Fig. 5: The MJ apparatus for mice plyometric training.
From: Plyometric training increases thickness and volume of knee articular cartilage in mice
a Full view of the MJ apparatus imaged on the lab table during the experiment. In panel b we show the basic mechanism of the apparatus. A mouse is sitting on the lower platform (1) when a green LED light (not shown) turns on. Shortly after that the gate opens and a mild electric shock is applied to the platform. The mouse learns that as soon as the gate opens she should jump onto the higher platform 2. When the mouse reaches platform 2, the gate closes, and the two platforms move (using motors M1 and M2) so that platform 1 is raised and platform 2 is lowered, and the cycle continues for the next jump, until the desired number of jumps is achieved. The platforms are located in the central (dark) part of the machine shown in panel a.
