Generally speaking, girls' arms have no strength; Boys have stronger arms. You may often see boys stretch upward when practicing the horizontal bar, because boys have the power to stretch their arms. Girls don't do this because their arms are weak. Generally speaking, boys have thick arms and girls have thin arms. It can also be judged that under normal circumstances, there is a big difference in arm strength between men and women. In the process of fitness and shaping, boys prefer to practice upper body, especially arms, such as arm muscles, which will make boys look healthier. Most of the girls' upper body exercises are waistline and buttocks.