I recently completed the Foundations online course in the Martial Body training methodology of long-time forum member Chris Davis ("middleway"). This course is well-organized and clearly demonstrated. Chris draws on more than a quarter-century of both training and teaching experience including basic grappling and boxing, jujutsu, aiki jujutsu, taijiquan, Hebei xingyiquan and baguazhang, as well as sound principles of physical conditioning, biomechanics and curriculum development, in offering specific principles, training methods and exercises to develop six broad groups of mental/physical attributes he calls Heavy Body, Stable Body, Connected Body, Elastic Body, Spiral Body and Fluid Body. These groups of attributes are readily translatable into specific martial arts and techniques.
I recognized many of the exercises and drills, having encountered them in slightly different formats with different arts and teachers. Most teachers/arts do not place such exercises and drills in a broader practical context, i.e., combative purpose. Chris organizes the training so that the student is specifically taught not only what to train but why. Following the idea of progressive and cyclical training, the same six sets of attributes can be revisited in a deeper intermediate context, and then again in a more specifically combative (usage/application) environment.
Chris is one of a small number of internal arts teachers who have worked with the idea of training the "combative body" as foundational development for progress and deepening actual fighting skills. In principle, this approach is not really different from building gongfu through jibengong and basic forms--but the scientific understanding of body/mind work is deeper today and it is helpful for modern students to have a clearer understanding of what their (hopefully) hard work and perseverance is building. I think of Rickson Gracie's embodiment of training connectivity, breath and Ginastica Natural exercises; Ken Fish's explanations for basic jibengong or the Tian Gen of Gao Yisheng baguazhang; Tim Cartmell's wide-ranging collection of solo exercises; Akuzawa Minoru's Aunkai; and Dan Harden's Sangenkai. I've explored all of those different approaches in some depth. All of them are good and worthwhile training methods. I found Martial Body Foundations to be the clearest and best-organized for the student, not as dependent perhaps on training in person and feeling the founder/teacher in order to make progress.
You can find more information about Chris Davis' MartialBody method here: https://www.martialbody.com/The-Method