ERGO BODY MECHANICS ELOIZA UNICE B. VASQUEZ Anterior Situated at or directed toward the front of a body or object; the opposite of posterior Base of support (BOS) The area on which an object rests and that provides support for the object. Center of gravity (COG)- The point at which the mass of a body or object is centered Core stabilization Relates to a group of muscles bounded by the abdominal wall, the pelvis, the diaphragm, and the lower back that are contracted to assist in posture, balance, and stability. Dysfunction KEY TERMS Disturbance, impairment, or abnormality of the functioning of a body part. Friction The act of rubbing one object against another Gravity The force that pulls toward the center of the Earth and affects all objects. Isometric Maintaining or pertaining to the same length. Kyphosis Abnormally increased convexity in the curvature of the thoracic spine as viewed from the side. Lateral Pertaining to a side; away from the midline of the body or a structure Lever arm KEY TERMS A component of a mechanical lever; it may be the force arm or the weight (resistance) arm; when the length of the force arm is increased or the length of the weight arm is decreased, a greater mechanical advantage is created for the lever system. Lordosis An increase in one of the forward convexities of the normal vertebral columns; a lumbar or cervical lordosis can occur. Lumbar Pertaining to the lower region of the back superior to the pelvis. Medial Pertaining to or situated toward the midline of the body or a structure Pelvic tilt (inclination) KEY TERMS Movement of the pelvis so the anterior superior iliac spine moves anteriorly or posteriorly to produce an anterior or a posterior tilt or inclination of the pelvis. Posterior Situated at or directed toward the back of a body or object; the opposite of anterior Recumbent Lying down Sagittal plane Anteroposterior plane or body section that is parallel to the median plane of the body. Squat To sit on the heels with the knees fully bent. Stoop To bend the body forward or downward by partially bending the knees. Torque The expression of the effectiveness of a force in turning a lever system; it is the product of a force multiplied by the perpendicular distance from its line of action to the axis of motion (T = F × D). KEY TERMS Valsalva phenomenon or maneuver Increased intrathoracic pressure caused by forcible exhalation against a closed glottis. Vector A quantity possessing magnitude and direction, such as a force or velocity. VALUE OF PROPER BODY MECHANICS It conserves energy It reduces stress and strain on muscles, joints, ligaments, and soft tissue It promotes effective, efficient, and safe movements It promotes and maintains proper body control and balance It promotes effective, efficient respiratory and cardiopulmonary function Value of Proper Body Mechanics PRINCIPLES OF PROPER BODY MECHANICS Mentally and physically plan the activity before attempting it. Position yourself close to the object to be moved so you can use short lever arms. Maintain your vertical gravity line within your base of support to maintain stability and balance. Position your center of gravity close to the object’s center of gravity to improve control of the object. Tighten your “core” muscles before beginning the lift; use the major muscles of the extremities and trunk to perform movements or activities and maintain your normal lumbar lordosis. Roll, push, pull, or slide an object rather than lift it. Avoid simultaneous trunk flexion and rotation when lifting or reaching. Look straight ahead and do not twist or turn your body while lifting. Take your time and lift the item with a smooth motion; avoid jerking movements. o Perform all activities within your physical capability. Do not lift an object immediately after a prolonged period of sitting, lying, or inactivity; gently stretch the back and lower extremities first. When performing a lift with two or more persons, instruct everyone how and when they are to assist; use a mechanical lift or other appropriate equipment if it is available COMMON CAUSES OF BACK PROBLEMS OR DISCOMFORT Faulty posture Stressful living and work habits, such as being unable to relax or staying in a posture for a prolonged period Faulty, improper use of body mechanics Repetitive, sustained microtrauma to structures of the back and trunk Poor flexibility of muscles and ligaments of the back and trunk A decline in general physical fitness Use of improper techniques to lift, push, pull, reach, or carry Episodes of trauma that culminate in one specific or final event (“the final straw”); stress, strain, or tearing of a muscle or ligament; change in the shape of a disk that then impinges on nerve roots; irritation of vertebral joint RATIONALE FOR LUMBAR LORDOSIS POSTURE Lordosis reduces mechanical stress to the lumbar ligaments and the intervertebral disk. When the back is in the lordosis posture, compression forces on the intervertebral disk are directed anteriorly rather than posteriorly, a direction that reduces the potential for a posterolateral rupture of the disk. Lumbar spine stability is increased as a result of the approximation of the vertebral facets. The function of the lumbopelvic force couple is maximized. The anterior and posterior lower trunk muscles and hip and thigh extensor muscles are positioned to function more effectively. GUIDELINES FOR LIFTING ACTIVITIES Stoop or squat to lift any object below the level of your hips. • Widen your feet to increase your base of support and improve your balance and stability. Move close to the object before you lift; keep the object close to your body as you lift or carry it. Maintain the lumbar curve in your lower back as you lift; do not flatten your lower back. Mentally plan the lift; be certain you can safely lift the object without assistance; have sufficient space to perform the lift, and test the weight of the object before you lift it. Tighten your core stabilizers before you perform the lift. Do not lift and twist your back simultaneously; instead, pivot when you need to turn. Do not lift quickly or with a jerky motion. Move the object by pushing, pulling, sliding, or rolling rather than by lifting when possible; push rather than pull. Avoid repetitive and sustained lifting; use equipment or assistance to lift heavy objects. Use care when removing groceries, tools, or other items from the trunk of a car; do not bend at the waist and lift; bend your hips and knees slightly, and move the object close to you before lifting it. LIFTING TECHNIQUES Before performing an activity, you should prepare yourself mentally and physically and palan for the series of events or movements that will be required to perform the activity. STRAIGHT LEG LIFT TRADITIONAL LIFT HALF-KNEELING LIFT POWER LIFT ONE-LEG STANCE LIFT (“GOLFER ’ S LIFT”) STOOP LIFT DEEP SQUAT LIFT STRAIGHT LEG LIFT The lifter ' s knees may be slightly flexed or totally extended in a straight leg lift. Lower extremities are parallel to one other or straddle the item, whereas upper extremities grab opposing sides. The lumbar spine stays in lordosis whether the trunk is positioned vertically or horizontally. TRADITIONAL LIFT Used for medium to heavy weights such as children, backpack, or boxes. Object starts in front of you, squat down but keep your hips above your knees, lift the object and bring it close to your body, then stand up. HALF KNEELING LIFT The lifter ' s knees may be slightly flexed or totally extended in a straight leg lift. Lower extremities are parallel to one other or straddle the item, whereas upper extremities grab opposing sides. The lumbar spine stays in lordosis whether the trunk is positioned vertically or horizontally. POWER LIFT Only a half squat is performed in a power lift, so the hips stay above the level of the knees. The lifter ' s trunk is kept vertical rather than horizontal, and the lumbar spine is kept in lordosis with an anterior pelvic tilt. ONE-LEG STANCE LIFT Used to pick up light objects from the ground. Stand on one leg with a slight bend in the knee while the other leg is straight behind you, parallel to the ground keeping a flat back. STOOP LIFT The lifter can descend to lift an object that is below the level of the waist but can be reached without crouching. The individual slightly extends the hips and knees while maintaining appropriate lumbar lordosis. The feet are placed shoulder width apart and slightly anteroposterior to each other to promote stability and balance. This move takes less energy than a deep or complete squat lift. DEEP SQUAT LIFT Used for heavier objects that only require 1 person such as boxes. Start with the object in front of you, squat down with your hips below your knees, bring the object close to your body and stand up as you lift at the same time. PUSHING Many people remember to bend their knees while lifting a large object but fail to do so when pushing or pulling. Bending your knees and bringing your belly button in to strengthen your deep core muscles protects your lower back against injury and suffering. When given the option of pushing or pulling, pushing is the safer option for your lower back since it allows you to use your own body weight while maintaining a neutral postural posture. Lean gently toward the thing you ' re pushing for optimal safety. PULLING If you must pull the object, bend your knees and position one foot in front of the other, keeping a wide base of support. You 'll have more leverage from your legs and less tension on your lower back if you keep the object near to you. Maintain a straight spine, keep your arms close to your body, and maintain your wrists straight to protect them. When you need to turn, use your feet to shift directions. Never, ever twist your spine. REACHING Reaching for an object above your shoulder or head will be less strenuous if the object is lowered or if you raise your position by standing on a wide-based footstool or ladder. These actions approximate the COG of the object and your COG, allow the use of shortened extremity lever arms, and decrease strain to back structures CARRYING If you cannot carry the load by yourself, get help, or use a cart. Keep your back straight, maintaining a small curve in lower back. Keep the load close to your body. Avoid twisting your body. Change direction by moving your feet and body in unison. Avoid changing handgrips while carrying the load. Face the area you wish to deposit load on. Bend your knees and keep back straight when depositing load. PRINCIPLES FOR PROPER POSTURE Maintain the normal anterior and posterior curves of the spine for proper balance and alignment. Stand and sit with your body erect so the shoulders and pelvis (hips) are level; avoid slouching or “ round back” positions. Stand with your ankles, knees, hips, and shoulders aligned; keep your head over your body, not in front of the shoulders. Stand with your abdominal wall flat, your head in neutral, your shoulders level, your chin parallel to the floor and slightly tucked, and your body weight evenly placed on each leg. Keep your knees slightly flexed and maintain Sit with your head in a neutral posture, your chin tucked or parallel to the floor, your elbows, knees, and hips flexed to 90 degrees, and your feet flat on the floor or slightly inclined. During extended sitting, your forearms and low back curvature should be supported. Slouching and kyphotic postures should be avoided. Avoid standing or sitting in one posture for an extended period of time; alternate your position on a regular basis. Periodically move your head, neck, shoulders, back, hips, knees, and ankles. Flex your hips and knees while supine or half resting on your side. Avoid laying prone by placing a cushion beneath or between the knees for support. To support your head, use a small or medium-sized cushion, but do not place it. ERGO THE END ELOIZA UNICE B. VASQUEZ
