Techniques to open the Root Chakra
Using the body and becoming aware of it
The Root chakra, being the first chakra, is the most physical one. This means that any activity that makes one more aware of the body, will strengthen this chakra.
This particularly goes for physical activity. One can do sports, martial arts, walking, yoga, Taichi, it all helps. But also house-cleaning, manual dishwashing and car-cleaning. It is important not to do things that make one insensitive to pain and not to overdo it. Exhaustion is just not good.
Zen meditation is an activity that seems to be the contrary of physical, but actually is. This can make one very aware of the body.
Grounding
The Root chakra is particularly about connecting to the ground. Expressions like "Be on firm ground" and "Getting on your feet again" convey a good connection and an open Root chakra. "To lose ground" and "Getting swept off your feet" convey a closed (or almost closed) Root chakra. When your Root chakra is closed too far, you may actually feel that your feet don't seem to really touch the ground.
This is an exercise to strengthen this connection to the ground.
Stand up straight and relaxed.
Put your feet shoulder width apart.
Slightly bend your knees.
Put your pelvis somewhat forward.
Keep your body balanced, so that your weight is evenly distributed over the soles of your feet.
Sink your weight downward.
Keep in this position for several minutes.
Contracting bottom muscles
By contracting the muscles that are between the anus and the genitals, the Root Chakra is stimulated. At each inhalation, contract these muscles inward, at each exhalation, relax. Do this for a few minutes.
This can be done while sitting, standing or walking.