Our Premium HD Soft Tiles are a high density foam tile that can handle a treadmill on of it. These tiles are also absorbent enough to handle weight training and cross fit style training as well. Since these tiles are made of foam, there is potential for the tiles to become indented due to the weight of the treadmill. Also with these being tiles, some exercises could cause the tiles to separate which can cause a trip hazard. The best products that we have for what you are looking for would be our rubber products. Our 8mm Strong Rubber Rolls and our 3/8" Heavy Duty Rubber Rolls would be able to handle the treadmills weight with ease and are also better able to handle most cross fit and weight training exercises.