ABSTRACT – MECHANICS & PLATFORM DEVELOPMENT CORE (B) The primary purpose of muscle is to provide mechanical activity and heat to support a variety of functions and move bodies through space. These functions are often compromised with disease, injury, and age, originating at different size and time scales. In turn, therapeutic interventions may be applied at these scales. As such, it is important to assess muscle structure and function at multiple scales and have the tools that can integrate information to provide detailed mechanistic insights. Technological advances are important to accelerating this understanding and to provide improved and novel treatments for muscle dysfunction, using targeted and potentially personalized approaches. The overall goal of the Mechanics and Platform Development Core is to continue to provide state-of-the-art mechanical and structural evaluation of muscle across scales to study disease, injury, aging, repair, and rejuvenation of muscle through training, recruitment, funding of new projects and providing expertise and guidance to accelerate discovery and advancement in research and development. Over the first 4 years of the Center, this Core has developed into a full-service resource for the muscle community in the Seattle region and beyond. New instrumentation has been developed or purchased that increases the capacity of the Core to meet the needs of users and allow more detailed studies and mechanistic insight. In this renewal application we propose to continue meeting user needs and further expand Core resources to offer improved multi-scale assessment. The Core will continue to operate under the Direction of Dr. Michael Regnier with additional expertise provided by Dr. Nathan Sniadecki, with training and operational support by Core research scientists. The goals of Core B remain to provide 1) state of the art instrumentation and other resources to investigators studying skeletal muscle development and diseases in human, animal and stem cell models, 2) assays for maturation and manipulation of early-stage muscle cells to develop new human- like models, and 3) testing and developing novel therapeutic interventions. The Core has instrumentation to assess contractile function (mechanics and kinetics) at the protein, organelle (myofibril), cell, tissue and organ levels, and assays for measuring early stage, maturing and adult muscle from animal and human sources and inducible pluripotent stem cell derived muscle cells. These studies are augmented by the ability to perform detailed structural and protein composition analyses, and protein biochemical kinetics. The Core also works with investigators to develop new assessment platforms and assays and trains investigators individually in Core facilities and through workshops, educates the research, clinical and lay community, and assists in development of new therapeutic approaches for clinical application and commercialization.