Ci a ion: P ie o-F esco, J.M.;
Medina-Rebollo, D.;
Fe nández-Ga i a, J.; Muñoz-Lle ena,
A. A S udy on he Inju y Ra e o
Spanish Compe i i e A hle es as a
Consequence o he COVID-19
Pandemic Lockdown. In . J. En i on.
Res. Public Heal h 2023,20, 420.
h ps://doi.o g/10.3390/
ije ph20010420
Academic Edi o : Paul B. Tchounwou
Recei ed: 28 Oc obe 2022
Re ised: 9 Decembe 2022
Accep ed: 16 Decembe 2022
Published: 27 Decembe 2022
Copy igh : © 2022 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
In e na ional Jou nal o
En i onmen al Resea ch
and Public Heal h
A icle
A S udy on he Inju y Ra e o Spanish Compe i i e A hle es as
a Consequence o he COVID-19 Pandemic Lockdown
JoséManuel P ie o-F esco 1, Daniel Medina-Rebollo 1,2 , Jesús Fe nández-Ga i a 1,3,* and
An onio Muñoz-Lle ena 1,3
1Resea ch G oup “Social Inclusion, Physical Educa ion and Spo , and Eu opean Policies in Resea ch”,
Uni e si y o Se ille, 41013 Se ille, Spain
2Physical Educa ion and Spo Depa men , Uni e si y School CEU San Pablo, 41013 Se ille, Spain
3Physical Educa ion and Spo Depa men , Uni e si y o Se ille, 41013 Se ille, Spain
*Co espondence: [email p o ec ed]
Abs ac :
The COVID-19 lockdown may ha e had colla e al e ec s on he condi ions o a hle es, wi h
possible inc eases in inju y isks upon he e u n o spo s. Due o he exis ence o mul iple ac o s
o inju y isks based on he lockdown and he e u n o spo s, he aim o his s udy was o analyze
he inju y a es a e he lockdown in compe i i e a hle es. A non-expe imen al quan i a i e design
based on a su ey was ca ied ou , and 94 a hle es (42 males and 52 emales;
23.57 ±6.20 yea s
)
pa icipa ed. S a is ical analyses we e ca ied ou using non-pa ame ic es s. Inju y a es did
no inc ease signi ican ly a e he lockdown, and he e we e no s a is ical di e ences be ween
pe o mance le els, ypes o spo s, he design o a speci ic aining p og am by spo s p o essionals
du ing he lockdown, he momen o inju y, and he mechanism o inju y. I is impo an o de elop
inju y p e en ion p o ocols o p epa e a hle es a e such a long pe iod o de aining.
Keywo ds: compe i i e spo ; physical heal h; i ness; inju y p e en ion
1. In oduc ion
The wo ld has ecen ly been hi by a pandemic o igina ing om COVID-19, an in ec-
ious disease caused by se e e acu e espi a o y synd ome co ona i us-2 (SARS-CoV-2),
which was i s de ec ed in Decembe 2019 in Wuhan, China [1]. Di e en es ic i e mea-
su es we e aken due o his pandemic, such as mo emen es ic ions, social dis ancing,
and he closu es o spo s acili ies [
2
–
5
], which led o psychosocial sequels (e.g., anxie y, de-
p ession o insomnia) [
6
] and a dec ease in spo s pa icipa ion and physical i ness [
2
,
7
,
8
].
These measu es also comp omised a hle e aining by limi ing hei physical ac i i y,
hinde ing hei access o many o ms o physical exe cise and mul idisciplina y spo s
eams (e.g., coaches, spo s scien is s, spo s medicine p o essionals), and hampe ing eam
p ac ices [
4
,
9
,
10
]. The eason o he closu e was he conce n abou he ele a ed isk o
COVID-19 in ec ions in a hle es due o he na u e o compe i i e spo s, i.e., close con ac ,
igh locke ooms and aining acili ies, sha ed equipmen , lack o social dis ancing, and
he absence o ace co e ings du ing aining and compe i ions [
11
]. A consequence o
hese es ic i e measu es was he in e up ion o spo s compe i ions, dis up ing spo s
and aining ou ines [
2
,
10
,
12
–
15
]. In Spain, he e was a lockdown en o ced by heal h au-
ho i ies, which las ed eigh weeks and en ailed a qua an ine o he popula ion, o bidding
a hle es om pa icipa ing in physical ac i i ies ou side o hei homes [12,15].
The suspension o compe i ions and he ban on o ganized p ac ices had signi ican
impac s on he psychological and physiological condi ions o a hle es, leading o dec eased
pe o mances [
16
]. On he one hand, some s udies ha e shown ha he e was a ela ionship
be ween isola ion and an inc ease in di e en psychological and emo ional diso de s, such
as dep ession o anxie y [
6
,
17
]. On he o he hand, i was di icul o spo s p o essionals o
In . J. En i on. Res. Public Heal h 2023,20, 420. h ps://doi.o g/10.3390/ije ph20010420 h ps://www.mdpi.com/jou nal/ije ph
In . J. En i on. Res. Public Heal h 2023,20, 420 2 o 14
ensu e ha he aining loads imposed on a hle es by home aining we e adequa e o educe
he po en ial losses o hei aining-induced physiological and mo phological adap a ions [
18
].
Acco ding o di e en au ho s, he es ic ions in accessing spo s acili ies and he
impossibili y o pa icipa ing in o ganized eam aining and compe i ion would induce a
o al o pa ial loss o aining-induced neu omuscula adap a ions, a p ocess known as
de aining [
19
], esul ing in a nega i e impac on he a hle e’s capaci y o pe o m spo s-
speci ic ac ions [
3
,
12
,
16
,
20
,
21
]. De aining can ha e a nega i e e ec on he neu omuscula
sys em (i.e., muscle mass loss, damage o he neu omuscula junc ion), muscle p o ein
me abolism (i.e., supp ession o muscle p o ein syn hesis), and ca dio espi a o y sys em
(i.e., educ ion o VO
2max
, impai men o he s eps along he O
2
pa hway) [
22
]. Examples
o de aining e ec s can be ound elsewhe e [23,24].
Based on all o he p e ious in o ma ion, i is e iden ha he COVID-19 pandemic
lockdown could lead o an inc eased numbe o inju ies upon he e u n o spo s [
16
]
as a esul o he de aining p ocess- ela ed e ec . In o de o explo e his issue, i is
necessa y o unde s and wha an inju y is and i s possible classi ica ions. This e m could
be de ined as “any acciden o physical dys unc ion occu ing du ing spo , o as a di ec
consequence o i ” [
25
] (p. 42), which leads o he una ailabili y o he a hle e o pa icipa e
in u u e aining o compe i ions [
26
]. Acco ding o [
27
], mos inju ies ake place in he
compe i ion, wi h an inju y a e (IR) o 23.8 inju ies/1000 h, while in aining, he IR was
3.4 inju ies/1000 h. Howe e , he e a e many disc epancies in he speci ica ions o he
IR h oughou he li e a u e, which makes i di icul o compa e exis ing da abases and
s udies [
28
]. To sol e his p oblem, he la e au ho s de ine he concep o inju y as “a
e m ha applies o all p ocesses ha esul in he des uc ion o al e a ion o he in eg i y
o a issue o pa o he o ganism” (p. 8). Table 1shows a classi ica ion ha alludes o
he ype o inju y and issues a ec ed, based on he o cha d spo s inju y classi ica ion
sys em (OSICS) [29–31].
Table 1. Classi ica ion acco ding o he ype o inju y and issue a ec ed.
Main Ca ego y Subca ego ies
F ac u es and bone s ess Bone ac u es
O he bone inju ies
Join s and ligamen s
Disloca ion/subluxa ion
Ligamen inju y
Meniscus/a icula ca ilage inju y
Syno i is
Muscles and endons Muscle up u e/ ea /spasm/c amp
Tendon ea / endinopa hy/bu si is
Skin Hema oma/con usion
Ab asion/lace a ion
Cen al/pe iphe al ne ous sys em
Concussion
S uc u al b ain inju y
Ne e inju y
Eye inju y
O he
Visce al
Den al inju y
Undiagnosed inju y
No e. Adap ed om [29–31].
The COVID-19 c isis has c ea ed many challenges, including an op imal and sa e
e u n o spo s compe i ion. In e ms o isk ac o s o inju ies du ing he lockdown (DL),
he ine i able change o ou ine, he sca ce spo s equipmen a ailable (in mos cases),
and home aining p og ams [
32
] should be highligh ed, since hey en ailed a ma ked
educ ion in aining speci ici y, in ensi y, equency, and du a ion [
9
,
11
,
33
]. The la e
can be conside ed he mos ele an , as he a hle es, accus omed o ace- o- ace aining
supe ised by mul idisciplina y eams o physical exe cise p o essionals (which a ies
depending on he compe i i e le el), began o ain on hei own, based on ins uc ions
In . J. En i on. Res. Public Heal h 2023,20, 420 3 o 14
p o ided by e-mail, ideo, o audio; hey we e equi ed o adap o hese aining sessions
acco ding o he eali y o he space and he ma e ial a ailable in each one [34].
To educe he de aining e ec s and o ca y ou an op imal and sa e e u n o spo s
aining and compe i ions, a p og essi e and well-s uc u ed exe cise p og am ollow-
ing he lockdown is essen ial [
13
]. A hle es usually ained a home DL, ocusing on
bodyweigh -based and weigh li ing s eng h aining, as well as ca dio ascula endu ance
condi ioning [
9
,
11
,
35
]. Howe e , home-exe cise p og ams (cha ac e ized by limi ed equip-
men and acili ies) do no p o ide enough s imuli o eplica e he condi ions o eal
compe i ions and usually lead o i egula aining loads and a educ ion in s eng h and
gene al i ness le els [2,7,9,11,12,19,36,37].
Mo eo e , assuming ha he a hle es’ wo kloads we e app oxima ely 20 o 40% o
hei no mal wo kloads, he ecommended ime o e u n o op-le el aining wi hou
a high isk o inju y would be es ima ed a 3–5 weeks [
38
], al hough he e u n was
u he complica ed by he ex eme need o e u n o no malcy in an ex emely sho
ime. This was he case o many eli e a hle es, who expe ienced a educ ion in es ime
be ween compe i ions [
2
,
10
,
11
,
13
], as well as changes in nu i ion, sleep, and exe cise
habi s [
7
]. This si ua ion esul ed in an inc ease in IR, especially musculoskele al inju ies,
upon e u n o spo s a all compe i i e le els, mos ly in he i s wo weeks a e he
e u n [
2
,
3
,
10
,
11
,
13
,
16
,
39
–
43
]. Due o he e idence o exis ing esea ch abou he mul iple
inju y isk ac o s a he ime o e u n o spo , which o igina e om he de aining e ec s
caused by insu icien spo s-speci ic aining s imuli and he lack o o ganized aining
and compe i ion DL, oge he wi h he inadequa e e u n o aining and compe i ion, a
esea ch ques ion a ose:
To wha ex en has he IR changed a e he lockdown (AL) when compa ed o be o e
he lockdown (BL) in compe ing a hle es?
Based on his ques ion, he main objec i e o his esea ch was o check whe he he e
was inc eased IR AL in compe i i e a hle es; we also analyzed he causali y o he da a in
ela ion o he spo s domain. The ollowing esea ch hypo heses a ose om his objec i e:
Hypo hesis 1 (H1). The e will be a highe IR AL compa ed o he pe iod BL.
Hypo hesis 2 (H2).
The di e ence in he numbe o inju ies be ween eli e and ama eu a hle es
inc eased AL.
Hypo hesis 3 (H3).
People who p ac ice con ac spo s will ha e g ea e endencies o be inju ed
compa ed o people who p ac ice non-con ac spo s.
Hypo hesis 4 (H4).
People whose aining sessions we e no designed by spo s p o essionals DL
had highe IRs AL han hose whose aining sessions we e designed by spo s p o essionals.
Hypo hesis 5 (H5).
The di e ence be ween he numbe o inju ies occu ing in aining and hose
occu ing du ing compe i ion inc eased in he AL pe iod.
Hypo hesis 6 (H6).
The ype o exe cise pe o med a home DL will in luence he IR in he
AL pe iod.
2. Ma e ials and Me hods
2.1. S udy Design
In his s udy, we used a non-expe imen al quan i a i e design based on an
online su ey [44].
2.2. Sample
The a ge popula ion o his esea ch was a hle es (men and women) o e 18 yea s
who p ac iced and compe ed in any spo (ac i e p ac i ione s, whe he ama eu o high-
In . J. En i on. Res. Public Heal h 2023,20, 420 4 o 14
le el a hle es) in Spain. The selec ion c i e ia we e ha he a hle e had o be (1) o e he age
o 18; and (2) an ac i e p ac i ione in a compe i i e spo since eigh mon hs BL. A mul i-
phase sampling was ca ied ou , he e was no exac lis o indi iduals who made up he
a ge popula ion, and he e was no way o eaching hese indi iduals di ec ly. The e o e,
membe s o he a ge popula ion we e linked o a g ouping ha could be sampled (in his
case, by geog aphical a eas and close con ac s). Access o he sampling ame was achie ed
h ough con enience sampling, i.e., he sample consis ed o a ques ionnai e in he Spanish
language c ea ed in Google Fo ms.
The inal sample was o med by 94 people, wi h a mean age o 23.57
±
6.20 yea s,
o whom, 42 we e men (45%) and 52 we e women (55%). The mos p ac iced spo by
he esponden s was olleyball (n= 25, 27%), ollowed by socce (n= 16, 17%), baske ball
(
n= 13
, 14%), and handball (n= 12, 13%). O he p ac iced spo s we e indoo socce (
n= 10
,
11%), paddle ennis (n= 7, 7%), a hle ics (n= 6, 6%), kayaking (n= 2, 2%), swimming
(
n= 1
, 1%), ia hlon (n= 1, 1%), and ennis (n= 1, 1%). I we di e en ia e be ween bo h
sexes, he mos p ac iced spo by men was socce (n= 15, 35.7%), while o women, i was
olleyball (n= 18, 34.6%).
Fu he mo e, in e ms o pe o mance le el, 41 pe sons (44%) conside ed hemsel es
ama eu s (i.e., compe ing a local and egional le els and o pe sonal sa is ac ion), while
53 (56%) de ined hemsel es as high-le el a hle es (i.e., compe ing p o essionally a a
na ional o in e na ional le el). O he o al sample, 88.3% (n= 83) claimed o ha e been
inju ed a leas once du ing hei spo s ca ee s, o which, 53% (n= 44) we e ama eu
a hle es and 47% (n= 39) we e high-le el a hle es.
2.3. Va iables
Apa om he pe o mance le el (i.e., ama eu and high-le el a hle es), which was
al eady explained in he p e ious pa ag aph, he e we e di e en a iables analyzed:
•
The ype o spo . I e e s o he dis inc ion o spo s based on con ac wi h he
opponen . This a iable has wo le els: con ac spo s (i.e., spo s ha in ol e di ec
body con ac wi h he opponen when pe o ming, e.g., socce , ugby, handball) s.
non-con ac spo s (i.e., spo s ha in ol e no di ec body con ac wi h he opponen ;
e.g., olleyball, ennis, swimming).
•
T aining design DL. I alludes o he p o essional design o he aining sessions
pe o med by a hle es DL. This a iable has wo le els: designed aining (i.e., ain-
ing sessions ha a e indi idually designed and moni o ed by spo s p o essionals,
e.g., ideocon e ences du ing home aining) s. non-designed aining (i.e., aining ses-
sions ha a e no designed by spo s p o essionals and a e pe o med au onomously
by he a hle es, e.g., YouTube i ness ideos).
•
Momen o inju y. This a iable desc ibes he momen wi hin he spo s season when
he a hle e is inju ed. This a iable has h ee le els: aining (i.e., he a hle e is only
inju ed in a aining session) s. compe i ion ( he a hle e is only inju ed in compe i ion)
s. aining + compe i ion ( he a hle e is inju ed in bo h).
•
Type o aining DL. The p esen a iable explains he ypes o exe cises pe o med
by he a hle es DL. I includes ou le els: no exe cise (i.e., he a hle e does no pe -
o m any exe cise) s. endu ance (i.e., he a hle e only pe o ms endu ance exe cises,
e.g., unning, cycling) s. s eng h (i.e., he a hle e only pe o ms s eng h and/o
esis ance exe cises, e.g., weigh li ing, eccen ic aining), s. s eng h + endu ance
(i.e., he a hle e combines bo h s eng h and endu ance exe cises).
•
Mechanism o inju y. The las analyzed a iable is ela ed o how he a hle e is inju ed.
I includes h ee le els: o e load (i.e., he e is no iden i iable single ex e nal ans e
o ene gy ha causes he inju y, bu mul iple accumula i e bou s o ene gy ans e ,
e.g., endinopa hies, ennis elbow) s. auma (i.e., he inju y is caused by an iden i iable
single ex e nal ans e o ene gy, e.g., concussions, disloca ions) s. o e load + auma
(i.e., he a hle e is inju ed a leas once because o each mechanism).
In . J. En i on. Res. Public Heal h 2023,20, 420 5 o 14
2.4. Da a Collec ion
The su ey was c ea ed based on he inju y egis e shee de eloped in he FIFA
Medical Assessmen and Resea ch Cen e (F-MARC) p ojec [
30
]. The ques ionnai e is
di ided in o ou sec ions: he i s sec ion includes sociodemog aphic ques ions (i.e., age;
gende ; spo played; spo le el; place o esidence/compe i ion; exis ence and numbe
o p e ious inju ies); he second sec ion includes ques ions abou inju ies su e ed in he
eigh mon hs BL, om July 2019 o Feb ua y 2020 (numbe and ypes o inju ies); he hi d
sec ion is simila o he second sec ion, bu e e s o he eigh mon hs AL; and he ou h
sec ion con ains a se ies o ques ions abou habi s DL.
The su ey was uploaded and sha ed on 2 Ma ch 2021 on he online pla o m Google
Fo ms, by sending he link o comple e i h ough di e en channels: email in i a ions;
mailings o coaches and manage s o local, egional, and na ional spo s clubs; and dis-
semina ion on pla o ms, such as Resea chGa e
™
, LinkedIn
™
, Facebook
™
, Wha sApp
™
,
and Twi e
™
. A e 15 days (17 Ma ch), he su ey was sha ed again o collec mo e
answe s. Thi y days a e he i s sha ing (1 Ap il), he su ey was closed; he esul s
we e egis e ed in a Mic oso Excel shee and included in he SPSS da abase.
The p esen s udy was conduc ed in acco dance wi h he Decla a ion o Helsinki (1964)
and was app o ed by he Resea ch E hics Commi ee o he Uni e si y o Se ille (in e nal
code 1667-N-22). The su ey included an in oduc o y page desc ibing he backg ound and
he aims o he su ey, along wi h e hical in o ma ion o pa icipan s. Su ey pa icipan s
we e assu ed ha all da a would be used only o esea ch pu poses. Thei answe s a e
anonymous and con iden ial, ollowing Google’s p i acy policy (h ps://policies.google.
com/p i acy?hl=en (accessed on 19 Decembe 2022). Pa icipan s we e no allowed o
p o ide hei pe sonal de ails a any poin du ing he su ey; u he mo e, pa icipan s
could wi hd aw om he su ey a any ime p io o submi ing hei esponses, which we e
collec ed only by clicking on he “Submi ” bu on. By comple ing he su ey, pa icipan s
ga e hei olun a y consen o pa icipa e in his s udy and we e equi ed o be hones
wi h hei esponses [4].
2.5. Da a Analysis
Following [
45
], a e sea ching o missing and ou lie alues, desc ip i e s a is ics
we e calcula ed and a no mali y es (i.e., Kolmogo o –Smi no ) was ca ied ou , showing
a non-no mal dis ibu ion. Fo checking di e ences be ween condi ions, di e en es s
we e u ilized: Mann–Whi ney and Wilcoxon ank-sum es s o a iables wi h only wo
condi ions (i.e., high-le el/ama eu a hle es, con ac /non-con ac spo , and designed/non-
designed aining p og am DL), and K uskal–Wallis es o a iables wi h h ee o mo e
condi ions (i.e., age, ype o aining DL, he momen o inju y, and mechanism o inju y).
When signi ican di e ences we e ound be ween condi ions in he K uskal–Wallis es ,
an adjus ed ollow-up pai wise compa ison was pe o med. Fo e alua ing di e ences
be ween he IR BL and AL, he Wilcoxon signed- ank es was used. E ec sizes we e
conside ed as small ( = 0.10), medium ( = 0.30), o la ge ( = 0.50), and we e calcula ed
based on he ollowing equa ion:
=
z−sco e
√N
S a is ical analyses we e ca ied ou using SPSS so wa e (26.0 e sion), and he le el
o signi icance was se a p= 0.05.
3. Resul s
The desc ip i e s a is ics o each le el analyzed a e shown in Table 2, and he o al
numbe o inju ies and IRs o he le els BL and AL o he a hle es a e shown in Figu e 1.

In . J. En i on. Res. Public Heal h 2023,20, 420 6 o 14
Table 2. Desc ip i e s a is ics o IRs BL and AL.
Inju ies N M SD Skewness Ku osis
BL AL BL AL BL AL BL AL BL AL
To al 94 94 0.65 0.49 ±0.839 ±0.864 1.303 2.534 1.756 8.388
A hle e (male) 42 42 0.57 0.43 ±0.991 ±0.887 1.764 3.635 2.652 17.030
A hle e ( emale) 52 52 0.71 0.54 ±0.696 ±0.851 0.461 1.663 −
0.820
2.168
A hle e (high-le el) 41 41 0.80 0.71 ±0.782 ±1.078 0.694 2.136 0.045 5.558
A hle e (ama eu ) 53 53 0.53 0.32 ±0.868 ±0.613 1.833 2.293 3.703 6.357
A hle e (con ac spo ) 51 51 0.69 0.57 ±0.787 ±0.944 0.885 2.620 0.055 9.245
A hle e (non-con ac spo ) 43 43 0.60 0.40 ±0.903 ±0.760 1.704 2.247 3.345 5.046
T aining (designed) 29 29 0.69 0.72 ±0.761 ±1.131 0.606 2.342 −
0.972
6.694
T aining (non-designed) 65 65 0.63 0.38 ±0.876 ±0.700 1.526 2.117 2.521 4.729
Inju y ( aining) 21 22 1.29 1.32 ±0.463 ±0.646 1.023 1.924 −
1.064
2.631
Inju y (compe i ion) 15 7 1.20 1.00 ±0.561 ±0.000 2.919 - 8.388 -
Inju y ( aining plus compe i ion) 7 3 2.29 3.33 ±0.756 ±1.528 2.646 0.935 7.000 -
Inju y (no exe cise) 14 14 0.43 0.29 ±0.646 ±0.469 1.303 1.067 0.951 −
1.034
Inju y (endu ance) 7 7 0.43 0.57 ±0.787 ±1.134 1.760 2.156 2.361 4.580
Inju y (s eng h) 31 31 0.61 0.65 ±0.761 ±1.170 0.806 2.359 −
0.756
5.965
Inju y (s eng h plus endu ance) 42 42 0.79 0.43 ±0.951 ±0.630 1.348 1.203 1.999 0.433
Inju y (o e load) 20 19 1.25 1.26 ±0.444 ±0.562 1.251 2.158 −
0.497
4.253
Inju y ( auma) 18 10 1.33 1.10 ±0.594 ±0.316 1.683 3.162 2.219 10.000
Inju y (o e load plus auma) 5 3 2.40 3.67 ±0.894 ±1.155 2.236 1.732 5.000 -
No e. N, sample; M, mean; SD, s anda d de ia ion.
In . J. En i on. Res. Public Heal h 2022, 18, x FOR PEER REVIEW 6 o 14
3. Resul s
The desc ip i e s a is ics o each le el analyzed a e shown in Table 2, and he o al
numbe o inju ies and IRs o he le els BL and AL o he a hle es a e shown in Figu e 1.
Table 2. Desc ip i e s a is ics o IRs BL and AL.
Inju ies N M SD Skewness Ku osis
BL AL BL AL BL AL BL AL BL AL
To al 94 94 0.65 0.49 ±0.839 ±0.864 1.303 2.534 1.756 8.388
A hle e (male) 42 42 0.57 0.43 ±0.991 ±0.887 1.764 3.635 2.652 17.030
A hle e ( emale) 52 52 0.71 0.54 ±0.696 ±0.851 0.461 1.663 −0.820 2.168
A hle e (high-le el) 41 41 0.80 0.71 ±0.782 ±1.078 0.694 2.136 0.045 5.558
A hle e (ama eu ) 53 53 0.53 0.32 ±0.868 ±0.613 1.833 2.293 3.703 6.357
A hle e (con ac spo ) 51 51 0.69 0.57 ±0.787 ±0.944 0.885 2.620 0.055 9.245
A hle e (non-con ac spo ) 43 43 0.60 0.40 ±0.903 ±0.760 1.704 2.247 3.345 5.046
T aining (designed) 29 29 0.69 0.72 ±0.761 ±1.131 0.606 2.342 −0.972 6.694
T aining (non-designed) 65 65 0.63 0.38 ±0.876 ±0.700 1.526 2.117 2.521 4.729
Inju y ( aining) 21 22 1.29 1.32 ±0.463 ±0.646 1.023 1.924 −1.064 2.631
Inju y (compe i ion) 15 7 1.20 1.00 ±0.561 ±0.000 2.919 - 8.388 -
Inju y ( aining plus compe i ion) 7 3 2.29 3.33 ±0.756 ±1.528 2.646 0.935 7.000 -
Inju y (no exe cise) 14 14 0.43 0.29 ±0.646 ±0.469 1.303 1.067 0.951 −1.034
Inju y (endu ance) 7 7 0.43 0.57 ±0.787 ±1.134 1.760 2.156 2.361 4.580
Inju y (s eng h) 31 31 0.61 0.65 ±0.761 ±1.170 0.806 2.359 −0.756 5.965
Inju y (s eng h plus endu ance) 42 42 0.79 0.43 ±0.951 ±0.630 1.348 1.203 1.999 0.433
Inju y (o e load) 20 19 1.25 1.26 ±0.444 ±0.562 1.251 2.158 −0.497 4.253
Inju y ( auma) 18 10 1.33 1.10 ±0.594 ±0.316 1.683 3.162 2.219 10.000
Inju y (o e load plus auma) 5 3 2.40 3.67 ±0.894 ±1.155 2.236 1.732 5.000 -
No e. N, sample; M, mean; SD, s anda d de ia ion.
Figu e 1. Numbe o inju ies (BL and AL) o he di e en le els o examined a iables.
When di e ences be ween he wo le els we e compa ed (Table 3), he esul s
showed no signi ican di e ences in he IR BL and AL be ween con ac and non-con ac
spo s. The e we e no signi ican di e ences be ween p o essionally-designed and non-
Figu e 1. Numbe o inju ies (BL and AL) o he di e en le els o examined a iables.
When di e ences be ween he wo le els we e compa ed (Table 3), he esul s showed
no signi ican di e ences in he IR BL and AL be ween con ac and non-con ac spo s.
The e we e no signi ican di e ences be ween p o essionally-designed and non-designed
aining DL. Fu he mo e, high-le el a hle es su e ed signi ican ly mo e inju ies han
ama eu a hle es BL, bu he e we e no signi ican di e ences be ween hem AL. All e ec
sizes we e small ( < 0.30).
In . J. En i on. Res. Public Heal h 2023,20, 420 7 o 14
Table 3. Compa ison o IR di e ences be ween a iables wi h wo le els (BL and AL).
Condi ions UWs
Mean
z-Sco e p
L1 L2
Male/ emale 1302.50 2680.50 0.50 0.63 1.777 0.18 0.076
High-le el/ama eu (p e) 1343.00 2204.00 0.80 0.53 2.171 0.22 0.030 *
Con ac /non-con ac (p e) 1198.00 2524.00 0.69 0.60 0.855 0.09 0.392
Designed/non-designed (p e) 1014.00 1449.00 0.69 0.63 0.650 0.07 0.516
High-le el/ama eu (pos ) 1301.00 2162.00 0.71 0.32 1.960 0.20 0.050
Con ac /non-con ac (pos ) 1219.50 2545.50 0.57 0.40 1.119 0.12 0.263
Designed/non-designed (pos ) 1102.50 1537.50 0.72 0.38 1.570 0.16 0.117
No e.U, Mann–Whi ney U; Ws, Wilcoxon’s W; L, le el; , e ec size; p, asymp o ic signi icance; * p< 0.05.
The compa ison o di e ences be ween h ee o mo e le els (Table 4) showed ha he
IR was signi ican ly a ec ed by he momen o inju y (i.e., i he playe was inju ed du ing
aining, compe i ion, o bo h) and he mechanism o inju y (i.e., i he playe su e ed an
o e load o a auma ic inju y). Howe e , he esul s showed ha he age and he ype o
aining pe o med DL had no e ec on he IR.
Table 4. Compa ison o IRs be ween a iables wi h h ee o mo e le els o BL and AL.
Le els HDeg ees o F eedom p
Age—p e 28.942 19 0.067
Age—pos 14.079 19 0.779
Type o aining DL—p e 2.266 3 0.519
Type o aining DL—pos 0.532 3 0.912
Momen o inju y—p e 88.232 3 0.000 *
Momen o inju y—pos 91.174 3 0.000 *
Mechanism o inju y—p e 87.371 3 0.000 *
Mechanism o inju y—pos 91.288 3 0.000 *
No e.H, K uskal–Wallis es s a is ic; p, asymp o ic signi icance; * p< 0.05.
Pai wise compa isons wi h adjus ed p- alues (Table 5) we e used o analyze he
di e ences be ween he le els included in he a iables Momen o inju y and Mechanism o
inju y. The analysis o he momen o inju y showed ha he e we e signi ican di e ences
and la ge e ec sizes ( > 0.50) be ween IRs when a hle es we e no inju ed compa ed o
hose who we e inju ed du ing aining, compe i ion, o bo h. Howe e , he e we e no
di e ences be ween he emaining le els (i.e., inju ed in aining, in compe i ion, and bo h).
Compa isons ela ed o he mechanism o inju y showed signi ican di e ences and la ge
e ec sizes ( > 0.50) be ween IRs when a hle es did no su e any inju ies compa ed o
hose su e ing om o e load inju ies, auma ic inju ies, o bo h. Howe e , he e we e no
di e ences be ween he o he h ee le els (i.e., su e ing an o e load inju y, a auma ic
inju y, o bo h).
The di e ences be ween BL and AL IRs (Table 6) showed ha he o al numbe o
inju ies was no signi ican ly di e en . Mos o he a iables (i.e., sex, pe o mance le el,
ype o spo , design o aining DL, he momen o inju y, and mechanism o inju y) did
no change signi ican ly. Wi hin he ype o exe cise pe o med DL, only he a hle es who
ained by combining s eng h and endu ance exe cises showed a signi ican educ ion in
hei IR in he AL pe iod when compa ed o BL; he IR o a hle es who did no ain o
ained only wi h s eng h o endu ance exe cises did no signi ican ly change. E ec sizes
we e small ( < 0.30) o mos o he le els; medium ( > 0.30 and < 0.50) o he IRs in bo h
aining and compe i ion and auma ic inju ies; and la ge ( > 0.50) in bo h o e load and
auma ic inju ies.
In . J. En i on. Res. Public Heal h 2023,20, 420 8 o 14
Table 5.
Pai wise compa isons o he di e en le els o he a iables ‘momen o inju y’ and
‘mechanism o inju y’ be ween BL and AL pe iods.
Le els
p
BL AL BL AL
Momen o inju y
None— aining 0.000 * 0.000 * −0.84 −0.90
None—compe i ion 0.000 * 0.000 * −0.73 −0.57
None—bo h 0.000 * 0.000 * −0.81 −0.55
T aining—compe i ion 1.000 1.000 0.05 0.07
T aining—bo h 0.846 1.000 −0.28 −0.19
Compe i ion—bo h 0.606 1.000 −0.35 −0.34
Mechanism o inju y
None—o e load 0.000 * 0.000 * −0.82 −0.86
None— auma ic 0.000 * 0.000 * −0.81 −0.67
None—bo h 0.000 * 0.000 * −0.71 −0.56
O e load— auma ic 1.000 1.000 −0.02 0.04
O e load—bo h 1.000 1.000 −0.28 −0.23
T auma ic—bo h 1.000 1.000 −0.27 −0.31
No e.p, adjus ed signi icance; , e ec size; * p< 0.05.
Table 6.
Compa ison o di e ences in he IRs o he examined a iables be ween BL and AL pe iods.
Inju ies T
Mean
z-Sco e p
BL AL
To al 360.00 0.65 0.49 −1.663 −0.12 0.096
A hle e (male) 74.50 0.57 0.43 −0.858 −0.09 0.391
A hle e ( emale) 110.50 0.71 0.54 −1.493 −0.15 0.136
A hle e (high-le el) 104.00 0.80 0.71 −0.773 −0.09 0.439
A hle e (ama eu ) 80.50 0.53 0.32 −1.566 −0.15 0.117
A hle e (con ac ) 147.00 0.69 0.57 −1.092 −0.11 0.275
A hle e (non-con ac ) 51.00 0.60 0.40 −1.240 −0.13 0.215
T aining ype (designed) 31.50 0.69 0.72 −0.136 −0.02 0.892
T aining ype
(non-designed) 183.50 0.63 0.38 −1.859 −0.16 0.063
Inju y ( aining) 18.00 1.29 1.32 0.000 0.00 1.000
Inju y (compe i ion) 0.00 1.20 1.00 −1.000 −0.21 0.317
Inju y ( aining plus
compe i ion) 3.00 2.29 3.33 1.342 0.42 0.180
Inju y (no exe cise) 13.50 0.43 0.29 −0.707 −0.13 0.480
Inju y (endu ance) 1.00 0.43 0.57 1.00 0.27 0.317
Inju y (s eng h) 51.00 0.61 0.65 −0.96 −0.12 0.923
Inju y (s eng h plus
endu ance) 59.50 0.79 0.43 −2.055 −0.22 0.040 *
Inju y (o e load) 20.00 1.25 1.26 0.302 0.05 0.763
Inju y ( auma) 0.00 1.33 1.10 −1.732 −0.33 0.083
Inju y (o e load plus
auma) 6.00 2.40 3.67 1.633 0.58 0.102
No e. T, es s a is ic; , e ec size; p, asymp o ic signi icance; * p< 0.05.
4. Discussion
The main objec i e o his esea ch was o check whe he he e was a highe IR AL
in compe i i e a hle es when compa ed o he ime BL, as well as o analyze he causali y
o he da a in ela ion o he spo s con ex . Rega ding he i s esea ch ques ion ( o wha
ex en has he IR changed AL when compa ed o BL in compe ing a hle es?), a e analyzing
he da a collec ed in he su ey, i was obse ed ha he IR did no inc ease signi ican ly
a e he e u n o spo s, bu a he dec eased among he esponden s, al hough no
signi ican ly. The null hypo hesis should be e ained o H1–H5, since no signi ican
di e ences we e ound be ween he di e en a iables analyzed. Finally, H6 was ul illed
In . J. En i on. Res. Public Heal h 2023,20, 420 9 o 14
due o he signi ican educ ion in he IR AL in he a hle es who, DL, combined s eng h
and endu ance aining.
The esul s ob ained o he IRs, in gene al, a e simila o hose ound in ecen s udies
in compe i i e a hle es [
12
,
46
], al hough he e a e s udies ha p esen ed signi ican changes
AL in college, ama eu , and high-le el a hle es [
10
,
16
,
39
,
41
–
43
,
47
]. This di e ence may
exis because a la ge pa o he popula ion was o ced o s op compe ing in spo s a e
he end o he qua an ine due o a ious ci cums ances a ising om he pandemic, such as
con inemen s o 10 o 20 days as a consequence o di ec con ac wi h a COVID-19-posi i e
pe son, posi i e es ing, o he es ic i e measu es. In addi ion, many clubs (gene ally
ama eu s) chose no o o m eams un il he si ua ion became clea e , educing he numbe
o compe i ions and, he e o e, he equi emen s necessa y o ace hem, which may ha e
led o his small dec ease in he numbe o inju ies.
I we look u he in o his aspec , we could see ha , based on he esul s o he
su ey, mos a hle es inju ed hei ankles, knees, and high a eas, wi h he mos equen
inju ies being sp ains, muscle inju ies, and endinopa hies, which is consis en wi h he
exis ing li e a u e [
12
,
25
,
48
]. The only inju ies ha inc eased AL we e muscle inju ies (by
14.5%) and endinopa hies (by 8.1%), indica ing ha he e was an inc ease in he ypes
o inju ies ha may be easie o p e en h ough indi idualized aining. This may be
caused by he ac ha compe en au ho i ies did no allow di e en clubs o ha e long
enough speci ic econdi ioning pe iods o he a hle es o eco e om hei neu omuscula
and ca dio espi a o y quali ies, simila o wha usually happens du ing p e-season a e a
ansi ion pe iod [
3
]. This is consis en wi h he esul s ob ained in he s udy ca ied ou
by [
39
], who ound ha muscle inju ies ha e been he mos common among Bundesliga
a hle es a e he esump ion o he season; howe e , in he compe i ions ha allowed o a
longe econdi ioning pe iod (e.g., o he Spanish na ional socce league, “La Liga”, when
compa ed o Bundesliga), he e we e no signi ican di e ences be ween he IR BL and
AL [
12
]. The e o e, coaches and aine s should be awa e o his inc eased isk o inju y
(especially musculoskele al inju ies) and inc ease he subjec i e and objec i e moni o ing
o a hle es.
When compa ing he pe o mance le els, he esul s showed ha , al hough he e
we e no s a is ical di e ences be ween bo h g oups AL, high-le el a hle es su e ed sig-
ni ican ly highe numbe s o inju ies BL han ama eu a hle es. This may a ise om he
g ea e demands in aining and compe i ions aced by high-le el a hle es [
49
], caused by
highe in e nal (i.e., psychophysiological esponses o he a hle es ha ake place du ing an
exe cise) and ex e nal loads (i.e., loads p esc ibed by he coach o elici psychophysiological
esponses) compa ed o ama eu a hle es [
16
,
50
]. Al hough se e al s udies ha e shown sig-
ni ican inc eases in he numbe o inju ies in high-le el a hle es, mainly due o he ab up
inc ease in he aining load a e e u ning o compe i ion and he g ea e concen a ion
o compe i ions in a sho pe iod o ime [
3
,
10
,
39
,
43
,
51
–
53
], o he s udies ha e shown ha
changes in IRs did no signi ican ly inc ease AL in high-le el a hle es [
12
,
46
], hanks o
indi idualized wo k du ing his ime. This di e ence could be a ibu ed o he di e en
concep ions o high-le el a hle es, which could lead o ec ui ing pa icipan s wi h di e en
cha ac e is ics and, hus, di e en esul s. Addi ionally, ama eu a hle es did no see an
inc ease in he IR AL ei he , as mos o hem s opped compe ing a he end o his pe iod.
The cessa ion o compe i ion and, in many cases, o aining, led o lowe in e nal and
ex e nal loads on hese a hle es and, he e o e, ewe inju ies.
In ela ion o he ype o spo (con ac o non-con ac ), despi e he ac ha he e was
a lack o signi ican di e ences in his a iable, con ac spo s had sligh ly highe inju y
a e ages a bo h ime poin s han non-con ac spo s, which may be logical, as he isk o
inju y om auma is highe in con ac spo s. Howe e , o he knowledge o he au ho s,
he e a e no p e ious s udies ha ha e add essed he di e ences in he IR be ween con ac
and non-con ac spo s.
I was also obse ed ha high-le el a hle es ained, o a g ea e ex en , using aining
p og ams designed by spo s p o essionals, when compa ed o ama eu a hle es (who, o