A common mistake with forward bends is placing too much intention on stretching the back of the legs and lower back. Yes, these stretches are a welcome benefit in forward bends, but should be placed as a secondary focus.
All forward bends (ie. Adho Mukha Svanasana, Uttanasana, Janu Sirsasana, Baddha Konasana) should originate from the hip joint. As one prepares to fold, one should draw awareness to how the head of the thigh bone connects into the hip socket.
Another useful guide is visualizing how and where the sitbones move in relation to the pelvic region and the rest of the spine. For example, when preparing for Janu Sirsasana (1 Leg Forward Bend), one should rise tall and clearly feel the center of the sit bones connecting to the earth. The lifting motion elongates the entire spine and prepares the body to fold from the hips and not the lower back. The first motion following elongation is the rolling forward motion of the entire pelvis so that one is moving forward from the center of the sit bones to the front edges.
The other motion to be sensing is the ball-and-socket rolling motion of the hip joint. Rather than pulling the chest into the legs, shrinking the belly and rounding the spine, start the forward bends from the hip joint/sit bone connection. This will retain healthy length and space in the vertebrae, thus reducing the chance of disc compression. When the pelvis no longer rolls forward with the ball-and-socket motion, the spine should also discontinue moving forward. Any further motion of the spine, without pelvic forward movement, will result in loss of spinal integrity and create blockages or injury. If the hamstrings (back of the thighs) greatly limit the forward motion of the pelvis, try softening the knees. Reducing the stretch in the hamstrings allows a larger range of motion of the hip joint and brings greater elongation of the spine and torso in one’s forward bends.
Bring healing intentions into your practice. Enjoy discovering your body awareness. Learn and relearn the functionality of our poses to maintain a life-long, revitalizing practice.