If you work with other peoples children, maybe you can get some help from the other adults to establish some better decorum. My wife worked with small kids and found that they will rise to the level of behavior that is expected from them. You will be surprised how well that can act when you explain the need to perform to a standard then recognize them for meeting that standard.

I have worked in nursery and toddler classes for years and see the same results. Then, mom or dad shows up and the other behavior returns.

Plus, children are quite resilient. They can take a fall or bump much easier than you can.

When they learn that they are responsible for their own bumps and bruises, they quickly learn. If they learn that they may cause you to be injured, they will likely be even more careful and disciplined.