by Have you ever thought that an ankle sprain is a brain injury? Most people probably wouldn’t do that.
However, we are beginning to understand how the brain continually adapts, known as plasticity.
Even though the damage from an ankle sprain happens to the ankle, there may also be some changes in the brain in how well it perceives pain or movement.
One of our PhD students, Ashley Marchant, has shown that something similar happens when we change how much weight (or load) we place on the muscles of the lower extremities. The closer the load is to the Earth’s normal gravity, the more accurate our sense of motion is; the lower the muscle load, the less accurate we become.
This work means we need to rethink how the brain controls and responds to movement.
Solving an important puzzle
Historically, exercise science has attempted to improve muscle function through resistance training, cardiovascular exercises and flexibility.
One of the major problems in the treatment and prevention of sports injuries is that even if the sports medicine team thinks an athlete is ready to return, the risk of a future injury remains two to eight times greater than if he had never had an injury had. .
This means that sports doctors have missed something.
Our work at the University of Canberra and the Australian Institute of Sport has focused on sensory input in an attempt to solve this puzzle. The aim was to assess the ability of the sensory reception or perception aspect of movement control.
The number of input (sensory) nerves outnumbers the output (motor) nerves by about ten to one.
Over the past two decades, scientists have developed tools that allow us to determine the quality of sensory input to the brain, which forms the basis of how well we can perceive movement. Measuring these inputs could be useful for everyone from astronauts to athletes and the elderly at risk of falls.
We can now measure how well someone retrieves information from three crucial input systems:
- the vestibular system (balance organs in the inner ear)
- the visual system (reactions of the pupils to changes in light intensity)
- the position detection system in the lower limbs (mainly from sensors in the muscles and skin of the ankle and foot).
With this information we can get a picture of how well a person’s brain collects movement information. It also indicates which of the three systems may benefit from additional rehabilitation or training.
Lessons from space
You may have seen videos of astronauts, like those on the International Space Station, moving with only their arms and legs behind them.
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This shows how humans, when they leave Earth’s gravity, receive minimal information to the sensory system through the skin and muscles of their legs.
The brain quickly deactivates the connections it normally uses to control movements. This is fine when the astronaut is in space, but once he has to stand or walk on the Earth’s or moon’s surface, he is at greater risk of falls and injury.
Similar brain changes can occur in athletes due to changes in movement patterns after an injury.
For example, limping after a leg injury means that the brain receives very different movement information than the movement patterns of that leg. In the case of plasticity, this may mean that the movement control pattern does not return to its optimal pre-injury status.
As previously mentioned, a history of injury is the best predictor of future injury.
This suggests that there is a change in the athlete’s movement control processes after an injury – most likely in the brain – that extends beyond the time when the injured tissue has healed.
Measures of how well an athlete perceives movement are related to how well they perform in a range of sports. Sensory awareness could therefore also be a way to identify athletic talent early.
In older adults and in the context of fall prevention, poor scores on the same sensory perception measures may predict subsequent falls.
This may be due to reduced physical activity in some elderly people. This “use it or lose it” idea could show how the brain connections for motion perception and control can deteriorate over time.
Accurate healthcare
New technologies to track sensory ability are part of a new direction in healthcare described as precision health.
Precision Health uses technologies and artificial intelligence to take into account the range of factors (such as their genetic makeup) that influence a person’s health and provide treatments designed specifically for them.
Applying a precision health approach to motion control could enable much more targeted rehabilitation for athletes, training for astronauts and earlier fall prevention for the elderly.
Gordon Waddington, AIS Professor of Sports Medicine Research, University of Canberra and Jeremy Witchalls, Associate Professor of Physiotherapy, University of Canberra
This article is republished from The Conversation under a Creative Commons license. Read the original article.
