A treadmill has an exercise deck, and a tread belt disposed on the exercise deck. The treadmill further has a tensioning mechanism attached to the exercise deck, and the tensioning mechanism has a selectively movable structure movable with respect to the exercise deck to push outward against an inward surface of the tread belt.

A treadmill includes a treadmill body including a main support unit and a belt mechanism. The main support unit includes at least one first frame, at least one second frame located under the at least one first frame, multiple first elastic shock-absorbing members mounted between the at least one first frame and the at least one second frame, and multiple second elastic shock-absorbing members mounted on a bottom of the at least one second frame. The at least one first frame and the at least one second frame are arranged and combined to construct a multi-layer frame structure. The belt mechanism is mounted on the at least one first frame.

A treadmill includes a treadmill body including a main support unit and a belt mechanism. The main support unit includes at least one first frame, at least one second frame located under the at least one first frame, multiple first elastic shock-absorbing members mounted between the at least one first frame and the at least one second frame, and multiple second elastic shock-absorbing members mounted on a bottom of the at least one second frame. The at least one first frame and the at least one second frame are arranged and combined to construct a multi-layer frame structure. The belt mechanism is mounted on the at least one first frame.

A treadmill running platform structure is provided, which includes a running platform, a running board, and a running belt. The running board includes two soft elastic strips adapted to two side bars of the running platform, a plurality of rigid support strips provided between the soft elastic strips, and strip-shaped connection plates respectively connected to two ends of the rigid support strips. Two strip-shaped connection plates are connected above the rigid support strips, and the strip-shaped connection plates are respectively fixed to a corresponding end of each rigid support strip. The present disclosure can achieve buffering of the entire running board, especially by connecting the rigid support strips together through the strip-shaped connection plates, thereby avoiding an uneven transition of the rigid support strips when a runner steps on the running board, improving the comfort of the runner's feet, and reducing the noise of the treadmill.

A system for adjusting a stiffness of a fitness machine having a base and a mobile portion that moves relative to the base. A resilient body that resists movement of the mobile portion towards the base in a height direction. The resilient body has a length defined in a length direction perpendicular to the height direction, which increases when the mobile portion moves towards the base. An end stop prevents the length from increasing beyond a set maximum, the end stop being fixed relative to the base in the length direction. An actuator is operable to adjust the set maximum at which the end stop prevents the length of the resilient body from increasing. Resistance provided by the resilient body to resist movement of the mobile portion towards the base is unaffected by operation of the actuator when the length of the resilient body is less than the set maximum.