In CAS give your Sim the Poor Coordination trait located in Lifestyles category.
Now your Sim will experience random injury buffs that will make them uncomfortable.
Each injury buff will give a detail on how to recover and remedy the issue.
Self click on your Sim for the First Aid Kit menu. Select the needed remedy.
When you use a remedy you’ll get this buff.
If you get the Nasty Fall buff, you’ll need to take physical therapy. In Build/Buy purchase the Physical Therapy Treadmill. You can place it at home or any gym. Select the “Do Physical Therapy Exercise” interaction to remedy a Nasty Fall.