When performing Uttanasan (standing forward bend), there are certain group of muscles are contracted to move into the pose the certain group of antagonists muscles are stretched that will resist the movement for getting into deeper pose. The goal is to close the hip joint (ball and socket joint) as far as possible so that your torso touches the thigh.
Lets examine what are the muscles that are activiated when you start to perform the forward bends.
Muscles that are contracted (indicated in blue color in the figure above) are iliopsoas, quadriceps (rectus femoris, vastus lateralis, vastus medialis and vastus intermedius) and satorius.
Muscles that are stretched (indicated in red color in the figure above) are the hamstring muscles (biceps fermoris (long and short heads), semimembranosus, semitendinosus), gluteus maximus and gastrocnemius. Quadriceps and hamstring are agonist/antagonist group which contracting the quads will release tension of the hamstring.
As you move deeper into the forward bends, the internal organs (lungs, heart, digestive organs) will be compressed. Transversus adominis, internal and external obliques and rectum abdominis will be contracted. Reciprocal inhibition of such contraction will release the erector spinae to stretch further.
Deeper bends will cause gluteus maximus to stretch further, this produce a pull in femur that can externally rotate the thigh. By contracting tensor fasciae latae (TFL) and gluteus medius (also know medial rotator of thigh), will counteract the effect of external rotation and facilitates to get into a deeper forward bends.
- Stretches your hips, hamstrings, and calves.
- Strengthens your thighs and knees.
- Massages your internal organs and helps improves digestion and cleanses mucous from the lungs.
- Relaxes you central nervous system and helps calm your mind
- Helps relieve stress