High heelsareamajorsourceofchroniclowerlimbpain.Yet,morethanonethirdofallwomen
compromise healthforlooksandwearhighheelsonadailybasis.Changingfrom flat footweartohigh
heels induceschronicmuscleshorteningassociatedwithdiscomfort,fatigue,reducedshockabsorption,
and increasedinjuryrisk.However,thelong-termeffectsofhigh-heeledfootwearonthemusculoske-
letal kinematicsofthelowerextremitiesremainpoorlyunderstood.Herewecreateamultiscale
computational modelforchronicmuscleadaptationtocharacterizetheacuteandchroniceffectsof
global muscleshorteningonlocalsarcomerelengths.Weperformacasestudyofahealthyfemale
subject andshowthatraisingtheheelby13cmshortensthegastrocnemiusmuscleby5%whilethe
Achilles tendonremainsvirtuallyunaffected.Ourcomputationalsimulationindicatesthatmuscle
shortening displayssignificant regionalvariationswithextremevaluesof22%inthecentralgastro-
cnemius. Ourmodelsuggeststhatthemusclegraduallyadjuststoitsnewfunctionallengthbyachronic
loss ofsarcomeresinseries.Sarcomerelossvariessignificantly acrossthemusclewithanaveragelossof
9%, virtuallynolossattheproximalanddistalends,andamaximumlossof39%inthecentralregion.
These changesrepositiontheremainingsarcomeresbackintotheiroptimaloperatingregime.
Computational modelingofchronicmuscleshorteningprovidesavaluabletooltoshapeourunder-
standing oftheunderlyingmechanismsofmuscleadaptation.Ourstudycouldopennewavenuesin