Filling Length in Finitely Presentable Groups
  Filling length measures the length of the contracting closed loops in a null-homotopy. The filling length function of Gromov for a finitely presented group measures the filling length as a function of length of edge-loops in the Cayley 2-complex. We give a bound on the filling length function in terms of the log of an isoperimetric function multiplied by a (simultaneously realisable) isodiametric function. 
S. Gersten and T. Riley