A ski coach is tasked with organizing the training regimen for her athletes. The goal of these sessions is to enhance the athletes' endurance, technical skills, and speed on the slopes. The training includes cross$-$country skiing, slalom drills, strength training, and balance exercises. The coach needs to allocate the limited training time to ensure wellrounded development across all these areas. She must also consider the potential absences of athletes due to injuries or personal commitments. Use this information to develop an optimization model, detailing variables, parameters, constraints, uncertainties, and the objective.