what's the best long term fitness metric? what is the best fitness metric? what is the best fitness metric what is the best metrics for fitness? what is the best fitness metric to use what is the best fitness metric what is the best fitness metric what is the best fitness metric what is the best fitness metric what is the good long term fitness metric what is the best fitness metric what is the best fitness metric what is the best fitness metric what is the best fitness metric what is the best long term fitness metric what is good fitness data what is the best long term data for fitness what is the best fitness metric what is the best fitness metric what is the best data metric