The top picture on the right shows a child who had placed his hand on top of a treadmill and the lower picture on the right is a child who had placed his hand under the treadmill. Unfortunately, as you can see from the left picture, when you are running on the treadmill, a child can come up behind you and put their hand on the treadmill or underneath it to get something and this is what results in these injuries.
Certainly these two examples are extreme, with full thickness injuries that required skin grafts. Most of them are not that severe and will heal per primum. These can be managed with topical agents alone. I have treated about 30 patients like this over a 12-year period and only 6 of them needed an operation.