There isn't a set number of "principles" for lifting, carrying, and moving heavy objects. However, there are a series of best practices and safety guidelines that are crucial to avoid injury.

Here are some of the most important ones:

Before You Lift:

* Assess the load: How heavy is it? What's its shape and stability? Can you get a good grip?

* Clear the path: Make sure the area you're moving through is clear of obstacles.

* Get help if needed: Don't be afraid to ask for assistance if the load is too heavy.

During the Lift:

* Keep your back straight: Bend your knees and hips, keep your back straight, and engage your core muscles.

* Lift with your legs, not your back: Use your legs to generate the power to lift, not your back.

* Keep the load close to your body: This helps maintain balance and reduces strain on your back.

* Maintain a firm grip: Hold the load securely and avoid twisting your body while lifting.

While Carrying:

* Keep your back straight: Avoid hunching over.

* Keep the load close to your body: This helps distribute the weight evenly.

* Walk with a steady pace: Avoid sudden movements or jerks.

Additional Important Considerations:

* Wear appropriate footwear: Good shoes with solid support are essential.

* Use lifting aids: When available, use equipment like dollies, carts, or slings to reduce the strain on your body.

* Take breaks: If you're lifting and moving heavy objects for an extended period, take regular breaks to avoid fatigue.

It's important to remember: There's no single "magic number" of principles. Instead, focus on mastering the fundamentals of safe lifting techniques to protect yourself from injury.