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Headstand and Neck Safety in Yoga: What You Need to Know
Headstand (Sirsasana) has long been called the “king of all postures.” That claim has now come under fire as the yoga community increasingly questions its safety. A new study published in the Journal of Bodywork & Movement Therapies reveals the potentially injury-causing weight-bearing responsibility of the head and neck at moments of peak force during headstand and questions whether its risks justify its rewards.
Researchers at the University of Texas at Austin recruited 45 experienced adult (18 years of age and older) yoga practitioners who were free from chronic neck injury and able to perform a supported headstand for at least 5 breath cycles.
Practitioners were divided into 3 groups depending on their preferred technique for entering and exiting headstand: symmetrical extended (SE), symmetrical flexed (SF) or asymmetrical flexed (AF). Those in the symmetrical extended group entered and exited the pose with legs straight and together. Symmetrical flexed participants entered the pose with symmetrical thighs and flexed knees, whereas those in the asymmetrical flexed group entered the pose one leg at a time with legs in some degree of flexion. Both groups were matched to be equivalent in age, gender and yoga experience, and did not differ significantly by weight, height, years of headstand experience or frequency of weekly yoga practice.
Each participant was individually invited into the laboratory and asked to complete a 10-minute warm up and a self-guided yoga practice. Following the warm up, 18 reflective markers were affixed to predetermined locations on their bodies (chin, center of forehead, spinous processes of C3, C7, T9, and L5 vertebrae, right and left earlobes, greater trochanters, base of the 2nd toe et cetera) so that their movement could be measured using a “camera motion capture system.” One marker was also positioned on a force plate to measure ground reaction force at the crown of the head during headstand.
Participants then completed 3 headstands that were each held for 5 breath cycles. A 2-minute interval between trials was included to prevent fatigue.
The researchers divided each posture into 3 phases (entry, stability and exit) during which they collected kinematic (body motion), force, average and maximum weight bearing load and cervical spine (neck) alignment data. Results from the 2nd and 3rd trial were averaged for each participant and used in the final analysis.
Headstand places considerable force on head and neck
Findings from the study were divided into 4 main categories: force, neck angle, loading rate and center of pressure. On average, the maximum force on the crown of the head during headstand ranged from 40-48% of an individual’s body weight. For an individual weighing 150 pounds that is the equivalent of placing a 60-72 pound weight on the top of their head. According to the study’s authors, this degree of force places a minimum of 50% of individuals at risk for “load failure” or neck injury.
As you might imagine, force on the crown of the head varies by phase, with the greatest force occurring during the stability phase (holding the pose) and the least occurring upon exit. The degree of force varied by technique, with the extended leg position (SE) showing the lowest overall force values, and little difference being detected between the flexed leg variations (SF and AF).
It is important to note that the maximum force placed on the crown of the head and neck increased in magnitude during the pose. This is because most practitioners slowly transferred weight from their arms into the head and neck during the stability phase. This suggests that as the duration of the pose increases, so does the pressure being placed on the head and neck and the potential for injury.
The researchers next examined loading rate, or the speed at which the neck and head bear weight during each of the 3 phases of headstand. Results suggested that the fastest loading rate occurred during entry into the pose, followed by exit and stability. Participants in the asymmetrical flexion group (AF), those who tend to kick up into the pose, had the most rapid rate of load bearing compared to those who entered into the pose using a controlled, double leg approach. Rapid load bearing may be associated with increased force and instability and greater risk for harm.
Neck angle also is an important variable to consider in headstand, as extreme flexion compromises the neck, which can cause damage. When examining the data from each of the 3 phases, the researchers found that extension of the cervical spine (compression of the back of the neck) at the time of maximum weight loading was greatest during the entry phase. This suggests that the neck is most vulnerable while individuals are entering into the pose.
Lastly, researchers examined changes in pressure at the crown of the head during entry, stability and exit. They discovered that individuals engaged in more side-to-side shifting at the crown of the head while attempting to balance between the arms and the head during the entry and exit phases of the pose regardless of technique. Again, this suggests that the neck is particularly vulnerable when practitioners are using the crown of the head for stabilization.
While many contend that the neck is not vulnerable during headstand because the arms assume the majority of weight bearing, these data confirm that even experienced practitioners shift their weight from their arms to the head and neck while sustaining the pose.
Is one yoga technique better than the others?
Regardless of technique, the average experienced yoga practitioner loads the head and neck with roughly 40-48% of their body weight during headstand. This represents considerable force to a potentially vulnerable region of the body. This force tends to increase with the duration of the pose.
When it comes to examining the 3 techniques, this study suggests that entering headstand with straight legs that lift and lower simultaneously results in the least amount of vertical weight loading and cervical flexion because entry and exit are slow and controlled. (It also requires a great deal of core strength).
Conversely, weight loads are greatest using the asymmetrical, single leg variation, most likely because entry into the pose is “the least predictable and most difficult to perform with consistency and controlled force,” say the authors of the study. This approach also has the fastest loading rates which, the researchers note, is often accompanied by the temporary stiffening of tissues, which increases the risk for failure loads and injury.
Although the sample size of this study may have been too small to detect potential differences between the 3 techniques, these findings suggest that a slow, controlled entry into headstand may limit the likelihood of excessive weight loading, decrease shifts in weight bearing, and reduce unhealthy extension of the cervical spine, all known to cause injury.
It is important to recognize that this study was conducted with a sample of experienced yoga practitioners with an established headstand practice as well as the strength and ability to hold the posture for 5 full breath cycles. It did not include individuals learning the pose, those who do not consistently succeed in achieving headstand, or those who cannot sustain it. In short, this study did not include those at greatest risk for injury. Consequently, factors such as weight bearing load on the neck and head may be underestimated.
This study provides several important take home messages if you choose to teach or practice headstand.
The posture places considerable weight load onto the head and neck that, with poor alignment, technique and/or repetition, may injure the cervical spine. There is also the risk for nerve damage in cases in which the neck is hyperextended or the head shifts to one side.
Headstand places less of a strain on the head and neck when entered into slowly and with control.
The pose is contraindicated when practitioners have one or more of the following conditions: osteoporosis/osteopenia, hypertension, glaucoma, detached-retina, pregnancy, menstruation, cervical injury or dysfunction, heart conditions or other serious medical diagnoses.
Students should learn headstand under the guidance of a highly experienced instructor, and only attempt the posture when the instructor and student are confident that the practitioner has sufficient core and upper body strength to sustain the pose.
Although headstand is one of my favorite inversions, I no longer teach or practice it. When comparing the research regarding the risks and biomechanics of the pose to its benefits I’ve concluded that there are many inversions and forearm balances that provide the same gains at a fraction of the risk. Personally, I choose safety and sustainability above all else for myself and the students in my care. Ultimately, it is a personal decision and one that all yoga instructors and practitioners should consistently reflect on.
B Grace Bullock, PhD, E-RYT 500, is the Founding Director of the International Science & Education Alliance, a firm that provides strategic planning, research consultation and assessment design to support the empirically rigorous evaluation and sustainable implementation of programs in education, leadership, health and human services. Grace is an intervention scientist, psychologist, yoga educator and author who has worked extensively in integrated behavioral health settings. Her research, clinical practice, teaching and writing emphasize the incorporation of empirically supported psychotherapy with yoga therapy and mindfulness practices to relieve the symptoms of stress, trauma, anxiety, depression and other psychological illnesses, and to promote healthy relationships. She is Faculty at the Integrated Health Yoga Therapy therapist training program, and Professor of Yoga & Neuroscience at the Taksha University School of Integrative Medicine. Grace is the former Editor in Chief of the International Journal of Yoga Therapy and recipient of a Francisco J. Varela Research Award from the Mind & Life Institute. For more information contact Grace at firstname.lastname@example.org or see http://isaeaorg.wix.com/isaea and http://www.mind-bodytherapy.com.
Hector, R. & Jensen, J.L. (2015). Sirasana (headstand) technique alters head/neck loading: Considerations for Safety. Journal of Bodywork & Movement Therapies, 19, 434-441.