Physical Elastic Motion Laws Applied to Anatomy and Movement deduces a Mechanism of all Musculoskeletal Injuries

Synopsis

Background: Musculoskeletal (MSK) injures are common and associated with significant morbidity. Our understanding of mechanism/s responsible for these injuries is incomplete resulting in varied treatment strategies, presenting a significant burden on health care resources. The aim of this research is to apply the appropriate laws of motion to the anatomy and movement patterns of the MSK structures. From this an insight into the application and timing of forces on MSK structures can be established and the mechanism/s of injury derived.

Method: Anatomical components of the MSK system are known. All MSK structures demonstrate varying degrees of elasticity and have a role in absorbing force. Movement occurs primarily as a consequence of Muscle Tendon Unit (MTU) shortening. MTU lengthening and shortening demonstrates a predictable force-length relationship.

Results: Applying elastic motion laws to MSK structures is appropriate. It is only in lengthening where the deformation limit can be exceeded and failure occurs. Injury during shortening can only occur if the structures experienced compressive forces, which is prevented by anatomy in normal operation. Understanding when a specific MSK structure is lengthening allows us to derive the mechanism of injury.

Conclusions: MSK Injuries are consequential on an inability to counter applied forces whilst the structure is being lengthened. Muscles, tendons and ligaments can only injure during their lengthening movement phase. Insertional tendons and bone near attachment points can only injure during the MTU shortening phase. Injuries to other structures, for example joint surfaces, can occur independent of the lengthening and shortening phases of elastic structures.

Research Applications:

1. A New Classification System for all MSK Injuries (COMI) based on elastic properties
2. Movement obeys Newton’s 3rd Law. We only shorten when we are in contact with the ground. Rewriting the functions of the muscle tendon units that move us
3. How Why and When does a hamstring strain
4. Free tendon injuries – A deformation response as a consequence of lengthening
5. Insertional tendon injuries as a consequence of Muscle Tendon Unit Shortening resulting in shear/friction - There is NO compression.
6. On the nature of stress fractures