You got to remember in the Rocky movies, they took a lot of liberty in 'training techniques' and 'character development' to develop a movie....a fantasy movie.
That movie still comes back to bit us trainers in the ass when you get some pumped up fighter who drops his guard and sticks his face out to let someone hit him just to show how tough he is, and that he other guy cant hurt him. One of our guys got knocked out by a younger kid showing off like that.
They showed 'chasing the chicken', 'bouncing the ball ..( which does more to develop the wrist then anything else.),' tying the string to his ankles...all old techniques boxers had used, and some still use today. Some of them work..some don't. Boxing has developed through the years, and so have training techniques. Be careful what you see in a boxing movie and think it is worth using. If I saw one of my fighters bouncing a ball around, I can think of better use of his training time then that.