Building strength as postures blend rejuvenates the entire body. The vigorous work from high plank through the chaturanga sequence is often repeated in every asana countless times. The four limbs supporting the body are the hands and feet while the movement integrates the upper and lower body.
To remain stable 2 rotations need to be active;
1. the shoulder blades remain wide across the back and drawing down.
2. the hip bones and pelvis revolve back drawing the abdomen upward lengthening the lower back arch and tail bone toward the heels.
Where ever the body comes in contact with the mat this is your foundation and the pose builds from there. In high plank the hands and feet are your foundation as well as a steady gaze at your finger tips. Line up the hands with the shoulders and this stacks the bones of the arms distributing weight equally. Press through the feet drawing the heels back aligns the ball of the foot with the ankle. This is your strong foundation and the work begins from here.
Here are two examples of high plank giving you a visual of a strong foundation and one that needs slight adjustment.
Integrating the upper and lower torso to keep the weight from collapsing into the low back when the sequence is in motion requires an understanding of internal locks or “bandhas”. If you can feel your breath move up and down the torso you can find the internal locks. Simplified explanation; the inhalation widens the low ribs side to side and front to back, the exhalation draws the back of the ribs and front of the ribs toward each other narrowing toward the waist (this is a lock). The same is true of the chest cavity the inhalation increases the volume and size of the chest, exhalation releases the breast bone and brings the upper spine toward the sternum (this is a lock).
I like to refer to this as staying close to the breath, always feeling the movement of the bones inside the body. Once you have established your foundation and found the locks internally you will breath easier and struggle less.
I like to introduce the idea of rocking forward and backward in high plank before running through the chaturanga sequence. This enables breath to movement, works on strengthening the upper body and internal locks while maintaining correct alignment.
From these photos you can see how the eyes and where your focus is can challenge the alignment of the pose. If your focus is out in front of your hands the spine remains long and weight is evenly distributed, if the focus is down the upper back rounds, the shoulders become compromised and the weight is unevenly distributed.