An exercise machine comprising a weighted spool assembly having a shaft that freely rotates upon bearings. To accelerate the weighted spool assembly, a user applies a pulling force to a strap assembly. With the strap assembly in a coiled position, the user applies the pulling force causing the weighted spool assembly to rotate in a first direction, uncoiling the strap assembly, until the length of the strap assembly is exhausted. Once exhausted, the weighted spool assembly continues to rotate in the first direction causing the strap assembly to coil upon it. While the strap assembly is coiling and to decelerate, the user then applies a resistance force. Once the strap assembly is coiled again, the user reapplies the pulling force causing the weighted spool assembly to rotate in a second direction, uncoiling the strap assembly, until the length of the strap assembly is again exhausted.