Balance training is different from strength training. With strength training, you can progressively load your musculoskeletal system (muscles and bones) and it will adapt by becoming stronger. But with balance training the process is not as straightforward.
For starters, there are multiple systems involved in keeping you upright, not just the musculoskeletal system. While you need strong muscles and a strong core to help you stay steady on your feet, your brain also relies on your visual and vestibular (inner ear) systems to ensure that your body stays upright.
Your eyes tell your brain important information about the world around you and how to adjust to what you see. Your vestibular system senses where your body is in space and how to move about. Your musculoskeletal system needs to be strong so it can move, stabilize, and catch you when something throws you off. Take any one of these systems away and it is much more difficult to maintain your balance. Don't believe us? Try balancing on one foot. Then try doing it with your eyes closed. You'll get the idea.
While incorporating exercises that promote posture and strength are important for balance training, it is also important to incorporate exercises that challenge these other systems in creative ways. Much of having good balance is developing the response of the automatic systems in your body. Balance exercises such as the ones incorporated into Wellen's workout programs do exactly that.