Gravity - bipedal standing

Bipedal standing

More energy efficient, relatively small area of contact with ground, plantar surface of feet

Quadrupedal standing

Provides a base of support, demands energy, limbs active at many joints

Gravity

makes upright standing for long periods of time energy efficient

Line of gravity

Runs through the Body

Line of gravity: lower limbs

Anterior to knee and ankle. Posterior of hip

Gravity bipedal standing: hips

Behind the hip pushing hip joint into extension, tightening ligaments, locking the joint.

Hip capsular ligaments: bipedal standing

Taut anteriorly, lax posteriorly

Anterior ligaments: hip (standing)

Pressure of taut anterior ligaments holds hip locked in extension, allowing muscles to relax

Hip joints: Flexion

Lax anteriorly, taut posteriorly

Gravity bipedal standing: knee

Line of gravity is anterior to the joint, pushing it into extension ligaments tighten and lock the joints. During extension, muscles are the joint are inactive due to gravity. No energy is used

Gravity bipedal standing: ankle

Line of gravity quite anterior to joint, pushing it into dorsiflexion. Energy is consumed as joint isn’t locked, plantar flexors are needed to stabilise