Neurology – the ability to throw hard. Physiology – the physical capacity to sustain throwing hard. This age group is critical because: 1) Athletes start developing the coordination needed to significantly improve their sequencing, leading to tremendous increases in output. This often results in overuse by coaches eager to maximize the performance of a standout player. 2) Many of these athletes lack a solid foundation in General Physical Preparedness (GPP) development. Often, they’ve missed their prime foundational years (ages 12-15) for building the prerequisite strength and conditioning needed to capitalize on this period of their life, leaving them playing catch-up. 3) The concept of ‘Workload Management’ is still very abstract for most athletes, except those who are deeply committed to optimizing their development. This gap in understanding often leads to fatigue, which can become a significant factor in injury risk.