My dear friend Sudhanshu Srivastava from Kolkata has been suffering when doing forward bends. He says in Paschimottanasana (Intense stretch pose for the West side of the body as seen below) that he is not able to bend forward but only a few degrees.
This is a difficult pose for any beginner and should not be considered until two things happen: the hamstrings loosen and the abdomen softens. That takes a few years of correct practice in the Iyengar method. Otherwise there is a risk of injury, particularly tearing a hamstring muscle. This pose does not appear until the second (Intro II) syllabus which assumes the practitioner has had at least three years of practice in the asanas preceding it.
Here is a sequence of forward bends for people with tight hamstrings and a hard abdomen.
Ardha Uttanasna with wall (hips directly above ankles, wrists on same plane as hips)
Chair Adho Mukha Svanasna (note heels are pressing down)
Chair Utthita Trikonasna
Parsvottanasna Stage I with chair and back heel pressing against wall
Prasarita Padottanasna Stage I with blocks
First roll a blanket about half way of what it is in picture…
Then insert it in the crease between the abdomen and thighs in a bent knee Uttanasna. Make sure the cavity of the abdomen fills with blanket. Eventually try to straighten the leg keeping the blanket in the cavity. This will be very uncomfortable because the abdomen is tight. Do what you can.
Supta padangusthasana with belt keeping abdomen soft.
Savasana with legs on chair, knees slightly in front of hips as seen above. Note that abdomen remains soft.
This is just an example of a simple forward bending sequence and should not be considered dogma by any means. My aim here is as mentioned above, to address tight hamstrings and abdominal muscles. I put a lot of emphasis on the “softness” of the abdomen because the rock hard “six pack” abdomen makes it very difficult to do forward bends due the overuse. The rectus abdomini are just superficial muscles. The muscles I am concerned with are the much deeper and stronger are the transversus abdomini.
To lastly illustrate my point, the above picture is taken at a Kofi Busia workshop a few years ago. That is me in Paschimottanasna with a little help from Kofi. I weighed about 175 lbs (80kg) in the photo and have a roundish soft abdomen. The red haired lady in the background is obviously much lighter and has a “six pack” style abdomen. That is as far as she got in the pose.