The use of restraints has the advantage that the transferability properties of the model are generally not affected. This is particularly true if the system is restrained to a state that was already a local energy minimum and therefore only requires sporadic biasing (such as a TM peptide). The downsides of this approach relate to the loss of freedom in the restrained degrees of freedom: dynamic behavior involving the restrained dimensions becomes an input of the system, and no longer something that can be explicitly modeled or inferred. For instance, with elastic-networked coiled coils one would be unable to comment on monomer affinity or on their dynamics of pairing.