This week we have our first ever repeat guest on the show. Kyle Spears, owner of Blacklisted HQ is on the show to talk about aerobic development. Kyle explains what energy systems are and how they show up in a CrossFit workout, how someone can build an aerobic base, what type of testers you can try to see where you lack the most, and much more. Building a solid engine is something that CrossFitters desire and Kyle Spears does a fantastic job at explain how to achieve it!