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Differences of free-throw shot in wheelchair basketball and conventional players

Differences of free-throw shot in wheelchair
basketball and conventional players
Giovana Duarte Eltz1, Enaile Farias Moraes2, Cína Mussi Alvim Stocchero3, Clarice Speroo dos
Santos Rocha4, Mauro Gomes Matos5
1 Physiotherapist, Mastering in Rehabilitaon
2 Physiotherapist.
3 Professor at the Instuto Federal de Educação,
Ciência e Tecnologia do Rio Grande do Sul - IFRS
(Federal Instute of Educaon, Science, &
Technology of Rio Grande do Sul).
4 Physiotherapist, Professor at the Universidade
Federal do Rio Grande do Sul - UFRGS (Federal
University of Rio Grande do Sul).
5 Physiotherapist, Centro Universitário Metodista,
Instuto Porto Alegre da Igreja Metodista - IPA.
Mailing address:
Giovana Duarte Eltz
Rua, 13b
CEP 13506-748
Rio Claro - SP
Received on November 21, 2014.
Accepted on September 14, 2015.
DOI: 10.5935/0104-7795.20150028
Wheelchair Basketball (WB) follows almost the same rules as Convenonal Basketball (CB). Ob-
jecve: Evaluate the electromyographic (EMG) acvaon of the pectoralis major (PM), anterior
deltoid (AD), and triceps brachii (TB) muscles during shoong in CB and WB athletes and to verify
whether there is any dierence in muscle acvaon between the categories. Method: Comparing
two groups in a transversal study, CB and WB, in which eleven individuals submied to an electro-
myographic examinaon, of muscles PM, AD, TB on the extremity that was doing the shoong. We
used a 4-channel EMG (Miotec/Brazil) (2000Hz/channel). Results: Comparing the muscles, the CB
group showed a signicant dierence: greater AD muscle acvaon compared to the others; how-
ever in the WB group, no dierences were found. When comparing between the groups, the PM
muscle showed greater acvaon in the WB group, while the AD muscle was more acve in the
CB group. The TB muscle showed no dierence between groups. Conclusion: From these results,
the athletes from the CB and WB groups showed dierences in muscle acvaon during shoong.
However, both groups acvated the AD the most, followed by the TB. The least acve muscle was
the PM, and these dierences were more visible in the CB group.
Keywords: Sports for Persons with Disabilies, Basketball, Upper Extremity, Electromyography
Acta Fisiatr. 2015;22(3):145-149 Eltz GD, Moraes EF, Stocchero CMA, Rocha CSS, Matos MG
Differences in free-throw shooting between conventional and wheelchair basketball
Shooting is considered the most impor-
tant element of basketball.1 In dealing with
wheelchair basketball (WB), the athletes
are known to have varying degrees of phy-
sical limitations so, to assure fair competi-
tions, a functional classification was crea-
ted in 1982. This system is based on ob-
servation of the athletes’ movements and
their abilities demonstrated while playing
the adapted sport.2
The classification is made by a skilled
team evaluating a group of actions perfor-
med by the athlete in his wheelchair. Each
player receives a score ranging from 1.0 to
4.5 and the sum of a team’s players on the
court cannot total more than 14 points.2
As for the wheelchair suitable for playing
basketball, there are some regulations that
have been established by the International
Wheelchair Basketball Federation (IWBF).
The measurements of the court and the ru-
les of the wheelchair game follow the rules
of conventional basketball exactly.3
Electromyography (EMG) is defined by
the measurement of the algebraic sum of
the action potentials of the motor units
of a muscle by means of electrodes, whi-
ch makes it possible to study the electrical
activity of muscles during a certain activity,
which can prove whether a proposed reha-
bilitation exercise is effective, and if and
when a muscle is solicited during a certain
There are only a few studies in the li-
terature evaluating electrical activity in the
muscles involving shooting a basketball
and that compare conventional basketball
and wheelchair basketball athletes. After
verifying which muscles are most summo-
ned in the shooting activity, preventive ac-
tivities can be emphasized that can reduce
the frequency of injuries in conventional
basketball players as well as in WB athle-
tes. Whether a distinct training approach
is necessary for these two groups remains
unknown, despite their making the same
movements in the same sport, nor is it
known whether their musculature is acti-
vated in the same manner.
The objecve of this study was to elec-
tromyographically evaluate the pectoralis
major (PM), the anterior deltoid (AD), and the
triceps brachii (TB) muscles during shoong,
and compare the acvity of the muscles be-
tween convenonal and wheelchair basketball
players, as well as to compare the acvaon
between the muscles in each group.
This was a cross-sectional study, inclu-
ding participants of CB and WB from the
metropolitan region of Porto Alegre, in the
state of Rio Grande do Sul, and was appro-
ved by the Committee on Ethics in Resear-
ch at the Centro Universitário Metodista
of the IPA under protocol No. 264/09. All
the athletes signed the terms of informed
Included in this study were 11 males
who had been playing basketball for at
least one year-6 in the CB group and 5 in
the WB group. Their ages ranged from 25 to
45 years and they all played at least twice
a week. Excluded from this study were tho-
se presenting symptomatic injuries for less
than 3 months on the upper extremities for
either group, or lower extremities for the
CB group. The WB players were unilateral
amputees with a functional class between
3.5 and 4.5 and they all used wheelchairs
as a means of routine locomotion.
The EMG signal from the PM, AD, and
TB muscles were collected during free-
-throw movements by using a 4-channel
Miotool 400 electromyography machine
(Miotec®/Brazil) with a sampling frequency
of 2,000Hz per channel (14-bit resolution,
common mode rejection of 110db) using
2.2 cm diameter bipolar electrode pairs
(Ag/AgCl from Meditrace, Canada) and
Miograph 2.0 software. Skin impedance
was reduced by shaving, and asepsis with
70% alcohol, following the guidance from
the International Society of Electrophysio-
logy and Kinesiology.5 The electrodes were
all positioned according to the norms of
the SENIAM project (Surface Electromyo-
graphy for the Non-Invasive Assessment
of Muscles). The reference electrode was
set on the anterior tibial tuberosity on the
same side as was being evaluated.
There was an initial ten-minute free
warm-up where they did free-throws, lay-
-ups, and passes. Then the players each
shot their free-throws, the second success-
ful of which was validated, and considered
for the study. Those who did not make 2
of their 5 attempts waited for 3 minutes
and tried again. The shots were made on
a basket of the same height and distance,
on the free-throw line, as adopted by the
FIBA (International Federation of Baske-
tball) and by the IWBF for conventional
players as well as wheelchair players. The
ball adopted for this study was the same
for all the individuals, weighing 0.555kg.
The WB players used a wheelchair that
complied with the requirements demanded
by the IWBF and the ranges contained in
their functional classification cards.
For later normalization of the muscle
activation data of each athlete in the tes-
ted tasks, maximum voluntary isometric
contractions (MVIC) were made in the mus-
cle function test position before the free-
To analyze the EMG signals, the SAD 32
program (version 2.61) was used, adopting
the following procedures: removal of conti-
nuous component, elimination of gain, fil-
tering, and signal cut. The signals were sub-
mitted to the filtering process by 3rd-order
FFT Butterworth filters (20-500Hz). The
RMS value (root mean square) was calcula-
ted for all the muscles evaluated, and then
normalized by the RMS and MVIC values of
each muscle of each individual. To analyze
the data, the averages of the normalized
RMS values were calculated for each mus-
cle within each group.
The Shapiro-Wilk test was used in the
statistical analysis to verify the normality
of the data distribution. To compare be-
tween groups, the Student T-test was used
for non-paired samples. The single-factor
ANOVA was used for comparisons within
the groups. The GraphPad Prism program
(version 5.0) was used adopting a signifi-
cance level of p < 0.05.
The characteriscs of the groups are des-
cribed in Table 1. A signicant dierence was
noted as to height and weight variables regar-
ding the characteriscs of the sample.
Comparing between the electrical ac-
vaon of the muscles within the CB group, a
stascally signicant dierence was found,
where greater acvaon of the AD muscle
was observed in relaon to the PM muscle (p
< 0,001) and in relaon to the TB muscle (p
< 0.001) (Figure 1). The WB group, however,
showed no stascally signicant dierence
between the muscles evaluated.
Comparisons between the two groups
show that the electromyographical acvity of
the PM muscle was greater in the WB group
Acta Fisiatr. 2015;22(3):145-149 Eltz GD, Moraes EF, Stocchero CMA, Rocha CSS, Matos MG
Differences in free-throw shooting between conventional and wheelchair basketball
Table 1. Characteristics of the CB and WB groups
Characteristics CB (n = 6) WB (n = 5) P value
Age (years) 32.17 ± 1.96 35.60 ± 2.62 0.311
Height (m) 1.92 ± 0.03 1.740 ± 0.06 0.016
Weight (Kg) 107.2 ± 7.55 78.20 ± 5.70 0.016
BMI (Kg/m2) 28.84 ± 1.40 26.19 ± 2.63 0.375
Training time (years) 14.83 ± 3.06 08.00 ± 2.78 0.137
*Legend: CB = Convenonal Basketball; WB = Wheelchair Basketball; n = number of subjects; p = stascal signicance value (p < 0.05)
Figure 1. Comparison of EMG activation between the CB group and the WB group
(p < 0.05) (Figure 2) while the AD activation
was greater in the CB group (p < 0.05) (Fi-
gure 3).
The TB muscle presented no statisti-
cally significant difference when comparing
between the groups (Figure 4).
The present study did not verify any
statistical differences regarding average
age, time of practicing the sport, or BMI
between the groups in spite of showing
a statistical difference between these
players’ weights and heights.
Despite their heights having a statistical
difference, the WB group was measured in
orthostasis even though they practice their
sport in the sitting position, because this
difference would be greater if we took the
height of the seated subject into conside-
ration. The height of the player influences
the shooting. Okazaki et al.7 reported that
during free-throws the knee flexion is less
relevant due to the height of the player-
s-the taller the player the less the legs
move, with the upper extremities being the
main engine in performing the movement.
In a contrasting study by Okazaki et al.,8
they state that the thrust from the lower
extremities is also of great importance in
improving the shot for it increases the body
leverage and allows the ball to be released
from a higher position in relation to the
Studies contend that the person’s hei-
ght and leg thrust can influence the execu-
tion of the shot.7,9 This gives the WB group
a great disadvantage in free-throwing sin-
ce they are down lower (sitting) and can-
not use their legs for thrust. Therefore it
is likely that the WB group adopts distinct
strategies to make this movement. Studies
from Elliott10 and Miller & Bartlett11 suggest
that a greater shoulder flexion allows the
subjects to increase the height of their re-
lease of the ball. This being the case, the
WB group needs a greater activation of the
shoulder muscles to make this shot. This is
what the study by Schwark et al.12 claims-
-that there is a greater demand from the
shoulder during a wheelchair free-throw;
the upper arm tends to remain more in a
vertical position than what is observed for
a conventional player making a shot.
This research observed the activations
of the AD, PM, and TB muscles in the WB
group similar to other muscles evaluated,
probably by the angle of the sports move-
ment being higher than in the CB group,
by playing sitting down, and by not having
the assistance of the leg muscles. Another
study states that, in this modality, there is
greater strength required due to the increa-
sed distance to the basket and that there is
a reduced ability to generate force due to
the lack of available energy from the lower
extremities.13 This concurs with the study by
Malone et al.14 which argued that, since WB
players are positioned lower and have to
generate propulsion mostly from the upper
body, it is reasonable to expect that the skill
would need to be somewhat modified.
We agree that this distinct shooting
strategy is necessitated by the non-use of
the lower extremities and by the low po-
sitioning for making this movement. These
factors can be directly related to the va-
riability of the movement, allowing simi-
lar activations to be generated among the
evaluated muscles. Another fact that con-
tributes to such a similarity of activation
is that these three muscles generate the
main thrust from the wheelchair15
Acta Fisiatr. 2015;22(3):145-149 Eltz GD, Moraes EF, Stocchero CMA, Rocha CSS, Matos MG
Differences in free-throw shooting between conventional and wheelchair basketball
Figure 2. Comparison between groups of the Pectoralis Major muscle.
Figure 3. Comparison between groups of the Anterior Deltoid muscle
The AD muscle along with the rotator
cuff are necessary driving components for
shoulder flexion and joint stabilization,16
which justifies their greater activation in
both groups. In the CB group this activation
is more visible, possibly because there is
less activation of the PM muscle for them.
In the WB group the greatest activation is
also in the AD, however a similar activation
can be seen in the PM muscle; this may be
a type of compensation and also because
this muscle is heavily used in the locomo-
tion of these players.
Some authors have considered the elbow
extension as the most important movement in
shoong, for this joint is considered most res-
ponsible in maximizing the speed at the ins-
tant of releasing the ball.13,17,18 The TB muscle,
responsible for this movement, was acvated
similarly between the two groups, suggesng
that it is a standard. In a study by Zachry et
al.,19 during the CB shoong, the EMG was
evaluated for the medial deltoid and the TB.
In that study the TB was more acvated, whe-
reas in the present study the TB was the se-
cond most acvated in both groups.
A recent study by Ozmen et al.20 showed
the importance of a training program for ex-
plosive strength in the upper extremies in
the sprint speed and agility of WB athletes.
Muscle strength is very important for com-
peve wheelchair basketball players. This is
why it is fundamental to idenfy which mus-
cles are most acvated in the fundamental act
of basketball: shoong.
The differences in muscle activation of
the upper extremities between conventio-
nal and wheelchair basketball athletes was
verified in this study. This information can
be important in improving technique while
training the athletes as well as for basing
physiotherapeutic conduct during treat-
ment and preventing injuries to these athle-
tes. This study evaluated a small sample due
to the difficulty in finding WB players that
would fit into our inclusion criteria, whi-
ch could be considered a limitation to this
Considering the results of the present
study, one could conclude that the athletes
from the WB and the CB groups showed di-
fferences in electrical activation during the
shooting movement. However, both groups
activated the AD the most, followed by the
TB, and the least was the PM; these diffe-
rences were most visible in the CB group.
Acta Fisiatr. 2015;22(3):145-149 Eltz GD, Moraes EF, Stocchero CMA, Rocha CSS, Matos MG
Differences in free-throw shooting between conventional and wheelchair basketball
Figure 4. Comparison between groups of the Brachial Triceps muscle.
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... To date, studies have focused on several factors of wheelchair basketball, such as shooting accuracy (Fay et al., 2013), game-related statistics (Valandewijick et al., 2004;Gómez et al., 2014), trunk function (Saltan & Ankarali, 2017;Santos et al., 2017), anthropometry (Cavedon et al., 2015), physical fitness test (Marszałek et al., 2019), and visual control training (Oudejans et al., 2012). In addition, several studies examined kinematic data on free-throw shooting in wheelchair basketball (Goosey-Tolfrey et al., 2002;Malone et al., 2002;Numome et al., 2002;Schwark et al., 2004;Eltz et al., 2015;Hanks & Oliver, 2018). Free-throw shooting skill and accuracy are important for all wheelchair basketball players as well as regular basketball players, irrespective of age, sex, position, and playing points. ...
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