Ski Fitness Workout Challenge Level Check each video for the difficult level. Skip to Videos All | Full Body Workout | Leg Strength & Endurance | Core Workout | Flexibility and Recovery | 2 Week Program | 4 Week Program | Core Workout, 15 Min Strength - Endurance Core Workout, 10 Min Strength - Stability Core Workout, 15 Min Endurance - Strength - Stability Core Workout, 10 Min Stability - Strength Core Workout, 10 Min Stability - Strength Core Workout, 10 Min Strength - Endurance