If you are doing weight training to shape your body, that’s fantastic; it’s great for shape, hormones, health, muscularity, aesthetics and strength.
However, most weight training comes from forward and back, and up and down, movement. In the fitness world, we call this the frontal plane.
There are different planes moving forward, back, sideways, and diagonally – as well as twisting. Which is why I would say for healthy longevity, all around fitness and performance, DO include mobility, athletics, sports movement or marital arts. Even running helps if that suits your body because what you want is bowel movement and repetitive motion. Running loosens all of the body, and creates endurance and movement of the feet, hips and shoulders.