Structure improvement of multifunctional body-building apparatus

The utility model provides a structural improvement for multifunctional body-building apparatuses, particularly a body-building apparatus which can be folded for retraction and can provide various usage modes. The body-building apparatus is composed of two seat plates, an adjusting frame group and two actuating rod groups together, wherein the two seat plates are pivoted and connected by a connecting rod member and are abutted on, assembled and positioned at the seat rod point of the adjusting frame group; the adjusting frame group is formed by matching and assembling a seat rod, an adapting rod and a T-shaped frame rod and then is matched and provided with an actuating rod group respectively by both horizontal ends of the T-shaped frame rod. The whole body can truly be folded for retraction so as to achieve the purpose of saving storage space by the forming of the constructional elements. In addition, the body-building apparatus has the practical benefit that users can be matched to change and adjust usage modes.