Muscle architecture for pennate muscles. Pennate muscles can be further divided into uni-, bi- or multipennate. Unipennate muscles are those where the muscle fibers are oriented at one fiber angle to the force-generating axis and are all on the same side of a tendon. The pennation angle in unipennate muscles has been measured at a variety of resting length and typically varies from 0° to 30°. The lateral gastrocnemius of wild turkeys is an example of this muscle architecture. Muscles that have fibers on two sides of a tendon are considered bipennate. The stapedius in the middle ear of humans, as well
Effect of spaceflight on the human body to best counteract the bone and muscle atrophy experienced by astronauts in microgravity environments for prolonged periods of time. The Human Research Program's Human Health Countermeasures Element chartered the Digital Astronaut Project to investigate targeted questions about exercise countermeasure regimes. NASA is focusing on integrating a model of the advanced Resistive Exercise Device (ARED) currently on board the International Space Station with OpenSim musculoskeletal models of humans exercising with the device. The goal of this work is to use inverse dynamics to estimate joint torques and muscle forces resulting from using the ARED, and thus more accurately prescribe exercise regimens