Stability Balance Centre of Gravity The point in

Stability & Balance

Centre of Gravity • The point in the body about which all parts of the body are in balance or the point at which gravity is centred (not necessarily inside the body) • COG is not confined to one location, as the body moves so the COG moves with it in the direction the movement occurs

RUNNING EXAMPLE • This runner has an upright trunk • Level pelvis • Centre of gravity is well behind the contact point of the leading foot • This allow progressive loading of the leading leg • With a trunk leaning forwards • The centre of gravity is almost directly over the foot as it lands • The loading on the foot, ankle, knee, pelvis rises steeply

Line of Gravity • This is a line that goes from the Centre of Gravity straight down to the ground.

Base of Support • The base of support refers to the area between the points of contact an object has with the ground.

Increasing Stability • Stability is increased when Centre of Gravity is lowered

Increasing Stability • Stability is increased when the line of gravity falls within the BOS (Base of Support)

Increasing Stability • Stability is increased when the size of the Base of Support is increased either by spreading points of contact or adding another one.

Increasing Stability • Stability is increased with increased mass Greater inertia – requires more force by an opponent to move the line of gravity Eg. Rugby – a bigger forward pack has an advantage in scrums

Increasing Stability • Stability also is increased when BOS is extended in the direction of an oncoming force • Stability is increased when the line of gravity is moved towards an oncoming force

Increasing Stability • Stability also is increased when a body part compensates for the movement of another body part. • For example: • A karate kick requires your trunk to move back as you kick to maintain balance.