The answer might come from researcher Dr. Carol Dweck, pioneer of the concept of “growth” and “fixed” mindsets. People with a fixed mindset believe abilities and talents are immutable traits; you either have them or you don’t. They take negative feedback personally because they don’t differentiate between their performance and themselves. They avoid challenge and see failures as being outside of their control.
On the other hand, those with a growth mindset believe skills and talents are acquired through education and hard work. They embrace challenge and use criticism to improve.
Those who see themselves as being unable to improve have fixed mindsets around fitness. They see themselves as a victim of circumstance, helpless to get fit. In reality, they need to hear some harsh truths and realize that fitness is as much of a skill as riding a bike.