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Pe o mance in dynamic mo emen asks and occu ence o low back pain in you h
loo ball and baske ball playe s
© The Au ho s. 2020
Published e sion
Rossi, M. K.; Pasanen, K.; Heinonen, A.; Äy ämö, S.; Räisänen, A. M.; Leppänen,
M.; Myklebus , G.; Vasanka i, T.; Kannus, P.; Pa kka i, J.
Rossi, M. K., Pasanen, K., Heinonen, A., Äy ämö, S., Räisänen, A. M., Leppänen, M., Myklebus ,
G., Vasanka i, T., Kannus, P., & Pa kka i, J. (2020). Pe o mance in dynamic mo emen asks and
occu ence o low back pain in you h loo ball and baske ball playe s. BMC Musculoskele al
Diso de s, 21, A icle 350. h ps://doi.o g/10.1186/s12891-020-03376-1
2020
RESEARCH ARTICLE Open Access
Pe o mance in dynamic mo emen asks
and occu ence o low back pain in you h
loo ball and baske ball playe s
M. K. Rossi
1,2*
, K. Pasanen
1,3,4,5
, A. Heinonen
2
, S. Äy ämö
6
, A. M. Räisänen
3
, M. Leppänen
1
, G. Myklebus
7
,
T. Vasanka i
1
, P. Kannus
1,8
and J. Pa kka i
1,9
Abs ac
Backg ound: P ospec i e s udies in es iga ing isk ac o s o low back pain (LBP) in you h a hle es a e limi ed. The
aim o his p ospec i e s udy was o in es iga e he associa ion be ween hip-pel ic kinema ics and e ical g ound
eac ion o ce ( GRF) du ing landing asks and LBP in you h loo ball and baske ball playe s.
Me hods: Th ee-hund ed-and-eigh y- h ee Finnish you h emale and male loo ball and baske ball playe s (mean
age 15.7 ± 1.8) pa icipa ed and we e ollowed up on o 3 yea s. A he beginning o e e y s udy yea he playe s
we e es ed wi h a single-leg e ical d op jump (SLVDJ) and a e ical d op jump (VDJ). Hip-pel ic kinema ics,
measu ed as emu -pel ic angle (FPA) du ing SLVDJ landing, and peak GRF and side- o-side asymme y o GRF
du ing VDJ landing we e he in es iga ed isk ac o s. Indi idual exposu e ime and LBP esul ing in ime-loss we e
eco ded du ing he ollow-up. Cox’s p opo ional haza d models wi h mixed e ec s and ime- a ying isk ac o s
we e used o analysis.
Resul s: We ound an inc ease in he isk o LBP in playe s wi h dec eased FPA du ing SLVDJ landing. The e was a
small inc ease in isk o LBP wi h a one-deg ee dec ease in igh leg FPA du ing SLVDJ landing (HR 1.09, 95% CI
1.02 o 1.17, pe one-deg ee dec ease o FPA). Ou esul s showed no signi ican ela ionship be ween isk o LBP
and le leg FPA (HR 1.04, 95% CI 0.97 o 1.11, pe one-deg ee dec ease o FPA), GRF (HR 1.83, 95% CI 0.95 o 3.51)
o GRF side- o-side di e ence (HR 1.22, 95% CI 0.65 o 2.27) du ing landing asks.
Conclusions: Ou esul s sugges ha he e is an associa ion be ween hip-pel ic kinema ics and u u e LBP.
Howe e , we did no ind an associa ion be ween LBP and GRF. In he u u e, he associa ion be ween hip-pel ic
kinema ics and LBP occu ence should be in es iga ed u he wi h coho and in e en ion s udies o e i y he
esul s om his in es iga ion.
Le el o e idence: P ognosis, le el 1b.
Keywo ds: Low back pain, Lumba spine, Team spo s, You h a hle es, Risk ac o s
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* Co espondence: [email p o ec ed]
1
Tampe e Resea ch Cen e o Spo s Medicine, UKK Ins i u e, 33501 Tampe e,
Finland
2
Facul y o Spo and Heal h Sciences, Uni e si y o Jy äskylä, Jy äskylä,
Finland
Full lis o au ho in o ma ion is a ailable a he end o he a icle
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350
h ps://doi.o g/10.1186/s12891-020-03376-1
Key poin s
Findings Based on he esul s o his s udy, peak GRF
is a poo isk ac o o LBP in you h eam spo playe s.
Hip-pel ic kinema ics a e associa ed wi h inc eased isk
o LBP; smalle angle be ween he emu and pel is in-
c eases he isk o all LBP and non- auma ic g adual
onse LBP.
Implica ions One canno disc imina e playe s wi h u-
u e LBP based on he emu -pel ic angle du ing SLVDJ
landing alone. The associa ion be ween hip-pel ic kine-
ma ics and o he mo emen pa e ns, such as unk
kinema ics, and isk o LBP in a hle es me i s u he
in es iga ions.
Cau ion The da a eco ding and s a is ical analyses in
his s udy did no ake in o accoun he empo al na u e
o physical abili ies du ing he ollow-up no did i in-
clude psychosocial ac o s. S a is ical powe migh no
ha e been enough o e eal small o mode a e associa-
ions. The esul s should be e i ied by u u e coho
and in e en ion s udies.
Backg ound
Back pain is common among you h a hle es [1]. Ou p e-
ious indings show ha nea ly hal o loo ball playe s
(45%) and 64% o baske ball playe s ha e had LBP du ing
he p eceding 12 mon hs [2]. Fu he mo e, lowe ex em-
i y inju ies (LEI) esul ing in ime loss a e common among
hese playe s [3]. Associa ion be ween LEI and back pain
has been sugges ed by p e ious esea ch [4–6]. I has been
specula ed ha changes in lowe ex emi y unc ion a e
an inju y, o sha ed isk ac o s, migh explain he associ-
a ion be ween LEI and LBP and ha plausible mecha-
nisms behind his ela ionship should be in es iga ed [5].
Spo s inju y s udies ha e in es iga ed he associa ion be-
ween LEI and lowe ex emi y kine ics and kinema ics,
such as g ound eac ion o ces and lowe ex emi y mo e-
men pa e ns, bu hey ha e no conside ed how hese
ac o s migh con ibu e o he cause o LBP.
P e ious s udies in es iga ing in insic isk ac o s o
LBP in you h ha e ocused mos ly on lowe ex emi y and
unk muscle s eng h and endu ance, lexibili y and an-
h opome ic measu es [1,7]. P ospec i e in es iga ions
in o associa ion be ween LBP and mo emen pa e ns in
you h a hle es a e sca ce [8] and mos o he p e ious
s udies in es iga ing back pain in a hle es ha e been
la gely c oss-sec ional [9].
I has been s a ed ha he unk, including lumbo–pel-
ic–hip complex, is he cen al poin o kine ic chains o
mos spo s ac i i ies and essen ial in dec easing back
inju ies [10]. Fu he mo e, i has been sugges ed ha o
he unc ional e alua ion o he unk and lumbo–pel-
ic–hip complex, dynamic hip-pel ic mo emen pa e ns
should be in es iga ed [10]. P e ious esea ch has iden i-
ied di e ences be ween you h a hle es wi h and wi hou
LBP on lumbo–pel ic–hip complex mo emen pa e ns
[11–14] and an associa ion be ween LBP and on al
plane hip-pel ic mo emen pa e ns has been obse ed
in single-leg dynamic asks in you h c icke playe s [15]
and in adul s wi h LBP [16].
Baske ball and loo ball (an indoo eam ball spo ha
esembles loo hockey) a e spo s ha include unning,
sudden di ec ion changes and s ops. In addi ion, baske -
ball playe s pe o m lo s o jumping and landing [17].
These mo emen s p oduce la ge g ound eac ion o ces
(GRF) [18,19] ha ans e o he lumba spine and hus
may p e-dispose playe s o LBP. Ye , o ou knowledge,
he associa ion be ween LBP and peak GRF no
lumbo–pel ic–hip complex mo emen pa e ns, using
kinema ic measu es, ha e no been in es iga ed in you h
loo ball and baske ball playe s.
The aim o his explo a o y p ospec i e s udy was o
in es iga e i hip-pel ic kinema ics, measu ed as emu -
pel ic angle (FPA), and peak GRF du ing landing asks,
a e associa ed wi h LBP incidence in a la ge coho o
you h baske ball and loo ball playe s. The p ospec i e
design and conside a ion o he indi idual aining and
game exposu e hou s adds o he no el y alue o his
s udy. The hypo heses we e ha [1] dec eased FPA in
on al plane du ing single-leg e ical d op jump
(SLVDJ) landing and [2] highe o asymme ic peak
GRF du ing e ical d op jump (VDJ) landing inc ease
he isk o LBP plausibly due o inc eased load and
s ain in he lumbo-pel ic a ea.
Me hods
S udy design and da a collec ion
This s udy is pa o he la ge Finnish PROFITS s udy
(P edic o s o Lowe Ex emi y Inju ies in Team Spo s)
ca ied ou be ween 2011 and 2015 [20] and he desc ip-
i e esul s ega ding LBP ha e been epo ed al eady in
p e ious epo s [1,2]. This s udy was app o ed by he
E hics Commi ee o he Pi kanmaa Hospi al Dis ic
(ETL-code R10169) and ca ied ou in acco dance wi h
he Decla a ion o Helsinki and he guidelines o good
scien i ic p ac ice. W i en in o med consen was ac-
qui ed om he pa icipan s (and a legal gua dian i he
playe was unde 18 yea s old).
Ten emale and male baske ball and 10 loo ball eams
we e ec ui ed om six spo s clubs in Tampe e,
Finland. Playe s olde han 21 and younge han 12 a
baseline we e excluded. Da a we e collec ed a baseline
in Ap il o May o 2011, 2012, o 2013 as he playe en-
e ed he s udy, and a he beginning o each s udy yea
in which he playe pa icipa ed. The playe s we e
ollowed p ospec i ely o up o 3 yea s. Da a om all
playe s en e ing he ollow-up we e included in he ana-
lyses o he ime hey pa icipa ed.
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 2 o 10
The baseline ques ionnai e co e ed he ollowing
demog aphics: age, sex, dominan leg, nico ine use, am-
ily his o y o musculoskele al diso de s, and aining and
playing his o y du ing he p e ious 12 mon hs.
The playe s’his o y o back pain was eco ded using he
S anda dized No dic ques ionnai e o musculoskele al
symp oms (modi ied e sion o a hle es) [21,22]. His o y
o p e ious LBP was de e mined based on he ques ion:
How many days ha e you had LBP du ing he pas 12
mon hs: ‘none’( eco ded as no LBP his o y), ‘1 o 7 days’,
‘8 o30days’,‘>30 days bu no daily’and ‘daily’( eco ded
as a his o y o LBP). The ques ionnai e has been alida ed
amongadul s[23]. The baseline ques ionnai e was com-
ple ed du ing he same day as he baseline es s.
The baseline es s we e pe o med a he UKK Ins i u e
o e 1 day a he beginning o e e y ollow-up yea . The
es p ocedu es a e ou lined in mo e de ail in p e ious e-
po s [20,24–29] and Table 1and only b ie ly desc ibed
below. Playe s wi h an ongoing inju y a he ime o he
baseline es and playe s who did no ha e a alid numbe
o es ials we e excluded om he isk ac o analyses.
The SLVDJ was used o in es iga e hip-pel ic kinema ics.
In he SLVDJ he playe d opped o om a 10-cm box
ollowed by a maximal e ical jump. Hip-pel ic angles
we e es ima ed om a s ill ideo image by an in es iga o
using Ja a-based so wa e (ImageJ, Na ional Ins i u es o
Heal h), and FPA, ou lined in Fig. 1, was chosen o isk
ac o analysis. The FPA measu ed in a simila , bu no
iden ical 2D single-leg landing ask has shown good co el-
a ion wi h 3D measu emen s [31]. Using he same me hods
as his s udy, S ens ud e al. obse ed mode a e o excellen
eliabili y when hey measu ed lowe ex emi y kinema ics
du ing he SLVDJ (ICC ange = 0.58–0.89) [26].
The VDJ was used o in es iga e he GRF du ing
landing. Du ing a alid VDJ es he playe s ood on he
30-cm box, d opped o he box and immedia ely a e
landing he playe pe o med a maximal e ical jump.
Absolu e and weigh adjus ed peak GRF and side- o-
side asymme y we e in es iga ed as po en ial isk ac-
o s. The same me hodology has been used p e iously
by, o example, Nils ad e al., Mok e al. and K osshaug
e al. [27–29]. They also demons a ed good o excellen
eliabili y o peak GRF measu e in a hle es (ICC
ange = 0.60–0.91) [28,29].
Inju y and spo exposu e egis a ion
The p ima y ou comes we e auma ic and non- auma ic
LBP. LBP was de ined as pain in he lowe back a ea ha
p e en ed he playe om aking ull pa in eam p ac-
ices and games o a leas 24 h. LBP ha esul ed om a
speci ic iden i iable e en , such as alling, was e e ed o
as acu e auma ic LBP. Non- auma ic LBP had g adual
onse , wi hou an iden i iable e en o auma. Acu e au-
ma ic LBP e en s we e ca ego ised as “con ac ”,“indi ec
con ac ”,and“non-con ac ”[32]. A con ac inju y was de-
ined as an inju y sus ained by he inju ed body egion be-
cause o di ec con ac wi h ano he playe o objec and
we e excluded om his in es iga ion. An indi ec con ac
and non-con ac inju y we e de ined as occu ing wi hou
di ec con ac o he inju ed body egion.
Once a week one o he wo s udy physicians con-
ac ed he eams o in e iew he inju ed playe s. A
s uc u ed inju y ques ionnai e (Supplemen a y Table 1)
Table 1 Desc ip ion o selec ed baseline es s and he
in es iga ed a iables
SINGLE-LEG VERTICAL DROP JUMP (SLVDJ)
P epa a ion Small pieces o spo s ape we e placed on he le and
igh side o he uppe an e io iliac ube cle (ASIS) and ube osi as
ibiae.
Equipmen A high-de ini ion digi al came a (Sony® Digi al HD Video
Came a Reco de HXR-NX70E, Sony Co po a ion, Tokyo, JAPAN).
Wa m up No sepa a e wa m-up was pe o med, as he SLVDJ immedi-
a ely ollowed a p e ious es (no included in his s udy). One p ac ice
ial on each leg was allowed.
Tes pe o mance Du ing he es he playe s ood in on o he
ideo came a, on a 10-cm box. Using one leg, he playe d opped o
he box and landed on one leg. Immedia ely a e landing, he playe
pe o med a maximal jump s aigh up wi h he same leg. (The es was
pe o med h ee imes.) An o e head goal was used o maximum e o
[30] and he es s a ed wi h he igh leg. T ials wi h jumping, a leg
ouching he g ound o alling/clea loss o balance, we e conside ed in-
alid. Two alid ials was conside ed accep able.
Measu emen s/Calcula ions The on al plane knee and pel ic angles
we e es ima ed by a physio he apis by ma king he knee join cen e
and ASIS in he s ill image cap u ed om a ideo. Join angles we e
es ima ed a he poin o maximum knee lexion du ing ini ial landing.
Femu -pel ic angle (FPA) desc ibed he angle be ween he emu and
pel is and was calcula ed om he in e sec ion o a line c ea ed by ASIS
and he knee join cen e. A smalle angle indica es inc eased emu
adduc ion and/o pel ic d op.
VERTICAL DROP JUMP (VDJ):
P epa a ion A s a ic calib a ion ial was pe o med.
Equipmen The 3D mo ion analysis consis ed o eigh came as (Vicon
T40, Ox o d, UK), 16 lowe body ma ke s (Plug-In Gai , Vicon, Ox o d, UK)
and wo o ce pla es (AMTI, Wa e own, Massachuse s) whe e da a we e
eco ded synch onously a 300 ps and 1500 Hz. A 30-cm box was used.
Wa m up Playe s pe o med a s anda dised wa m-up (5 min o cycling)
be o e es ing. One p ac ice ial was allowed.
Tes pe o mance The playe s ood on he 30-cm box, d opped o he
box and landed symme ically on bo h ee on he o ce pla es. Immedi-
a ely a e landing he playe jumped as high as possible. An o e head
goal was used o maximum e o [30] and he playe ied o ouch
he goal wi h hei head. Th ee alid ials we e collec ed. The ials we e
accep ed i he en i e oo landed on he o ce pla e and he ma ke s
s ayed igh ly on he a hle e’s skin h oughou he ask.
Measu emen s/Calcula ions Vicon Nexus Plug-in Gai model was used
o he analyses. Peak GRF and GRF asymme y we e in es iga ed as
po en ial isk ac o s. Th ee ials om bo h legs we e a e aged and he
side wi h he la ge alue was chosen o analyses as peak GRF. Peak
GRF was no malized by bodyweigh . The GRF asymme y was calcu-
la ed as he di e ence be ween he igh and le legs. GRF was il e ed
using a ou h-o de Bu e wo h il e wi h cu o equencies o 15 Hz
and he landing phase was de ined as he pe iod when he un il e ed
g ound eac ion o ce exceeded 20 N.
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 3 o 10
was used o egis e he inju y/pain loca ion, cause, ype,
ime o onse and he suspec ed mechanism (acu e au-
ma ic s. non- auma ic g adual onse ) based on ecom-
menda ions o Fulle e al. [33]. Du ing he ollow-up,
he coaches collec ed all hou s in games and eam p ac-
ices o each playe on a mon hly basis. Indi idual p ac-
ice pe o med ou side he scheduled eam e en s was
no included in he exposu e da a.
S a is ical me hods
IBM SPSS S a is ics ( . 23–24.0) and Chi-squa e es and
he - es (Mann-Whi ney es whenapp op ia e)we eused
o desc ip i e s a is ical analyses and he esul s we e e-
po ed as he mean and s anda d de ia ion (SD). Cox’sp o-
po ional haza d models wi h mixed-e ec s we e used o
in es iga e he associa ions be ween po en ial isk ac o s
and LBP (yes/no). This me hod accoun s o he spo s ex-
posu e and a iance in ollow-up ime be ween he playe s.
Mixed e ec s we e used o accoun o he spo s club as a
andom e ec . Time-dependen a iables we e used, when
possible, due o he endency o changes in in es iga ed a -
iables o e ime. The indi idual game and p ac ice hou s
om he s a o he ollow-up un il he i s e en (LBP) o
he end o ollow-up (i no e en ) we e included in analyses.
Fo playe s epo ing mo e han one LBP a e he baseline,
only he i s was included. Da a om all eligible playe s en-
e ing he ollow-up we e included in he analyses o he
ime hey pa icipa ed.
R ( 3.1.2; R Founda ion o S a is ical Compu ing [34])
package coxme [35] was used o he isk ac o analyses.
Uni a ia e analyses we e ollowed by mul i a iable analyses,
whe e he numbe o adjus ing a iables was dependen on
he numbe o e en s (10 pe a iable) included in he ana-
lysis, as ecommended by Peduzzi e al. [36,37]. The
adjus ing a iables we e selec ed om he ollowing ac o s:
age, sex, BMI, nico ine use, leg dominance, amily his o y o
LBP, and his o y o LBP. Leg dominance was used as a
wo-ca ego y a iable: he ca ego ies ‘le ’and ‘ igh ‘we e
me ged in o ‘unila e al leg dominance’and he ca ego y
‘don’ know/bo h’in o ‘bi-la e al/unknown leg dominance’.
The adjus ing ac o s we e selec ed by d opping ac o s
om he model one by one, based on hei s a is ical signi i-
cance. Only nico ine use, a his o y o LBP and leg domin-
ance showed a s a is ically signi ican associa ion wi h LBP.
The analyses we e pe o med using con inuous and dicho -
omized a iables. Va iables we e dicho omized in o ‘high’
and ‘low’using he median. The esul s a e p esen ed as
haza d a ios (HR), 95% CIs and p- alues. The playe was
conside ed as he uni o analysis, bu in unila e al asks he
igh and le sides we e in es iga ed sepa a ely.
Resul s
Nine eams o bo h spo s ag eed o pa icipa e (Fig. 2),
wi h a mean ollow-up ime o 16.5 mon hs ( ange 1 o
36 mon hs). Playe demog aphics and baseline es e-
sul s om each s udy yea a e p esen ed in Table 2.
The e we e some di e ences be ween he playe s in-
cluded and excluded om he es s (Supplemen a y
Table 2). Fo example, mo e male playe s and hea ie
playe s we e excluded om he SLVDJ es due o on-
going inju ies and o no ha ing a alid es esul . The
playe s excluded om he VDJ es we e olde and hea -
ie han hose ha we e included.
Du ing he ollow-up, al oge he 566 a hle e-yea s
we e eco ded. Fi y- ou pe cen o playe s (n= 205) e-
po ed no his o y o LBP a baseline. O he 383 playe s,
13% (n= 48) sus ained LBP du ing he ollow up, 35% o
hem (n= 17) had no had back pain p io o he s udy.
Hal o he playe s de eloping LBP du ing he ollow-up
Fig. 1 Femu -pel ic angle (FPA) measu ed om he s ill- ideo image
in single-leg e ical d op jump (SLVDJ) es
Fig. 2 S udy pa icipan low
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 4 o 10

Table 2 Baseline cha ac e is ics, baseline es esul s, and p ac ice and game exposu e du ing he ollow up o playe s wi h and
wi hou LBP
LBP
du ing
ollow-
up
S udy yea 2011–2012 S udy yea 2012–2013 S udy yea 2013–2014
n Mean SD P
alue
n Mean SD P
alue
n Mean SD P
alue
Age, yea s No 106 16.2 1.7 0.009 138 16.7 2.0 0.659 266 16.1 2.0 0.109
Yes 6 18.0 1.5 10 16.3 2.2 32 15.5 2.0
Sex, % 100 20.3 5.2 0.743 128 19.3 4.4 0.569 228 18.8 3.9 0.043
Female No 80 95.2 85 92.4 107 88.4
Yes 4 4.8 7 7.6 14 11.6
Male No 26 92.9 53 94.6 159 89.8
Yes 2 7.1 3 5.4 18 10.2
Heigh , cm No 106 170.4 8.5 0.138 138 173.2 9.1 0.609 259 174.2 9.4 0.929
Yes 6 175.8 10.9 10 171.7 10.1 32 174.1 7.7
Weigh , kg No 106 63.8 9.8 0.646 138 66.9 10.5 0.124 259 66.3 11.0 0.598
Yes 6 67.3 12.4 10 62.1 8.4 32 65.1 9.0
BMI No 106 21.9 2.6 0.776 138 22.2 2.6 0.140 259 21.8 2.8 0.633
Yes 6 21.6 2.0 10 21.0 1.6 32 21.4 2.1
Spo , %
Baske ball No 58 96.7 0.307 58 96.7 0.717 133 88.1 0.504
Yes 2 66.7 2 3.3 18 11.9
Floo ball No 48 92.3 80 90.9 133 90.5
Yes 4 7.7 8 9.1 14 9.5
Nico ine use, %
No No 103 94.5 0.676 134 93.7 0.230 257 89.9 0.103
Yes 6 5.5 9 6.3 29 10.1
Yes No 3 100.0 4 80.0 9 75.0
Yes 0 0.0 1 20.0 3 25.0
Peak GRF, N/kg No 100 20.3 5.2 0.743 128 19.3 4.4 0.569 228 18.8 3.9 0.043
Yes 5 19.7 4.2 6 18.0 3.7 29 20.2 4.2
Absolu e Peak GRF, N No 100 1289.1 392.3 0.774 128 1269.1 357.4 0.224 228 1216.7 321.3 0.122
Yes 5 1316.5 345.5 6 1077.4 118.5 29 1298.2 308.7
Peak GRF asymme y, N/kg No 100 2.5 2.0 0.584 128 2.0 1.8 0.464 228 2.1 1.8 0.641
Yes 5 2.1 2.0 6 2.4 1.8 29 2.1 2.0
Absolu e Peak GRF asymme y, N No 100 161.2 131.6 0.662 128 131.1 123.4 0.572 228 133.6 119.4 0.735
Yes 5 143.5 144.3 6 143.1 95.9 29 132.9 125.8
Le leg emu -pel ic angle, deg ees No 85 80.9 4.5 0.375 103 79.9 4.4 0.303 202 80.5 5.0 0.740
Yes 6 78.9 5.4 7 79.1 7.2 20 80.1 5.3
Righ leg emu -pel ic angle, deg ees No 91 77.5 4.9 0.905 95 76.9 4.5 0.587 199 77.1 4.7 0.033
Yes 6 77.6 5.4 7 75.6 5.4 22 74.6 4.9
Team p ac ice hou s du ing he ollow-up, mean
hou s
No 106 238.1 104.5 0.341 138 201.1 89.4 0.356 266 229.0 114.6 0.923
Yes 6 279.6 77.7 10 227.8 60.2 32 227.0 101.5
Game hou s du ing he ollow-up, mean hou s No 106 7.1 6.0 0.597 138 8.4 5.8 0.247 266 9.1 6.0 0.240
Yes 6 5.8 4.8 10 10.6 4.8 32 7.8 4.4
GRF e ical g ound eac ion o ce, Nnew on, cm cen ime es, kg kilog ams, LBP low back pain, SD s anda d de ia ion
S a is ically signi ican esul s a e indica ed wi h bold
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 5 o 10
we e emales (52%, n= 25). Fi y- ou pe cen o loo -
ball playe s and 46% o baske ball playe s had LBP du -
ing he ollow-up. Mos o he playe s who de eloped
back pain du ing he ollow up did so du ing hei i s
ollow-up yea (81%) and only one playe was ollowed
o 3 yea s be o e de eloping LBP. LBP incidence was
add essed in a p e ious publica ion [1].
Risk ac o analyses
Ou esul s showed ha he playe s who had a
smalle FPA du ing SLVDJ when landing on hei
igh leg we e a inc eased isk o all LBP and o
g adual onse non- auma ic LBP (Table 3). The ana-
lysis using dicho omous isk ac o s showed ha
playe s wi h 80° FPA o less du ing igh leg landing,
had 2.2 imes highe isk o LBP du ing he ollow-
up, han playe s wi h mo e han 80° FPA. The e was
no s a is ically signi ican associa ion be ween isk o
LBP and FPA du ing le leg landing om he SLVDJ.
In he hi d s udy yea , mean peak GRF was sig-
ni ican ly highe in playe s who de eloped LBP du ing
he ollow-up (20.2 s. 18.8 N/kg, p- alue 0.033), bu
no signi ican di e ences we e obse ed be ween p e-
ious s udy yea s (Table 2). The Cox isk ac o ana-
lyses showed no associa ion be ween peak GRF
measu es and LBP incidence in young loo ball and
baske ball playe s (Table 4).
Discussion
The aim o his s udy was o in es iga e whe he hip-
pel ic kinema ics and peak GRF du ing landing asks
we e associa ed wi h LBP incidence in you h loo ball
and baske ball playe s. The i s hypo hesis was ha he
mo emen pa e n, whe e he FPA is dec eased du ing
SLVDJ landing due o inc eased mo emen o he hip in
he di ec ion o adduc ion and con ala e al pel is d op
migh p edispose o LBP. The second hypo hesis was
ha playe s wi h highe o asymme ic peak GRF du -
ing VDJ landing a e a inc eased isk o LBP. Con a y
o ou second hypo hesis, we did no ind a s a is ically
signi ican associa ion be ween LBP and peak GRF.
Howe e , ou esul s sugges ed ha he e is an associ-
a ion be ween hip-pel ic kinema ics and LBP.
The lumbo-pel ic unc ion is an essen ial pa o suc-
cess ul a hle ic pe o mance [10]. Acco ding o a con-
cep ual amewo k o he kine ic chain [38], a dec eased
o inc eased mo emen somewhe e in he kine ic chain
is compensa ed o elsewhe e along he chain. This has
also been sugges ed by Ga ci e al. (2015), who obse ed
ha a change in on al plane knee kinema ics esul ed
in changes highe in he kine ic chain [39]. I has also
been shown ha s abili y in in e io segmen s, such as
he lowe leg, is signi ican ly co ela ed wi h supe io
segmen s, such as pel is and back, and he e o e unk
s abili y may be dependen on he s abili y o lowe seg-
men s [40]. Thus, based on he kine ic chain heo y i
Table 3 Cox eg ession analysis esul s o emu -pel ic angle (FPA) du ing single-leg e ical d op jump
Con inuous a iables
b,c
Uni a ia e Adjus ed
HR 95% CI P alue HR 95% CI P alue
All LBP
Femu -pel ic angle, le side (
a
) 1.04 (0.97 o 1.11) 0.240 1.04 (0.97 o 1.11) 0.310
Femu -pel ic angle, igh side (
a
)1.09 (1.02 o 1.17) 0.011 1.09 (1.02 o 1.17) 0.014
G adual onse non- auma ic LBP
Femu -pel ic angle, le side (
a
) 1.04 (0.96 o 1.11) 0.370 1.03 (0.95 o 1.11) 0.480
Femu -pel ic angle, igh side (
a
)1.10 (1.02 o 1.18) 0.013 1.09 (1.01 o 1.18) 0.021
Dicho omous a iables
d
All LBP
Femu -pel ic angle, le side (low s high) 1.80 (0.91 o 3.57) 0.094 1.86 (0.94 o 3.71) 0.076
Femu -pel ic angle, igh side (low s high) 2.15 (1.10 o 4.21) 0.026 2.19 (1.12 o 4.30) 0.023
G adual onse non- auma ic LBP
Femu -pel ic angle, le side (low s high) 1.72 (0.79 o 3.73) 0.170 1.80 (0.83 o 3.90) 0.140
Femu -pel ic angle, igh side (low s high) 2.25 (1.07 o 4.72) 0.033 2.30 (1.09 o 4.84) 0.028
HR Haza d a io, CI con idence in e al, all LBP acu e auma ic and g adual non- auma ic low back pain
a
deg ees
b
Adjus ed wi h his o y o LBP, leg dominance
c
HR calcula ed pe one-deg ee dec ease
d
Adjus ed wi h his o y o LBP
Femu -pel ic angle, le side high > = 80.0°, low< 80.0°
Femu -pel ic angle, igh side high > = 76.3°, low< 76.3°
S a is ically signi ican esul s a e indica ed wi h bold
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 6 o 10
could be hypo hesised ha he dec eased FPA may esul
in mo emen compensa ions and inc eased load and
s ain up and down he kine ic chain, ha is in he
lumbo-pel ic a ea as well as in he knee and lowe leg.
The associa ion o unk, pel is and hip kinema ics in e-
la ion o lowe ex emi y complain s has been discussed
[41] and p e ious esea ch sugges s ha dys unc ion dis-
al o he inju y si e can be associa ed wi h u u e inju y
occu ence [42,43].
Ou esul s showed a small inc ease in isk (8%) o LBP
wi h a one-deg ee dec ease in he igh leg FPA du ing he
SLVDJ landing. This means a 2.2- old inc ease in isk in
playe s wi h less han 80° FPA du ing he igh leg landing,
compa ed o he playe s wi h mo e han 80° FPA. How-
e e , no associa ion was de ec ed be ween he le leg FPA
and he isk o LBP. The di e ence be ween he igh and
le leg esul s migh be due o he es p ocedu e whe e
he s a ing leg was no andomized, ha is, he es was
always s a ed wi h he igh leg. Ano he explana ion may
be he ac ha in mos playe s he igh leg was hei
dominan (kicking) leg and he le leg was hei suppo -
ing leg. This may explain why he le side was mo e s able
du ing he SLVDJ. Ou esul s a e in line wi h p e ious
s udies sugges ing ha hip-pel ic kinema ics a e associ-
a ed wi h inju ies in a hle es [11,44,45]. Fo example,
indings om Bayne e al. indica ed ha inc eased knee
algus and hip adduc ion mo emen s migh esul in in-
c eased epe i i e compensa o y mo emen s om he pel-
is and unk [45]. F on al hip-pel ic kinema ics ha e
been linked wi h unk kinema ics, o example inc eased
unk la e al lean, du ing single-leg asks [46]. Glu eal
muscle dys unc ion has been associa ed wi h LBP [47],
and i could be specula ed ha glu eal muscle dys unc ion
could esul in inabili y o con ol he mo emen o he
hip-pel ic complex du ing single-leg landing. In addi ion,
he hip-pel ic mo emen pa e n obse ed in his s udy
Table 4 Associa ion be ween peak GRF measu es and inju y isk o all LBP and g adual onse non- auma ic LBP
Uni a ia e Adjus ed
HR 95% CI P alue HR95% CI P alue
Con inuous a iables
a
All LBP
Peak GRF, N/Kg 1.03 (0.97 o 1.11) 0.340 1.03 (0.96 o 1.11) 0.380
Absolu e Peak GRF, N 1.00 (1.00 o 1.00) 0.760 1.00 (1.00 o 1.00) 0.870
Peak GRF asymme y, N/Kg 1.00 (0.85 o 1.18) 0.990 1.00 (0.85 o 1.18) 0.990
Absolu e Peak GRF asymme y, N 1.00 (1.00 o 1.00) 0.970 1.00 (1.00 o 1.00) 0.940
G adual onse non- auma ic LBP
Peak GRF, N/Kg 1.00 (1.00 o 1.00) 0.610 1.00 (1.00 o 1.00) 0.690
Absolu e Peak GRF, N 1.04 (0.96 o 1.12) 0.370 1.03 (0.96 o 1.12) 0.420
Peak GRF asymme y, N/Kg 1.03 (0.87 o 1.23) 0.720 1.02 (0.86 o 1.22) 0.810
Absolu e Peak GRF asymme y, N 1.00 (1.00 o 1.00) 0.710 1.00 (1.00 o 1.00) 0.790
Dicho omous a iables
b
(high s. low)
All LBP
Peak GRF, N/Kg 1.92 (1.00 o 3.68) 0.051 1.83 (0.95 o 3.51) 0.070
Absolu e Peak GRF, N 0.99 (0.53 o 1.83) 0.960 0.94 (0.51 o 1.76) 0.860
Peak GRF asymme y, N/Kg 1.23 (0.66 o 2.30) 0.510 1.22 (0.65 o 2.27) 0.530
Absolu e Peak GRF asymme y, N 1.21 (0.65 o 2.25) 0.550 1.20 (0.64 o 2.23) 0.580
G adual onse non- auma ic LBP
Peak GRF, N/Kg 1.47 (0.73 o 2.98) 0.610 1.41 (0.69 o 2.86) 0.340
Absolu e Peak GRF, N 0.98 (0.49 o 1.97) 0.370 0.94 (0.47 o 1.88) 0.850
Peak GRF asymme y, N/Kg 1.31 (0.65 o 2.64) 0.720 1.30 (0.64 o 2.61) 0.470
Absolu e Peak GRF asymme y, N 1.28 (0.64 o 2.58) 0.710 1.26 (0.63 o 2.54) 0.510
HR Haza d a io, CI con idence in e al, LBP low back pain, GRF e ical g ound eac ion o ce, NNew on;
a
Adjus ed wi h his o y o LBP, leg dominance and nico ine use
b
All LBP: Adjus ed wi h his o y o LBP and leg dominance. G adual onse LBP: Adjus ed wi h his o y o LBP
Peak GRF high > = 18.5, low< 18.5
Absolu e Peak GRF high > = 1191.0, low< 1191.0
Peak GRF asymme y high > = 1.6, low< 1.6
Absolu e Peak GRF asymme y high > = 103.3, low< 103.3
S a is ically signi ican esul s a e indica ed wi h bold
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 7 o 10
migh also be a compensa o y mo emen esul ing om
se e al o he ac o s, such as dec eased con ol o he
unk o e he pel is o e en con ol o he ankle. The e-
o e, in u u e s udies, i is impo an o s udy he kine-
ma ics o he en i e kine ic chain and no jus a pa o i .
Ou second hypo hesis was ha GRFs ha a ec he
lumba spine [19] could po en ially p edispose o back
pain. Howe e , o ou knowledge he associa ion be-
ween peak GRF and LBP incidence in you h a hle es
has no been s udied p e iously. Acco ding o ou ind-
ings, he e was no associa ion be ween LBP incidence
and peak GRF o GRF side- o-side asymme y, mea-
su ed in VDJ landing. In a c oss-sec ional in es iga ion,
Mülle e al. we e also unable o ind a di e ence in
GRFs o you h a hle es wi h and wi hou LBP [48]. Fu-
u e s udies should in es iga e i loading a e is associ-
a ed wi h LBP, because i has been shown o be a
s onge isk ac o o lowe ex emi y inju ies han
peak GRF [49].
Me hodological conside a ions
The s eng hs o his s udy we e he p ospec i e design
and he me hods o LBP and playing exposu e egis a-
ions. In addi ion, he sample size was ela i ely la ge.
The leng h o ollow-up a ied ac oss he sample and
he e o e we used Cox eg ession analysis. Cox eg es-
sion analysis can adjus o a ia ions in he amoun o
spo pa icipa ion ( ollow-up ime). Ye , due o he ela-
i ely low numbe o LBP e en s, we we e unable o
s a i y he analyses by sex. Howe e , i seemed ha sex
was no signi ican ly associa ed wi h LBP in his sample.
Risk ac o s can change o e ime and he e o e we
used ime- a ying a iables in he Cox analysis, when
possible. In addi ion, o e hal (54.5%) o he playe s had
a his o y o LBP a he beginning o he s udy and 35%
(n= 17) o he LBP eco ded du ing ollow-up was i s -
ime LBP. We compensa ed o his by adjus ing he isk
ac o analyses wi h a his o y o LBP.
We should no o e look he ac ha up o 25% o all
playe s pa icipa ing (n= 383) we e no included in he
isk ac o analyses. In he SLVDJ 25% o he playe s and
in he VDJ 19% o he playe s had incomple e baseline
es da a. The absence o hese playe s migh a ec he
esul s o his s udy. We a e also unawa e whe he
playe s e using o pa icipa e di e om ou sample.
Ano he limi a ion is ha we did no es he eliabili y
o he selec ed es s du ing his s udy. Howe e , he eli-
abili y o GRF measu emen s has been demons a ed
p e iously by K osshaug and Mok and hei colleagues
[28,29]. He ing on and o he s demons a ed in a simi-
la es ha on al plane FPA is a eliable measu emen
[31]. One limi a ion is ha in he SLVDJ es he s a ing
leg was no andomized. The playe s pe o med he es
i s wi h he igh leg and his migh ha e had an e ec
on he esul s. When pe o ming he es wi h he le
leg, he playe s we e mo e expe ienced.
The ae iology o LBP has been shown o be mul i ac-
o ial [50], meaning ha , in addi ion o ex e nal loading,
in e nal loading such as psychosocial s ess should also
be eco ded. The la e has been associa ed wi h he isk
o spo s inju ies in gene al [51]. The e a e also se e al
o he isk ac o s ha should be aken in o accoun ,
such as unk muscle symme y [52], in addi ion o ac-
knowledging he ac ha isk ac o s a e dynamic in na-
u e and change o e ime [53].
Conclusions
Ou esul s sugges ed ha he e is an associa ion be-
ween hip-pel ic kinema ics and LBP, as measu ed in
his s udy. Howe e , we did no ind a s a is ically sig-
ni ican associa ion be ween LBP peak GRF o side- o-
side asymme y o GRF du ing VDJ landing. In he u-
u e, he associa ion be ween hip-pel ic kinema ics and
LBP incidence should be in es iga ed u he o e i y
he esul s om his s udy.
Supplemen a y in o ma ion
Supplemen a y in o ma ion accompanies his pape a h ps://doi.o g/10.
1186/s12891-020-03376-1.
Addi ional ile 1 Supplemen a y Table 1. Da a collec ed in he
s uc u ed inju y ques ionnai e.
Addi ional ile 2 Supplemen a y Table 2. Di e ences be ween
playe s wi h and wi hou baseline es esul .
Abb e ia ions
LBP: Low back pain; CI: Con idence in e al; SLVDJ: Single-leg e ical d op
jump; VDJ: Ve ical d op jump; HR: Haza ds a io; FPA: Femu -pel ic angle;
GRF: Ve ical g ound eac ion o ce; GRFs: G ound eac ion o ces; 2D: Two-
dimensional; 3D: Th ee-dimensional; SD: S anda d de ia ion; N: New on;
Kg: Kilog ams
Acknowledgemen s
We a e g a e ul o s a is ician Ka i Tokola o his indispensable suppo wi h
he s a is ical me hods. We a e also hank ul o s udy physicians Jussi
Hie amo and Teemu Ekola o inju y da a collec ion, and esea ch assis an
I ja Lah inen o he collec ion o aining and ma ch da a and keeping
con ac wi h he pa icipa ing eams.
Financial disclosu e and con lic o in e es
The au ho s a i m ha we ha e no inancial a ilia ion (including esea ch
unding) o in ol emen wi h any comme cial o ganiza ion ha has a di ec
inancial in e es in any ma e included in his manusc ip , excep as
disclosed in an a achmen and ci ed in he manusc ip . Any o he con lic o
in e es (i.e., pe sonal associa ions o in ol emen as a di ec o , o ice , o
expe wi ness) is also disclosed in an a achmen .
Au ho s’con ibu ions
All au ho s con ibu ed o he s udy concep and design. KP was esponsible
o conduc ing he da a acquisi ion. AMR was esponsible o p epa a ion o
2D ideo analysis da a. ML was esponsible o p epa a ion o he 3D mo ion
cap u e da a. MR was esponsible o he main da a analysis, in e p e a ion
and w i ing he i s d a o he manusc ip . KP, AH, SÄ, AMR, ML, GM, TV, PK,
and JP we e signi ican manusc ip e ise s. All au ho s ha e app o ed he
submi ed e sion o he manusc ip . KP is he gua an o .
Rossi e al. BMC Musculoskele al Diso de s (2020) 21:350 Page 8 o 10