For Child's pose what I sometimes do is use cushions or block to rest my head on, so I bring the ground to me and this way it may be more stress-free. This doesn't mean the heels have to touch the ground; They only should be transferring in that course. https://www.takeyearsaway.com/yoga_and_aging_benefits/Yoga%20Poses%20for%20Boosting%20Collagen%20Production/i_did_the_downward_dog_exercise_every_day_for_a_month,_here_is_what_happened_to_my_core_strength_and_also_stability.html