Child's Pose takes the pressure off your lower back by elongating and aligning the spine, which decompresses it and gives you a nice stretch
GOAL: Strengthen your core and lower back
The plank is a handstand and balance pose that strengthens the abdominal and lower-back muscles as well as the shoulders and upper back. Variations of the plank provide different levels of challenge and work diverse muscle groups. For example, the high and low planks engage the rectus abdominus and lower-back muscles, while the side plank focuses more on the obliques. The reverse plank focuses more on the lower back.