Similar to cyclooctane, a cyclodecane ring exhibits several conformations with two lower energy conformations.  The boat-chair-boat conformation is energetically minimized, while the chair-chair-chair conformation has significant eclipsing interactions.
These ground-state conformational preferences are useful analogies to more highly functionalized macrocyclic ring systems, where local effects can still be governed to first approximation by energy minimized conformations even though the larger ring size allows more conformational flexibility of the entire structure.  For example, in methyl cyclodecane, the ring can be expected to adopt the minimized conformation of boat-chair-boat. The figure below shows the energetic penalty between placing the methyl group at certain sites within the boat-chair-boat structure. Unlike canonical small ring systems, the cyclodecane system with the methyl group placed at the "corners" of the structure exhibits no preference for axial vs. equatorial positioning due to the presence of an unavoidable gauche-butane interaction in both conformations.  Significantly more intense interactions develop when the methyl group is placed in the axial position at other sites in the boat-chair-boat conformation.