This preparation is very easy and does not take much time in everyday life. Yoga is ideal for this purpose, it strengthens, stretches, and keeps you flexible. Yoga is suitable for everyone, regardless of age.
In the next two exercise sequences I will show you short and optimal preparation exercises out of yoga. In sequence 1 you will strengthen your thighs in Utkatasana (the chair) and your back. In exercise sequence 2 you will stretch your hips with Eka Pada Rajakapotasana (The Pigeon) to keep you flexible while skiing or snowboarding.
Your breathing is your own personal regulation. When you inhale, you contract and when you exhale, you relax and let go. Try to regulate the stretching stimulus or stress pain mindfully with your breathing. Stay calm by breathing evenly and consciously. As you breathe out, you can slowly try to intensify the position a little more if you notice that the stretching stimulus is diminishing over time. Then let yourself sink even deeper into the stretch. But BE CAREFUL: no pain! Only go as far as you feel safe.
Daily practice brings you sustainable success that is fun. You'll be more powerful in your thighs, so you'll have more fun on the slopes, and you'll be more flexible in your hips, which helps prevent injuries.
Note that it is not you who has to be adapted to yoga, but yoga has to be adjusted to your physical constitution. Yoga is not a competition and also not a comparison with others. So only do the exercises as far as your range of motion in the joints and muscles allows.
Just do it.
Yoga is for everyone.
Namaste, Esther