I am a heavyweight. When I sit on any furniture on carpet the furniture makes impressions in the carpet. I put the mat under my swival rocker recliner. It is not making an impression in the carpet now.
I was having problems with an old mat which had turned yellow and began to crack into pieces. The Economical Mat by Staples is the perfect replacement in my home computer room. It does just fine on the short pile rug. It doesn't creep or buckle and my chair glides across its surface very smoothly.