To dance is human; people of all ages and levels of motor ability express movements in response to music. Professional dancers exert a great deal of creativity and energy toward developing their skills and different styles of dance. How dancers move in beautiful and sometimes unexpected ways can delight, and the synchrony between dancers moving together can be entrancing.
To us as a neuroscientist and biomechanist (Lena), and a rehabilitation scientist and dancer (Madeleine), understanding the complexities of motor skill in a ballet move, or the physical language of coordination in partner dance, is an inspiring and daunting challenge.
Understanding how dancers move has important real-world implications, too. In our work, we’re studying gait and balance in different populations, as well as how holding hands – such as in partner dance – can actually help people walk and balance better. The ultimate goal is to help better design and prescribe rehabilitation to those with reduced mobility, as well as to develop robots that can physically interact with people to help with both motor assistance and motor learning.
Ballet training affects walking and balance
It’s easy enough to distinguish a dancer from a football player just based on the way they walk in everyday life – one glides like a liquid, the other is grounded and solid. That fits with our finding that ballet training alters how a person walks. But it also counters the sports training principle that motor skill is specific to the practiced movement, such as such as swinging a bat or doing a cartwheel.
On the other hand, rehabilitation relies on the idea that motor skill generalizes across different tasks. It would be impossible to practice every possible scenario a person with mobility impairment will encounter in real life. Therapists hope that helping patients develop strength and skill in a few tasks in the gym will be generalizable to improvements out in the world.
In a study led by Andrew Sawers, now an assistant professor of kinesiology at the University of Illinois at Chicago, we didn’t look at ballet dancing per se. Instead we took advantage of the dancers’ rigorous, years-long training regimen to test whether learning to move in a specialized context affects how we perform everyday tasks. We wanted to know whether ballet dancers actually differ from you and me in performing tasks that they didn’t explicitly practice.
It turned out that, when confronted with a challenging, narrow beam, ballet dancers still used the same preferred, habitual patterns of muscle coordination that they used when walking across a normal, level floor. These patterns are called “motor modules”; the nervous system uses them to construct movements, akin to the concept of “muscle memory”. To find each participant’s motor modules, we measured the electrical activity from many muscles in the leg and trunk as they walked across beams of varying difficulty.
In contrast to the ballet dancers, non-dancers who struggled to traverse the beam couldn’t rely on the same motor modules they used in normal walking. Why? Our research suggests that the long-term ballet training of the dancers refined a set of motor modules used for walking so that they could also be applied in more challenging related tasks; this in turn changed how dancers walk in everyday conditions.
Using dance training in rehabilitation settings
The same principles of motor skill acquisition in highly trained individuals – like the ballet dancers – may also be at play in rehabilitation and motor skill reacquisition in people with mobility impairments.
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