Author Archives: Swetha Rajagopalan

Salut mes amis!

It is the first Saturday in Paris, and after a long week, sleep was well deserved. I woke up around noon and headed straight for lunch with a friend. We got ourselves an amazing baguette and my very first set of chocolate macarons. They were absolutely to die for! Later that day, though, was the real treat. We got tickets to go see La Romanès Cirque Tzigane. While we were waiting outside, we saw the cutest kittens and one very unamused little puppy who I assume just wanted to take a full day nap.

The show, on the other hand, kept me on my toes the whole time. It was a phenomenal sight and many of the performers were multi-talented and a part of so many different acts. There were the obvious ones which included some juggling and acrobats, but some of the acts that put me in awe were rope and aerial dancing. Their coordination and ability to move so smoothly is fascinating and definitely something I have always wanted to learn. And not to mention, the tight-rope walker, who not only did stunts on the ropes but managed to walk across in HIGH HEELS. I find myself tripping over my own feet on solid ground, let along on a 1 inch rope.

It is quite amazing how these performers have perfected each of their moves with such ease, even when flying through the air. We know of our five senses: touch, smell, taste, sight, and hearing. We also have a sense called proprioception which is our ability to have a sense of our own body parts in relation to one another and in space. It is essentially how our body sees itself and the world. So how exactly does this work?

Muscle spindles and Golgi tendon organs provide the information on joint angle, muscle length, and muscle tension. Our brains integrate this information with our vestibular system, which helps us in balance and spatial orientation, and actually helps to prevent us from injury. Take for example, the patellar reflex test they do at every doctor’s

visit. The tap on the knee causes a stretch in the extrafusal muscle fibers of the quadriceps. The muscle spindle afferent fibers sense the stretch in the intrafusal fibers (located within the extrafusal fibers that mimic the extrafusal fibers) and relay that information to the spinal cord. An alpha motor neuron, located in the spinal cord will then conduct an electrical impulse back to the quadriceps to contract the muscle, which is what leads to the kicking motion of your leg. This whole system exists throughout our body in order to prevent injury of our muscles by excessive stretching or contraction.

We clearly do not consciously think about this on a daily basis, but a lot of our motions are dependent on our proprioceptors functioning properly and efficiently. For dancers and acrobats, training their proprioceptive sense refines “speed, accuracy, and quality of movement as well as expressiveness” (“Proprioception”, 2008). So maybe their abilities to do such incredible tasks were enabled through their background in dance.

In a recent study, Washburn et al (2014) explored into whether dancers were more able to entrain, or mimic, the movements of an instructor than non-dancers would. In the experiment, they evaluated seventy undergraduate students with three routines, the first being the easiest and the third being the hardest. Using a cross-recurrence quantification analysis (CRQA), they quantified a coefficient magnitude that essentially produced a score on the level of coordination of each individual to the instructor. This value showed to be consistently greater in the dancers versus the non-dancers group for each dance sequence. They also used two other methods, including a cross-correlation analysis and cross-wavelet spectral analysis. The cross-correlation analysis was used to measure a shorter time scale and showed that the synchrony in dancers were significantly better than that of the non-dancers. The cross-wavelet spectral analysis provided information on subsections within a dance sequence: full dance phrase, ½ dance phrase, ¼ dance phrase, and 1/8 dance phrase. Each phrase was a set of movements of 8 counts. By doing so, they analyzed the stability of interpersonal coordination. The use of multiple analyses helped to break apart the data into various time intervals in order to prevent any bias that may have occurred from a particular sequence or movement. The significance was observed across the short and long-time scale and the relationship of a particular group was able to be more readily accepted (Washburn, 2014).

From the data, it appears that dancers are better able to entrain with the instructor during both short and long-time scales, whereas the non-dancers were only able to coordinate on a count-to-count basis. This effectively supports that, dancers are able to improve their proprioceptive sense in order to more fluidly and synchronously mimic the instructors moves than non-dancers were (Washburn, 2014). Relating back to these acrobats in the circus, the performers are essentially engaged in a kind of social entrainment with themselves, the audience, and other performers in order to coordinate their movements and synchronize their entire piece into the show put forth to you (Phillips-Silver, 2010).

Interestingly, this study only had dancers experienced in ballet, modern and hip hop which really narrows down the generalizability of this study and although they had both male and female dancers and non-dancers, they did not perform any analyses comparing the effects of gender. As a dancer myself, there are different roles and movements that are targeted to be performed by either a male or female dancer, but not both. Personally, I would expect there to be some influence in the training of one’s proprioceptive sense by the specific differences of male and female dance movements of any style. Another thing to look at in future studies is motor modules, which are Neuromechanical pathways that are unique for different types of movement. Studies in the past have looked at these pathways for dancers and non-dancers and it would be really interesting to see of there exists a correlation between the consistency of a pathway with their proprioceptive sense in an experiment like this.

Just this past semester, I took an interdisciplinary course where they combined Human Physiology with dance, and it was really interesting to see how both dancers and non-dancers perceived and executed a movement. We were able to listen to the activity of our calf muscles using surface electrodes and it was very evident that dancers had specific and sharp points of activity when performing a dance movement whereas non-dancers had more soft and constant muscle activity. We were also able to understand our own proprioceptive sense and feel the stability of our bodies while balancing in ways that we normally would not. For example, it is much harder to balance on our heels or toes than it is when we are standing straight, and that is due to a lack of sufficient proprioceptive information (“Proprioception”, 2008). However, this can be improved with practice, just as the performers, and who knows, maybe with enough practice, we can walk across a tight rope too!

 

À bientot!

Swetha Rajagopalan

 

Bibliography

Washburn, A., DeMarco, M., de Vries, S., Ariyabuddhiphongs, K., Schmidt, R. C., Richardson, M. J., & Riley, M. A. (2014). Dancers entrain more effectively than non-dancers to another actor’s movements. Frontiers in Human Neuroscience, 8, 800. http://doi.org/10.3389/fnhum.2014.00800

Phillips-Silver J., Aktipis C. A., Bryant G. A. (2010). The ecology of entrainment: foundations of coordinated rhythmic movement. Music Percept. 28 3–14 10.1525/mp.2010.28.1.3

Proprioceptors. (n.d.). Retrieved June 05, 2017, from https://courses.washington.edu/conj/bess/spindle/proprioceptors.html

Proprioception. (2008, October 4). Retrieved June 6, 2017, from http://c.ymcdn.com/sites/www.iadms.org/resource/resmgr/imported/info/proprioception.pdf

Images Retrieved from these sites:

https://commons.wikimedia.org/wiki/File:Muscle_spindle_model.jpg

https://commons.wikimedia.org/wiki/File:Patellar-knee-reflex.png

http://www.spangdahlem.af.mil/News/Article-Display/Article/295295/zumba-provides-alternative-work-out/

https://commons.wikimedia.org/wiki/File:Muscle_Whistler_with_EMG_surface_electrodes_(1971).jpg

https://simple.wikipedia.org/wiki/Pointe_shoes