Can I use this underneath a weight bench and treadmill?

You can use our 5mm Plyo Tiles under a stationary weight bench and a stationary treadmill. We don't recommend dropping any heavy weights over these tiles, and we don't recommend moving your treadmill over the flooring. These rubber floor tiles were designed as underlayment, so they are thin. There is potential for the floor tiles to become damaged when moving a heavy treadmill over them.