Question

Define the load-deformation curve and use it to describe any injury. Be sure to include the terms elastic region, plastic region, elastic limit, ultimate-yield point when describing the load-deformation curve.

Answer 1

LOAD DEFORMATION CURVE

When human tissues are subjected to loading force (or stress) such as they are during activity,then they will deform( or strain).

the relationship between stress and strain can be shown graphically and it is often referred to as a LOAD DEFORMATION CURVE.

APPLICATION IN INJURY

Tissues will injured when performing high impact activity will depend upon the forces (stresses) within the tissues, and may therefore also influenced by an individual's own structure / anatomy and its ability to tolerate such loads.

deformation of tissue is initially proportional to load.

1) Using an Achilles Tendon is an example

Most daily movement' s will occur within this region ,the initial deformation due to the straightening out of crimped fibres. As stress and strain increase the tissue moves into the linear portion of the curve known as the ELASTIC REGION.

2) In this region it will return to its original shape when the force is removed.So in Achilles example ,the tendon will deform /elongated when loaded (when running for bus) it will return for its previous state.this is a mechanical property known as Viscoelasticity.

At higher or repetitive forces (such as training for marathon) a tissue may become stressed beyond its elastic range,and into the PLASTIC REGION where it may enter the microfailure Zone (Elastic Limit.)

3) Clinically This ,may seen as a tendinopathy. If loading continues furthur (i.e , training through this niggle) the tissue may permanently deform or potentially fail. (Ultimate yield point)

4) Clinically this may present as a partial or complete rupture of Achilles tendon.It is this mechanism of tissue damage which is responsible for the majority of chronic overuse spoirting injury.

In order to remain injury free human tissues ( bone, cartilage,tendon ,ligament and skin ) must function at stress levels that are within the elastic region of their load/defoirmation curves.