Footprint Assay
The footprint pattern assay is designed to measure a rodent's gait after some sort of drug administration. First, the mouse is trained to walk forward in a straight line on a white piece of paper. Then, the mouse is given some sort of drug, and its front paws are painted a different color than its back paws. The mouse is then put back on the same paper, and is supposed to walk forward in a straight line again. After that, the distance between the paws on the same side are measured to determine stride width, length, and any overlap between sides. Footprint pattern assays are most commonly done to see if/how the drug changes the way the mouse walks. Another reason they are conducted is to establish whether a mouse has a movement, or motor control disorder. Footprint tests can also be used to determine if a gene mutation has motor control issues (compare young mutant mouse walking pattern to old mutant mouse walking pattern). Necessary equipment would be some sort of paper, nontoxic paint, mouse, drug, measuring tool (ruler).
I think some concerns with using the footprint assay would be that the mouse might backtrack or retrace its steps, which would mess up the data. I think the footprint tests are probably face valid, especially when being used to inquire further into things like Parkinson's Disease, with known motor issues.Â