A system for examining resistance exercise includes a first trap compartment, a second trap compartment, a main track compartment and a pulley system which can be aligned to form a continuous tunnel. Each of the compartments can have adjustable dimensions to retain small animals of various sizes. The pulley system includes a clamp and a pulley shaft. The pulley shaft is pivotally attached to the clamp at a lower end and a first pulley wheel at an upper end. A second pulley wheel is pivotally attached to the clamp. A rope is trained on the pulley wheels. The tunnel can be positioned on an elevated support surface. One end of the rope is attachable to a rat on the elevated support surface and the other end of the rope is to attached to liftable strength training objects positioned below the elevated support surface.