There are many ways to twist.
I often see people perform twists in yoga by turning the chest in the direction they want to go and then getting leverage by by hooking or pressing or bind their arms in an attempt to pull themselves deeper into the posture.
If you twist this way you lose the potential benefit of active spinal movements and even risk hurting your back if you 'pull' yourself further than your spine can naturally go.
I use the principle of active spinal movements to twist. First, it ensures I only moves as far as my body can go without external forces. Second, by actively moving in a particular way it brings firmness to my belly without me having to think about tensing it, which helps to protect the spine.
Before performing any yoga pose it is important to lengthen your spine. Melt the sitting bones down (see my earlier post) and then try the three tips I suggest below. The video and these tips generally deal with postures that involve spinal twisting as their main component. Of course, a posture can combine spinal twisting with spinal forward bending, side bending and/or back bending.
Remember, only do what is comfortable. Practice safely and ask your teacher for guidance. These posts are intended for my students who come to class and whom I can discuss these movements with.
1. Turn From The Navel Up
Move actively from the lower belly first. Move the navel area of the spine towards the hip that you are trying to twist towards. You should feel that the side of the belly between the navel and the hip you are turning towards becomes firm. Some people find it hard to imagine moving this part of their body. For those people it can sometimes help to imagine just trying to firm the side of the belly that you are trying to turn towards. If you do this you should find that you have started to twist slightly.
Once the navel has turned, then try to turn the lower ribs as well. Follow this with the chest and then the shoulders. The idea is to turn from the bottom of the spine upwards.
Once you have actively moved the spine you should feel firm on the side of the belly that you are turning towards. But firm in a way that you can still breathe into the belly.
2. Lengthen The Side Ribs/Waist
After performing the active twist you will probably find you need to lengthen the side ribs and waist of the side that you are turning towards. Active spinal twisting tends to draw the lower ribs towards the hip (on the side you are turning towards). If you bring your awareness to this area you might be able feel that the waist feels shorter or that you feel squashed on that side.
To resolve this (if it has happened) you can either think of lifting the lower ribs up if you are in an upright position or lengthening them away from the hip if your spine is parallel to the floor. The idea is to maintain length.
Here I should make a special note that some postures (like parsvakonasana or parivrtta parsvakonasana) involve twisting and side bending. In those cases one side waist will feel shorter than the other although neither should feel squashed. The spine should never feel squashed.
3. Move The Hip
Twisting the spine also tends to cause the hips to turn with you. When you turn to the right, the right hip will tend to also turn to the right so that it moves behind you (or above you if your spine is parallel to the floor). I tend to allow a small movement of the hips when I am performing the active spinal twist and, when I have completed the spinal movement, I carefully adjust the hips.
In an upright position this means moving the hip of the side you are turning towards forwards. If your spine is more parallel to the floor it generally means lifting the opposite hip, as I show in the video.
When you add this movement of the hip you will find that the belly on the side you are turning towards naturally becomes firmer.
Summary
Active movements are the safest movements for yoga postures. Try not to lever yourself into twists and only ever bind the arms if the hands come together without strain. Always lengthen the spine before twisting. Move from the navel upwards, lengthen the side waists, and adjust the hips. Feel natural firmness in the belly. Relax, breathe, and be content!
I learned about active movements and free spines from my teachers Paddy McGrath and Yoga Synergy of Bondi Junction. Please try to practice with them if you are ever in Sydney or Thailand!
Happy and safe practicing!