Limit on backbone movement in relax?

Hi, I am using Rosetta 3.7 and the following flags for relax:

relax.linuxgccrelease -s complex.pdb -out:suffix _relax -nstruct 5 -relax:default_repeats 5 -out:path:pdb ./ -out:path:score ./ -ignore_unrecognized_res

I was wondering if there are any default restraints on backbone displacement in this, I believe in principle unconstrained, procedure.

With thanks and best regards,

Szymon