Hero's Pose can be a very tricky posture to come into for anyone with knee issues, tight quads or low back/SI joint problems. Luckily, with props, this posture can be made available to most people--comfortably--not just to "get through it."
Setting up for the pose:
Gather a number of different props: a few pillows/bolsters, a few blankets, and a couple of blocks. Test your ability to sit on your shins with your bum on the floor between your feet. If this does not happen for you in an upright, seated position, it is not going to happen in the reclining version either. You need support.
Set up a bolster or a thickly-rolled blanket behind you lengthwise. Place a block, bolster, or additional pillows under the end of the bolster where your head is going to lay to create a ramp set-up. Like so:
|This bolster set-up is good for Reclining Hero's Pose or for Reclining Bound Angle.|
Coming into the pose:
Sit in Dandasana (sit on your bum with legs straight) in front of your bolster ramp. Get very close to your props - let your back body touch the bolster. Bend one leg and tuck your foot by your outer hip. Carefully lower your body toward your bolster ramp, coming into Supported Reclining Half Hero's Pose.
If this feels ok and you want to go for full Supported Reclining Hero's Pose, come back to seated and tuck your other foot next to your other hip and repeat the careful laying down process.
If your knees are saying "NO WAY" then you need more propping. Give yourself something to sit on - like a folded blanket or a small bolster and make your bolster ramp higher. With these modifications, most folks should be able to do this pose. But if it isn't working for you, be kind to your body and settle into Reclining Bound Angle instead:
While in the pose:
Keep breathing, keep observing the pose in your body, and allow the body to open at its own rate. Commit to the stillness but do allow yourself to adjust your props and your body as you settle deeper in. Notice if you are gripping the knees, quads, hips or back (or of course the usual places like the jaw, forehead or shoulders). Try to let these parts soften. Stay as long as you are comfortable.
Coming out of the pose:
To come up, support the torso with the hands on the floor, and either push yourself to a seated Hero's Pose or roll to one side slightly and untuck your feet, one at a time. If you were practicing 1/2 Hero's take the 2nd side. After the second side you can be done or you could try the full version of the pose.
This posture is great for creating length in the quads. There may be discomfort in the knees to start but by lengthening the quads this problem can go away - at least for me it did. However, if the knee discomfort is sharp, stabbing or causes you to hold your breath, I would recommend doing this pose only with supervision.