If it's physical, go to the gym. Go there often. Some can practice ligaments. For example, there is a device on which you can sit and step on the front panel.
If it is psychological, you have to increase it through experience. If you can persist in doing the same thing every day, the same boring and boring thing, then your perseverance will be developed. Psychological resilience should refer to people's psychological state when they are experiencing ups and downs ~ Hehe.