Whats the optimal balance between frequency and intensity of training sessions to maintain peak performance, and how do you determine when to push through fatigue versus take a rest day to avoid burnout? Does the traditional periodized training model still apply in a world where many of us are riding 4-5 times a week, or is a more nuanced approach needed to account for the cumulative effects of frequent hard efforts? Are there any specific physiological markers or metrics that can be used to gauge when an athlete is at risk of overreaching, and what are the most effective strategies for mitigating that risk while still driving progress and improvement?