This is an excellent exercise to massage and treat with care our lower back.
Pull the knees up towards the chest and stretch the hips and lower back. The lumbar spinal area is pressed into the floor. Roll up and down and from side to side upon the lower back. This loosens into the hip joint and massages and stimulates the lower back.
The hardness and firmness of the floor are important and should be used to press into stiff, tight areas. The back may crunch and snap :)
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