Combined friction resistance and elastic resistance exercise device

An exercise device, comprising:

• a shell body configured for attachment to a substantially stationary object;
• a core cylinder rigidly mounted to said shell body, said core cylinder having a wall with an arcuate friction surface;
• a substantially non-elastic strap having a first end, a strap segment partially wound around said core cylinder and hugging said friction surface, and a second end opposite said first end, wherein, when said strap is pulled at said second end and a resistive force is applied at said first end, a frictional force between said friction surface and said strap opposes a movement of said strap across said friction surface;
• said arcuate friction surface being formed with surface profiling for providing a resistive form-lock between said friction surface and said strap when said strap is being pulled at said second end;
• said arcuate friction surface being formed with a depression and elevations adjoining said depression;
• and
• a counterbrake projecting towards said depression in said friction surface and deflecting said strap towards and into said depression to define an undulating course of said strap along said friction surface and said counterbrake, and to provide an additional frictional force opposing the movement of said strap through said shell body;
• wherein a total frictional force opposing the movement of said strap through said shell body is defined by the friction between said strap and said friction surface and the additional friction between said strap and said counterbrake, and wherein a magnitude of the total frictional force is proportional to the resistive force applied at said first end.