Playing Basketball on Wooden and Asphalt Courts-Does Court Surface Affect Foot Loading?

Abstract

This study aimed to examine the influence of court surface on foot loading when executing typical basketball tasks. Thirteen male basketball players performed three basketball related tasks: Layup, jump shot, and maximal effort sprint on wooden and asphalt courts. In-shoe plantar loading was recorded during the basketball movements and peak force (normalised to body weight) was extracted from eight-foot regions. Perceptions of discomfort at the ankle, knee, and back were surveyed using a 10-cm visual analogue scale. Landing from a layup on the wooden court resulted in elevated peak forces at the hallux (p = 0.022) and lesser toes (p = 0.007) compared with asphalt court. During the sprint acceleration step, higher peak forces were observed at the hallux (p = 0.048) and medial forefoot (p = 0.010) on wooden court. No difference between court surfaces was found for perception ratings at the ankle, knee, or back. These results suggested that players can experience greater impact forces at the toes and medial forefoot when performing basketball tasks on the more compliant wooden court than asphalt courts.

Full text

Kong et al. Int J Foot Ankle 2018, 2:009
Volume 2 | Issue 2
International Journal of
Foot and Ankle
Citaon: Kong PW, Nin DZ, Quek RKK, Chua YK (2018) Playing Basketball on Wooden and Asphalt
Courts-Does Court Surface Aect Foot Loading?. Int J Foot Ankle 2:009.
Accepted: July 18, 2018; Published: July 20, 2018
Copyright: © 2018 Kong PW, et al. This is an open-access arcle distributed under the terms of the
Creave Commons Aribuon License, which permits unrestricted use, distribuon, and reproducon
in any medium, provided the original author and source are credited.
Kong et al. Int J Foot Ankle 2018, 2:009
Open Access
• Page 1 of 9 •
Playing Basketball on Wooden and Asphalt Courts-Does Court
Surface Aect Foot Loading?
PW Kong*, DZ Nin, RKK Quek and YK Chua
Physical Educaon and Sports Science Academic Group, Naonal Instute of Educaon, Nanyang
Technological University, Singapore
*Corresponding author: Pui W Kong, Associate Professor, Physical Educaon and Sports Science Academic Group, Na-
onal Instute of Educaon, Nanyang Technological University, 1 Nanyang Walk, 637616, Singapore, Tel: +65-6219-
6213, E-mail: puiwah.kong@nie.edu.sg
Abstract
This study aimed to examine the inuence of court surface
on foot loading when executing typical basketball tasks.
Thirteen male basketball players performed three basket-
ball-related tasks: Layup, jump shot, and maximal effort
sprint on wooden and asphalt courts. In-shoe plantar load-
ing was recorded during the basketball movements and
peak force (normalised to body weight) was extracted from
eight-foot regions. Perceptions of discomfort at the ankle,
knee, and back were surveyed using a 10-cm visual an-
alogue scale. Landing from a layup on the wooden court
resulted in elevated peak forces at the hallux (p = 0.022)
and lesser toes (p = 0.007) compared with asphalt court.
During the sprint acceleration step, higher peak forces were
observed at the hallux (p = 0.048) and medial forefoot (p =
0.010) on wooden court. No difference between court sur-
faces was found for perception ratings at the ankle, knee, or
back. These results suggested that players can experience
greater impact forces at the toes and medial forefoot when
performing basketball tasks on the more compliant wooden
court than asphalt courts.
Keywords
Plantar pressure, Layup, Jump shot, Sprinting
exist between the various court surfaces; wooden sur-
faces consist of a supercial layer of beech wood, while
asphalt courts are typically surfaced with a layer of rub-
ber coang for shock absorpon [2]. Among coaches,
PE teachers and players, landing on wooden courts is
generally perceived to be ‘soer’ with lower impact
forces than landing on arcial surfaces. This percep-
on can be partly aributed to the lower sness of
wooden courts which allows them to undergo a greater
extent of deformaon upon impact [3]. Although the
injury stascs for wooden and arcial playing surfac-
es in basketball are not known [4], one simulaon study
has shown that wood resulted in lower landing forces
compared to asphalt grounds [2]. The study, howev-
er, simulated only vercal landing from 300 mm and
modelled the human body as a rigid lower limb. This
simplicaon fails to take into account the natural joint
movements (e.g. knee exion) that occur during land-
ing. Furthermore, basketball players execute many oth-
er impacul movements besides vercal jump landings
[5]. Thus, it is necessary to verify the simulaon study
ndings using an experimental approach.
Previous experimental studies found a higher risk of
knee (anterior cruciate ligament) injury for female team
handball players [6] and traumac injury for female
oorball players [7] on arcial surfaces than wooden
oors, possibly inuenced by shoe-court fricon. The
physical demands of basketball are considerably dier-
ent from those of team handball or oorball, with bas-
ketball players being reported to jump approximately
44 mes and sprint every 39 s in a game [5]. Given that
ORIGINAL ARTICLE
Check for
updates
Introducon
Basketball is one of the most played sports in the
world [1]. While professional basketball games are usu-
ally played on indoor wooden courts, asphalt-based
arcial courts are also popular especially for outdoor
sengs given the lower maintenance cost and higher
durability. Schools are oen equipped with both wood-
en and asphalt courts for physical educaon (PE) les-
sons and co-curricular acvies. Structural dierences

• Page 2 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
free from any lower-extremity injuries for six months
prior to the me of study. The procedures were ap-
proved by the Nanyang Technological University Instu-
onal Review Board. Parcipants were informed about
the experimental procedures, potenal benets and
risks, and their rights to withdraw at any point of the
study. Prior to tesng, wrien consent were obtained
from all parcipants.
Procedures
The experiment took place in an indoor wooden bas-
ketball court and an outdoor asphalt court coated with
All Sport surface (California Products Corporaon, An-
dover, USA). The Novel Pedar-X system (Novel GmbH,
Munich, Germany) with 99 sensors within each insole
was used to measure plantar forces. Two pairs of in-
soles, US size 9.0 and 11.0, were calibrated to 700 kPa
with the Trublu calibraon device (Novel GmbH, Mu-
nich, Germany) according to the manufacturer’s guide-
lines. To avoid the inuence of footwear, the same make
and model of basketball shoes (US size 9.0 or 11.0, Nike
Black Mumba 24, Portland, USA) were used across all
parcipants. Parcipants also wore a new pair of socks
provided by the researchers and used the same ball (Li
Ning B6000, Beijing, China) for all shoong tasks.
Eligible parcipants reported for experimental test-
ing on one occasion. First, they were surveyed on their
playing preferences and habits on wooden and arcial
courts. Next, the wireless Pedar-X device with the in-
soles was aached to the parcipants. Aer ve min-
utes of warm-up using their own rounes, parcipants
proceeded to an assigned basketball court (wooden or
asphalt, presented in a randomized order) for familiar-
izaon with the test tasks. Three typical basketball-re-
lated tasks were selected: 1) Layup; 2) Jump shot, and 3)
Sprint (Figure 1). In-shoe plantar loading was recorded
at 100 Hz while performing these tasks.
Layup (Figure 1a): The layup is the most common-
ly employed technique for scoring during basketball
games [20], and the landing biomechanics of this task
has been evaluated in numerous studies [14-17]. For
consistency, dribbling was prohibited prior to the run-
up and a right-handed layup was performed by all par-
cipants [10,18,19]. A recent study showed that for bas-
ketball layup tasks, a minimum of six to eight trials were
needed to obtain stable peak force of the whole foot
using the Pedar-X system [18]. To ensure that the peak
force data collected were suciently reliable, 10 valid
trials were recorded in the present study. A trial being
considered valid if (i) The shot was successful; (ii) The
ball made contact with the rim; or (iii) The ball made
contact with both the back-board and the rim.
Jump shot (Figure 1b): The jump shot is idened as
an eecve and frequently used shoong technique,
receiving much aenon in biomechanical studies
[17,21]. Parcipants were tasked to perform jump shots
the foot loading during basketball related movements
such as layup and side-cung are considerably higher
than that during running [8], it is crucial to understand
the forces acng on players when execung basketball
skills on dierent playing surfaces. Using a force plat-
form, McClay and colleagues [9] quaned the ground
reacon forces during typical basketball tasks in profes-
sional players and reported elevated forces of up to nine
mes an individual’s body weight upon landing from a
jump. To replicate a more realisc playing surface, Nin,
Lam and Kong, [10] used a wooden-top force plaorm
to measure impact forces during basketball layup, simu-
lated shot blocking, and drop landing tasks. Comparable
force data of such high-impact acvies, however, are
not available for other arcial playing surfaces com-
monly used in basketball.
While tradional force plaorms are useful to quan-
fy the total ground reacon forces [9-11], they are of-
ten limited to laboratory sengs and unable to locate
regional load at specic parts of the foot. Recently,
there has been increasing use of mobile in-shoe plan-
tar measurement systems to gain insights into the foot
loading when execung sports tasks on various playing
surfaces. For example, Ford, et al. [12] compared the
in-shoe loading paerns during cung on natural grass
and synthec turf among male football players. Similar-
ly, Tessu, Ribeiro, Trombini-Souza, and Sacco, [13] ex-
amined foot pressure during running on four dierent
surfaces: Asphalt, concrete, rubber, and natural grass.
Although several studies have reported plantar pres-
sure data on basketball-related tasks [8,14-19], to our
best knowledge, the inuence of basketball court sur-
faces on foot loading remains unknown.
The purpose of this study was, therefore, to inves-
gate the inuence of court surface on foot loading
during typical basketball tasks using an experimental
approach. It was hypothesized that lower forces, meas-
ured using an in-shoe system, would be observed on
wooden courts compared with asphalt courts.
Methods
Parcipants
Based on simulaon results reported by Kim, et al.
[2], a very large dierence in peak ground reacon force
between asphalt and wood surfaces were found. Thus,
a large eect size of 0.8 was used in a power analysis
to determine the minimum sample size of 12 (α = 0.05,
power = 0.80, one-tail). To account for potenal drop-
out and technical errors, thirteen healthy basketball
players (age = 23.0 (1.4) years, height = 1.75 (0.05) m,
mass = 68.4 (8.6) kg) were recruited for the study. The
inclusion criteria were 1) Males; 2) University students
who parcipated in the Instute Inter-hall Basketball
Games; 3) Had more than ve years of recreaonal bas-
ketball experience, and 4) Had foot size of US 9.0 or 11.0
measured by a Brannock device. All parcipants were

• Page 3 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
the foot on the same side of the shoong arm (right n =
12, le n = 1). For the sprint, the second (right) step rep-
resenng the acceleraon phase was chosen for anal-
ysis [8,19,22] (Figure 1c). A mask of the eight regions
(hallux, lesser toes, medial, central and lateral fore-
foot, medial and lateral arch, and heel) created using
the Novel Mulmask soware (Novel GmbH, Munich,
Germany) was applied to extract the peak force in each
foot region (Figure 2). The peak force indicates the max-
imal force in one-foot region during one step, and this
variable is commonly used in other studies examining
plantar loading during basketball-related tasks [14-18].
Peak forces were then normalised to parcipants’ body
weight (BW). An average value of all valid trials for each
movement was used for subsequent analysis.
Stascal analysis
Stascal analyses were performed using SPSS Ver-
sion 21.0 (IBM Corp, Armonk, NY, USA), with signi-
cance was set at P < 0.05. Data are expressed in mean
(standard deviaon). For the layup and jump shot land-
ings, analysis of variance (ANOVA) with repeated mea-
sures (Side × Court) was applied to the peak forces in
each of the eight foot regions. To correct for violaon
of sphericity, signicance was assessed from the Green-
house-Geisser correcon for epsilon values ≤ 0.75, and
the Huynh-Feldt correcon for epsilon > 0.75. Eect size
(paral eta squared, ηp
2) was calculated to describe the
magnitude of the dierence and values of 0.01, 0.09 and
at the free throw line using their preferred arm. All ex-
cept one parcipant shot with the right arm. Ten valid
trials were recorded using the same criteria as for the
layup described previously.
Sprint (Figure 1c). Maximal forward sprinng is highly
relevant to basketball since players sprint approximate-
ly every 39 s in a game [5]. Parcipants sprinted at max-
imal eort across the court, using the le foot as the
rst step. Since the sprint task was performed at max-
imal eort and hence more demanding than the other
tasks, ve instead of 10 successful trials were recorded
as done in a previous study on basketball-related move-
ments [8].
Aer compleng all tasks on one court surface
(wooden or asphalt), parcipants were asked to rate
their perceived level of discomfort at their ankles, knees,
and back using a visual analogue scale (VAS). The VAS
ranged from 0 (No discomfort) to 10 cm (Worst possible
discomfort) and was measured to the nearest 0.1 cm.
The same in-foot loading measurements and subjecve
percepon procedures were then repeated for the oth-
er court condion (wooden or asphalt).
Data processing
The double-leg landing steps of the layup and jump
shot were analyzed (Figure 1a and Figure 1b). Data of
the le and right feet were arranged into the shoong
and non-shoong side. The shoong side was dened as
Figure 1: Sequences of three typical basketball-related tasks: a) Layup; b) Jump shot; and c) Maximum forward sprint. Grey
circle indicates the step selected for analysis in each task.

• Page 4 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
eect size). During the sprint acceleraon step, higher
peak forces were observed on the wooden court com-
pared to asphalt court in two regions: hallux (P = 0.048,
medium eect size) and medial forefoot P = 0.010, large
eect size, Table 3).
Eight out of thirteen (61.5%) parcipants generally
preferred to play on wooden than arcial courts. Aer
performing the three basketball-related tasks on both
surfaces, no signicant dierences were found in the
VAS rangs at the ankle (wooden = 0.92 (1.11) cm, as-
phalt = 1.05 (0.99) cm, P = 0.635, r = -0.09), knee (wood-
en = 1.13 (1.68) cm, asphalt = 1.46 (1.64) cm, P = 0.293,
r = -0.21), and back (wooden = 0.89 (1.25) cm, asphalt =
0.94 (0.93) cm, P = 0.929, r = -0.02).
Discussion
This study invesgated the inuence of court surface
(wood and asphalt) on foot loading during three basket-
ball-specic manoeuvres. Contrary to our hypothesis
that lower forces would be observed on wooden than
asphalt court, our ndings showed that wooden court
resulted in higher peak forces at the toes and medial
forefoot during layup landing and sprinng. These nd-
ings oppose the common beliefs by coaches, PE teach-
ers and athletes that wooden courts can provide beer
force aenuaon compared to asphalt courts.
Landing from jumps
Although a wooden court presents a soer landing
0.25 were interpreted as small, medium and large ef-
fects, respecvely [23]. Should a signicant Side × Court
interacon be found, post-hoc pairwise comparisons
with Bonferroni adjustment were applied.
For VAS rangs and sprint acceleraon peak forces,
Wilcoxon signed-rank test was used to compare be-
tween the wooden and asphalt courts data. Non-para-
metric test was chosen owing to the relavely small
sample size. Eect size (r) was calculated and interpret-
ed as follows: Small 0.1 ≤ |r| ≤ 29, medium 0.3 ≤ |r| ≤
0.49, and large |r| ≥ 0.5 [24].
Results
For the layup landing, elevated peak forces were
found on the wooden court than the asphalt court in
two-foot regions (Table 1): Hallux (P = 0.022, large ef-
fect size) and lesser toes (P = 0.007, large eect size).
There were a few bilateral dierences of large eect
sizes between the shoong and non-shoong sides. For
the only signicant Side × Court interacon observed in
the medial forefoot (P = 0.036, large eect size, Table
1), post-hoc analysis showed signicant side-to-side dif-
ference on the asphalt court but not the wooden court.
During jump shot landing, there was no main eect of
the court type or Side × Court interacon (Table 2). As
shown in Table 2, only signicant bilateral dierences
were found, with the non-shoong side displaying high-
er forces than the shoong side at the medial forefoot (P
= 0.039, large eect size) and the heel (P = 0.002, large
Figure 2: The eight-region mask for data extraction of in-shoe foot loading measurements.

• Page 5 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
likely to adopt slightly dierent landing techniques in re-
sponse to the landing surface [25]. The present study al-
lowed players to perform typical basketball tasks on real
courts, providing good ecological validity over mechan-
ical tests, simulaon studies, and controlled laboratory
experiments (e.g. drop landing on a force plaorm). Our
ndings are consistent with previous experimental stud-
ies in which higher peak vercal forces were associated
with landing onto a mat compared to a non-mat condi-
surface [3], the present study showed that force aen-
uaon was less eecve on the wooden than asphalt
court when landing from a layup. This is in contrast to
the results obtained from a simulaon study conduct-
ed by Kim, and colleagues [2], which demonstrated that
wood ground produced lower peak forces than asphalt.
It is believed that the simulaon study over-simplied
the human body as a rigid lower limb with no exion/
extension movement abilies. In reality, parcipants are
Table 1: Statistical results of peak forces (in body weight) in eight foot regions during layup landing.
Region Court Side Statistical Results
Side Court Interaction
Non-shooting Shooting P (ηp
2)P (ηp
2)P (ηp
2)
Hallux
Wood 0.15 (0.06) 0.09 (0.06)
< 0.001
(0.716)
0.022
(0.367)
0.383
(0.064)
Asphalt 0.15 (0.06) 0.08 (0.05)
Lesser toes
Wood 0.24 (0.09) 0.30 (0.09)
0.008
(0.461)
0.007
(0.466)
0.799
(0.006)
Asphalt 0.22 (0.09) 0.28 (0.08)
Medial
forefoot
Wood 0.27 (0.06) 0.22 (0.07)
0.011
(0.431)
0.142
(0.171)
0.036
(0.317)
Asphalt 0.28 (0.05) 0.18 (0.07)
Central
forefoot
Wood 0.39 (0.07) 0.41 (0.08)
0.214
(0.126)
0.083
(0.230)
0.793
(0.006)
Asphalt 0.41 (0.08) 0.43 (0.10)
Lateral
forefoot
Wood 0.25 (0.08) 0.28 (0.08)
0.351
(0.073)
0.200
(0.133)
0.079
(0.235)
Asphalt 0.27 (0.10) 0.28 (0.08)
Medial arch
Wood 0.15 (0.11) 0.21 (0.12)
0.049
(0.286)
0.347
(0.074)
0.128
(0.182)
Asphalt 0.17 (0.09) 0.22 (0.11)
Lateral
arch
Wood 0.22 (0.11) 0.30 (0.12)
0.058
(0.268)
0.095
(0.215)
0.103
(0.206)
Asphalt 0.26 (0.09) 0.31 (0.11)
Heel
Wood 0.29 (0.24) 0.65 (0.35)
0.003
(0.543)
0.718
(0.011)
0.653
(0.017)
Asphalt 0.33 (0.19) 0.64 (0.27)
Total
Wood 1.71 (0.31) 2.06 (0.51)
0.055
(0.274)
0.376
(0.066)
0.330
(0.079)
Asphalt 1.81 (0.26) 2.07 (0.63)
Note: Data are expressed in mean (SD). The shooting side was dened as the foot on the same side of the shooting arm (right
for all participants). Signicant P-values from repeated measures ANOVA (P < 0.05) are shown in bold. Effect size (ηp
2) values of
0.01, 0.09 and 0.25 were interpreted as small, medium and large effects, respectively.

• Page 6 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
Sprint acceleraon
It was found that when sprinng on the wooden
court, parcipants pushed o with greater force at the
hallux and medial forefoot compared to when moving
across the asphalt court. While it is possible that par-
cipants required more forces to push o from a more
compliant surface, the adopon of a dierent sprint
technique (increased planng at the forefoot) is likely
to be part of a compensatory mechanism to augment
on [25,26]. It is possible that parcipants in the pres-
ent study adopted a ser landing strategy owing to the
perceived higher compliance of the wooden compared
to asphalt surface. The higher force experienced when
landing on a more compliant surface is due to a ser
landing strategy characterized by reduced hip and knee
joint exion, coupled with increased acvaon of mus-
cles crossing the knee joint [25]. Future studies can con-
rm this speculaon by including kinemac variables.
Table 2: Statistical results of peak forces (in body weight) in eight foot regions during jump shot landing.
Region Court Side Statistical Results
Side Court Interaction
Non-shooting Shooting P (ηp
2)P (ηp
2)P (ηp
2)
Hallux
Wood 0.12 (0.06) 0.08 (0.04)
0.073
(0.244)
0.906
(0.001)
0.240
(0.113)
Asphalt 0.11 (0.07) 0.09 (0.05)
Lesser toes
Wood 0.21 (0.10) 0.22 (0.10)
0.432
(0.052)
0.283
(0.095)
0.782
(0.007)
Asphalt 0.18 (0.10) 0.21 (0.11)
Medial
forefoot
Wood 0.25 (0.10) 0.18 (0.09)
0.039
(0.309)
0.820
(0.004)
0.268
(0.111)
Asphalt 0.24 (0.10) 0.20 (0.09)
Central
forefoot
Wood 0.40 (0.11) 0.34 (0.23)
0.260
(0.105)
0.535
(0.033)
0.673
(0.015)
Asphalt 0.36 (0.10) 0.32 (0.13)
Lateral
forefoot
Wood 0.23 (0.09) 0.20 (0.12)
0.568
(0.028)
0.580
(0.026)
0.227
(0.119)
Asphalt 0.20 (0.07) 0.21 (0.11)
Medial arch
Wood 0.07 (0.07) 0.05 (0.06)
0.751
(0.015)
0.185
(0.142)
0.115
(0.194)
Asphalt 0.07 (0.07) 0.08 (0.10)
Lateral
arch
Wood 0.16 (0.10) 0.10 (0.08)
0.192
(0.139)
0.584
(0.026)
0.091
(0.220)
Asphalt 0.15 (0.06) 0.13 (0.10)
Heel
Wood 0.38 (0.24) 0.23 (0.23)
0.002
(0.564)
0.728
(0.010)
0.957
(< 0.001)
Asphalt 0.35 (0.18) 0.22 (0.17)
Total
Wood 1.30 (0.40) 1.09 (0.58)
0.483
(0.042)
0.834
(0.004)
0.244
(0.111)
Asphalt 1.23 (0.26) 1.20 (0.53)
Note: Data are expressed in mean (SD). The shooting side was dened as the foot on the same side of the shooting arm (right
n = 12, left n = 1). Signicant P-values from repeated measures ANOVA (P < 0.05) are shown in bold. Effect size (ηp
2) values of
0.01, 0.09 and 0.25 were interpreted as small, medium and large effects, respectively.

• Page 7 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
Potenal role of footwear
Both the layup and sprint are common movements
in basketball; the eect of increased peak forces experi-
enced while execung these manoeuvres on the wood-
en court is amplied due to the frequency at which they
are performed. Players, PE teachers and coaches should
be mindful of the loading demands across dierent
shoe-court combinaons, in parcular, the increased
forces associated with a more compliant and slippery
surface. Although the playing environment is usually un-
modiable, wearing appropriate footwear can play an
important role in aenuang forces. Most studies inves-
shoe-court fricon on the wooden court. Wooden sur-
faces have been found to possess fricon coecients
which are less than half of those of their asphalt coun-
terparts [27]. Thus, it was probable that parcipants
executed a sprinng technique which induced greater
tracon, in order to reduce the likelihood of slipping and
its resultant injury. However, it is also essenal to ac-
knowledge that excessive shoe-court fricon might give
rise to lower extremity injuries caused by overloading
[28]. Moreover, increased regional loading at the foot
could lead to higher skin temperature which could in
turn result in blistering [29].
Table 3: Statistical results of peak forces (in body weight) in eight foot regions during sprint acceleration step.
Region Surface Peak Force P-value Effect size (r)
Hallux
Wood 0.13 (0.07)
0.048 -0.39
Asphalt 0.12 (0.07)
Lesser toes
Wood 0.34 (0.10)
0.140 -0.29
Asphalt 0.30 (0.06)
Medial forefoot
Wood 0.36 (0.12)
0.010 -0.50
Asphalt 0.34 (0.10)
Central forefoot
Wood 0.57 (0.12)
0.387 -0.17
Asphalt 0.56 (0.13)
Lateral forefoot
Wood 0.27 (0.10)
0.350 -0.18
Asphalt 0.25 (0.11)
Medial arch
Wood 0.04 (0.04)
0.573 -0.11
Asphalt 0.03 (0.04)
Lateral arch
Wood 0.10 (0.08)
0.289 -0.21
Asphalt 0.08 (0.07)
Heel
Wood 0.18 (0.26)
0.721 -0.07
Asphalt 0.14 (0.28)
Total
Wood 1.62 (0.26)
0.011 -0.50
Asphalt 1.53 (0.28)
Note: Data are expressed in mean (SD). Signicant P-values from Wilcoxon signed-rank tests (P < 0.05) are shown in bold. Effect
sizes were interpreted as: small 0.1 ≤ |r| ≤ 29, medium 0.3 ≤ |r| ≤ 0.49, large |r| ≥ 0.5.

• Page 8 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
tensive unilateral upper-limb usage had an imbalanced
strengthening eect on the lower-limbs, thereby result-
ing in asymmetrical landing strategies. As such, players
and coaches should be aware of the loading asymmetry
when landing from these movements and implement
appropriate intervenons such as using customised or-
thoses. Future research should consider examining the
eect of upper-limb dominance on lower-limb biome-
chanics during basketball tasks.
Limitaons
There were a few limitaons to this study. Firstly,
no kinemac or performance variables such as jump
height and sprint speed were obtained. Such informa-
on would have been useful in understanding the re-
laonship between surface compliance and movement
technique adopted by the parcipants. Considering that
the parcipants in the present study were skilled play-
ers and that the movement tasks studied were basic and
frequently executed skills [5,17,20,21], it is unlikely that
they would alter their performance substanally due to
surface compliance. Moving forward, kinemac analy-
sis should be included in addion to foot loading such
that jump height and landing techniques between sur-
faces can be compared. Secondly, mechanical tests to
accurately measure surface compliance and shoe-sur-
face tracon were not conducted due to the constraints
in facilies and resources in our laboratory. Since the
wooden and asphalt surfaces used in the present study
are standard sport courts, it is expected that their re-
specve mechanical properes are similar to those re-
ported in the literature. To strengthen the study design,
future studies should include mechanical tests to meas-
ure the sness of dierent court surfaces. Thirdly, only
peak forces at the foot were measured and these forces
do not necessarily reect the loading at individual joints
such as the knee and the hip. Inverse dynamics calcu-
laons would be needed to quanfy joint kinecs for a
more comprehensive analysis. Finally, it should be ac-
knowledged the P-values reported throughout are un-
adjusted nominal values. Since the peak force in several
foot regions were stascally compared, readers should
be aware of the increased change of comming type I
error resulng from mulple comparisons.
Conclusion
As opposed to common percepon and previous
simulaon study ndings, the present experimental
study on basketball players showed that wooden courts
did not provide beer impact force aenuaon com-
pared to asphalt courts. Instead, players experienced
greater peak forces at the toes and medial forefoot on
the more compliant wooden court during layup landing
and sprinng. Coaches, PE teachers and athletes should
be informed that playing basketball on wooden courts
can expose players to higher forces in the foot. Future
studies should invesgate the interplay between playing
surface, foot loading, and risk of injuries.
gang the interacon between athlec shoe and play-
ing surface have focused on the property of shoe-sur-
face tracon [30,31]. The ndings of this study suggest
that shoe-surface interacon can also aect vercal im-
pact loading alongside shearing forces. Thus, shoe cush-
ioning properes such as midsole hardness should be
invesgated along with friconal properes to provide
a beer understanding of the shoe-surface interacon.
This is especially imperave for sports such as basket-
ball which frequently involves both jumping and running
movements. Future work could look at how both the
friconal and cushioning properes of a shoe inuence
contact forces at foot-shoe and shoe-surface interfaces.
Perceptual response to playing surfaces
In addion to biomechanical loadings, perceptual
responses of the parcipants to landing on the dier-
ent surfaces were also studied. It was found that parc-
ipants perceived landing on both surfaces to be equally
comfortable. A previous study showed that basketball
players are able to disnguish between shoe midsole
hardness condions through the perceptual parame-
ter of comfort level while performing several basketball
movements [10]. In another study on layup and side-cut-
ng tasks, recreaonal basketball players indicated sim-
ilar perceived stability for shoes with soer and harder
midsoles, and that there was no relaonship between
biomechanical and subjecve measurements [32]. In
the present study, the majority of parcipants preferred
playing on a wooden to an asphalt court. There were,
however, no dierences in perceptual responses to
comfort at the ankle, knee, and back aer performing
basketball-related movements on both courts. This sug-
gests that players might be more sensive to changes
in shoe hardness [10,19] compared to surface compli-
ance. It is also likely that a certain threshold of impact
force may be required for neural feedback of the body
before an individual can accurately dierenate be-
tween shoe-surface compliance condions. Given that
players’ court preference can be inuenced by factors
other than comfort, future studies should consider in-
vesgang the relaonship between perceived surface
compliance and landing biomechanics.
Bilateral asymmetry
The layup and jump shot are movements involving
a double-leg landing; the bilateral asymmetry of such
landings has been found to be associated with low-
er-limb injuries [33]. An interesng secondary nding
in the present study showed that when landing from a
layup, side-to-side asymmetry of impact forces exists,
with substanal asymmetry directed towards the shoot-
ing side at the lateral arch and heel regions. This bilat-
eral asymmetry might have developed from prolonged
parcipaon in a sport which relies predominantly on
unilateral upper-limb movements, for example, drib-
bling and shoong in basketball. It is possible that in the
kinec chain of dierent basketball movements, an ex-

• Page 9 of 9 •
Kong et al. Int J Foot Ankle 2018, 2:009
16. Queen RM, Mall NA, Nunley JA, Chuckpaiwong B (2009)
Differences in plantar loading between at and normal feet
during different athletic tasks. Gait Posture 29: 582-586.
17. Pau M, Ciuti C (2013) Stresses in the plantar region for
long- and short-range throws in women basketball players.
Eur J Sport Sci 13: 575-581.
18. Chua YK, Quek RK, Kong PW (2017) Basketball lay-up-foot
loading characteristics and the number of trials necessary
to obtain stable plantar pressure variables. Sports Biomech
16: 13-22.
19. Lam WK, Ng WX, Kong PW (2017) Inuence of shoe mid-
sole hardness on plantar pressure distribution in four bas-
ketball-related movements. Res Sports Med 25: 37-47.
20. Wang J, Liu W, Moft J (2009) Skills and offensive tactics
used in pick-up basketball games. Percept Mot Skills 109:
473-477.
21. Okazaki VH, Rodacki AL, Satern MN (2015) A review on
basketball jump shot. Sports Biomech 14: 190-205.
22. Coh M, Tomazin K, Stuhec S (2006) The biomechanical
model of the sprint starts and block acceleration. Facta Uni-
versitatis Series Physical Education and Sport 4: 103-114.
23. Hanna D, Dempster M (2012) Psychology Statistics for
Dummies. John Wiley and Sons, West Sussex, 165-183.
24. Field A (2009) Discovering Statistics Using SPSS. (3rd edn),
SAGE Publication, London, 56-57.
25. http://www.asbweb.org/conferences/2012/abstracts/225.
pdf
26. McNitt-Gray JL, Yokoi T, Millward C (1994) Landing strat-
egies used by gymnasts on different surfaces. J Appl Bio-
mech 10: 237-252.
27. Carre MJ, Clarke JD, Damm L, Dixon SJ (2014) Friction
at the tennis shoe-court interface: How biomechanically in-
formed lab-based testing can enhance understanding. Pro-
cedia Engineering 72: 883-888.
28. Wannop JW, Worobets JT, Stefanyshyn DJ (2010) Foot-
wear traction and lower extremity joint loading. Am J Sports
Med 38: 1221-1228.
29. Yavuz M, Davis BL (2010) Plantar shear stress distribution
in athletic individuals with frictional foot blisters. J Am Podi-
atr Med Assoc 100: 116-120.
30. Bentley JA, Ramanathan AK, Arnold GP, Wang W, Abboud
RJ (2011) Harmful cleats of football boots: A Biomechanical
Evaluation. Foot Ankle Surgery 17: 140-144.
31. Grund T, Senner V (2010) Traction behavior of soccer shoe
stud designs under different game-relevant loading condi-
tions. Procedia Engineering 2: 2783-2788.
32. Leong HF, Lam W, Ng WX, Kong PW (2018) Centre of
pressure and perceived stability in basketball shoes with
soft and hard midsoles. J Appl Biomech 3: 1-7.
33. Hewett TE, Myer GD, Ford KR, Heidt RS Jr, Colosimo AJ,
et al. (2005) Biomechanical measures of neuromuscular
control and valgus loading of the knee predict anterior cru-
ciate ligament injury risk in female athletes: A prospective
study. Am J Sports Med 33: 492-501.
Disclosure of Interest
The authors declare that they have no compeng in-
terest.
References
1. Daneshvar DH, Nowinski CJ, McKee AC, Cantu RC (2011)
The epidemiology of sport-related concussion. Clin J Sports
Med 30: 1-17.
2. Kim SH, Cho JR, Choi JH, Ryu SH, Jeong WB (2012) Cou-
pled foot-shoe-ground interaction model to assess landing
impact transfer characteristics to ground condition. Interac-
tion and Multiscale Mechanics 5: 75-90.
3. Bartlett R, Gratton C, Rolf C (2006) Encyclopedia of Inter-
national Sports Studies. Routledge, London.
4. Dragoo JL, Braun HJ (2010) The effect of playing surface
on injury rate. Sports Med 40: 981-990.
5. Ben Abdelkrim N, El Fazaa S, El Ati J (2007) Time-motion
analysis and physiological data of elite under-19-year-old
basketball players during competition. Br J Sports Med 41:
69-75.
6. Olsen OE, Myklebust G, Engebretsen L, Holme I, Bahr R
(2003) Relationship between oor type and risk of acl injury
in team handball. Scand J Med Sci Sports 13: 299-304.
7. Pasanen K, Parkkari J, Rossi L, Kannus P (2008) Articial
playing surface increases the injury risk in pivoting indoor
sports: A prospective one-season follow-up study in nnish
female oorball. Br J Sports Med 42: 194-197.
8. Kong PW, Lam WK, Ng WX, Aziz L, Leong HF (2018) In-
shoe plantar pressure proles in amateur basketball play-
ers-implications for footwear recommendations and ortho-
sis use. J Am Podistr Med Assoc 108: 215-224.
9. McClay IS, Robinson JR, Andriacchi TP, Frederick EC,
Gross T, et al. (1994) A prole of ground reaction forces in
professional basketball. J Appl Biomech 10: 222-236.
10. Nin DZ, Lam WK, Kong PW (2016) Effect of body mass
and midsole hardness on kinetic and perceptual variables
during basketball landing manoeuvres. J Sports Sci 34:
756-765.
11. Zhang S, Clowers K, Kohstall C, Yu YJ (2005) Effects of
various midsole densities of basketball shoes on impact at-
tenuation during landing activities. J Appl Biomech 21: 3-17.
12. Ford KR, Manson NA, Evans BJ, Myer GD, Gwin RC, et
al. (2006) Comparison of in-shoe foot loading patterns on
natural grass and synthetic turf. J Sci Med Sport 9: 433-440.
13. Tessutti V, Ribeiro AP, Trombini-Souza F, Sacco IC (2012)
Attenuation of foot pressure during running on four different
surfaces: Asphalt, concrete, rubber, and natural grass. J
Sports Sci 30: 1545-1550.
14. Guettler JH, Ruskan GJ, Bytomski JR, Brown CR, Richard-
son JK, et al. (2006) Fifth metatarsal stress fractures in elite
basketball players: Evaluation of forces acting on the fth
metatarsal. Am J Orthop 35: 532-536.
15. Yu B, Lin CF, Garrett WE (2006) Lower extremity biome-
chanics during the landing of a stop-jump task. Clin Bio-
mech 21: 297-305.