I was very impressed in 2019 at the 40th Festival Mondial du Cirque de Demain when I saw the contortionist Enkhtsetseg Lodoï performing the same contortion act for which she had won the gold medal 36 years ago (1). I wondered how contortionists could fold like cooked spaghetti, whereas most people have trouble touching their toes. Are contortionists physiologically made like ordinary people or do they have superpowers hidden in their bodies? Their fascinating ability is now revealed by science.
Hypermobility, or hyperlaxity, describes the ability to move joints beyond the normal range of movement. For example, can your thumb be pushed back to touch your forearm? This measure is one of the manipulations of the Beighton score (2). The Beighton score is the most common tool to measure joint hypermobility on a 9-point scale. The five manipulations that make up this scale are:
- Little finger dorsiflexion beyond 90° (left and right)
- Thumb dorsiflexion to the flexor aspect of the forearm (left and right)
- Elbow hyperextension beyond 10° (left and right)
- Knee hyperextension beyond 10° (left and right)
- Flat palms on the floor with a forward flexion of trunk and knees full extended
The presence of hypermobility at each manipulation gives 1 point, for a maximum total of 9 points. Contortionists usually have the maximum score of 9 for the Beighton score (3). Hypermobility traits are 2 to 3 times more common among women compared to men and decline with aging (4). Factors contributing to this mobility difference related to sex could be linked to the muscle mass, the joint geometry, and the degree of collagen in muscle, tendon, and fascia. We also know that hypermobility is more prevalent in African or Asian ethnicity when compared with the Caucasian ethnicity.
Genetic factors have a substantial contribution to joint hypermobility as well. The most complete familial data of 1264 Canadians shows that the transmissibility from parents to offspring for trunk flexibility is 48% (5). Another study from 2007, focusing on 483 monozygotic and 472 dizygotic twin, adult women, confirms the influence of genetics in joint hypermobility (6). The high heritability for flexibility could be explained by the influence of genes on the physiology of muscles, bones, tendons, and ligaments.
Researchers found that hyperlaxed people have an abnormal ratio of Type III to Type I collagen. Type I collagen is the most common collagen in the human body. Type I and, to a lesser extent, Type III collagen are found in tissues like tendons or ligaments. Type III collagen is more elastic than type I. A normal ratio of type III collagen to type III+type I in tissues is between 18 and 21%. In hyperlaxed people, this ratio goes up to between 28 and 46% (2). More research is needed to confirm these ratios with contortionists.
Genetics is not the only important factor- becoming a contortionist also requires long and rigorous training. Acquired contortionism is related to intense training and is strongly dependent on physical activity. Many contortionists start training at the age around 8 years old (3). Development of their capacity requires many hours of training every day for many years. ‘’It’s a long discussion. It will depend of the predisposition and the physical aptitudes, if the person needs to control the flexibility, needs stability or not.’’ Answered Daniela Arendasova, the Director of Studies of the national circus school of Montréal when I asked her how many years of training it takes. Contortionists also need to develop a lot of strength to manage their flexibility. Contortionists must stretch their muscles while maintaining stability and balance. In fact, a joint requires mobility in a range of motion adapted to a physical activity but, most importantly, requires stability during the physical activity. A low joint stability is often associated with injury. Hyperlaxed people work harder during physical activity so that their joints don’t dislocate or doesn’t go into an unhealthy range of motion. Despite the extreme flexibility and load on the spine, contortionists do not appear to suffer. Two studies reported the use of magnetic resonance imaging of contortionists during extreme body contortions. These studies published in 2006 and 2008 included one and five contortionists, respectively (3,7). The average total range of motion of the spine from the third lower cervical region (C3) to the fifth lumbar vertebrae (L5) was 238° (full extension of 218° to full flexion of 50°). The areas that created the most extreme angles during full extension are the mid to lower cervical regions, the lower thoracic and upper lumbar regions. The researchers in both studies concluded that, despite extreme range of motion, there were limited amounts of pathological change, no abnormal subluxations, or spinal segmental motions. They indicate that this excessive motion results from an astonishing spinal flexibility and this mobility no doubt reflects their regular and rigorous training. One common myth is that contortionists have a short life expectancy, but many examples contradict this myth. This theory may come from a confusion with diseases of collagen such as Marfan and Ehlers-Danlos syndromes as these diseases are often associated with painful joint subluxation and osteoarthritis.
What is happening in the body during stretching?
Bone-to-bone articulations are connected by ligaments. Tendons attached from muscle to the bone allow for movement of the bone during muscle contractions, like a rope. During a stretch, it is primarily the muscular fibers that stretch, but the ligaments and tendons can stretch as well. Muscle cells called myofibrils can be stretched to twice their resting length without damage. Other than contortion or other activity that needs a great range of motion, the ligaments should not elongate too much because it often leads to injury. Nerves also have the capacity to elongate between 6% and 20% of its resting length8, although it should not be a goal in itself.
Neuronal adaptations also play a role to have greater muscular flexibility during stretching. When a muscle is stretched, a signal is sent to the spine without going through the brain. Activation of spinal motoneurons causes a contraction and thus the shortening of the muscle. This is called myotatic effect or reflex. Researchers found that regular stretching leads to an inhibition of this reflex (9). There are several different types of stretching that contribute to the inhibition of this reflex. Passive stretching that is either preceded by a hold-relax method of the stretched muscle or assisted by the contraction of its antagonist muscle, is associated with greater reflex inhibition when compared to the passive stretching technique alone.
Flexibility can be attributed to a psycho-physiological effect at the sensory level. In a review of 26 studies, stretching for 3 to 8 weeks does not seem to affect the muscular properties, although it does increase the range of movement at the joints. Increase of flexibility during this period comes from a better pain tolerance under a greater traction force in the muscle (10). Neural adaptations and pain tolerance occur in the first weeks of training while structural changes of tissue require longer, consistent training.
Temperature is also important during stretching. Warming the muscles will easily improve flexibility. A traditional warm-up or a sauna will have the same effect. The underlying mechanism of this effect is related to viscoelasticity. If a muscle is cold, it increases viscosity in muscle fibers, tendons, and fascia, and thus provides more resistance to the movement of tissue (8).
Stretching, or contortion, requires good physical health and specialized coaching. Flexibility depends on genetics, sex, age, lifestyle, medical history, and, of course, physical activity. Not everyone finds that all kinds of stretching are beneficial or without risk. Pain is not normal and should not be ignored. However, movement depends on the range of motion. Limited range of motion or musculo-tendinous tensions (like hypertrophied muscle) is not beneficial either. It is like practicing a sport in a T-shirt that is too small- it’s uncomfortable and limiting. Some circus performers also need to attain extreme levels of flexibility. Individual differences should be considered in stretching, and coaching should be personalized. Certainly, contortionists have genetic predispositions and a long training; they are artists and athletes. More research is still needed to better understand their astonishing spinal flexibility.
- BnF CNAC. (2021). Mlle Enkhtsetseg Lodoï, tir à l’arc en contorsion. BnF CNAC Encyclopédie des arts du cirque. http://expositions.bnf.fr/cnac/grand/cir_1770.htm
- Russek, L. N. (1999). Hypermobility syndrome. Physical therapy, 79(6), 591-599.
- Peoples, R. R., Perkins, T. G., Powell, J. W., Hanson, E. H., Snyder, T. H., Mueller, T. L., & Orrison, W. W. (2008). Whole-spine dynamic magnetic resonance study of contortionists: anatomy and pathology. Journal of Neurosurgery: Spine, 8(6), 501-509.
- Decoster, L. C., Vailas, J. C., Lindsay, R. H., & Williams, G. R. (1997). Prevalence and features of joint hypermobility among adolescent athletes. Archives of pediatrics & adolescent medicine, 151(10), 989-992.
- Katzmarzyk, P. T., Gledhill, N., Pérusse, L., & Bouchard, C. (2001). Familial aggregation of 7-year changes in musculoskeletal fitness. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 56(12), B497-B502.
- Hakim, A. J., Cherkas, L. F., Grahame, R., Spector, T. D., & MacGregor, A. J. (2004). The genetic epidemiology of joint hypermobility: a population study of female twins. Arthritis & Rheumatism: Official Journal of the American College of Rheumatology, 50(8), 2640-2644.
- Hahn, F., Kissling, R., Weishaupt, D., & Boos, N. (2006). The extremes of spinal motion: a kinematic study of a contortionist in an open-configuration magnetic resonance scanner: case report. Spine, 31(16), E565-E567.
- Behm, D. G. (2018). The science and physiology of flexibility and stretching: Implications and applications in sport performance and health. Routledge.
- Guissard, N., Duchateau, J., & Hainaut, K. (2001). Mechanisms of decreased motoneurone excitation during passive muscle stretching. Experimental Brain Research, 137(2), 163-169.
- Freitas, S. R., Mendes, B., Le Sant, G., Andrade, R. J., Nordez, A., & Milanovic, Z. (2018). Can chronic stretching change the muscle‐tendon mechanical properties? A review. Scandinavian journal of medicine & science in sports, 28(3), 794-806.
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