Here is how you can set up a pulley system to help you with your flexibility and strength.  Please remember that this setup is for helping you stretch, not performing the stretches themselves.

What you’ll need

A place at home, such as your garage, where you can safely screw the eye hook into a ceiling joist.  Be sure that this space is open enough for you to perform the stretches and is free of things that can hurt you if you lose balance.
An eye hook rated to about 100 pounds. Home Depot or Lowes
A small pulley rated to about 100 pounds. The pulley can either be a “fixed eye” or “rotating eye” type. Home Depot or Lowes
A small carabiner, like those used for keys and securing small items. Home Depot or Lowes or Harbor Freight
A roll of “parachute cord,” you will probably only need 15 to 25 feet.  This needs to be a soft and flexible braided cord, about 1/8″ in diameter. Home Depot or Lowes
You’ll want to ensure that the carabiner can fit through the eye of the eye hook and the pulley.  The links shown aren’t necessarily the right items for this setup.  They’re shown as examples.

Set Up

Locate a ceiling joist about 6 or more feet from any walls.  Pre-drill a hole through any sheetrock and into the joist, slightly smaller than the diameter of the threads on the eye hook.
Screw the eye hook into the hole.  Make sure you have engaged several threads.  Ensure that the eye hook is well secured, but doesn’t have to be excessively tight.
Connect the carabiner to the pulley and the eye hook so that the pulley hangs freely and can swing.
Run the cord through the pulley, making sure that both ends of the cord can touch the ground.
Tie a knot in the cord that won’t slip, with a loop big enough for your foot to easily go through, but not so big that your foot slips out accidentally.