Body Mechanics deals with the forces working inside and outside the body, both in movement and during rest. You may think of the joints of the human body as a system of levers connected together through bones and muscles, to allow movement and strength; however, the flexibility of the body makes it easily injured by forces which can damage joints and muscles. Body mechanics are concerned with improving movements and posture during daily living activities, to reduce strain on joints and muscles. This is done by distributing work over several sets of muscles and using the stronger ones to do the job. By using the principles of body mechanics, you will reduce strain on smaller, weaker joints and muscles, and help save your energy.
- Muscles used in lifting or handling any weight should be properly "set." This means they should be tightened and ready to lift a weight. This will avoid injuries which can occur even during mild exertion, when an object which is heavier than expected is lifted and moved, the muscles can suddenly "give way" under unexpected weight.
- Use smooth, slow, steady motions; avoid jerky or sudden motions.
- Avoid exerting a force when your trunk is in a twisted or awkward position, as this may strain your joints or pull your muscles.
- When a position of strain is unavoidable, take frequent intervals of rest, to avoid over-fatigue, and move the object in stages. When it is necessary to lean over a table or bed, one elbow or hand should be rested on the table or bed to help support the trunk.
- Muscles not needed for activity should remain as relaxed as possible.
- Try to arrange work area to minimize strain. The area should allow you to stand close to the object to be lifted, with equipment close at hand. Work surfaces should be at proper work heights, so you do not have to bend or straighten your back too much.
- Keep lower back bowed inward during activities. Maintain normal back curves.
- When pivoting, turn with your feet, not at the waist.
In addition, to help you save energy for difficult tasks:
- Allow enough time for a task so you do not need to rush. If you rush, you may forget to use proper body mechanics principles.
- Plan ahead to avoid over-tiring yourself. Tired, fatigued muscles may be more easily injured.
- Avoid running up or down stairs.
- Avoid lifting, pushing, pulling, or carrying very heavy objects.
A. Lifting Objects
- When lifting, keep low back bowed in. Avoid twisting. Raise your body and the object using only the leg muscles. This method of lifting may require practice for you to do it spontaneously. Do not lift with your back by keeping your legs straight and bending at the waist. This puts too much strain on your lower back, and can result in back pain or injury. Contract the stomach muscles when lifting to provide a wall of support to the back. Assistance should be sought to lift any items that you cannot lift in this way.
- When lifting an object or setting it down always have it directly in front of you.
- Heavy items should not be lifted overhead.
- Exhale while stooping, lifting or pulling.
- Keep the object you are lifting as close to you as possible.
- When removing light weight items from a high shelf, use a step stool whenever possible. Place one foot forward and reach for the object with body weight on the forward foot. Transfer your weight to the back foot as you bring the object down, keeping the back bowed in, but not swayed. Reverse the process for placing an object on the shelf. Do not keep feet even or parallel when reaching high.
- Keeping the head up helps maintain the inward curve of the low back.
- Think through the lift and perhaps practice lifting and lowering to see if the load is manageable. If not, get help from another.
B. Transporting Objects
- Carry objects as close to you as possible, because stress to the spine increases in proportion to the distance away from your body that you carry an object. Try to center objects as nearly as possible over the pelvis.
- Do not carry heavy or large bulky objects that necessitate leaning backwards for balance, as this increases the curve of your back, and may cause back strain.
- When possible, slide objects along counters, tables, or floors instead of carrying them. Never lift an object if you can push it across a surface, as this will use less energy and place less strain on your joints.
- When pushing an object, keep one foot forward, with knees bent. Keep low back bowed in and then use the leg muscles to move the object.
- When possible, use a wheeled cart to transport heavy items, instead of carrying them yourself. This will help to take strain off your muscles and joints.
- Push objects instead of pulling them if at all possible. If you must pull an object bend your knees and pull with your legs while keeping your low back bowed in. Do not pull with your back while bending at the waist, keeping your legs straight.
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