Research on the Distribution Characteristics of Plantar Pressure of Cha-Cha-Cha

M & D FORUM
Research on the Distribution Characteristics of Plantar Pressure of
Cha-Cha-Cha
JIANG Lanqiong1, PENG Xiaoqian2
1. Quzhou Professional Technology College, Quzhou, Zhejiang, China, 324000
2. Zhejiang Normal University, Jinhua, Zhejiang, China, 321004
[email protected]
Abstract: This paper makes measurement and analysis on force distribution of foot for several
outstanding cha cha cha dancers by using the Footscan insole 2.39 system, discusses the distribution
characteristics of plantar pressure in four aspects about the F average, F max, % Peak and % Contact.
The result shows that the forepaws are under high pressure when doing cha cha cha dance, especially the
big toe and the first metatarsales area, and the heel parts are under small force. In the fifth step, male
athletes reach maximum pressure in right foot inside metatarsal, the left one reach a maximum when the
focus back in the second step. Female athletes reach maximum pressure in booth feet in the first step. In
cha cha cha square step, the forepaws hardly leave the ground, especially the foot inside.
Keywords: Cha-Cha-Cha, plantar pressure, characteristics
1 Preface
Cha Cha Cha is an artistic sports item for the purpose of competition to express their emotions and skill
through body movements and performance the beauty of the combine from heart and body. Its footwork
and music is 5 steps per bar: slow, slow, fast, fast, and slow. The speed is light, lively, warm and witty.
And the plantar forced pattern is characteristic. With the continual development of the Modern Dance
Sport to competitive, novelty, elegance, not only the athletes' Physical and mental qualities is continual
developing, but also the requests of sports technology. But after searching documents, it is scarcely for
the research of this side. The basic movements are the basis of forms action. This article reveal the
dynamic distribution characteristics of its plantar pressure and offer the theory evidence for competition,
sports training, sports injury prevention and Other related researches through the practice of Cha Cha
Cha which young men and women athletes wear the Latin dance shoes to take.
2 Subjects and Methods
2.1 Subjects
This research chooses 12 professional Latin Dance players as subjects (they are the winner in the
National Latin Championship). 6 men and 6 women, the men’s average age is 22.16±1.22, the average
height is 175.38±4.47cm, the average weight is 65.42±3.51 kg. the women’s average age is 21.92±2.14,
the average height is 162.19±2.53cm, the average weight is 47.32±4.26 kg. They are healthy on foot.
2.2 Methods
The test adopts Belgium Footscan insole 2.39 System, reflects the plantar pressure distribution during
movement. The test chooses the typical basic steps of Cha Cha Cha-the square steps are the analytical
action. During the test, men wear 4cm height Latin dance shoes and women wear 7.5cm height Latin
dance shoes and warm up before the test. In order to make sure the accuracy of data and follow the
unitized music rhythm of Cha Cha Cha during the test, every one tests 2 times. Then choose 3 steps
during every time to observe the pressure distribution characteristics on foot, then obtain the related data
average. According to the automatic partitioning of insole (picture 1), reflect the in regions pressure
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distribution characteristics by the changes of sensor pressure in regions.
No.9 area: big toe region and No.1 metatarsus
bones region.
No.8 area: No.2, 3 toe region and No. 2, 3
metatarsus bones region.
No.7 area: No.4, 5 toe region and No. 4, 5
metatarsus bones region.
No.6 area: central forefoot region
No.5 area: lateral forefoot region
No.2, 4area: inside heel region
No.1, 3area: lateral heel region
Picture1 Plantar pressure distribution in regions
3 Results and Analysis
3.1 Plantar pressure
Pressure on foot reflects the acting force which make from the plantar pressure insole vertical to the
surface. Please look at picture 1, No.7, 8, and 9 region bear a big pressure during the movement of Cha
Cha Cha. And the heel bear a smaller pressure, NO.5, 6, that is middle of the foot bear the smallest
pressure. Adopt two-sample t test assuming heteroscedasticity, and then find NO.7-9 region and NO.1-6
region have significant difference. Because during the movement, Latin male and female athletes wear
4cm and 7.5cm height Latin dance shoes and gravity line of the body forward. The athletes have been
lifted their heels before dancing. And in order to make the body straight, the heel of non-core foot often
lift. So the pressure of forefoot increases, while the pressure of the heel reduces correspondingly. During
the course of the square steps movement of Cha Cha Cha, require to use 1 beat to finish NO3 and NO4
steps, called chasses. High-level athletes’ foot always does not fall to the ground during chasses. Power
concentrated in medial forefoot to make the chasses finish more lightly, offer enough time for the
extension of step2 and step5; make the rhythm of whole dance better and shining. So the pressure
distribution of forefoot region, middle region and heel region has significant difference.
L
245.80±2
7.05
Table1 Pressure value in different region (N)
No.8area No.7area No.6ar
No.5are No.4are
ea
a
a
198.43±3 118.53±2 10.60± 29.93±5. 19.73±8.
8.48
8.63
7.20
35
20
R
220.10±3
5.57
168.33±4.
74
116.03±1
0.53
16.13±
4.62
38.10±1
8.71
40.80±1
1.06
62.60±5.
80
45.73±1
2.08
57.17±1
6.11
L
202.53±3
1.33
128.90±1
0.39
69.53±4.2
7
25.40±
1.04
26.73±5.
66
47.10±2
1.67
55.30±1
8.34
51.23±2
3.79
58.30±2
5.04
R
189.63±1
5.47
156.03±3
3.20
98.77±16.
60
10.02±
3.12
31.90±7.
97
19.00±1
0.18
74.80±4
1.35
14.25±1
7.47
56.87±5
4.88
No.9area
Male
Fem
ale
Note: L is left foot, R is right foot
483
No.3are
a
20.47±9.
31
No.2are
a
34.37±1
3.13
No.1are
a
41.57±1
5.26
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3.2 Plantar peak value of pressure
The peak value reflect the highest level of every region on foot during the steps, also is the biggest
impact force which the plantar bear during the movement. It is one of important measures in related
plantar research.
Plantar peak value of pressure
400
value of pressure
350
300
Male
Male
Female
Female
250
200
N
（ 150
） 100
50
0
No.9
area
No.8 area No.7 area No.6 area No.5 area No.4 areaNo.3 areaNo.2 area No.1 area
Picture 2 Plantar peak value of pressure in different region
As picture2 shows, NO.9 area, that is big toe region and NO1 metatarsus bones region have the biggest
peak value. Because during the dancing, it requests main foot inside toe area push the power to finish
the transfer of body’s gravity. Also during NO.2 and NO4 step of square step, in order to elongated
body’s lines as long as possible and increase the aesthetic sensibility of dance, it also requests the big toe
nailing up the ground to lateral rotate during continuous exertion. The body still turns to front, but the
hip in stretching toe side opens backward to make the body’s line more beautiful. So the big toe region
and NO1 plantar metatarsus bones region bear the biggest pressure.
In addition, can also be seen from picture 2, other regions in heel part also have big peak value,
especially lateral heel area. Because the music rhythm of Cha Cha Cha is light and the square step need
to finish five steps with four beats. The action must be snappy and spiffy. If step backward after NO.2
step, the heel must be on ground. But in order to avoid the center of gravity appearing a sudden "out" to
the back, the action of leg and foot must be strong. And that will leads to a big pressure. Also because
the heel isn’t onto the ground at many times during dancing, so the average in heel region in picture 1 is
small.
3.3 Plantar Peak pressure phase
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Male
Femal
e
（ ）
L
39.67±33.
84
Table 2
plantar Peak pressure phase %
No.8are No.7are No.6are No.5are No.4ar
a
a
a
a
ea
63.00±
61.67±
63.67±
43.67±5 64.33±
27.87
20.46
10.44
.54
5.51
R
76.67±32.
15
44.00±
31.32
60.67±
24.59
36.67±
6.35
74.67±1
5.50
66.67±
21.08
68.33±
17.24
74.67±1
8.88
74.67±
14.05
L
23.67±14.
43
78.33±
1.15
84.00±
1.73
70.33±
25.98
82.00±2
.21
56.33±
19.35
69.33±
10.97
67.00±1
3.86
70.33±
10.97
R
9.67±0.58
44.00±
23.39
46.33±
14.43
10.00±
8.09
66.50±4
.17
75.00±
5.66
55.00±
22.52
66.50±3
.54
55.67±
23.09
No.9area
No.3ar
ea
63.33±
2.08
No.2are
a
62.00±3
.46
No.1ar
ea
63.67±
1.53
Different player grasping the rhythm of music is different. This article use unitary processing according
to the experiment dada. And adopt the Peak pressure phase, the appearance time of plantar Peak pressure
occupy one step percentage of the total time in every region. It is more meaningful and objectively
reflects the appearance time of plantar Peak pressure.
Combined with the previous chart, it is easy for us to see the plantar pressure distribution in NO.9 region
has a crucial influence on Cha Cha Cha. This article analyses the plantar Peak pressure phase on stress
in NO.9 region. Generally speaking, male players’ medial metatarsal areas on the right foot bear the
biggest pressure at around 75% of the first step.
That is rising on the medial metatarsal zones of the right foot to push the body’s gravity to the left to
reach the maximum. The left foot reaches the maximum when the gravity of second steps backwards. At
the second step, the left foot exerts from the whole foot supporting to front foot supporting, then tiptoe
supporting, pushes the gravity to posterior. At this time, the pressure of left big toe and medial
metatarsal area reach the maximum.
The female players’ medial metatarsal area on the right foot bears the biggest pressure at around 10% of
the first step. That is at the first inhibiting step, the left big toe and medial metatarsal area support the
ground. And the pressure reaches the maximum. The left foot reach the maximum at around 75% of the
first step. At this time, medial phalanx area still bears a big pressure in the final episode of the inhibiting
step.
3.4 The contacting time percentage of plantar pressure
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% Contact
120
100
80
%
Male
Male
60
Female
40
Female
20
0
No.9 areaNo.8 areaNo.7 areaNo.6 areaNo.5 areaNo.4 area No.3 area No.2 area No.1 area
Picture 3 the male and female’s contacting time percentage of plantar pressure (%)
The contacting time percentage of plantar pressure is a total time percentage between the time of plantar
force and one step. Can see from picture 3, the contacting time percentage of plantar pressure in the big
toe area and the first metatarsal area are 100%. Central forefoot is the second. The contacting time
percentages of plantar pressure in lateral forefoot area are also close to 100%. That means the forefoot
off the ground, especially the medial forefoot. At one side, because the music of Cha Cha Cha is fast, the
heel doesn’t have enough time to fall; at another side, speeding up the horizontal movement of the foot
comes up to the features of Cha Cha Cha. Also it is in order to avoid a big fluctuation affecting the
aesthetic sensibility of the dance and the force of feet. But the beginners always use the step slightly off
the ground to express the Cheerful mood of Cha Cha Cha.
We also can see the curve in the male and female’s contacting time percentage of plantar pressure is
broken-line shape. The contacting time percentage of Plantar pressure in NO.1, NO.3, NO.5 region is
bigger than in NO.2, NO.4, and NO.6 region. That means the contacting time percentage of Plantar
lateral pressure on central foot and heel is bigger than medial. Because Cha Cha Cha requests the feet be
a small horoscope during movement, also due to wearing the Latin dance shoes. In order to maintain the
stable of gravity during the standing and movement, while the big toe area and medial metatarsal area
are exerting, the lateral of central foot and heel bear a bigger pressure than medial to maintain the stable.
The contacting time increases correspondingly.
4 Conclusions and Recommendations
4.1 The forefeet bear the bigger pressure during the Cha Cha Cha. Especially the big toe region and
No.1 metatarsus bones region. The heels bear the smaller pressure. So the players should strengthen the
practice of medial metatarsal region and the big toe region, make the action stronger and prevent from
injuring at the same time.
4.2 The pressure reaches the maximum when right foot medial metatarsal areathe of male players is at
5th step. The left foot reaches the maximum during the gravity back warding at the second step. Both
feet of female players reach the maximum during the first inhibiting step.
4.3 During the square step, the forefoot off the ground, especially the medial forefoot. At one side it is in
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order to avoid a big fluctuation affecting the aesthetic sensibility, at another side speeding up the
horizontal movement.
Author in brief:
Writer introduction: Lanqiong, Jiang(1959-), Female, Quzhou, Zhejiang, vice-professor, the research
direction is athletic sports, Tel:13059765665 ,E-mail: [email protected];
Xiaoqian, pen(1985-), Female, Quzhou, Zhejiang, master graduate in study, the research direction is
sports technology measure and evaluation, E-mail: [email protected].
Writer Entity: Quzhou Professional Technology College, Quzhou, Zhejiang, China, 324000
Zhejiang Normal University, Jinhua, Zhejiang, China 321004
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