An evidence-based analysis of resistance training splits, exploring how different workout structures organize training volume, frequency, and intensity to achieve various physiological adaptations like muscle growth and strength. It traces the historical evolution of training philosophies, from early full-body routines to the popular "Bro Split" and modern hybrid approaches like Push/Pull/Legs (PPL) and Upper/Lower, highlighting the influence of commercial factors and pharmacology on their adoption. The document then examines the advantages and disadvantages of each split, considering their impact on muscle protein synthesis, fatigue management, and crucially, long-term joint and tendon health. Ultimately, it provides a decision-making framework for selecting an optimal training split based on an individual's training experience, goals, time availability, and recovery capacity, emphasizing the principles of progressive overload and sustainability over rigid adherence to any single method.