Principles of Body Mechanics

When you practice good body mechanics, you use your body in a safe and efficient way to accomplish tasks such as lifting, pushing and pulling. Good body mechanics are all about alignment, balance, and coordination.

Alignment

Alignment is good posture (Figure 7-1). If you have ever driven a car that is out of alignment, you know that it’s hard to steer, the tires wear down unevenly, and it's unsafe. Human bodies that are out of alignment have similar problems. Body parts get pulled out of shape, which leads to discomfort and injury. Holding your body in alignment reduces strain on your joints and muscles.

Standing

To practice good alignment while standing, keep your knees slightly bent and stand with your feet shoulder-width apart. Put your weight evenly on both legs. Keep your shoulders straight and centered over your hips, your stomach muscles tightened and buttocks tucked under, your head up and your chin level (hover over the picture below to read more about alignment).

Sitting

Sitting. To practice good alignment while sitting, sit with your knees level with your hips, your back straight, your stomach muscles tightened, and your shoulders straight and centered above your hips (see Figure 7-1, B).

Balance

Balance is stability achieved through the even distribution of weight. Having a wide base of support and keeping the heaviest part of your body (your center of gravity) close to your base of support helps you to stay balanced. When you are standing, your feet and legs are your base of support, and your torso is your center of gravity. Therefore, spreading your legs apart and bending your knees to bring your torso lower helps you to remain stable on your feet (Figure 7-2).

Coordination

Coordination is the use of direction and force for purposeful action. For example, when you are moving a person up in bed, you will place one of your feet in front of the other. Shifting your weight from your back foot toward your front foot gives you additional power and helps you to move the person toward the head of the bed. Coordination also means working with someone, rather than against them. For example, when you are repositioning a person, encourage the person to help you as much as possible. Similarly, if you are working with another nurse assistant to reposition a person, you will want to use good communication to make sure you are both performing the same movements at the same time. This will give you twice the power and make the move easier.

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Learning Objective: Apply principles of body mechanics.

Simmers, L., Simmers-Nartker, K., & Simmers-Kobelak, S. (2017b). Promotion of Safety. In Diversified Health Occupations (8th ed., pp. 361–385). Boston: Cengage Learning.

There are four main reasons for using good body mechanics:

1. Muscles work best when used correctly.
2. The correct use of muscles makes lifting, pulling, and pushing easier.
3. The correct application of body mechanics prevents unnecessary fatigue and strain and saves energy.
4. The correct application of body mechanics prevents injury to self and others.

Eight basic rules of good body mechanics include:

1. Maintain a broad base of support by keeping the feet 8-10 inches apart, placing one foot slightly forward, balancing weight on both feet, and pointing the toes in the direction of movement.
2. Bend from the hips and knees to get close to an object, and keep your back straight (Figure 14–1A). Do not bend at the waist.
3. Use the strongest muscles to do the job. The larger and stronger muscles are located in the shoulders, upper arms, hips, and thighs. Back muscles are weak.
4. Use the weight of your body to help push or pull an object. Whenever possible, push, slide, or pull rather than lift.
5. Carry heavy objects close to the body (Figure 14–1B). Also, stand close to any object or person being moved.
6. Avoid twisting your body as you work. Turn with your feet and entire body when you change the direction of movement.
7. Avoid bending for long periods.
8. If a patient or object is too heavy for you to lift alone, always get help. Mechanical lifts, transfer (gait) belts, wheelchairs, and other similar types of equipment are also available to help lift and move patients.

Watch this very short video to see a demonstration of proper body mechanics.

Body Mechanics Links to an external site.