Ask students to design a week-long (7-day) training and nutrition plan for a high-school cross-country runner aiming to improve endurance while preventing overtraining; the plan should list daily sessions (type, intensity, duration or mileage), recovery strategies (sleep, rest, active recovery, cross-training), basic daily nutrition and hydration targets appropriate for adolescents, and monitoring indicators and adjustment strategies, with brief justification referencing periodization, progressive overload, and safe youth training principles.