Journal of Physical Education and Sports Management, Vol. 2(1) pp. 37-44, April 2011
Available online http://www.acadjourn.org/jpesm
ISSN 1996-0794 ©2011 Academic Journals

Full Length Research paper

Mechanical impacts analysis in judoists body of
different weight categories
Tatiane Piucco* and Dra. Saray Giovana dos Santos
Laboratório de Biomecânica, Centro de Desportos Universidade Federal de Santa Catarina, Florianópolis SC Brasil.
Accepted 2 March, 2011

This study aimed to analyze the impacts generated in different body regions of judoists of different
weight categories during falls cushioning. Four black belt judoist, with at least 14 years of experience,
participated in this study: three “uke” half-light, half-middle and half-heavy categories were thrown in
“ippon-seoi-nage” technique by a “tori” with 77 kg. A triaxial Brüel and Kjaer accelerometer was
alternately fastened with straps in the “uke” fist, hip and ankle to verify the impacts. Descriptive
statistics, one way ANOVA and Tukey test were applied, with p≤0.05. The bigger impact magnitudes
occurred in vertical axis, in the fist and for the half-middle category judoist; the impact times were
larger in the hip for all athletes and in vertical axis. According to Macaulay criteria, the impact values
founded represents severe injury risks in fist and ankle and moderate risk in judoists hip. Initiatives
should be taken to reduce the damage due to impact during judo training and competitions.
Key words: Judo, impact, transitory, vibrations, injury.
INTRODUCTION
The mechanical impacts, also defined as transient
vibrations, occur frequently in sports, not only in
combative sports, when the body sock against a fixed
external surface, like landing in the ground or falling
(Roquette, 1994). Although the agreement in literature
that mechanical impacts comprise vibration levels
dangerous to the organism (Mansfield, 2005), there is no
rules that limit human exposure to transient vibrations,
especially those that occur during sports performance.
The only criterion that can be taken as reference for
sports impacts is the one elaborated for Macaulay (1987).
This criterion consider the pulse duration as the total time
of impact, and is graphically plotted for three regions: a
short-term region from 0.001 to 0.01 s, an intermediateterm region and a long-term region to impact time
durations larger than 0.1 s. This criterion postulates that
the lower the impact duration, greater accelerations the
body can stand without being damaged. On the other
hand, it is not mentioned in this criterion the number of

*Corresponding author. E-mail: tatianepiucco@yahoo.com.br.
Tel: (48) 3721 8530. Fax: (048) 3721-9792.

impact events that the body can withstand during a
specified period of time, neither the minimum interval
required between impact repetitions. Some researchers
like Voloshin (2004), Lafortune et al. (1995) and Derrick
and Mercer (2003) and others point out that the repetition
of sports movements are the main mechanisms of sports
injuries. As a result, sports which require high
magnitudes of impact applied without rest period, like the
landings in volleyball and basketball and falls in
combative sports, are the ones who mostly collaborate
for athlete damages during regular practice (Santos and
Piucco, 2006).
In judo practice, the transient vibrations occur
frequently in the judokas body during damping falls
(ukemi) of different throw techniques. The number of
ukemi accomplished during a judo training sessions
comes to 73.60 ± 42.34 (Santos and Melo, 2003), and it
depends of the training stage, intensity and the athlete’s
technical level (Melo et al., 2009). The high rates of
“ukemi” repetition is a contributing factor for the trauma
occurrence (James and Pieter, 2003), as well as the
incorrect “ukemi” results in many kind of injuries (Santos
and Shigunov, 2001; Santos and Melo, 2003; Santos,
2003), what indicates that is necessary to accomplish

38

J. Phys. Educ. Sport Manag.

Figure 1. Accelerometer settling at the judokas wrist, hip and ankle, according to the method adopted by Santos
(2003). Source: Santos (2003: 45).

more researches to assess the implications of
consecutive falls on a judoka body. Despite the constant
exposure of judokas to transient vibration, few studies
like those of Santos (2003) and Piucco and Santos
(2010) investigated the vibrations generated in the
judokas body during falls, and there is no investigation
about the impacts on the body of judokas of different
weight categories. Thus, based on the theoretical
assumptions pointed out, and considering the importance
of studying the variables that can provide damages to the
athlete’s body to propose future actions to prevent or at
least mitigate the adverse effects, the following questions
were proposed: what are the magnitude and duration of
impacts suffered by judokas of different weight categories
during the ukemi? Are these impacts harmful to them?
Considering these issues, this study aimed at analyzing
the transient vibrations generated in three different
judokas body regions and weight categories, during the
ukemi in ippon-seoi-nage throwing techniques.
METHODS
Three judokas of different weight categories were investigated
(designed by uke): one of half lightweight category, brown belt, 21
years old, 168 cm, 63 kg and 16 years of practice; one of half
middleweight category, black belt, 27 years old, 175 cm, 74 kg and
15 years of practice; one of half heavyweight category, black belt,
24 years old, 175 cm, 95 kg and 14 years of practice. These three
judokas were projected by a “tori” black belt, with 27 years old, 174
cm, 77 kg and 15 years of practice, using the “ippon-seoi-nage”
judo technique. The acceleration (m/s2) generated by the shock of
judoka on the mat was measured using a triaxial accelerometer
type 4321 from Brüel and Kjaer, previously calibrated, made of
titanium, with dimensions of 28.6 x 28.6 x 17 mm, maximum shock
of 1000 g (gravity acceleration), frequency range of 0.1 to 12,000
Hz, sensitivity of 10 pC/g and resonance frequency of 40 kHz. For
the amplification and filtering of signals three pre-amplifiers type
2635 from Brüel and Kjaer were used, and signal acquisition was
made by a Lynks module MCS1000-v2, composed of 16 channels
with configurable output voltage ± 10 V. The signals were digitally
converted by a Lynks A/D converter model AC1112 with 16 analog
inputs and 12 bit resolution. From the fulfillment of legal
requirements of National Health Council, Resolution 196/96, and
upon approval by the Ethics Committee of Universidade Federal de
Santa Catarina (project number 073/07), the athletes signed an
informed consent before the data collection.

Samples were collected in a laboratory where an area was
mounted with three mats of 297.0 x 199.0 x 4.0 cm in total size. The
accelerometer was fixed at the judokas wrist (on the left distal
radioulnar joint), hip (in the upper right iliac crest) and ankle (two cm
proximal to the left medial malleolus) (Figure 1), according to
Santos (2003) methodology. The judokas were projected 30 times
(10 times for each body segment - wrist, hip and ankle) using the
“ippon-seoi-nage” judo technique. The accelerometer and cables
were settled with elastic ribbons to enable the natural execution of
the techniques avoiding the accelerometer and cables oscillation.
The athletes were instructed to start the movement simultaneously
with data acquisition. The electrical charge generated by
piezoelectric transducer (accelerometer) during the fall, in the three
directions (x, y and z) was transmitted through cables to the
respective pre-amplifiers, adjusted for values of acceleration (m/s2).
After that, the signals were converted to digital form and acquired
by the software AqDados 7.02 at a frequency of 4000 Hz in order to
preserve signal integrity, according to the Nyquist theorem which
states that the sampling frequency of an analog signal must be
equal to or greater than twice the highest frequency spectrum of
signal (Fa ≥ 2F), so it can later be reconstituted with a minimal loss
of information.
The motion axes orientation (x, y and z) of acceleration followed
the ISO 2631-1 (1997) standardization, designated in the standing
position on the longitudinal axis (± z), anterior-posterior axis (± x),
and transverse axle (± ay). When falling on the mat (ukemi), the
judoka assumes the supine position. So, the axes orientation during
the impacts were arranged according to Figure 2. Signals were
analyzed by the AqDAnalysis 7.0 software. After the signal baseline
off-set adjustment, the peak values of signals in time domain (m/s2)
were taken and corrected by the amplification factor. These values
were divided by 9.81 to be transformed into gravitational units (g).
The impact duration (milliseconds) were determined by the
difference between the final time and initial time of the event (Figure
3). Data were analyzed by the SPSS 15.0 statistical program. The
results were descriptive represented by mean and standard
deviation values. The normal distribution of data was checked by
Kolmogorov-Smirnov (n ≥ 50) normality test, and then, ANOVA One
Way was applied in order to compare the values between the
movement axes, body regions and athletes. Since significant
differences were found, the Tukey HSD multiple comparison test
was applied. For all tests a significance level of 95% was adopted.

RESULTS
The descriptive values of impacts magnitude and
duration generated on the judokas wrist, hip and ankle, in
each motion axis, are shown in Figure 4 A, B and C

Piucco and Santos

39

Y
Z
X

Y
Z
X

Y
Z
X

Figure 2. Axes orientation during judokas body impact.

Figure 3. Criteria used to determinate the peak and the duration of each impact.

respectively. It is observed in Figure 4 that the half
middleweight athlete had the highest impact magnitude
average on the wrist, reaching 351.94 g in the y-axis. The

longest impact duration occurred on the y-axis for the half
heavyweight athlete. Figure 4B shows that the half
heavyweight athlete had lower impact magnitude on the

J. Phys. Educ. Sport Manag.

500

x
y
z

A

0,018
0.018
0,016
0.016

350

0,014
0.014

300

0,012
0.012

Duration (s)

400

250
200

x
y
z

0,020
0.020

Duration (s)

Impact (g)

450

0,010
0.010
0,008
0.008
0,006
0.006

150

0.004
0,004

100
0.002
0,002

50

0.000
0,000

h.lightweight

0

h.lightweight

h.middleweight

18

x
y
z

B

0,6
0.6

14

Duration (s)

0,5
0.5

Duration (s)

Impact (g)

h.heavyweight
x
y
z

0,7
0.7

16

12
10
8

0.4
0,4
0,3
0.3

6

0,2
0.2

4

0.1
0,1

2

0.0
0,0

h.lightweight

0

h.lightweight
400

h.middleweight

h.heavyweight

20

h.middleweight

C

h.middleweight

h.heavyweight
x
y
z

350

h.heavyweight
x
y
z

0,022
0.022

0.020
0,020
0,018
0.018

300

0,016
0.016

Duration
Duration(s)
(s)

250

Impact (g)

40

200
150

0,014
0.014

0.012
0,012
0.010
0,010
0,008
0.008
0,006
0.006

100

0.004
0,004
50

0,002
0.002
0,000
0.000

0

h.lightweight

h.middleweight

h.heavyweight

h.lightweight

h.middleweight

h.lightweight

Figure 4. Mean and SD of magnitude (g) and duration time (s) of impact measured on the judokas wrist (A), hip (B) and ankle
(C), in x, y and z axes.

Piucco and Santos

41

Table 1. Comparison of impact magnitude (g) between the axes (x, y and z), joints (wrist, hip and ankle) and judokas
(half lightweight, half middleweight, half heavyweight).

Categories
H. Lightweight
H. Middleweight
H. Heavyweight

X
106,96* ψ ξ
140,212* ξ
36,364* ξ

Y
263,110* ψ ξ
351,947* ψ
171,836* ψ ξ

z
59,023ψ
75,994*
42,701* ξ

Hip

H. Lightweight
H. Middleweight
H. Heavyweight

7,865ξ
9,326* ξ
5,081* ξ

12,730 ψ ξ
13,506 *ψ ξ
9,631* ψ ξ

9,367* ξ
5,180 ξ
4,474 ξ

Ankle

H. Lightweight
H. Middleweight
H. Heavyweight

204,886* ξ
76,090 ξ
69,815 ξ

214,483 ξ
242,888 ψ
232,741 ψ ξ

123,583 ψ ξ
101,974
86,642 ξ

Wrist

ψ

ξ

Where: *differences between categories; differences between axis; differences between joints. p≤0.0.

hip, and the higher value occurred in the y-axis for the
half middleweight athlete. The duration of impacts on the
hip was greater in the y-axis for the half middleweight
athlete. In Figure 4C it is observed that the magnitude of
impacts on the ankle were similar between athletes,
being more evident for the half lightweight athlete in the
x-axis. The duration of impacts on the ankle was greater
in the y-axis for the half middleweight athlete.
It is also noted in Figure 4 (A, B, C) that for all athletes
and in all regions investigated, the highest values of
impact magnitude and duration occurred in the y-axis,
except for the half lightweight athlete’s wrist. The result of
comparing the magnitude of impacts between the axes
(x, y and z), joints (wrist, hip and ankle) and judokas (half
lightweight, half middleweight, half heavyweight), and the
post-hoc test are presented in Table 1. It is observed in
Table 1 that there were significant differences between
the joints investigated, except between the wrist and
ankle to the half middleweight athlete in y and z axes.
The hip region had the lowest magnitude of impact, and
the ankle suffered greater magnitude of impact than the
wrist, except the y-axis for the half lightweight athlete and
the x-axis for the half middleweight athlete. Regarding
differences between the motion axes, the magnitude of
impact on the y axis was significantly higher compared to
the other axes for all joints and all the athletes
investigated. Among the weight categories, the half
heavyweight athlete suffered the lower magnitude of
impact on the wrist and hip in all axes. The half
lightweight athlete showed higher magnitude of impact
than the other athletes in the x and z axis at the ankle
joint.
DISCUSSION
The magnitude of impacts founded in the different motion
axes and body regions of judokas during falls are similar

to the values founded by Santos (2003) and Piucco and
Santos (2010). The increase of vertical impact strength
when collision occurs is attributed, among other factors,
to the action of gravitational force, the height and speed
with which athletes are projected (Santos and Melo,
2001). The increase of impact values of y to z axis can be
explained by the characteristics of the “ukemi” technique
used by athletes, called “zempo-kaiten-ukemi”. According
to Santos (2003), during the “zempo-kaiten-ukemi”, the
hit on the mat occur with combined displacement of the
vertical and medial-lateral direction, providing an
approach from the inside out, justifying the incremental
values in vertical, lateral and longitudinal direction. The
lowest impact values found in judokas hip as well as the
high values found in the wrist and ankle during the fall,
were also confirmed by Santos (2003) and Piucco and
Santos (2010). This distribution of impact forces occurs
because of the first hand beat on the mat, followed by the
support of shoulder which acts as the hip axis rotation,
dissipating the greater impact forces of this region
(Santos and Melo, 2001). By the other hand, the ankle
accomplishes the biggest trajectory during the throwing
due to the length of the radius formed by the distance
between hip and foot, creating a large tangential velocity,
and therefore a great impact value (Santos, 2003).
The high magnitudes of impact generated at the
judokas wrist and ankle can be explained by the relatively
small mass of these segments/limbs when compared with
the region of the trunk and pelvis. Nussenzveig (1996)
explains that body mass provides variations in time of
contact between bodies, that is the greater the mass, the
greater the deformation of bodies and the greater the
contact time between them, which reduces the magnitude
of impact forces generated. The lower magnitudes of
impact suffered by the half heavyweight judoka category
may be justified basically by three factors: the inverse
relationship between the magnitude of impact and the
mass of bodies involved in the collision; the decrease of

42

J. Phys. Educ. Sport Manag.

throwing speed due to the large mass; the difference
between fat-free mass and fat mass relationship in body
composition of athletes, since the increase in % G
facilitates the nonlinear damping of the shocks (Jarrah et
al., 1997). Despite the magnitude of impacts were lower
in the higher weight category judoka, the nonlinear
impact attenuation effect promoted by adipose tissue
does not necessarily means a positive factor, since,
according to Jarrah et al. (1997), the vibration energy
generated during these impacts starts to be dissipated in
the joints and ligaments, causing damages over the years
of exposure.
Another factor to consider is that heavier categories
athletes are subject to larger forces and surcharges
during falls, considering that the ground reaction force
increases directly with the mass of the bodies involved in
the collision, according to Nussenzveig (1996). The
higher is the overload the higher is the injury risk,
specially the acute ones, as bone fracture, damage to the
ligaments, tendons and muscles (Nigg et al., 1995). All
these factors relate to the importance of judokas physical
readyness, training not only to improve performance, but
also to prevent injuries resulting from impacts between
the athlete and the mat. Overall, in all body regions the
impacts attenuation is influenced by intrinsic and extrinsic
factors, as the viscoelastic properties of muscles and
bones, the degree of joints stiffness, the angular
movement and positioning of body segments, the muscle
contractions during the impact, as well as the type of floor
where the impact occurs (Nigg et al., 1995). So, to be
able to correctly analyze the relationship between body
mass and the impact forces, is important to consider the
participation of all dissipative elements at the time of the
collision, as deformation of body tissues and mat.
Even though researchers suggest that the submission
of the body to repeated impact forces can cause injuries
(Voloshin et al., 1998; Voloshin et al., 1982; Voloshin and
Wosk, 1982), there is no criterion to limit athlete’s
exposure to sports impacts. For this type of event (short
term), the criterion developed by Macaulay (1987) can be
used, which relates graphically the lengths of impacts
(0.001 to 0.1 s) with the magnitudes of impacts (g).
According to this criterion, the shorter the duration of
impact, the higher acceleration body can stand.
Therefore, considering that the greatest magnitude and
duration time of impacts in judokas body occurred in the
vertical direction, it can be stated that the impacts in this
direction are the mainly responsible for the possible
injuries that occur during falls in judo. The lowest values
of impacts duration founded on the wrist and ankle
occurred probably due to the great speed that the hand
and foot hit the ground, resulting in a high separation
speed between these limbs and the mat and,
consequently, shorter impact duration. The highest
values of impacts duration in the hip occurred probably
because to the hip location, near to the body center of
mass. According to Piucco and Santos (2010), the body

mass increases the mat deformation during the collision
of judoka, and therefore the contact time.
The results of this study indicate an increasing trend in
the time duration of the impacts on the wrist according to
the weight increase of the athletes. This result is justified
by the increase in the duration of the impact according to
the increase in body mass involved during the collision,
as previously mentioned. In the hip this feature was
observed only for the impacts on the x axis. In the ankle
no trend was observed. It is likely that the small
differences between the values of impact time
(milliseconds) and the athlete’s particularities during the
“ukemi” accomplishment have influenced these results.
Analyzing the results founded on the judokas wrist,
according to the Macaulay (1987) criterion, for the half
lightweight athlete, the values of the time duration of the
impacts in the y and z-axes are within the short duration
region (<0.01 s), and the x-axis in the intermediate
duration region (between 0.01 and 0.1 s). Associated with
the impact magnitudes, in the x-axis (106.96 g) and the yaxis (263.11 g), these values are in the severe injury risk
area, and in the z-axis (59.02 g) these values are in the
moderate injury risk area of the criterion. For the half
middleweight athlete's category, the duration times of
impacts in the x and z axes of the wrist were within the
short duration region, and in the intermediate region in
the y-axis. Considering the impacts magnitudes in the
axis x (140.21 g) and the y-axis (351.94 g), these values
are in the severe injury risk area, and the z-axis (75.99 g)
in the moderate injury risk area.
For the half heavyweight category athlete, the impacts
time duration on the wrist in all axes investigated are in
the region of intermediate duration. Considering the
magnitude of impacts, these values in the x-axis (36.36
g) and z-axis (42.70 g) represent risk of moderate injury,
and in the y-axis (171.83 g) risk of severe injury. On the
wrist, although the characteristics of impact support the
increase of the injury risk in this region, there is no report
about the shocks numbers and the time of rest necessary
to avoid injuries. Some studies have reported some
medical conditions such as hand-arm vibration syndrome,
the carpal tunnel syndrome and tendinitis with exposure
to periodic high-frequency vibrations (Starck and Pyykkö,
1986). Moreover, considerable amount of vibration
energy generated in the hands can be transmitted by the
arm to the head (Denisov and Sergeev, 1968; Dupuis
and Zerlett, 1986), which increases the difficulty to
understand the body damages resulting from a particular
vibration, as well as to determine limits of tolerance.
Other factors such as the upper limb tissue
characteristics, the position adopted and the degree of
muscle tension during the fall also influence the level of
damage caused by transient vibrations (Mansfield, 2005;
Griffin, 1998), and so, these factors should also be
considered. In the hip region, for the half lightweight
category athlete, the duration times of the impacts in all
axes are in the region of intermediate duration, but the

Piucco and Santos

impact magnitudes are less than 13 g, meaning no injury
risk according to the Macaulay criterion. For the half
middleweight athlete, the duration of impact on the hip x
and z-axes are in the chart intermediate-term region,
while the y-axis values are in the region of long duration
(> 0.1 s).
The magnitude of impacts in x and z-axes, associated
with the impacts duration does not represent hip injury
risk. However, in the y-axis, the values of impacts (13.5
g) and duration (0.58 s) represent moderate risk of injury
in this region. For the half heavyweight athlete, the
impacts time duration on the hip in all axes are in the
region of intermediate duration, and the magnitude of
impact varied from 5 to 13.5 g, which represents no
injuries risk in this region. Although the Macaulay criterion
indicates a lower risk of injury in the pelvic region
resulting from the impacts generated during judo falls,
Mertz (1993) argues that due to the high concentration of
internal organs in this region, the tolerance rate of force
application on the pelvis to cause injury is more sensitive
to short impacts pulses. Santos et al. (2005) indicate that
the ground reaction forces (N) are higher in the hip during
the judokas fall, reaching 6.9 times their body weight.
Data founded in the literature showed that the 10th
percentile for moderate injury in the pelvis is 0.22 kN, the
50th percentile is 2.6 kN and the 90th percentile is 6.7 kN
(Zong and Lam, 2002). Considering that the judoka
investigated by Santos et al. (2005) weighed 647.46 N,
and that the athlete's center of mass is located on the hip
at the fall moment, this athlete suffered 4.46 kN of force
in the pelvis region during the impact with the mat,
exceeding the values that represent the 50th percentile of
moderate injuries risks for this region.
In the ankle region, the half lightweight athlete category
had values of the impacts time duration referent to the
short term Macaulay chart region on the x and z-axes,
and for the y-axis these values are in the region of
intermediate duration. Linking these values to impact
magnitudes values, these numbers indicate risk of severe
injury on the x axis (204.88 g) and the y-axis (214.48 g),
and risk of moderate injury for the z-axis (123.58 g). For
the half middleweight athlete, the impacts time duration
on the ankle on the x-axis are in a short duration region,
and the y and z-axes in the intermediate duration region.
Magnitudes of impacts associated with these values in
the x-axis (76.09 g) represent moderate risk of injury and
in the y-axis (242.88 g) and z-axis (101.97 g) risk of
severe injury. The half heavyweight athlete had values of
impact duration in the ankle classified as short
duration/term to the axes x and z and medium duration to
the axis y. These values, associated with the magnitude
of impacts in the x axis (69.81 g) and z axis (86.64 g) are
in the moderate injury risk area, whereas the values in yaxis (232.74 g) represent severe injury risk. As in wrist,
although the characteristics of the impacts generated in
the judokas ankle represent a high risk of injury, no other
factors likely to influence the involvement of injury

43

resulting from impact loads was found in the literature, for
example the impacts number and the time between them,
the body position adopted on impact and the distribution
of tissues in the region of impact.
In judo, the correct final position adopted during the
“ukemi” is with the knees bent about 90°, as shown in
Figure 2. The dangerous frequency range for this joint
decreases from 20 Hz for extended knee to 2 Hz for the
bent knee (Rasmussen, 1982), which shows the
influence of body position adopted during the fall in the
increase of judo injuries risk. It is therefore important that
teachers emphasize the proper execution of “ukemi”,
especially for amateur judokas, in order to mitigate the
damage caused by transitory vibrations in the judoka
body.
Despite Macaulay criterion being the only one that can be
used to refer the transitory vibrations, characteristics of
the impact in sports, this criterion does not cite the
number of impacts, the exposure time or the interval
between repetitions of the same which are minima for no
injuries. According to Radin et al. (1998), the smaller the
duration of impacts, the greater are the magnitudes that
the body can bear, and that only the random impacts are
not sufficient for the onset of damage, but the continuous
application of these impacts in the body. Therefore,
without the control of these variables it is not possible to
infer about the biomaterials self-healing capacity
considering the load characteristics and the fatigue
process, arising from falls in judo. The onset of fatigue
and the application of excessive loads decrease the
cellular synthesis in joint cartilage and increase the
tissues degradation, causing common deterioration due
to overuse that follow the accentuate practice of exercise
(Vazan, 1983). Therefore, the deleterious effects to the
judokas body caused by impact loads over time practice
are evident, considering the high number of falls that
athletes perform in competitions and especially training.
While there are no satisfactory answers and further study
to formulate a limit criterion of transient vibration body
exposure, Mansfield and Griffin (2000) reaffirm that the
reduction of deleterious effects caused by the human
body vibration can be obtained by reducing the
movement magnitude that causes the vibration.
In judo, despite being impracticable to reduce the
magnitude of the motion projection during training and
competitions, the correct execution of the art projection
and damping of fall and the use of properly prepared site
(flexible base under the mat) may reduce the magnitudes
of impacts and vibrations caused by the body of judo,
mitigating the adverse effects on the body of judokas.
Conclusions
Considering the results found in this study and
understanding the limitations, as well as answering the
problems subject, it can be stated that judokas of

44

J. Phys. Educ. Sport Manag.

different categories are often exposed to impact of high
magnitude and short in time duration. The impacts
characteristics, especially in vertical axis represent a
severe injury risk in the judokas wrist and ankle, and
moderate injury risk in the hip of the athletes. Since the
high concentration of internal organs in the hip increases
the risk of damage to this site, and those impacts
generated in the body of judokas over years of practice
can cause serious damage to the body, it is
recommended to the sport practitioners to apply some
preventative initiatives in terms of training intensity,
number and technical quality of the falls taken and the
type of mat used.
ACKNOWLEDGMENTS
This paper was made with the assistance of the
Laboratory of Acoustic and Vibration of Mechanical
Engineering Department of Federal University of Santa
Catarina.
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