Skiing & snowboarding can be demanding. The fitter you are, the better you will do and the lower your risk of injury.
Knee bends - Flex down through 45 degrees, then push back to standing. Keep your heels on the floor. Try 20 times.
Abdominal raises - Lie on your back with slightly bent legs, and your hands clasped behind your head. Lift your shoulders, keeping your lower back on the floor. Try 20 times. If you find this hard, cross your arms on your chest or let them rest on your thighs.
Leg raises - Kneeling on all fours, bring one knee in toward your chest, then push the leg back behind you, toe pointed. Raise the extended leg. After 20, repeat with the other leg.
Triceps raises - Sit on the floor with your knees bent and your palms on the floor behind your hips, fingers facing forward. Relax your stomach muscles and lower your body towards the floor, keeping your back straight. Bring your body up again by straightening your arms. Try 20 times.
Lunges - Lunge forwards onto one leg, flexing the knee through 45 degrees. Make sure your knee doesn't go in front of your foot and stays in line with the middle two toes. Push back upright and lunge forwards onto the other leg. Try 20 times.