  Between the Tevatron and LHC, top-quark physics is now becoming an area for
precision physics. This has lead to an increase in theoretical activity to
match the experimental accuracy of top anti-top production. We discuss the
difficulty in properly defining the top-quark mass as measured by experiments
and present results for differential distributions of top-quark pair production
in a running mass scheme. The use of such a scheme shows better convergence in
the perturbative expansion and improves the scale dependence as opposed to the
typical on-shell scheme.
