Pushing/Pulling

There are seven essential rules for safe pushing and pulling:

Push and pull with the strength of your legs. Your arms do not have the muscle mass or power of your legs. As much as possible, avoid using your lower back to push/pull things.
Change direction while pushing or pulling by moving your feet to turn your body. Never twist the torso, as this puts undue stress on your lower back and knees.
Pushing or pulling an item, even one that is on wheels, can still cause injury if the weight is excessive. Reduce the weight or seek assistance if necessary.
Push whenever possible. Pushing a load is generally preferable to pulling, since pulling involves twisting of the spine and extending the shoulder behind the body. When pulling a cart, it is possible for the cart to move too quickly, with the wheels and running over your ankles or feet. When pulling something behind you, facing forward, it puts undue stress on your shoulders, potentially causing injury. You are also generally stronger when pushing than when pulling.
Adjust the position of your hands so that you are pushing at a height that is between your waist and lower chest. Do not push with your hands elevated as this will increase stress on your lower back.
Stand erect when pushing or pulling. Leaning forward when pushing, or leaning backward when pulling, is an indication that the weight is more than you can handle.
Be aware of your surroundings and plan your route. When pushing or pulling, consider environmental factors, such as hills or obstacles, that may cause the force to become more than your body can safely bear

Many factors affect the amount of force that a worker can acquire in a horizontal push and pull:

Body weight and strength
Height of force application
Direction of force application
Distance of force application from the body
Posture (bending forward or leaning forward)
Friction coefficient (amount of friction or grip between floor and shoes)
Duration and distance of push or pull