The development in recent years of single-molecule force spectroscopy experiments allowed a better knowledge of macromolecules of biological interest, such as DNA and proteins. The work presented here describes the modelling of the macromolecules' response to deformation and to thermal fluctuations with the help of the statistical mechanics, through comparison with the experimental results obtained by single-molecule force spectroscopy, providing valuable information on the static and dynamic responses induced by applied forces. These analyses are even more important for bistable macromolecules with conformational transitions, thus corresponding to folding/unfolding processes and to two stable positions (folded and unfolded). In order to analytically obtain the force-deformation response of a chain composed of bistable units, it is necessary to calculate the partition functions, which are essential in the statistical mechanics and allow to obtain average values of parameters of interest. Thus, the bistable potential energy is decomposed into two parabolas, both corresponding to the folded and unfolded states and identified using the spin variable technique. Several extensions are added to this technique, in order to bring the model closer to reality, such as the extensibility of the bonds between the bistable units, the interactions existing among the bistable units, thanks to the Ising model, or again the heterogeneity, an important parameter to determine the unfolding sequence in proteins folding. Finally, the influence of the pulling speed on the force peaks is considered in the dynamic study, provided with the help of the Langevin method.