https://www.facebook.com/photo.php?v=10150259317459132
He is a famous classical guitar player and teacher in Turkey.
I went to a few kung-fu courses with him while in college. He finds martial arts helpful for guitar playing and shared this video, it not a warmup for guitar but good for specially shoulder health. Advised to do it once daily for musicians.
Its Turkish but I guess the video is explaining well enough, let me know if anything needs translating.