Free weights are the gold standard for resistance exercise, but a sizable market has developed that revolves around alternatives to free weights. Spring-based systems are well known, do not accurately simulate the lifting of free weights. Free weights and weight stack-based system tend require significant floor space. There is a market for a compact exercise system that can be easily stored, but that provides the benefits associated with free weights. Stroke victims often experience muscle weakness and paralysis of one or both sides of the body. Intensive movement practice helps "rewire" the brain. More specifically, undamaged cortical areas can assume control functions that were previously allocated to damaged areas. Streamline Automation is pursuing the development a derivative controlled physical therapy system. It will be capable of providing motion assistance to guide the upper and lower-body limbs to help restore coordination, balance, and strength. The proposed exercise countermeasure could be used in virtually any aspect of NASA's current and proposed human spaceflight missions. Near-term application aboard the International Space Station could serve as an on-orbit trial for the system. The next major application envisioned for the system is aboard the Altair lunar lander. Initial lunar missions are expected to be a week duration, but Altair is designed to allow the crew to operate on the lunar surface for more than 200 days. Later missions are expected to be of relatively long duration in order to enable NASA to prepare for Mars missions that will involve extended stays. These long term missions will require a resistance exercise system in order to enable the crew to maintain muscle mass and bone density.