  We establish a non-local integral difference quotient representation for
symmetric gradient semi-norms in $BD(\Omega)$ and $LD(\Omega)$, which does not
require the manipulation of distributional derivatives. Our representation
extends the formulas for the symmetric gradient established by Mengesha for
vector-fields in $W^{1,p}(\Omega;\mathbb R^d)$, which are inspired by the
gradient semi-norm formulas introduced by Bourgain, Brezis and Mironescu in
$W^{1,p}(\Omega)$ and by D\'avila in $BV(\Omega)$.
