  Prediction and prevention of musculo-skeletal injuries is an important aspect
of preventive health science. Using as an example a human knee joint, this
paper proposes a new coupled-loading-rate hypothesis, which states that a
generic cause of any musculo-skeletal injury is a Euclidean jolt, or
SE(3)-jolt, an impulsive loading that hits a joint in several coupled
degrees-of-freedom simultaneously. Informally, it is a rate-of-change of joint
acceleration in all 6-degrees-of-freedom simultaneously, times the
corresponding portion of the body mass. In the case of a human knee, this
happens when most of the body mass is on one leg with a semi-flexed knee -- and
then, caused by some external shock, the knee suddenly `jerks'; this can happen
in running, skiing, sports games (e.g., soccer, rugby) and various
crashes/impacts. To show this formally, based on the previously defined
covariant force law and its application to traumatic brain injury (Ivancevic,
2008), we formulate the coupled Newton--Euler dynamics of human joint motions
and derive from it the corresponding coupled SE(3)-jolt dynamics of the joint
in case. The SE(3)-jolt is the main cause of two forms of discontinuous joint
injury: (i) mild rotational disclinations and (ii) severe translational
dislocations. Both the joint disclinations and dislocations, as caused by the
SE(3)-jolt, are described using the Cosserat multipolar viscoelastic continuum
joint model.
  Keywords: musculo-skeletal injury, coupled-loading--rate hypothesis, coupled
Newton-Euler dynamics, Euclidean jolt dynamics, joint dislocations and
disclinations
