal status and to identify indicators of physical performance in post-menarcheal girls. Methods: Nineteen young female judo athletes (age 13.9 ± 2.3 years) were divided into a pre-menarche (n = 7) and a post-menarche (n = 12) group. The athletes were evaluated through neuromuscular tests, including standing long jump (SLJ), medicine ball throw (MBT), and handgrip strength (HGS), and judo-specific assessments, including the Special Judo Fitness Test (SJFT) and the Judogi Grip Strength Test (JGSTISO). Furthermore, years of experience in judo and the age at menarche were determined. Results: The main results showed higher performance for the post-menarche group for most variables (p < 0.05) compared to the pre-menarche group. A multiple linear regression analysis demonstrated that age at menarche, chronological age, and body mass explained close to 70% of JGSTISO, while training experience, chronological age, and age at menarche explained close to 59% of SLJ. Additionally, chronological age and age at menarche explained 40% of MBT, and chronological age and height explained 52% of HGS. Conclusions: Age at menarche and somatic growth variables explained moderate proportions of the variance of physical performance, thereby providing evidence that these parameters are the primary indicators of physical performance in young female judo athletes.
... During throwing techniques, muscle power has also been considered extremely relevant [60][61][62]. Iteya et al. [61] reported higher power values in the sleeve pull movement in Japanese elite judo athletes in relation to university and regional level athletes. As the pulling movement is important for the opponent's imbalance and can reach values of 3.0 N/kg in the pull of the sleeve and 1.5 N/kg in the pull of the collar [60], the improvement of muscle power for execution of these actions is paramount for the successful execution of throwing techniques. ...
... Additionally, during the execution of the throwing techniques, athletes need high power in the lower limbs [64]. In fact, Zaggelidis, Lazaridis, Malkogiorgos, and Mavrovouniotis [62] reported higher values of vertical ground reaction force in advanced-level judo athletes during harai-goshi (4.0 ± 0.6 times body weight) compared to beginners (3.3 ± 0.2 times body weight). Additionally, advanced athletes reached the peak force in less time in the two executed techniques (harai-goshi = 117 ± 33 ms; uchi-mata = 127 ± 20 ms) compared to beginners (harai-goshi = 178 ± 29 ms, uchi-mata = 197 ± 27 ms). ...
Full-text available
In combat sports, the specificity of the training requires that the athlete improve all performance indicators associated with the match. For this reason, muscle power seems to be determinant during the application of the techniques that result in scores, specifically punches, kicks, elbows, knees, throwing techniques, transitions to the groundwork and some groundwork techniques and sometimes, the win match by knockout. Based in these information's, the present chapter will approach items referring to the muscle power manifestation and monitoring, and to the training prescription of exercises for the grappling, striking and mixed combat sports.
... In addition, many sports involve movements that require generation of force over a short period of time (McBride, Triplett, Davie & Newton, 1999), for example, in the case of sprint performance along with the speed increase, the groundcontact time typically decreases (Haugen et al. 2015) and there is evidence that higher level athletes of a combat sport present lower contact time compared to lower level athletes when executing different vertical jumping tasks (Zaggelidis, Lazaridis, Malkogiorgos & Mavrovouniotis, 2012). Along with this, certain joint angles of the body are more favorable for the development of muscle power (Garhammer, 1993). ...
... Millett, Moresi, Watsford, Taylor & Greene, (2018) showed that stiffer athletes showed lower contact times in sprint test than the control group (p<.001 -.003). In a combat sport, Zaggelidis et al. (2012) reported that higher level athletes present lower contact time compared to lower level athletes when executing different vertical jumping tasks (p<.05 -p<.01). In fencing, the control of contact time has been made through the calculation of the RSI (through its components flight time and contact time) and correlation with CODS has been reported (r=-.41; ...
Full-text available
Background: Fencing is an Olympic combat sport divided into three different disciplines: the foil, the épée and the sabre. The most used attack movement by fencing athletes is the lunge. Problem and Aim: The main objective of this study was to correlate joint positions of the lower limb with the contact time of the lunge attack followed by the recoil. Methods: Ten male (mean ± SD, age = 22.0 ± 5.7 years; body mass = 70.3 ± 11.1 kg; height = 174.6 ± 9.4 cm) fencing athletes (sabre) from national and international teams participated. Results: We observed a correlation between the contact time of the lunge attack and hip angle (r =-.75, p = <.05). Conclusions: The degree of flexing of the hip joint, evaluated through video, was inversely related to the contact time in the lunge attack and recoil in male sabre athletes. Resumen. Antecedentes: La esgrima es un deporte de combate olímpico dividido en tres diferentes armas: florete, espada y sable. El movimiento de ataque más utilizado por los esgrimistas es el fondo. Problema y objetivo: El principal objetivo de este estudio fue correlacionar las posiciones articulares de las piernas con el tiempo de contacto del fondo seguido por el recobro. Métodos: Diez esgrimistas (sable) masculinos (media ± DS, edad = 22.0 ± 5.7 años; peso corporal = 70.3 ± 11.1 kg; talla = 174.6 ± 9.4 cm) de equipos nacionales e internacionales participaron. Resultados: Observamos una correlación entre el tiempo de contacto del ataque de fondo y el ángulo de la articulación de la cadera (r =-.75, p = <.05). Conclusiones: El grado de flexión de la articulación de la cadera evaluado a través de video, estuvo inversamente correlacionado con el tiempo de contacto en el ataque de fondo y el recobro en sablistas masculinos.
... training preference for bilateral or unilateral movements during sports practice). On the other hand, the SJFT INDEX represents the combination of aerobic and anaerobic capacity (Franchini et al., 2011(Franchini et al., , 2009, and so it is possible that higher BLD values in the CMJ may be related to poor performance in judo throwing techniques, especially those involving powerful actions and aspects related to the stretch-shortening cycle performance (Detanico et al., 2012;Kons et al., 2018), which are identified in several judo techniques (Detanico et al., 2012;Zaggelidis et al., 2012). ...
This study aimed to describe the bilateral deficit (BLD) during the countermovement jump (CMJ) in judo athletes and determine the relationship between the BLD and judo-specific performance. Fourteen male judo athletes participated. The athletes performed tree specific judo tests: Maximal Sprint Speed Judo Test, Maximal Aerobic Speed Judo Test, Special Judo Fitness Test (SJFT), and double-and single-leg CMJ. The follow CMJ variables were used: jump height JH, mean-MPO and peak-PPO power output, peak force-PF, peak velocity-PV and impulse-IMP. The Pearson's or Spearman's test were used (p<0.05). The results show that the BLD is found in all CMJ parameters (27% in JH; 20% in MPO; 22% in PPO, 61% in PF, 41% in PV and 31% in IMP). Negative correlations between first set of SJFTTT (total throws) and BLD in PF (r=-0.60; p=0.022) and between the second set of SJFTTT and BLD in MPO (r=-0.74;p=0.002), PV (r=-0.59;p=0.025) and IMP (r=-0.55; p=0.040) were found. Also, negative correlations between SJFTTT and the BLD in all CMJ parameters (r=-0.53 to-0.85;p<0.05) were found. The BLD in most CMJ variables is negatively correlated (large to very large) to the SJFTTT. So, high BLD values are related to poor SJFTTT performance.
... In adulthood, previous studies have found that advanced judo athletes (i.e. high experience time, mostly black belts) showed higher strength and power in the upper and lower limbs compared to novices at the same age, probably due to specific muscular adaptation and optimization of elastic structures (particularly in lower limbs) over the years of formal judo training (Detanico, Dal Pupo, Graup, & Santos, 2016;Zaggelidis, Lazaridis, Malkogiorgos, & Mavrovouniotis, 2012). Other studies have analyzed different competitive levels (elite vs. non-elite) and identified higher aerobic and anaerobic power, upper and lower body strength and judo-specific performance in elite compared to non-elite athletes (Drid et al., 2015;Franchini, Takito, Kiss, & Sterkowicz, 2005). ...
This study aimed to analyze whether judo experience, somatic maturation, growth, and physical capacities discriminate young judo athletes from different competitive levels (state and national). Sixty-six young male judo athletes (36 from state and 30 from national level) participated in this study, divided from the annual competitive season. The assessments were performed in two stages separated by 48 hours: anthropometric measurements and physical tests (standing long jump – SLJ, medicine ball throw test-MBT, handgrip strength test – HGS, Special Judo Fitness Test – SJFT and Judogi Grip Isometric Strength Test–JGST). Judo athletes were asked for their date of birth and judo experience. T-test and discriminant analysis were used to compare and discriminate the variables between young judo athletes from state and national groups with the level of significance set at 5%. The main results showed that stature, judo experience, JGST, and SLJ performance were higher in the national group (p < 0.05) and could adequately discriminate competitive levels (structural coefficient >30, p < 0.001). It was concluded that young male judo athletes who compete at the national level are taller, more experienced, and present superior physical performance in tests related to strength and power than athletes from the state group of the same age.
... The ability to generate a high rate of mechanical work by the lower limbs (i.e., mechanical power capability) during a propulsive phase of a ballistic movement is a determinant factor in many sports [1][2][3][4]. Therefore, the evaluation of this physical capacity is a common practice among professionals of sports training, usually aiming to monitor training effects and muscle recovery, as well as to predict performance [5][6][7]. ...
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Purpose. This study aimed to analyze the relationship between vertical jump parameters—jump height (JH), peak power output (PPO), and mean power output (MPO)—and specific physical performance in different sports using the allometric approach. In this sense, it was verified whether scaled power output for body mass may have a stronger correlation with physical performance than raw power output. Methods. Fifty-two male athletes (21 judokas, 18 futsal players and 13 sprint runners) participated. Athletes performed the following tests: vertical jumps (countermovement and squat), specific physical tests for judo (Special Judo Fitness Test), repeated sprint ability for futsal players and sprint running (20m and 200m) for runners. A specific allometric exponent for PPO and MPO was established. Pearson’s correlation was used to determine the relationship between physical tests and vertical jump parameters for absolute and allometric scales. Results. Moderate to very large correlations were found between physical performance and jump height (r=0.47 to 0.87), PPO (r=0.47-0.75) and MPO (r=0.49 to 0.81). Considering power output scaled for body mass, the correlation between jump parameters and physical performance was greater than absolute values, in which the r values ranged between 0.46 to 0.81 for PPO and 0.52 to 0.84 for MPO. Conclusion. Jump height and power output seem to correlate in a similar magnitude with physical performance tests for most variables and sports analyzed. From a practical point of view, coaches and physical trainers are encouraged to use the jump height to monitor training, considering the cost of equipment and practicality.
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Background: Judo has a higher risk of traumatic injuries during training. Thus, efficient training programs should be accomplished to decrease injury risk and improve performance. Objectives: Given the necessity of developing injury prevention approaches in programming the training, this study aimed at investigating the effect of an injury prevention program on traumatic factors and athletic performance in junior judokas. Methods: 46 subjects were randomly classified into 2 groups of experimental (N: 23) and control (N: 23) groups. For eight weeks, the experimental group attended a specific Judo functional training program designed by the researchers. The control group participated in the usual judo training program presented by the coaches. The exercises were accomplished 3 times per week for 90 minutes each session. The subjects participated in pre-and post-tests. To approve the data normality and compare the variables, Shapiro-wilk, ANCOVA analysis was implemented at the significant level of p˂ 0.05 using SPSS (version 21). Results: The outcomes showed that the scores of functional movement screening (p = 0.001), upper extremity Y balance test (p = 0.001), vertical jump (p = 0.001), and special judo fitness test (p = 0.001) significantly increased among the experimental group. Conclusions: This intervention can modify or decreases the injury risk factors and improves athletic performance and offers more efficiency and effectiveness rather than the common judo training programs.
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Volume 16(1s) ~ 2021 ~ DOI: 10.18002/rama.v16i1s Strength and conditioning for combat sports athletes
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جودو یکی از پرمخاطب¬ترین هنرهای رزمی دنیا است، پژوهشگران¬ خطر بروز آسیب در هنگام تمرین جودو را بیشتر از زمان مسابقه گزارش کرده اند. بنابراین، رو¬ش های تمرین ایمن¬تر و اثربخش¬تر باید مورد توجه قرار گیرد. با توجه به ضرورت توسعه و کاربرد رويكردهاي پيشگيري از آسيب و بهبود عملکرد ورزشی، هدف از پژوهش حاضر بررسي اثر هشت هفته تمرين عملکردی اختصاصی جودو بر عوامل خطرزای بروز آسیب و عملکرد ورزشی جودوكاران پسر غیر نخبه می باشد. 46 نفر جودوکار غیر نخبه به صورت هدفمند انتخاب و به روش تصادفی در دو گروه آزمایش(23نفر)و کنترل(23نفر) تقسیم شدند. گروه تجربی هشت‌هفته در برنامه تمرینات عملكردي اختصاصي جودو كه توسط محققان طراحي شده بود، شرکت نمودند. گروه کنترل در مدت مشابه، به تمرینات مرسوم جودو پرداختند. تمرینات سه‌بار در هفته و در هر جلسه 90 دقیقه انجام شد. آزمودنی¬ها 24 ساعت پیش از شروع و پس از پایان دوره در پیش آزمون و پس آزمون شرکت کردند. برای بررسی نرمال بودن داده¬ها از آزمون شاپیرو-ویلک و برای اندازه¬گیری اختلاف بین میانگین گروه¬ها از تحلیل کوواریانس (ANCOVA) در سطح معناداری(05/0p≤) استفاده شد. آنالیزها با استفاده از نرم افزار(21)SPSS انجام شد. بر اساس یافته¬ها افزایش معناداری در امتیاز آزمون¬های غربالگری حرکت عملکردی(001/0p=)، تعادلY اندام فوقانی(001/0p=)، پرش عمودی (001/0p=) و آمادگی اختصاصی جودو (001/0p=) در گروه تجربی مشاهده شد. مداخله تمرینی این پژوهش به طور همزمان بر کاهش یا تعدیل عوامل خطرزای بروز آسیب و ارتقای عملکرد ورزشی اختصاصی موثر بود. بنابر این نسبت به برنامه¬هاي تمريني رایج کارآمدتر است.
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Study aim: To analyse struggle dynamics of the best European judoists (male and female). It was assumed that finalists of top-rank European tournaments demonstrated supreme skills. Material/methods: The analysis included 14 final contests, male and female (7 each) from European Championships in Rotterdam 2005. The following indices of struggle dynamics were determined: of offensive/ defensive activity (AI), of effective offensive actions (EA), of effective counterattacks (EC), of effective actions without counterattacks (ED), and global index of struggle dynamics (SDI). Results: The gold medallists exhibited a markedly higher struggle dynamics in mean EA, EC and SDI values than their opponents. Otherwise, no significant differences were noted between male and female athletes or between weight categories. Conclusions: Changes in the rules of judo contest should aim at increasing struggle dynamics. Besides, training of tactical skills should focus on fastest gaining a point advantage (by throw or holding, or by making the competitor break rules), as well as on effective defensive actions and on making use of opponent's potential mistakes in the situation of own advantage.
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Background and Study Aim: The aim of this paper is to establish biomechanical optimization of the high-flying front kick (in taekwon-do terminology referred to as twimyo nopi ap chagi), which would result in developing a more effective method of executing this particular kick. Material/Methods: The study analysed movements of 14 ITF taekwon-do athletes (age: 16.5±0.7 years; weight 64.1±7.0 kg; height 176.5±4.6 cm). A system of complex analysis of movement called Smart-D made by the Italian company BTS Spa was used for the tests. For the purpose of the experimental part of the study the study participants were asked to adopt the same initial stance (in taekwon-do terminology called Niunja So Palmok Degi Maki) and perform the high-flying front kick in two different techniques - using the traditional technique (scissors) and the natural technique (non-scissors). Results: In case of the natural technique used for executing this kick the COG usually starts from the height of 0.9 m. After 0.5 sec. the COG is lowered by 0.1 m so that the athlete can take off having developed the required velocity At the maximum height of the flight the COG reaches 1.54 m (having risen by 0.64 m), and this is the moment when the knee extension for kick completion occurs. In the traditional technique the COG is located at 0.9 m at the start and then lowers by 0.1 m. When leaping up at take-off the velocity increases immediately and at the flight maximum the COG reaches 1.46 m. This is also the height when the landing stage starts. The local maximum is marked at the height of 1.40 m, which corresponds to the moment of the knee extension needed to complete the kick. Conclusions: The observation shows that there are four main elements which influence the height achieved by an athlete in his jump and these include the height of the centre of gravity at take-off, the flight height of the COG as well as the height determined by the length of the lower limb and the angle formed between the plane perpendicular to the board and the limb. In the natural technique the athletes managed to raise their COG by an average of 74 mm higher than in the traditional technique (p<0.01).
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Background and study aim: The aim of this study was to compare biomechanics and special methods control of judo training process. Material and methods: The study was conducted on eight junior judoists. Special abilities was evaluated using a Special Judo Fitness Test (SJFT). Muscle torque measurements in static conditions were performed. Ten muscle groups were examined: flexors and extensors of the trunk, shoulder, elbow, hip and knee. The maximal power and height of jump were measured at BCMJ and CMJ jumps. Power-velocity relations were determined from 5 maximal cycle ergometer exercise bouts at increasing external loads equal to 2.5, 5.0, 7.5, 10.0 and 12.5% of body weight. Results: Mean values (±SD) index of Special Judo Fitness Test was 12.71±1.94. The values of BCMJ relative maximal power and height of jump were 44.75±8.97 W•kg-1 and 0.526±0.071 m, respectively. The mean values of Pmax 900.8±152.9 W and Pmax/mass 13.44±1.28 W•kg-1 were corresponding to mean optimal velocity 119.316.0 rpm. The relative values of the muscle torque were correlated with index of SJFT, the coefficients ranging from -0.15 to -0.68. Index of SJFT correlated significantly with BCMJ values of the relative power and height of jump (r = –0.72 and –0.88, respectively). SJFT index correlated with power output and velocity in the maximal cycloergometer test, the coefficients ranging from -0.71 to 0.48. Conclusion: In training process should be used biomechanics measurements, physical fitness tests and special fitness tests characteristic for own discipline as well. It will give optimal training control.
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The purpose of the present study was to determine the lower extremities biomechanical differences between prepubescent and adult males during drop jumps (DJs). Twenty-four untrained males (12 prepubescents, 12 adults) performed DJs from 20 cm height. Kinematics of the lower extremities were captured, in addition with vertical ground reaction forces (vGRFs) and EMG activity of the gastrocnemius medialis (GM), soleus (SOL) and tibialis anterior (TA) muscles. The results showed that men jumped higher, as expected, but their knees were more flexed prior to landing, and their preactivation level was higher and longer in duration compared to prepubescent boys. During landing, men had shorter contact times, lower vGRF normalized to body mass, and less maximal knee joint flexion. Regarding EMG activity men presented higher stretch reflex and higher EMG activity during the braking phase but the level of coactivation (TA to GM + SOL ratio) was lower. It is seems that pre-landing and landing patterns during a complex task such as DJ are affected by physical development. There are indications that men had higher performance in a DJ than prepubescent boys because they activated more effectively their muscles during the preactivation and braking phase. The above-mentioned data support the hypothesis that prepubescent boys might be inferior in optimal regulation of their muscle-tendon unit stiffness.
Background This study attempted to produce answer to the question: Is physical endurance in judo contestant at junior age and Study Aim: related to the adopted fighting strategy and the level of sports performance?Material/Methods: The study covered 10 judo contestants from three clubs in Poland. First stage encompassed registration of their competitive activity level. On the basis of this record, contestant's fighting activity, efficiency and level of perfor- mance was assessed. Another stage of the investigations focused of evaluation of their aerobic and anaerobic en- durance on the basis of testing methods used in the Institute for Human Physiology in the University School of Physical Education in Cracow. The strength of the relationship was concluded based on the value of Spearman's rank correlation coefficient.Results: As was observed on the basis of statistical analysis, level of anaerobic endurance shows strong relationship with the method of fighting observed among young judokas. Time to reach maximal power seems to be of particular importance. Its value correlated with efficiency of contestants' actions taken during second phase of fight and with the level of sports achievement.Conclusions: The results of the present study should be taken into consideration by judo club coaches during planning and implementation of training schedules among young contestants.
Performance of a vertical jump was analyzed with respect to the contribution of the different body segments to the forces acting on the whole body center of gravity. Both cinematograph and force-platform techniques were employed. The data disclosed that the take-off velocity in vertical jumps was caused by the different components as follows: knee extension 56%, plantar flexion 22%, trunk extension 10%, arm swing 10%, and head swing 2%. However, the average take-off velocity of the total performance (3.03 m/s) was only 76% from the theoretical maximum calculated from the segmental analyses. Optimal timing of the segmental performances was calculated to increase this "efficiency" to 84%. Great variance were observed among individuals in the total performance despite the similarities in utilization of the performance of individual segments.
An alternating cycle of eccentric-concentric contractions in locomotion represents a sequence when storage and utilization of elastic energy takes place. It is possible that this storage capacity and its utilization depends on the imposed stretch loads in activated muscles, and that sex differences may be present in these phenomena. To investigate these assumed differences, subjects from both sexes and of good physical condition performed vertical jumps on the force-platform from the following experimental conditions: squatting jump (SJ) from a static starting position; counter-movement jump (CMJ) from a free standing position and with a preparatory counter-movement; drop jumps (DJ) from the various heights (20 to 100 cm) on to the platform followed immediately by a vertical jump. In all subjects the SJ, in which condition no appreciable storage of elastic energy takes place, produced the lowest height of rise of the whole body center of gravity (C.G.). The stretch load (drop height) influenced the performance so that height of rise of C. of G. increased when the drop height increased from 26 up to 62 cm (males) and from 20 to 50 cm (females). In all jumping conditions the men jumped higher than the women. However, examination of the utilization of elastic energy indicated that in CMJ the female subjects were able to utilize most (congruent to 90%) of the energy produced in the prestretching phase. Similarly, in DJ the overall change in positive energy over SJ condition was higher in women as compared to men. Thus the results suggest that although the leg extensor muscles of the men subjects could sustain much higher stretch loads, the females may be able to utilize a greater portion of the stored elastic energy in jumping activities.
The physiology of Canadian National Judo Team members is described. These athletes differed widely in body size (height 157.4-187.7 cm; mass 56.5-100.8 kg). Aerobic fitness (treadmill) was high (VO2max = 4.49 I.min-1; 59.2, but relative VO2max decreased with increasing body mass. Elite judoka of other nations (Australia, 53.2; Poland, 59.0; Norway, 58.5) had comparable aerobic fitness. Significant (p less than 0.05) correlations between upper- (arm cranking, PWC170) versus lower-body aerobic fitness (r = 0.48), and upper- versus lower-body anaerobic power (r = 0.89) and capacity (r = 0.88) (Wingate) were observed. Peak power output (AnPP = 9.3 and anaerobic capacity (AnCap = 260 during arm cranking averaged 80% of leg-cranking values (AnPP = 13.7; AnCap = 320 Upper-body strength (bench press, one repetition, maximum = 100 kg) was also associated with upper-body anaerobic power (r = 0.72). Judoka exhibit a high degree of aerobic and anaerobic conditioning, and a pattern of total body fitness that is specifically required for their sport.
Mechanical efficiency of positive work (eta+) and elastic behavior of human skeletal muscles were investigated on a special sledge apparatus which allowed the use of the normal stretch-shortening cycle exercises. Twenty-five young men were investigated in a total of 92 exercise situations, in which the intensity of the prestretch (eccentric contraction) was different, but the shortening phase (concentric contraction) was kept constant in all conditions. The results demonstrated that eta+ was on the average 35.8% +/- 6.4% and correlated positively with the prestretch intensity (r = 0.413; P less than 0.001), reaching a highest individual value of 51.5%. Estimation performed on the elastic characteristics of the leg extensor muscles confirmed an earlier suggestion that the pure muscle elasticity plays an important role in potentiating performance in stretch-shortening cycle exercises. The analysis of the myoelectrical activity of the leg extensor muscles showed that the nervous system plays an essential role in regulating muscle stiffness and thus utilization of muscle elasticity in ballistic exercises.
The objective of the present work was to study the interaction between the tendon elasticity, the muscle activation-loading dynamics, specific actions of the biarticular muscles, preloading and jumping performance during maximal vertical jumping. Six male expert jumpers participated in the study. They performed maximal vertical jumps with five different preloads. The kinematics and dynamics of the jumping movements were analysed from force plate and high speed film recordings. The amount of elastic energy stored in the tendons of the leg extensor muscles was calculated by a generalised tendon model, and the muscle coordination was analysed by surface EMG. The best jumping performances were achieved in the jumps with low preloads (counter movement jumps and drop jumps from 0.3 m). A considerable amount of the energy imposed on the legs by prestretch loading was stored in the tendons (26 +/- 3%), but the increased performance could not be explained by a contribution of elastic energy to the positive work performed during the push off. During the preloading, the involved muscles were activated at the onset of the loading. Slow prestretches at the onset of muscle activation under relatively low average stretch loads, as observed during counter movement jumps and drop jumps from 0.3 m, prevented excessive stretching of the muscle fibres in relation to the tendon length changes. This consequently conserved the potential of the muscle fibres to produce positive work during the following muscle-tendon shortening in concert with the release of the tendon strain energy. A significant increase in the activity of m. rectus femoris between jumps with and without prestretch indicated a pronounced action of m. rectus femoris in a transport of mechanical energy produced by the proximal monoarticular m. gluteus maximus at the hip to the knee and thereby enhanced the transformation of rotational joint work to translational work on the mass centre of the body. The changes in muscle activity were reflected in the net muscle powers. Vertical jumping is like most movements constrained by the intended direction of the movement. The movements of the body segments during the prestretches induced a forward rotation and during the take off, a backward rotation of the body. A reciprocal shift in the activities of the biarticular m. rectus femoris and m. semitendinosus indicated that these rotations were counteracted by changes in the direction of the resultant ground reaction vector controlled by these muscles.(ABSTRACT TRUNCATED AT 400 WORDS)