Dr. Spencer Nadolsky and Karl sit down with Dr. Stuart Phillips, senior author on the newly updated American College of Sports Medicine position stand on resistance training, to break down what 137 systematic reviews and over 30,000 participants actually tell us about building muscle, getting stronger, and improving function across the lifespan. From rep ranges and training frequency to power development, eccentric loading, and why periodization may matter less than you think, this is the evidence-based conversation that cuts through 17 years of social media noise in one episode.