The riddle of Gaspar's knee
By Len Johnson
June 11 2003
Did Darren Gaspar's knee give out in the final minutes of last Friday night's dramatic match against the Kangaroos because it forgot how to protect itself, or was it too tired to remember?
Ligaments and joints are protected by receptors that receive information on how and how far they are being asked to move and react accordingly.
In the case of the anterior cruciate ligament ruptured by Richmond defender Gaspar last Friday, the receptors would have sent out an alert and another set of muscles and ligaments, normally the hamstrings, would have responded to protect the knee.
Something short-circuited the process, switching the receptors off, leaving Gaspar on the turf and out for the rest of this season. The receptors were either overwhelmed, or failed to do their job properly.
Possible explanations include fatigue or pain from an existing injury inhibiting the receptors, or that micro-damage from the training scare Gaspar had a few days before the game might have damaged the receptors, causing them, in effect, to "forget" how the knee was supposed to work.
Given the statistical correlation between ground hardness and knee injuries, there is the contentious state of the Docklands stadium surface. Although the surface is within the prescribed parameters, it is always firm and, anecdotally at least, inconsistent.
"It's the six-million-dollar question," said Julie Steele, associate professor of biomechanics at Wollongong University. "There is no answer."
Steele did pioneering work on anterior cruciate ligament injuries in netballers and heads a study, partly funded by the AFL and the CSIRO, into developing an intelligent sleeve that will give footballers and netballers feedback on correct landing technique.
It needs to be said that Richmond responded in all the right ways to the Gaspar training scare. He had scans and hands-on assessments and, without symptoms, there was no rational basis on which to rule him out of playing.
But Steele said it is possible there was micro-damage that did not show up on the scans. Even if there was not, the fact that the knee had "failed" once might have been enough to throw the receptors off enough to explain the subsequent injury.
Steele said that one participant had actually suffered an ACL rupture during the 1984 netball study. Close examination of the videotapes revealed that "in two or three incidents she had fumbled the ball. We weren't sure whether that had weakened the tissue".
The process by which the various joints and ligaments within the body remember how to move, and react to movement, is also sometimes known as proprioception.
Steele said that the mechano-receptors within the ligaments and joints gave feedback on movement.
"They send a message, 'Oops, something is happening', when the ligament is over-stretched - either the amount or direction of the stretch. They will send a message to let the muscle, or some other part of the body, respond."
The possibility is that that did not happen with Gaspar on Friday night. Nor, perhaps, with others of the 70 per cent or so of anterior cruciate ligament ruptures that are non-contact. A good number of that 70 per cent occur in situations apparently as innocuous as the Gaspar one.
But it is a beguiling explanation, that they might occur because of something as simple as a receptor being too tired, or even forgetting, to do its assigned task.
• Despite the round-11 toll, anterior cruciate ligament injuries for 2003 are projected to reach about the average of 12 to 14 a season. There have been nine to date, but most occur in the first half of the season.
By Len Johnson
June 11 2003
Did Darren Gaspar's knee give out in the final minutes of last Friday night's dramatic match against the Kangaroos because it forgot how to protect itself, or was it too tired to remember?
Ligaments and joints are protected by receptors that receive information on how and how far they are being asked to move and react accordingly.
In the case of the anterior cruciate ligament ruptured by Richmond defender Gaspar last Friday, the receptors would have sent out an alert and another set of muscles and ligaments, normally the hamstrings, would have responded to protect the knee.
Something short-circuited the process, switching the receptors off, leaving Gaspar on the turf and out for the rest of this season. The receptors were either overwhelmed, or failed to do their job properly.
Possible explanations include fatigue or pain from an existing injury inhibiting the receptors, or that micro-damage from the training scare Gaspar had a few days before the game might have damaged the receptors, causing them, in effect, to "forget" how the knee was supposed to work.
Given the statistical correlation between ground hardness and knee injuries, there is the contentious state of the Docklands stadium surface. Although the surface is within the prescribed parameters, it is always firm and, anecdotally at least, inconsistent.
"It's the six-million-dollar question," said Julie Steele, associate professor of biomechanics at Wollongong University. "There is no answer."
Steele did pioneering work on anterior cruciate ligament injuries in netballers and heads a study, partly funded by the AFL and the CSIRO, into developing an intelligent sleeve that will give footballers and netballers feedback on correct landing technique.
It needs to be said that Richmond responded in all the right ways to the Gaspar training scare. He had scans and hands-on assessments and, without symptoms, there was no rational basis on which to rule him out of playing.
But Steele said it is possible there was micro-damage that did not show up on the scans. Even if there was not, the fact that the knee had "failed" once might have been enough to throw the receptors off enough to explain the subsequent injury.
Steele said that one participant had actually suffered an ACL rupture during the 1984 netball study. Close examination of the videotapes revealed that "in two or three incidents she had fumbled the ball. We weren't sure whether that had weakened the tissue".
The process by which the various joints and ligaments within the body remember how to move, and react to movement, is also sometimes known as proprioception.
Steele said that the mechano-receptors within the ligaments and joints gave feedback on movement.
"They send a message, 'Oops, something is happening', when the ligament is over-stretched - either the amount or direction of the stretch. They will send a message to let the muscle, or some other part of the body, respond."
The possibility is that that did not happen with Gaspar on Friday night. Nor, perhaps, with others of the 70 per cent or so of anterior cruciate ligament ruptures that are non-contact. A good number of that 70 per cent occur in situations apparently as innocuous as the Gaspar one.
But it is a beguiling explanation, that they might occur because of something as simple as a receptor being too tired, or even forgetting, to do its assigned task.
• Despite the round-11 toll, anterior cruciate ligament injuries for 2003 are projected to reach about the average of 12 to 14 a season. There have been nine to date, but most occur in the first half of the season.
