@mattrmd unsure if I follow your comment fully but the 12 min run/walk has been linked to all cause mortality. I view movement as a window into health, not necessarily fitness. Health is definitely a construct with movement as one of the major subcontracts to measure. The question, I think that you well posed to the community, is what test of movement is most meaningful to health? I'm unsure as a medical community we have that answer yet. To date, we like the 12 min walk/run test as a movement measure to indicate CRF therefore health. Grip strength has been related to mortality as well so grouping these two tests together (with others as you intimate the "subjective") could help indicate health.