When working out the human body, it is possible to use external exercise that engages the muscles and tendons in repetitive motion on isolated tension.
But for internal exercise, there are two prime methods. The first is to use the mind to control the breath, and once the qi or breath or energy has accumulated in the head and torso, where the important organs are, it disperses to the rest of the body.
The second method is to move the limbs of the body in movements that resemble natural motion, and watch the energy accumulate in the limbs and afterwards spread to the head and torso.
This perspective on exercise is largely that of qi gong practitioners. Now to answer wich exercise is preferable, the answer is both. External exercise is what every athlete does, things like pushups and squats and bench presses and deadlifts. But the breath goes before the body, and even athletes totally ignorant of qi gong theory have already mastered some of the basics of the discipline.
Qi Gong literally translates as ‘breath work’. Any effort to control or regulate the breath is a primitive or not so primitive form of qi gong. Even yoga has breath control exercises within, called pranayama. Prana means qi or breath and yama means control.
If you do just strength training exercise and neglect cardio and internal conditioning, you might have an impressive physique but you wont be able to do anything with it. The very basic health regimen for any human being is walking (the most natural cardio) and stretching, which is a form of qi gong or yoga if you will.
Your workout regimen should not only be effective, it should be easy and fun and doable at any age. If it isn’t you will eventually quit, and your results will disappear. Longevity exercise like walking, pushups, stretching, and breath work are good for the goose and the gander.