Managing the return to sport of the elitefootballer following semimembranosusreconstruction
Matt Taberner ,1 Fares SHaddad,2,3 Andy Dunn,4,5 AdamNewall,6 Lloyd Parker,1,7
Esteban Betancur,8 Daniel D Cohen 8,9
ABSTRACTHamstring strains are the most common injury in elite footballand typically occur during high-speed running. Despite itsimportant contribution to power production in the late swingphase, injury to the semimembranosus (SM) is less commonthan to the biceps femoris, but may involve the free tendon anddepending on the degree of retraction, warrant surgical repair.Few case reports detail clinical reasoning, supported byobjective data during rehabilitation in elite footballers, andnone have described the return to sport (RTS) processfollowing this type of hamstring injury. In this article, we outlinethe management and RTS of an English Premier League (EPL)footballer who suffered a high-grade SM proximal tendon tearduring training. Due to the degree of retraction of the freetendon, the player underwent surgical reconstruction at therecommendation of an orthopaedic surgeon. Earlyphysiotherapy care, nutritional support, on- and off-pitchinjury-specific reconditioning and global athletic developmentare outlined, alongside strength and power diagnostic andglobal positioning systems data, assessment of pain, playerfeedback and MRI informed clinical reasoning and shareddecision-making during the RTS process. 18 weeks post-surgery the player returned to team training, transferring to anew club 3 weeks later. 2.5 years post RTS, the playerremains free of re-injury playing regularly in the EPL.
CASE SCENARIOHamstring injuries are the most prevalent inelite football and the biceps femoris long head(BFlh) the most frequently injured muscle.1
Injury to the BFlh typically occurs during high-speed running (HSR) as the muscle undergoeshigh strain. Despite its important contributionto force production during the late swing phaseof maximal speed running, injuries to the semi-membranosus (SM) are less frequent, and tendto occur in slow stretch type activities.2 3 Thistype of injury may also involve a degree ofretraction of the proximal free tendon, whichmay warrant surgical intervention.3
In this article, we outline the managementand return to sport (RTS) of an English Pre-mier League (EPL) footballer who suffereda high-grade SM proximal free tendon tear(figure 1). The injury occurred during train-ing as he overstretched stepping over the ball.
Surgical repair was required, and 18 weekspost-injury, the player returned to team train-ing. Two and a half year’s post RTS, he isplaying regularly in the EPL without re-injury.There are few case reports in the literaturedescribing the rehabilitation and RTS of elitefootballers in detail and none following thistype of hamstring injury. We share theplayer’s pre-injury and RTS running loads,strength and power (S&P) diagnostic data,on- and off-pitch physical preparation, andthe clinical reasoning and considerationsinvolved in the decision-making process.
DECISION-MAKING PROCESS LEADING TOSURGERYAs the post-injury MRI revealed a retracted tear(figure 2A and table 1), an orthopaedic sur-geon recommended an operative approachover the conservative option which was deemedto present a greater risk of re-injury, extending
To cite: Taberner M, HaddadFS, Dunn A, et al. Managing thereturn to sport of the elitefootballer followingsemimembranosusreconstruction. BMJ Open Sport& Exercise Medicine 2020;0:e000898. doi:10.1136/bmjsem-2020-000898
► Supplemental material ispublished online only. To viewplease visit the journal online(http://dx.doi.org/10.1136/bmjsem-2020-000898).
Accepted 26 September 2020
© Author(s) (or theiremployer(s)) 2020. Re-usepermitted under CC BY-NC. Nocommercial re-use. See rightsand permissions. Publishedby BMJ.
For numbered affiliations seeend of article.
Correspondence toMatt Taberner;[email protected]
Key points
► Semimembranosus injuries tend to occur duringslow stretch type activities and may involve thefree tendon. Depending upon the upon the degreeof tendon retraction, these injuries may warrantsurgical repair.
► Off-pitch rehabilitation progressively integratedhigh-intensity isometrics, high strain eccentricsand exercises requiring intermuscular coordination— emphasising involved limb loading. Alongsidereconditioning specific to the injury, rehabilitationalso provided a ‘loading opportunity’ to integratejump-landing activities to improve the player’soverall athletic qualities.
► On-pitch rehabilitation followed the ‘control–chaoscontinuum’ considering important factors specific tohamstring injury; positional-specific conditioning,progressive exposure to HSR volume and maximalspeed running under increasingly chaotic conditions.
► Communication and a player-centred shareddecision-making process involving externalhealthcare professionals and a multidisciplinaryteam help to ensure optimal player care during RTS.
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Taberner M, et al. BMJ Open Sp Ex Med 2020;0:e000898. doi:10.1136/bmjsem-2020-000898 1
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ctober 2020. Dow
nloaded from
RTS and potentially placing the player’s career in jeopardy.Progressing with a conservative approach would haveincreased the formation of scar tissue and resulted ina loss of tension within the SM. This would be expected tohave profound consequences for an elite footballer, interms of the decreased ability to generate force, powerand run at high-speeds, and potential increased risk ofinjury to other hamstring musculature due to compensa-tory demands. Furthermore, delaying surgery or operatingon a scarred tissue bed would increase the challenge ofrestoring anatomy.4
The procedure was undertaken under general anaes-thesia (prone position). A longitudinal incision is neces-sary to access these tears, allowing tracking into themedial window between the hamstring and adductorcompartments. The SM injury lies next to the sciaticnerve and the tendon tends to tear in a staggered way sothere is one segment still connected to the membraneand muscle distally and one segment connected to thetendon insertion proximally. The two segments are iden-tified, the sciatic nerve and its branches protected. Thetwo tendon ends are re-approximated to the correct levelof tension, assessed by restoring anatomy and held
together with Ethibond non-dissolving sutures whichhold in situ long enough for the tendon to heal. Theseare reinforced with Vicryl dissolvable sutures to regain theappropriate tendon length (restore pre-injury length)and to provide tensile strength. The repair is then testedby manual pressure and by applying stretch to the ham-string musculature.
Figure 1 Overview of the return to sport (RTS) of an elite male football player following semimembranosus free tendonreconstruction. Early rehabilitation is divided into two phases: physiotherapy care (Weeks 1–7) and transition into gym-basedphysical preparation (Weeks 8–12) including isometrics (ISO), dynamic strength (DYN) and jump-landing preparation (J-L Prep)and progression from stationary bike to anti-gravity treadmill running (A-GR) (Alter-G, Fremont, CA, USA). Return to participationphase (Weeks 13–17); on-pitch sports-specific reconditioning using the ‘control–chaos continuum’ (weeks displayed on-pitch)plus progression (+) of gym-based physical preparation; ISO+, DYN+ and J-L Prep+. RTS decision=return to team training (Weeks18–20; return to train) and continued progressive optimal loading with reduced volume (sets) of ISO+, DYN+ and J-L Prep+. Arrowsindicate timepoints of isometric posterior chain (IPC), eccentric knee flexor (ENF) and countermovement jump (CMJ) assessments.Data from these strength and power diagnostic tests, quantifying neuromuscular deficits relative to his healthy preseason (PS)values, and his response to on- and off-pitch reconditioning, informed exercise and phase progression decisions.
Nutritional considerations following muscle-tendon injury
Nutritional support had two principal aims► to minimise muscle atrophy by maintaining caloric intake,5 taking
creatine (5g) and 3g omega-3 poly-unsaturated fatty acidsupplements (750 mg docosahexaenoic acid, 1500 mgeicosapentaenoic acid)6 and to promote maximal muscle proteinsynthesis by consuming approximately 35 g every 3 hours (5/day) toachieve a protein intake of ~2 g/kg/BM (170 g).6 Daily energyintake, monitored by 24-hour dietary recall and analysed usinga nutritional software package (Nutritics, v5, Ireland), wasestimated to be ~3000 kcal.
► to promote tendon healing. Beginning at 8 weeks post-surgery, an hourbefore activity the player consumed a collagen (20 g) and vitaminC (80 mg) supplement shown to be beneficial for tendon remodelling.7
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nloaded from
MECHANICAL LOADING AND RTSAnMRI 7 weeks post-surgery, following early post-surgicalphysiotherapy management, showed a good healingresponse (table 1; figures 1 and 2B). Reconditioningthen began under sports science supervision, with dailycommunication including pain response (numerical rat-ing scale; NRS) and periodic checks of the player with theclub physiotherapist (table 1). Submaximal isometrics(at 60–90° knee flexion) were introduced in Week 7and a week later the player performed his first post-injury unilateral isometric posterior chain (IPC) test(figure 3).8 9The IPC test was used to quantify the players’ability (and willingness) to produce maximal force (IPCpeak force', IPC-PF) and early rate of force development(RFD) (force at 100 ms).10 Week 8 interlimb asymmetry(ILA) in IPC-PF was 13% and in force at 100 ms was 7%.While the force at 100 ms ILA was low relative to that ofIPC-PF, this should be considered in the context of thesubstantially larger magnitude declines in force at100 ms than peak force on both limbs (figure 4). Thesedata highlight both the importance of evaluating RFD-related variables following injury and of having healthybenchmark values to reduce the dependence on %ILAas a marker of status and progress.11 12
Exercise selection and programming was based on theoptimal loading concept — to maximise physiologicaladaptation of the involved structures.13 Isometrics werethe predominant mode of strength training during initialprogramming, with the conceptual aims of increasingtendon stiffness and enhancing maximal force
development.14 15 Programming began with unilateralshort-lever overcoming isometrics at 90° hip and kneeflexion (figure 5; single-leg (SL) heel drives — kneedominant; online supplemental video 1) to bias medialhamstring recruitment.9 While this exercise remainedkey prior to gym-based rehabilitation sessions to‘prime' the injury site, progression involved integratinglong-lever yielding isometric variations such as double-leg isometric hip extension, followed by its SL deriva-tive — hip dominant, with knee involvement as the ham-string is elongated (figure 5).16We used >80%ofmaximalvoluntary contraction — the threshold to stimulate thedevelopment of mechanical and material tendonproperties17 and programmed in clusters (3–5×~3–5 s iso-holds), to develop maximal strength, RFD and strength-endurance.15 18 19 We delayed integrating high straineccentric exercises in the initial 2 weeks of reconditioningto avoid excessive mechanical strain on the healingstructures.20 Furthermore, post-injury inhibition isreported during bilateral eccentric loading, potentiallycompromising adaptations,21 whereas maximal iso-metrics elicit higher voluntary muscle activation andlower inhibition.22
With no pain reported (<2/10 NRS) following earlyisometric loading, we added dynamic strength exercises,coaching ‘intent’23 to move as explosively as possible todevelop power, with the conceptual goals of promotingcollagen synthesis, fibre alignment and improving ten-don-tensile strength.24–26 We first introduced the heelelevated hip thrust (hip dominant, with the hamstrings
Figure 2 MRI throughout the return to sport process. Green arrows indicated key prognostic features. (A) 24 hours post-injury: (1)semimembranosus (SM) free tendon laxity and muscle retraction, (2) longitudinal split tearing at SM tendon origin. (B) 7 weekspost-surgery: (1) normal SM tendon/myotendinous junction tension, (2) maturing granulation tissue in SM tendon repair site. (C) 11weeks post-surgery: (1) segmental tendon thickening and restoration of tension, (2) intratendinousmaturing fibrous scar tissue. (D)17 weeks post-surgery: (1) continued maturation of scar tissue throughout the site of surgical repair of the free proximal extramuscular portion of the SM tendon, (2) long segment of tendon repair shows relatively uniform low signal intensity scarring andmaintains normal tension throughout the extra muscular portion and the proximal intramuscular portions of the tendon.
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Taberner M, et al. BMJ Open Sp Ex Med 2020;0:e000898. doi:10.1136/bmjsem-2020-000898 3
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ugust 24, 2021 by guest. Protected by
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MJ O
pen Sport E
xerc Med: first published as 10.1136/bm
jsem-2020-000898 on 24 O
ctober 2020. Dow
nloaded from
Tab
le1
Injury
details,surgica
linterve
ntion,
cons
ultant
summaries,phy
siothe
rapyca
rean
dMRId
etailsthroug
hout
reha
bilitatio
nfollo
wingse
mim
embrano
susreco
nstruc
tion
Injury
14Aug
ust20
17
Surgical
interven
tion
19Aug
ust20
17(5
day
spost-injury)
Early
phy
siotherap
yca
re(W
eeks
1–7)
Rep
eatMRIa
ndco
nsultant
chec
k-up
(7wee
kspost-o
p)
Phy
siotherap
yca
re→
sportssc
ienc
e(W
eeks
7–11
)
Rep
eatMRIa
ndreha
bilitationup
date
(11wee
kspost-o
p)
Rep
eatMRIa
ndco
nsultant
chec
k-up
(17wee
kspost-o
p)
Playe
rfelta‘sha
rp’ac
ute
painin
pos
terio
rthigh
(proximal)a
fter
step
ping
over
theballa
ndstretching
.Playe
rimmed
iatelystop
ped
andwith
drewfrom
thepitc
h—icean
dco
mpress
ion
applied(pha
se1;
rest,ice
,co
mpress
ionan
delev
ation
(RICE).
MRIp
erform
ed24
hours
pos
t-injury.
MRIs
ummary(A):ac
ute
high
-gradepartia
ltea
ring
extend
ingthroug
hout
along
cran
ioca
udal
dim
ension
invo
lvingtheproximal
free
extramus
cularportio
nof
these
mim
embrano
sus(SM)
tend
on,w
ithlong
itudinal
splittearingat
theoriginan
dpartia
ltrans
versefib
redisruptio
nof
the
mem
brano
usportio
nof
the
tend
on,w
hich
compris
esap
proximately50
%disruptio
nof
thetend
onfib
resco
ntinuing
into
along
segm
ento
fminor
partia
ltearingof
themyo
tend
inou
sjunc
tion(M
TJ)rep
rese
nting
agrad
e3C
injury.
Ass
ociatedlaxity
ofthe
pelvictend
inou
sportio
nof
thefree
tend
onan
dmild
distalretractionof
the
mus
clebellyaread
verse
imag
ingprogn
ostic
features
.Exten
tofinjuryex
plained
toplaye
rbymed
ical
team
;co
nsultw
ithan
orthop
aedic
surgeo
n—su
rgical
repair
advise
d.
Playe
rund
erwen
tsurge
ryat
thePrin
cess
Grace
Hos
pita
l,Lo
ndon
.Bothse
gmen
tsof
the
horsetail(ruptureden
dof
thetend
on)w
eremob
ilise
dan
dhe
ldwith
No.
5Ethibon
d.F
ourse
tsof
Kes
sler
sutureswereus
edto
reco
nstitutean
dbrin
gbac
kthetens
ions
tocrea
teatubular
tend
onproximally.
Themem
brane
was
recrea
tedwith
No.
5Ethibon
dan
dthen
with
1Vicryltoco
verthesu
tures.
Astrong
repairob
tained
andtested
with
thekn
eebac
kin
extens
ion,
thorou
ghwas
hout
perform
ed.
Thene
urov
ascu
lar
structures
werese
enclea
rlyan
dprotected
—intact.
Closu
rewas
affected
inlaye
rsus
ing1Vicryl,2-0
Vicrylfollowed
by3-0
Mon
ocryltosk
in.
Operationdisch
arge
plan:
Tend
onin
a‘shred
ded
’state—
~8wee
kshe
aling
beforeprogres
sing
tostreng
then
ingprogram
me.
Pos
t-ch
eck-up
:6–8wee
kspos
t-op
forclinical
asse
ssmen
tand
obtain
updated
MRI.
Mob
ilise
NWBwith
crutch
es,b
race
at60
–12
0°~4wee
ks+grad
ualw
ean-
off.
Asp
irin+
TEDan
ti-em
bolism
stoc
king
sforVTE
prophy
laxis.
Wou
ndca
re(clean
ing/fres
hdressings
)Sciatic
nervemob
ilisa
tion
Minim
iseatrophy
:co
mbinationof
isom
etric
knee
extens
ion+
NMES
(atrop
hyse
tting)
(60°→90
°)progres
sing
tosu
pported
fund
amen
talm
ovem
ent
patternssu
chas
squa
t(→
ROM),isolated
hipab
/ad
duc
tor+an
klefle
xor/
extens
orstreng
then
ing.
Isolated
hamstrin
gco
ntractionon
invo
lved
limbav
oided
.Hyd
rotherap
y;walking
insh
allow
end.
Softtissu
e;sc
armob
ilisa
tion.
MRIs
ummary(B):Goo
dpos
t-op
features
follo
wing
along
segm
ento
fsurgica
lrepairof
theproximal
extra
mus
cularSM
tend
onan
dproximalregion
ofMTJ
.The
majority
ofthetend
onrepair
show
smaturelow
sign
alfib
rous
tissu
ewith
asm
aller
volumeof
maturingfib
rous
tissu
e.Signific
antly
,the
reis
good
restorationof
the
norm
altens
ionof
the
tend
onrepairsite
aswella
stheintram
uscu
lartend
on.
Thereareno
complicated
features
orco
ncerning
mus
cleatrophicch
ange
.Con
sulta
ntsu
mmary:
satis
factoryprogres
s.Slig
htne
ural
tens
ion
apparen
tbut
notune
xpec
ted,sca
ralittle
distally
thicke
ned→
progres
sso
fttis
sue.
Goo
dhip+kn
eemob
ility/
ableto
gene
rate
reas
onab
leha
mstrin
gco
ntraction
+mus
clebulk‘fa
rbetter’
than
pee
rsat
thisstag
e.MRIs
howsgo
odhe
aling
resp
onse
alon
gsidego
odtens
ionin
theintram
uscu
lar
tend
on+distalm
uscle.
Plan:
progres
sto
S&C
program
me→
football-
spec
ificac
tivity
.Nb.
Objectivestreng
thtesting
prio
rto
RTS
.
Pha
se2:
restorepain-free
rang
eof
motion,
FWB,
integrateprogres
sive
optim
alload
ing.
(criterion:
<2/10
NRS,<
5%ILASLR
/PKE)
Con
tinue
sciatic
nerve
mob
ilisa
tion+
softtis
sue;
scar
mob
ilisa
tion.
Inco
rporatemea
suremen
tsof
SLR
+PKE.
AtW
eek9:
SLR
:87°
each
side
PKE(gen
tle):69
°ea
chside.
Beg
inisolated
hamstrin
gco
ntraction;
includ
ing
progres
sion
ofisom
etric
s(sho
rt→
long
leve
r)—
combinationof
overco
ming/yielding
derivatives
,progres
sintens
ity(%
MVC)a
ndvo
lumetargetinginvo
lved
limb.
Beg
intran
sitio
nto
stationa
rybike(con
centric
actio
n;sh
ort-rang
e).
Gradua
llyintrod
uce
exercise
selection
inco
rporatingsimultane
ous
hipan
dkn
eeex
tens
ion
(interm
uscu
larco
-ordination).
Introd
ucerunn
ing
mec
hanics
(startingwith
walking
derivatives
alon
gsideus
eof
aeroflo
orto
↓im
pac
tforce
s/’elastic’
dem
andwhe
nintrod
ucing
dyn
amic
mov
emen
tsthat
is,A
-skips).
Asses
sIPCstreng
th/R
FD(IP
Cat
90°:biasmed
ial
hamstrin
grecruitm
ent—
startin
gat
Wee
k8,
evalua
tedwee
kly
throug
hout
theRTS
proce
ss.
MRIs
ummary(C):go
odpos
t-op
appea
ranc
esfollo
wingsu
rgical
repairof
theproximal
extramus
cular
SM
tend
onan
dproximal
extent
oftheintram
uscu
lar
portio
nof
thetend
on.
Interval
maturationof
intraten
dinou
smaturing
fibrous
scar
tissu
eisno
ted.
Res
toratio
nof
theno
rmal
tens
ionof
thetend
onan
dmus
clebellyareag
ain
noted,w
ithno
conc
erning
mus
clevo
lumereduc
tionor
MTJ
fattyinfiltration.
Reh
abilitatio
nplanup
date
follo
wingMRI:
Con
tinue
sciatic
nerve
mob
ilisa
tion+
softtis
sue;
scar
mob
ilisa
tion.
Initiatean
tigravity
runn
ing
whe
nsu
pportedby
objectivemea
sures/playe
rco
nfiden
ce(criterion:
<10
%PF%ILA,fullp
ain-free
ROM
<5%
%ILA),MRIp
ositive
healingresp
onse
,playe
rpain-free
<2/10
NRS).
Asses
sENFstreng
thbi-
wee
klyfollo
wingreturn
toon
-pitc
hrunn
ing.
Asses
sCMJperform
ance
compared
topre-injurydata
duringon
-pitc
hreco
ndition
ing.
Pha
se3:
progres
sop
timal
load
ing(S&C)+tran
sitio
nto
on-pitc
hsp
ort-sp
ecific
reco
ndition
ingus
ingthe
‘con
trol–ch
aosco
ntinuu
m’
(pre-injurydata).
(criterion:
<10
%IPC-P
F%
ILA,<
15%
IPC-F
at10
0ms
%ILA,E
NF<15
%ILAplus
tren
dsin
relatio
nto
pre-
injury
data,
pain-free
(<2/10
NRS)o
nan
ti-grav
itytrea
dmillrunn
ingat
90%
BW).
MRIs
ummary(D):
Con
tinue
dmaturationof
fibrous
scar
tissu
ethroug
hout
thelong
segm
ento
frep
airinvo
lving
theex
tramus
cularportio
nof
therig
htSM
tend
on.T
his
refle
ctsun
complicated
pos
t-op
healingwith
good
prese
rvationof
tend
ontens
ionproximal
toan
dwith
intheSM
mus
clebelly.
Mild
residua
lrem
odellin
grelatedmus
cleoe
dem
aat
proximal
extent
ofMTJ
and
mild
perite
ndinou
soe
dem
a,bothof
which
areex
pec
ted
pos
toperativefin
dings
Con
sulta
ntsu
mmary:
Exc
ellent
progres
s.Sca
rlong
but
wellh
ealed;
thisou
tcom
eex
pec
tedan
dex
plained
toplaye
rprio
rto
surgerydue
toex
tent
over
long
tend
inou
sportio
nof
thestag
geredSM
injury.
Mus
clemas
s‘rea
sona
ble’
relativ
eto
visu
alinsp
ectio
nof
theco
ntralaterallim
b.
None
uraltens
ionno
ted/SM
shap
esimilaro
nbothsides
.No'red
flags
'displaye
d.
Planto
reintegratein
team
training
(pha
se4)
with
grad
ualp
rogres
sion
ofhigh
load
san
dhigh
-spee
dac
tivity
while
mon
itorin
gfor
anysymptomsof
tired
ness/
neural
features
(criterion:
<10
%IPC-P
F/F
at10
0ms%ILA,<
10%ENF
%ILAplustren
dsin
relatio
nto
preinjury
data,
GPS
training
load
data(pre-
injury),playe
rpainfree
(<2/
10NRS,p
ositive
playe
rfeed
bac
k,su
rgeo
ndisch
arge
,MRIh
ealin
gstatus
).
MRIs
cans
aresh
ownin
figure1.
BW,b
odyw
eigh
t;CMJ,
coun
term
ovem
entjum
p;~
,Circ
a;↓,Dec
reas
e;ENF,
ecce
ntric
knee
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acting isometrically to resist knee extension) and the splitsquat (hip and knee hybrid), subsequently progressedwith external load, and increasing exercise complexityto provide additional challenges to the neuromuscularsystem (figure 5).13 A positive response to these explo-sively performed dynamic hip dominant exercises along-side progressive high-intensity isometrics may beapparent in the IPC response 2 weeks (Week 11) later.IPC force at 100 ms showed large increases in both limbs,although greater on the non-involved side, whileimprovements in IPC-PF were smaller but favoured theinvolved limb. High strain eccentrics were now intro-duced, and to emphasise bi-articular loading and medialhamstring recruitment, we selected the sliding leg curl(SLC),27 later progressed to the SL derivative to increaseinvolved limb overload (online supplemental video 2).28
Slow-stretch shortening cycle (SSC) jump-landing activ-ities were now added, to enhance the global athleticqualities of lower-limb stiffness, neuromuscular controland power.29
PROGRESSING TO ON-PITCH REHABILITATIONAt 12 weeks post-surgery, with 10% ILA in IPC-PF andfollow-up MRI showing further positive healingresponse (table 1; figures 2C and 4), the playerinitiated 70% bodyweight anti-gravity treadmill run-ning (AG-R), progressing to 90% bodyweight (com-pleting three sessions during Week 12; 70%, 80%and 90% bodyweight) (online supplemental video 3).Prior to each AG-R session, the player performeda series of running mechanic drills including A-skipsand straight-leg bounds to replicate the co-ordinationdemands and proximal-distal energy sequencing asso-ciated with running (figure 5).30 These drills were alsoimplemented within on-pitch warm-ups alongsidedrills to develop acceleration and deceleration quali-ties. At Week 12, IPC-PF ILA was <10%, IPC force at100ms ILA was 14%, and to further inform clinicalreasoning and decision-making at 13 weeks, we alsoassessed ENF strength, the player showing 11% ILA aswell as ENF force substantially above threshold pro-spectively associated with elevated hamstring injuryrisk (figure 4).31 We considered that these data pro-vided evidence to support our clinical judgement thatthe level of risk tolerance was above the level of riskexposure and did not warrant a delay in initiating thehigh control phase of the ‘control–chaoscontinuum’.32 The goal of this phase was to exposethe player to submaximal running speeds (<60% pre-injury maximal speed) monitored using global posi-tioning systems, promoting neuromuscular recoveryin preparation for HSR33 and to build player confi-dence in his return to on-pitch activities. The similarimprovements in IPC-PF and IPC force at 100 ms inthe involved limb between Weeks 13 and 14 (figure 4)suggested a positive response to the initial exposure tothe return to running phase and lack of load involvedlimb avoidance in on-pitch activities. Consequently, inWeek 14, we progressed to a low dose of ‘controlled’HSR (within-session 0.30 gameload HSR) alongsidethe introduction of directional change load and tech-nical skill integration (figures 4 and 6). Prior to begin-ning Week 3 of on-pitch reconditioning (Week 15post-surgery), IPC %ILAs (in PF and force at 100ms) were <10% and involved limb IPC-PF and ENFstrength increases of ~15% since Week 13 (figure 3).This gave us confidence in implementinga progressive increment in ‘controlled’ HSR volumethrough aerobic power conditioning (online supplemental video 4) alongside more chaotic activities —
phase-specific pass and move, and positional accelera-tion drills, in the transition to football-specific weeklyperiodisation.32 Off-pitch conditioning progressed(online supplemental videos 5 and 6), increasingmovement velocity emphasis (online supplementalvideos 7 and 8) (figure 5). Additionally, due to thestretch mechanism of the injury in which hip flexioncombined with an inability to control knee extension,we considered the barbell split squat with forward lean
Figure 3 Isometric posterior chain (IPC) test performedusing a portable force platform at 1000 Hz (PS-2141,Pasco, Roseville, CA, USA) with proprietary software(ForceDecks, Vald Performance, Brisbane, Australia). Testperformed with the player lying supine position, the heel ofthe testing limb placed on the force platform resting ona firm plinth with the testing angle set at 90° hip and kneeflexion using a goniometer (Physio Parts, Twickenham, UK)and the non-testing limb relaxed and fully extended. Theplayer was instructed to push the heel of the testing limbinto the force platform exerting as much force as fast aspossible while keeping the buttocks, hips and head on themat and hands crossed on chest. External pressure wasapplied to the non-tested pelvis/hip to prevent hipextension. The player was familiar with the test, butstandardised instructions were given before theassessment, a verbal command of ‘3, 2, 1 GO’ countdownbefore the initiation of a maximal effort contraction whichwas held for 3 s during which consistent verbalencouragement was given ‘PUSH, PUSH, PUSH, RELAX’.Three maximal voluntary contractions were performed with10 s rest between repetitions.
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a key exercise (online supplemental video 9),34 pro-gressed using external load and increasing exercise com-plexity (figure 4). Accommodating resistance was alsoadded to the SL eccentric SLC to increase the speedand strain rate of eccentric loading7 25 while fast SSCplyometric activities were also integrated into the player'sprogramming (online supplemental video 10) (figure 5).We took advantage of this period to integrate condition-ing aimed at developing the capacity to rapidly decele-rate the centre of mass and follow with rapid increasesin concentric force, power,32 explosive and reactive qua-lities important to the player’s playing characteristics.Our S&P diagnostic criterion for progression to the
moderate chaos phase29 was an IPC-PF and IPC force at100 ms ILA <10% and stable outputs (lack of regression)in response to the control to chaos phase (figure 4).The transition to the moderate and high chaos phases isimportant as it exposes the player to substantiallyhigher cumulative weekly HSR, and subsequently pro-gressing to HSR loads reflecting game output, progres-sively higher maximal speed exposure, alongsidepositional requirements and technical skill components(figures 4 and 6; online supplemental videos 11
and 12).10 32 Pre-injury running load and HSR volumesused to plan running load targets were based on playeroutputs under the previous manager’s regime. However,we anticipated higher team training loads under the newregime and therefore aimed to return the player to hismaximum cumulative training HSR volume to adequatelyprepare the player for these demands (figure 6). As anattacking midfielder, it was important to include additionalshooting practice in themoderate and high chaos phases tomitigate injury risk associated with inadequate exposure toball-striking (online supplemental video 13).35 Based ona combination of objective injury-relevant S&P and trainingload data (figures 4 and 6),MRI results highlighting healingand maturation (figure 2D), the surgeons' positive opi-nion (table 1), and positive feedback/lack of painreported by the player, we concluded that the players’level of risk tolerance was above estimation of re-injuryrisk, and 18 weeks post-surgery, the player resumedteam training. Furthermore, comparing the player’scountermovement jump profile to that of pre-injurysuggested a positive response to the off- and on-pitchloading (figure 7). Notably, at Week 17 despite mod-est deficits in jump height (5%) and peak power
Figure 5 Optimal loading approach following semimembranosus free tendon reconstruction during the earlyrehabilitation phase onwards; gym-based physical preparation (Weeks 8–20). Running mechanics prior to anti-gravitytreadmill running and implemented during on-pitch rehabilitation warm-ups. Dark grey=exercise, Light grey=exercisederivative. Strength (strain/stress) and (intermuscular emphasis)=dynamic strength training. w/=with, ↑=increase,↓=decrease, ~=circa, > progression/onto. DB, dumbbell; early, early-stage; end, end-stage; GCT, ground contact-time;mid, mid-stage; Nb., note; reps=repetitions; RFD, rate of force development; ROM, range of motion; S-E, strength-endurance.; SL, single-leg.
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(7%), relative to pre-injury, suggestive of performancedecline secondary to the injury/deconditioning, therewere substantial improvements in strategy/kinetic vari-ables such as eccentric deceleration RFD (20%), con-centric impulse-100 (8%) and lower limb stiffness(13%), indicative of improved SSC ability.11 36 Impor-tantly, at this time point, the player had achieved 97% ofpre-injury maximal speed (figures 4 and 6), without fullrecovery of aspects of neuromuscular performance, andseveral weeks remained before expected return to com-petition to further recover these.In the first week following return to team training
(online supplemental video 14), within-session HSRincreased (a 0.12 gameload increase from previousmax rehabilitation session) while cumulative HSR waswithin his range of chronic weekly volume and otherrunning load markers monitored across the playingsquad (figure 6). Importantly, the player communicatedthat he felt the demands of team training were below
that of rehabilitation (figure 6), suggesting he was ade-quately prepared to cope with a return. Within 2 weeksof his RTS, the player was the subject of a bid fromanother EPL team competing within the UEFA Cham-pions League. Twenty weeks post-surgery and following11 team training sessions, he passed a medical anda transfer was agreed.
SUMMARYFollowing surgery and early care management, on- andoff-pitch loading stimuli were progressively integratedwith global positioning systems and S&P diagnosticsused to quantify running load and monitor player neuro-muscular status, respectively. This objective data, in con-junction with clinical experience from several sourcesand player feedback, informed decisions on phase andloading progression to raise the level of risk tolerance andultimately facilitate a successful outcome for club andplayer.
Figure 6 Return to chronic running loads following semimembranosus free tendon reconstruction using the ‘control–chaoscontinuum’ as a framework for return to sport. Tables show the player’s pre-injury ‘gameload’ running load metrics from season2016/2017. Total distance (TD), high-speed running (HSR)=>5.5ms-1, explosive distance (Exp-D)=accelerating/decelerating from2ms to 4ms-1 <1 s, highmetabolic load distance=distance above 25 w•kg-1; HSR plus Exp-D). Gold box are absolute values. Lightblue and dark blue boxes show relative (multiples of) gameload (ie, 2×=2 games worth) and absolute, mean and max training andconcurrent (training plus game), respectively.Weekly absolute (left y-axis) and relative (right y-axis) TD, high metabolic load distance, HSR and Exp-D are shown foreach week of on-pitch rehabilitation in graphs. Session rate of perceived exertion (session-RPE) (y-axis=arbitrary units)shows weekly accumulated session-RPE (training session duration (min)×RPE). % max speed=(maximum speedachieved in session/player’s pre-injury maximal speed (8.95 ms-1)×100). Control–chaos continuum: Control; highinfluence on behaviour/actions/movement—controlled situations. Chaos; behaviour/actions/movement, unpredictable/random/reactive—chaotic situations. Green=high control, pale green=moderate control, yellow=control to chaos,orange=moderate chaos, red=high chaos and grey=return to team training (RTT). Global positioning systems;augmented 10 Hz Apex (StatSports, Belfast, UK).
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Author affiliations1School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK2University College London Hospitals NHS Foundation Trust, London, UK3Institute of Sport, Exercise and Health, London, UK4Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, UK5The OrthTeam, Spire Healthcare Ltd, Manchester, UK6Medical Department, Everton Football Club, Liverpool, UK7Nutrition Department, Everton Football Club, Liverpool, UK8Sports Science Center (CCD), Colombian Ministry of Sport (Mindeporte), Colombia9Masira Research Institute, Universidad de Santander, Bucaramanga, Colombia
Twitter Matt Taberner @MattTaberner, Lloyd Parker @parkernutrition and Danielcohen @daniecohen1971.
Contributors FSH surgically operated on the player, AD provided MRI reports, ANprovided physiotherapy care, LP provided nutritional support, MT led on- and off-pitchphysical preparation, planned and wrote the manuscript, DC provided assistance writingthe manuscript and feedback. MT, DC and EB provided an analysis of S&P diagnostics.
Funding This research received no specific grant from my funding agency in thepublic, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained (BMJ consent form).
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has notbeen vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of theauthor(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibilityarising from any reliance placed on the content. Where the content includes anytranslated material, BMJ does not warrant the accuracy and reliability of thetranslations (including but not limited to local regulations, clinical guidelines, ter-minology, drug names and drug dosages), and is not responsible for any error and/oromissions arising from translation and adaptation or otherwise.
Open access This is an open access article distributed in accordance with theCreative Commons Attribution Non Commercial (CC BY-NC 4.0) license, whichpermits others to distribute, remix, adapt, build upon this work non-commercially,and license their derivative works on different terms, provided the original work isproperly cited, appropriate credit is given, any changes made indicated, and the useis non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
ORCID iDsMatt Taberner http://orcid.org/0000-0003-3465-833XDaniel D Cohen http://orcid.org/0000-0002-0899-4623
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