defineSectionTextCommand
  {dowithnextbox
     {beginhbox
        blackrule[width=dimexpr(hsize-nextboxwd-2emwidth)/2relax,height=0.8ex,depth=-0.6ex,color=middlecyan]%
        quad
        copynextbox
        quad
        blackrule[width=dimexpr(hsize-nextboxwd-2emwidth)/2relax,height=0.8ex,depth=-0.6ex,color=middlecyan]%
      endhbox}
     hbox}

setuphead
  [subject]
  [style=sans,textstyle={setcharactercasing[WORD]tfa},
   textcommand=SectionTextCommand]

starttext

subject{Skills}

stoptext