An Investigation of an Anterior Cruciate Ligament Injury as a Result of a Rucking Duel
Description
An elite Australian Rules footballer, contesting a rucking duel, slipped
on an artificial take-off surface hyperextending the knee and rupturing
the anterior cruciate ligament. It was accepted initially that the artificial
take-off surface introduced by the sports governing body was solely responsible
for the injury. Perform Enhance instead was of the opinion that the rucking
action was atypical of that stipulated in official coaching literature,
and recommended analysis of the players technique, together with comparative
testing of the take-off surfaces, both artificial and natural turf.
Procedures
Investigation was undertaken at three levels.
- Digital film analysis of test subjects to determine whether the action was atypical of that recommended in official coaching literature. This was compared with actual film of the incident.
- Microphotography of the boot to determine wear patterns and cleat penetration at demonstrated angles of dorsiflexion and inversion.
- Force plate testing of test subjects of comparable height and weight, using the same atypical action. This determined the typical forces generated in three planes of motion at heel strike and foot plant of the take-off leg.
- Slip testing of the players boot on both artificial and natural turf to determine the degree of cleat penetration at the instant of heel strike. A slip resistance cart was used with attached prosthesis. The prosthesis was inserted into the players boot and a co-efficient of friction determined.
Conclusions
Following testing of the two surfaces, artificial and natural
turf, the slip resistance factor with the foot in the heel
strike position
was
found to be almost identical to that of natural turf. The
surface was therefore
eliminated as a causal factor. Digital film analysis of the
actual incident revealed that the take-off action used was
contrary
to that recommended
in the coaching literature. At the instant of heel strike
it was found that the take-off leg was already in a position of
hyperextension
with
the anterior cruciate ligament already stressed. This position,
with the players weight now superimposed, was impossible
to reverse and
was contraindicated
in terms of sound anatomical and biomechanical theory. The
atypical action set in motion a series of events that resulted
in easily
explained behaviour
of all relevant soft tissue structures and a rupturing of
the anterior cruciate ligament.
|
