Why Is My Punching Bag Hard as a Rock at the Bottom? (And How to Fix It)
Punching bags get hard at the bottom because gravity causes the internal filling (usually compressed rags, foam, or sand bags) to settle over time, leaving the top hollow and the base compacted. You can fix this easily by unhanging the bag, rolling it on the floor, and hitting it with a baseball bat or rolling pin to redistribute the stuffing.