A weight loading 
system for fitness equipments includes a fitness equipment support, a rally 
rope, a motor, a motor driving and a 
motor control unit. The motor is a permanent 
magnet brushless 
DC motor with an external rotor structure, and the motor includes a 
stator mounted onto the fitness equipment support and an external rotor sheathed on the 
stator and rotatable with respect to the 
stator, and the rally 
rope is wound around the external rotor of the motor, and an end of the rally 
rope is coupled to the external rotor of the motor, and the other end of the rally rope is coupled to the power driving mechanism of the fitness equipment; the power driving mechanism is provided for driving the external rotor of the motor through the rally rope to rotate and generate a rally, and the 
motor control unit controls the motor to rotate in an opposite direction through the motor driving module, so as to produce a 
load force opposite to the rally. The weight loading 
system for fitness equipments structure is simple, lightweight, and achieves the effect of a stepless 
weight control.