Exercise is gradual, and blind practice will only strain your muscles. My original training method was to start with 2 blocks, pull 20 times at a time, practice for 2 months, and then start pulling 3 blocks, each block 15. After pulling for 3 months, I changed 4 pieces, which is also the group of 15. It will be more difficult to change from 4 to 5. My impression is that four springs can be pulled 20 times at a time and then five springs can be tried, but don't worry. The number of times can be adjusted according to your own feelings, and you can use 10-20 next time. 16-20 years old is the best period for exercise. Come on, exercise with sit-ups, push-ups and pull-ups is better.