body mechanics and bed mobility

Body mechanics

Safe, efficient, energy-conserving movement

Purpose of body mechanics

Reduce injury

Key benefits

Conserve energy, reduce strain, improve safety

Gravity & friction

Increase resistance to movement

Center of gravity (COG)

Point where weight is concentrated

Adult COG level

S2

Base of support (BOS)

Area supporting the body

Vertical gravity line (VGL)

Line through COG; must stay in BOS

Lever arm

Distance affecting torque

Before lifting

Keep COG close to object

Short lever arm

Less torque

Long lever arm

More strain

Key lifting rule 1

Close to object

Key lifting rule 2

Wide BOS

Key lifting rule 3

Reduce gravity/friction

Proper mechanics

Plan movement first

Spine position

Maintain lumbar lordosis

Avoid during lifting

Twisting, jerking

Lumbar lordosis benefit

↑ stability, ↓ disc stress

Common injury site

Lumbar spine

Deep squat lift

Hips below knees

Power lift

Half squat

Straight leg lift

Minimal knee flexion

Golfer’s lift

One-leg stance, light objects

Half kneeling lift

Lift to thigh first

Traditional lift

Uses hips/knees

Stoop lift

Partial hip/knee flexion

Push/pull principle

Force parallel to surface

Push/pull force

More to start than continue

Carrying rule

Keep load close

Reaching rule

Avoid reach + twist

Bed mobility

Movement in bed

Bed mobility goal

Patient & caregiver safety

Posterior hip precautions

No add/rot/flex >90°

Anterior hip precautions

Limit ext & add

Low back precaution

Avoid trunk flex/rotation

SCI precaution

Logroll, avoid rotation

Burns precaution

Avoid shear

Hemiplegia precaution

Do not pull affected limb

Observation focus

Posture, movement, gait

Documentation rule

Objective descriptions only