Focusing on mechanical and dielectric relaxation, we study the dynamics of semiflexible linear chains, stars, and dendrimers. For this, we use an extension of the Rouse-model in which we include, in the spirit of Bixon and Zwanzig (J. Chem. Phys. 1978, 63, 1896) and of von Ferber and Blumen (J. Chem. Phys. 2002, 116, 8616), restrictions on the bonds' orientations. In every case the dynamical matrix in the bonds' representation turns out to be a sparse matrix, a fact which simplifies its diagonalization and may pave the way for further analytical treatments.