Many of us have very tight hamstrings (muscles of the back of the thighs). Standing Forward Bend poses are great to stretch these muscles. When we sit for long hours, our hamstrings are in their shorter state. And when we exercise, these repetitively get contracted. If we neglect to stretch them, they get stiffer.
There are several versions of Standing Forward Bend poses. Each will work on your body slightly differently. The main muscles that will get stretched are the hamstrings and glutes (buttock muscles). But depending on which variation you choose, you can stretch your lower back, upper back and neck.
In Half Forward Bend, the goal is to hinge at the hips and keep the back flat. Do not round the lower back. If it starts to round, come up until you can flatten your back.
Do not forcefully push yourself further than what your body is ready for. Feel a stretch, not pain. Hamstrings can be fragile and you could injure yourself by not respecting your body's limits.
Try releasing the hands down to the floor, without rounding your back. If your back starts rounding, come up and use yoga blocks under each hand to make up for the gap or simply keep your hands on your legs.
To do Half Forward Bend with the hands at shoulder height:
If you have tight shoulders, it will be difficult to get your hands up at shoulder height. But this is a good practice for your shoulders as it will strengthen them and help to open them up at the same time.
To get into the posture, follow the same steps as in the Hands Up variation above. Then relax your hands, head and neck down. Bend the knees if your hamstrings ar tight. Release your hands to the floor or grab your big toes with the first two fingers. Press the elbows out and away from each other. Feel the added stretch on each side of your spine.