Yes. That's a big part of the first and most fundamental lesson.
When you start to learn box horse and your legs are on fire and you're crying and sweating and straining and barely able to keep from falling over, and you start to realize that everything you ever learned before is basically useless in this method, just remember that you asked for this....
The good news is that although the training is difficult, it's worth it. Just follow the instructions, work hard, pay attention to detail, don't try to "speed the plow", and you will be happy with the results.