How to do it?
It's quite simple: you take the weight with which you can perform about 20 reps in a set. If you take as a percentage of your one-time maximum it is about 55-60 percent. You do 10 reps with this weight, take a short rest for about 30 seconds and then return to the exercise. You should have a total of 10 sets. Ideally, you should do 10 reps in each set, but in practice it is unlikely to succeed. The key training parameter in this case is a rest between sets - it must be minimum, during the pause the blood must not leave muscles. As for the weight, don't let it bother you that it is too small - your muscles will get a great stimulus for growth.
Muscle Groups and Exercises
The 10x10 method was originally designed exclusively for arm training - it gave the best results for biceps and triceps. We tried it on the shoulders and decided it would be appropriate for the development of deltoid muscles as well. To work with this technique, one exercise on the selected muscle group per workout is enough. What exercises can they be? The best exercises for biceps are arm bends with a barbell while standing or on a Scott Bench. You can vary your grip from workout to workout putting an emphasis on the long and short heads of the biceps muscle.
Triceps: Bench Press with straight, curved or cable grip (again, they can be alternated), or French bench press. Although, in our opinion, you can add "California" bench press to this list. As for the delts, we liked only the bench press from behind the head in a Smith.
Mistakes and tips
The main mistake is a wrong choice of weight. Here are a few hints: if you can do 10 reps in each set, the weight is too low. If you can't do 10 reps in the seventh set already, the weight is too much. Ideally, you should do 10 reps in the first seven sets, 9 in the eighth and ninth sets, and no more than eight in the last, tenth set. Yes, the last three sets should be very difficult for you. Well, another mistake would be to try to use this method to train big muscle groups and also the calves, which, despite being a small group, should be "pumped" in a completely different way.
Source Iron World #3
Source: http://sportwiki.to/10_%D0%A5_10