背中の屈曲と持ち上げの重量

When my stepbrother is out for a date, I sneak into his room to lift his dumbbells, cos I love to look at my arm muscles after a workout! So I start with some tilts, bends of the spine, a warm-up of the shoulder joints so you can see how the back muscles are flexing. Then I perform some weight lifting, exposing my biceps, triceps and shoulder muscles :)