A virtual reality (VR) system includes a VR display and a VR movement apparatus that includes hand user interfaces (UIs) and foot UIs that can support the hands, feet, and total weight of a user. The VR movement apparatus allow the user's hands and feet to move in 3-dimensional space that include vertical, lateral, and fore-aft direction movements. A computer running VR software coordinate and synchronizes the VR movement apparatus and the VR display to provide system users with simulated activities in a VR environment.

A linkage mechanism with an elliptical motion trajectory includes a main body having two guiding tracks with a changeable lifting angle, a flywheel assembly and two handles installed on a front side of the main body, a first linkage rod pivotally attached between guiding rods of two driving linkage assemblies and two cranks of the flywheel assembly. The two pedals respectively include a front end pivotally attached onto each one of the cranks. Each one of the pedals moves together each one of the guiding rods and along each one of the guiding tracks and drives the flywheel assembly and each one of the handles to move forward and backward.

A linkage mechanism with an elliptical motion trajectory includes a main body having two guiding tracks with a changeable lifting angle, a flywheel assembly and two handles installed on a front side of the main body, a first linkage rod pivotally attached between guiding rods of two driving linkage assemblies and two cranks of the flywheel assembly. The two pedals respectively include a front end pivotally attached onto each one of the cranks. Each one of the pedals moves together each one of the guiding rods and along each one of the guiding tracks and drives the flywheel assembly and each one of the handles to move forward and backward.

An exercise device including a frame with a first crank assembly rotatably coupled to the frame about a first axis and a second crank assembly rotatably coupled to the frame about a second axis. A control system may be used in communication with the first crank assembly and the second crank assembly, which may provide a synchronous movement of the first crank assembly relative to the second crank assembly. A pedal arm may be provided with a first end pivotally coupled to the first crank assembly and a pedal positioned on a second end. A crank link may be used with one end coupled to the second crank assembly and a second end coupled to the pedal arm. The crank link may be movable on the pedal arm which may provide varying paths of motion of the pedals.

In an exercise machine, foot platforms may travel in inclined circular paths to establish three dimensional operational characteristics. Platform support members may be rotationally synchronized by connected mechanical components such that they are maintained out of phase with each other by one half of a cycle or 180 degrees in counter rotational directions. Crank synchronization in an inclined plane during operation of the exercise machine may provide three-dimensional foot travel in vertical, lateral and longitudinal directions.

An exercise machine with a more natural gait which, in some embodiments, further allows for a variable stride length while in use. In one configuration, each side of the exercise machine has a first crank assembly connected at an upper location on a pedal arm and a second crank connected at a middle location on the pedal arm, and a pedal is attached to a lower location of the pedal arm. The first crank assembly is connected to the pedal arm by a crank arm. The second crank assembly is connected to the pedal arm via a crank arm pivotally attached to a crank link. The path of each pedal is determined by the lengths of crank arms and crank links of the first and second crank assemblies rotating in synchronous motion.

An exercise machine with a more natural gait which, in some embodiments, further allows for a variable stride length while in use. In one configuration, each side of the exercise machine has a first crank assembly connected at an upper location on a pedal arm and a second crank connected at a middle location on the pedal arm, and a pedal is attached to a lower location of the pedal arm. The first crank assembly is connected to the pedal arm by a crank arm. The second crank assembly is connected to the pedal arm via a crank arm pivotally attached to a crank link. The path of each pedal is determined by the lengths of crank arms and crank links of the first and second crank assemblies rotating in synchronous motion.

An exercise device including a frame with a first crank assembly rotatably coupled to the frame about a first axis and a second crank assembly rotatably coupled to the frame about a second axis. A control system may be used in communication with the first crank assembly and the second crank assembly, which may provide a synchronous movement of the first crank assembly relative to the second crank assembly. A pedal arm may be provided with a first end pivotally coupled to the first crank assembly and a pedal positioned on a second end. A crank link may be used with one end coupled to the second crank assembly and a second end coupled to the pedal arm. The crank link may be movable on the pedal arm which may provide varying paths of motion of the pedals.

An exercise machine with a more natural gait and computer gaming interface which, in some embodiments, further allows for a variable stride length while in use. In one configuration, each side of the exercise machine has a first crank assembly connected at an upper location on a pedal arm and a second crank connected at a middle location on the pedal arm, and a pedal is attached to a lower location of the pedal arm. The first crank assembly is connected to the pedal arm by a crank arm. The second crank assembly is connected to the pedal arm via a crank arm pivotally attached to a crank link. The path of each pedal is determined by the lengths of crank arms and crank links of the first and second crank assemblies rotating in synchronous motion.

An exercise device including a frame with a first crank assembly rotatably coupled to the frame about a first axis and a second crank assembly rotatably coupled to the frame about a second axis. A control system may be used in communication with the first crank assembly and the second crank assembly, which may provide a synchronous movement of the first crank assembly relative to the second crank assembly. A pedal arm may be provided with a first end pivotally coupled to the first crank assembly and a pedal positioned on a second end. A crank link may be used with one end coupled to the second crank assembly and a second end coupled to the pedal arm. The crank link may be movable on the pedal arm which may provide varying paths of motion of the pedals.