So looking to put on my concrete floor in-home gym. I'm looking primarily for it to cushion my knees when doing burpees or if doing a mountain climber. Is the 3/8" thick enough to achieve this?

Our 4' x 6' Premium Mats are thick enough to cushion your knees when doing burpees. Since these mats are vulcanized, they may not be the most comfortable choice, but they will work for this activity. If you are wanting something with a little more cushion, our Impact Mats would the mat we would recommend.