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Sirsasana (headstand) technique alters head/ neck loading: Considerations for safety
Abstract
This study examined the weight-bearing responsibility of the head and neck at moments of peak force during three headstand techniques.
Three matched groups of 15 each (18-60 years old) were formed based upon lower limb entry/exit technique: symmetrical extended, symmetrical flexed, and asymmetrical flexed. All 45 practitioners performed 3 headstands. Kinematics and kinetics were analyzed to locate peak forces acting on the head, loading rate, center of pressure (COP) and cervical alignment.
During entry, symmetrical extended leg position trended towards the lowest loads as compared to asymmetrical or symmetrical flexed legs (Cohen's d = 0.53 and 0.39 respectively). Also, symmetrical extended condition produced slower loading rates and more neutral cervical conditions during loading.
Subjects loaded the head with maximums of 40-48% of total body weight. The data support the conclusion that entering the posture with straight legs together may reduce the load and the rate of change of that load.
Copyright © 2014 Elsevier Ltd. All rights reserved.
... Concerning the Quadruped Inverted V, the rather larger base of support and the rather central projection of the body's center of gravity during the quadruped inverted V stance may most likely explain the inability of abdominal breathing to induce a postural stability difference compared to regular breathing [65]. The inverted stances are expected to induce postural instability and elicit compensatory motor control segmental strategies (enhanced motion at the distal segments of the legs and the elbow joint in order to minimize motion variability in the head and trunk) [26][27][28][29][30][31][32][33]. The isometric contraction of the abdominal muscles is among the segmental motor control strategies aiming at postural stability correction during inverted body stances (i.e., handstand) [29]. ...
... The isometric contraction of the abdominal muscles is among the segmental motor control strategies aiming at postural stability correction during inverted body stances (i.e., handstand) [29]. Furthermore, during the Headstand inverted stance, the neck area adopts the antigravity support role and sustains muscular and spinal loads that contrast or exaggerate those that the neck musculature is designed for (i.e., increased lateral deviations in the thoracic spine) [26,28,29]. As such, contrasting or exaggerating muscular and spinal loads, in combination with the resistance rather than assisted by gravitational force activation of the Ext-IC and the Diaphragm muscles, may also associate with the non-consistency of the significance of the abdominal breathing effect across muscles and body stances. ...
In popular fitness modalities, the participants often perform abdominal breathing while maintaining stable or rather unstable as well as inverted body stances that may challenge the respiratory muscles’ activation. This study aimed to examine the abdominal breathing effect on postural stability and the respiratory muscles’ activation during four body stances: the Upright Stance, the Quadrupled Inverted V, the Elbow Side-Bridge, and the Headstand. Participants (n = 29) maintained (40 s) the body stances under regular and abdominal breathing (the latter verified through visual inspection and 3D inertial sensing of the abdominal wall angular displacements, LORD-MicroStrain®, 100 Hz, MicroStrain, Inc., Williston, VT, USA). The trajectory of the center of pressure (CoP) (Kistler force plate, 100 Hz, Kistler Group, Winterthur, Switzerland) was recorded in synchronization with the respiratory muscles’ (sternocleidomastoid, external intercostals, diaphragm, rectus abdominis) vibromyographic activation (Biopac VMG sensors, 2000 Hz, Biopac Systems, Inc., Santa Barbara, CA, USA). Abdominal breathing had a significant (p ≤ 0.05) deteriorating effect on postural stability and an increasing one on the respiratory muscles’ activation; however, this was not consistent across body stances. The body stance specificity of the abdominal breathing effect justifies the purpose of the present study. Thus, before the request for abdominal breathing in popular fitness modalities, one should acknowledge the postural and the breathing demands of each particular stance, particularly for the inverted ones.
... Altering the alignment of yoga asanas can also lead to nonintuitive changes in joint and limb loading. For example, entering headstand pose (Sirsasana) with symmetrical extended legs reduced loading and loading rates (defined by GRFs applied to the head and the maximal rate of change of the GRFs) and created safer spine conditions compared to entering the asana with asymmetrical or symmetrical flexed legs (Hector and Jensen, 2015). The authors attributed these results to the slower and more controlled entry and an improved ability to maintain a straighter cervical alignment during the symmetrical extended leg technique. ...
... Thus, as the stance width became wider, the participants increased reliance on their leading limb and unloaded the trailing limb. These results confirm that loading is influenced by postural alignment similar to prior yoga research that observed spinal loading was influenced by postural alignment when entering and exiting Headstand asana (Sirsasana) (Hector and Jensen, 2015). These data are important to consider when refining recommendations to adjusting postural alignments. ...
Background
Limited biomechanical data exist describing how yoga asanas (postures) load the limbs and joints, and little evidence-based recommendations for yoga injury prevention are available. This study aimed to establish joint loading metrics for an injury-prone, yet common yoga pose, the Triangle asana (Trikonasana) by identifying how stance width adjustments alter lower extremity loading.
Methods
Eighteen yoga practitioners underwent 3D motion analysis while performing Trikonasana with self-selected (SS) stance width and −30, −20, −10, +10, +20, and +30% of SS stance width. Ground reaction forces (GRFs), joint forces, and joint moments were calculated for the leading and trailing limb ankle, knee, and hip. One-way repeated-measures analysis of variance determined differences in loading due to stance width.
Results
GRFs, net joint forces, and net joint moments were significantly affected by stance width where increasing stance width increased leading limb loading but decreased trailing limb loading.
Conclusions
Altering stance width of Trikonasana influences lower extremity limb loading, and these loading responses were limb-dependent. Yoga practitioners and instructors can use this information to objectively support increasing or decreasing stance width to reduce or increase limb loading according to their goals or to make accommodations to groups such as beginners or at-risk populations for safer, more accessible yoga practices. Cuing a wider or narrower stance width will not have the same effect on both limbs.
... The yoga posture that is most often associated with adverse events is sirshasana, headstand (Cramer et al., 2013). Sirshasana may lead to high stress loads on the cervical spine, placing some people at risk, such as the ones with compressive myelopathy with myelomalacia (Ferreira & Galvez-Jimenez, 2013;Hector & Jensen, 2015). Nevertheless, some yoga practitioners have reported that they feel a decrease in load in the lumbar spine during this headstand position. ...
... Following those upright tasks that were used as references for the analysis, participants performed sirshasana. Participants were instructed to perform the most commonly practised version of headstand, with forearms on the floor, hands clasped around the back of the skull and the crown of the head in contact with the floor (Hector & Jensen, 2015). They were instructed to stay in position for a period sufficient to stabilize their posture. ...
This study analysed the behaviour of the geometric curvature of the spine during sirshasana. The position of dorsal retroreflective markers was computed via stereophotogrammetric analysis in six males and five females (29.4 ± 8.8 years, 63.0 ± 11.4 kg, 1.66 ± 0.08 m [average ± standard deviation]). The spinal points were projected onto the sagittal and frontal planes of the trunk, a polynomial was fitted to the data and the two-dimensional geometric curvature was quantified. The inferior lumbar lordosis decreased compared to the orthostatic position and gait, which may favour the posterior protrusion of the lumbar spinal nucleus pulposus in people with posterior herniation. The lateral deviation at the middle of the thoracic spine increases during sirshasana, which may reflect increased difficulties for postural control and spinal loads. It could be useful for promoting positive spinal structural and functional chronic adaptations for healthy participants, if the yoga program is carefully planned and the spinal alignment is carefully monitored during a headstand. However, it may aggravate some spinal diseases, especially scoliosis.
... Hector and Jensen measured the forces on the head during headstands (Sirsasana pose) and reported that participants placed 40-48% of their body weight on their heads when stable. 5 The only other possibly relevant data come from studies of people who carried loads on their heads for employment. [6][7][8][9] Not surprisingly, these studies show that chronic load bearing on the head leads to premature cervical spinal degeneration, and that it seems independent of the weight carried (10-100 Kg). ...
The kipping handstand push-up (kHSPU) is an exercise performed by many thousands of CrossFit participants. The safety of kHSPUs has been questioned because of vertical impacts upon the head. Here, we measured the axial loads placed upon the head during kHSPUs and sought to identify other factors that may place participants at risk of injury. 16 volunteers from a single gym performed 3 sets of up to 7 kHSPUs with their head and one hand contacting force platforms. Forces were recorded continuously and video recording were made while performing the exercises. The force profiles showed distinct landing and kipping peaks. Participants landed with more force than during their normal headstand, but less than their body weight. The force on the head was greatest during the "kip," and was usually more than body weight. Participants who reported pain following kHSPUs moved their head into extension during the exercises. Forces to the head during kHSPUs were below forces proposed for damage to the young male cervical spine, but overlapped those proposed for female cervical spines. While kipping handstand push-ups may be safe for young and previously uninjured male athletes, they may be unsafe for females and for those with previous injury or other compromising factors.
... Hector and Jensen measured the forces on the head during headstands (Sirsasana pose) and reported that participants placed 40-48% of their body weight on their heads when stable. 5 The only other possibly relevant data come from studies of people who carried loads on their heads for employment. [6][7][8][9] Not surprisingly, these studies show that chronic load bearing on the head leads to premature cervical spinal degeneration, and that it seems independent of the weight carried (10-100 Kg). ...
The kipping handstand push-up (kHSPU) is an exercise performed by millions of people. The safety of kHSPUs has been questioned because of vertical impacts upon the head. Here, we measured the axial loads placed upon the head during kHSPUs and sought to identify other factors that may place participants at risk of injury. 16 volunteers from a single gym performed 3 sets of up to 7 kHSPUs with their head and one hand contacting force platforms. Forces were recorded continuously and video recording were made while performing the exercises. The force profiles showed distinct landing and kipping peaks. Participants landed with more force than during their normal headstand, but less than their body weight. The force on the head was greatest during the "kip," and was usually more than body weight. Participants who reported pain following kHSPUs moved their head into extension during the exercises. Forces to the head during kHSPUs were below forces proposed for damage to the young cervical spine, with minimum estimated safety factors of 4.3 for landing and 3.8 for kipping. While kipping handstand push-ups may be safe for young and previously uninjured athletes, they may be unsafe for those with previous injury or other compromising factors.
... Also, it may have a delirious effect on intraocular pressure. [5,6] It may also cause neck injuries, spine, and joint injuries involving shoulder and wrist. [7] Headstand-induced subdural hematoma has been also reported. ...
Context: Sirshasan is supposed to increase blood flow to the brain and considered to be beneficial for intellectual function, however
mastering these techniques may be difficult. Aims: To see the effect of headstand using a tilt table on heart rate variability (HRV).
Settings and Design: A cross‑sectional study that was done on 26 healthy volunteers. Methods and Material: HRV was assessed in
the supine position and 30° head tilt position for 5 min. HRV recording was done on the power lab (AD Instruments P Ltd, Castle
Hill Australia). The tilt table used was Medica Podium, New Delhi, HLT‑200. Statistical analysis used: Paired t‑test. Results: All the
HRV parameters showed non‑significant change except low‑frequency parameters which showed significant change during head
tilt. Conclusions: Headstand to a 30° using tilt table cause a decrease in the autonomic activity which is mainly because of decrease
in sympathetic activity
... Also, it may have a delirious effect on intraocular pressure. [5,6] It may also cause neck injuries, spine, and joint injuries involving shoulder and wrist. [7] Headstand-induced subdural hematoma has been also reported. ...
Abstract
Context: Sirshasan is supposed to increase blood flow to the brain and considered to be beneficial for intellectual function, however
mastering these techniques may be difficult. Aims: To see the effect of headstand using a tilt table on heart rate variability (HRV).
Settings and Design: A cross‐sectional study that was done on 26 healthy volunteers. Methods and Material: HRV was assessed in
the supine position and 30° head tilt position for 5 min. HRV recording was done on the power lab (AD Instruments P Ltd, Castle
Hill Australia). The tilt table used was Medica Podium, New Delhi, HLT‐200. Statistical analysis used: Paired t‐test. Results: All the
HRV parameters showed non‐significant change except low‐frequency parameters which showed significant change during head
tilt. Conclusions: Headstand to a 30° using tilt table cause a decrease in the autonomic activity which is mainly because of decrease
in sympathetic activity.
Keywords: Headtilt, heart rate variability, Yoga
Objective: The main purpose of our case reports and literature review is to make individuals aware about possible catastrophic events which may be associated with some particular Yoga asanas, which result too much straining on craniovertebral junction and cervical spine, particularly in individuals with congenital anomalies of craniovertebral junction and cervical spine as well as osteoporotic and degenerative weakness of this region. Method: We presented our two case reports and literature review of case reports of compressive myelopathy and vascular accidents of this region associated with various Yoga asanas. Results: Both of the patients in our case reports had Os odontoideum, one was taking steroid for bronchial asthma and they were practicing Sirsasana (Headstand) and Halasana (plow pose). In review of literature we found four cases of compressive myelopathy, two cases were associated with multilevel cervical spondylosis and other two cases were associated with osteoporosis. Three of these patients were practicing Sirsasana (Headstand) and one Halasana (plow pose). We also found three cases of vascular accidents at craniovertebral junction. Two cases related to vertebral artery and one related to basilar artery while practicing Setubandha (Bridge pose), Sarvangasana (Shoulder stand) and Sirsasana (Headstand) respectively. Conclusion: Though yoga practices are considered safe and without harmful effects, some yoga asanas, resulting significant strain on craniovertebral junction and cervical spine, may land up individuals in catastrophic complications such as quadriparesis, stroke and respiratory paralysis with ventilator dependency. Individuals wishing to commence these asanas should have prior proper assessment osteoligametous structures of this region to rule out underlying osteoporosis, any osseous pathology, congenital osseous malformations, basilar invagination, vascular malformations etc.
Resumo FUNDAMENTO-Yoga é uma prática psicofísica com enfoque na conexão entre mente, respiração e corpo (RAUB, 2002). OBJETIVO-analisar a literatura científica publicada sobre alterações cardiovasculares em postura invertida, em praticantes de Yoga, utilizando as bases de dados completas da Science Direct, PubMed/MEDLINE, CENTRAL (Cochrane Central Register of Controlled Trials), LILACS (BIREME), IndMED e Scielo; essas bases foram escolhidas pela representatividade, abrangência internacional e relevância e impacto dentro da pesquisa médica. MÉTODO-Os termos de busca utilizados incluíram combinações entre as palavras-chave yoga, inversion, blood pressure, heart rate, Sarvangasana e Sirsasana, em inglês e português. RESULTADOS-A partir do conjunto de combinações de termos, 5 artigos foram identificados e selecionados para estudo. A análise considerou periódico, natureza do estudo, número de participantes, população investigada, amostra, parâmetros cardiovasculares investigados, métodos de aferimentos utilizados, e resultados obtidos. Dois dos artigos foram publicados na Indian Journal of Physiology and Pharmacology, um no Jounal of Applied Physiology, um no BMC Research Notes e um no Ancient Science of Life. Cinco pesquisas foram quantitativas (100% dos estudos selecionados), com um total de 71 participantes (média de participantes=14,2). As populações de estudo foram, em sua maioria, jovens não-portadoras de doença cardiovascular preexistente, sem lesões musculo esqueléticas ou doenças crônicas, predominantemente do sexo masculino (67 dos participantes). Os estudos foram conduzidos em dois países diferentes, Índia (n=4) e Suécia (n=1). O método de coleta de dados foi através de aferimento direto com equipamentos específicos (n=5). Somente dois avaliaram os voluntários durante a inversão. Os parâmetros investigados foram frequência cardíaca (n=4), pressão arterial (n=4), variação de frequência cardíaca (n=2), intervalos sistólicos (n=1), medidas anatômicas (n=1) além de medidas não-cardiovasculares complementares para fins de elucidação sobre controle neurológico (n=2). CONCLUSÕES-1) a prática de posturas invertidas, tanto sozinhas, quanto em sequências com outras posturas, pode resultar em redução da frequência cardíaca de repouso em pessoas sadias imediatamente após a execução das mesmas, assim como no médio prazo. 2) Os resultados sugerem que há aumento de pressão arterial sistólica e diastólica braquial na inversão postural, com retorno aos seus valores de repouso após a cessão da postura.
This study compares two different methods of headstand practice. One is a practice progression inspired by breaking (dance) that can be practiced on hard ground and the other is a common trial-and-error method as practiced on gymnastics mats. This study includes analyses of data gathered from field observation, one randomized control trial, and one intervention treatment. All three analyses reveal that the breaking headstand practice progression on hard ground results in significantly less occurrences of crashing when compared to the trial-and-error-based headstand practice on gymnastic mats (p < 0.5). This could mean that this method is the safer of the two, and also support the claim that use of good method is more important than the presence of safety equipment when assessing the risk of a physical activity. Further investigation should be done on breaking training methods, as well as other material-independent athletic skill training methods, so to increase and perfect physical education and dance-related pedagogical content knowledge.
Objectives
Fibromyalgia (FM) is a chronic condition characterized by widespread musculoskeletal pain, fatigue, depression, and hypocortisolism. To date, published studies have not investigated the effects of yoga on cortisol in FM. This pilot study used a time series design to evaluate pain, psychological variables, mindfulness, and cortisol in women with FM before and after a yoga intervention.
Methods
Participants (n = 22) were recruited from the community to participate in a 75 minute yoga class twice weekly for 8 weeks. Questionnaires concerning pain (intensity, unpleasantness, quality, sum of local areas of pain, catastrophizing, acceptance, disability), anxiety, depression, and mindfulness were administered pre-, mid- and post-intervention. Salivary cortisol samples were collected three times a day for each of two days, pre- and post-intervention.
Results
Repeated measures analysis of variance (ANOVA) revealed that mean ± standard deviation (SD) scores improved significantly (p < 0.05) from pre- to post-intervention for continuous pain (pre: 5.18 ± 1.72; post: 4.44 ± 2.03), pain catastrophizing (pre: 25.33 ± 14.77; post: 20.40 ± 17.01), pain acceptance (pre: 60.47 ± 23.43; post: 65.50 ± 22.93), and mindfulness (pre: 120.21 ± 21.80; post: 130.63 ± 20.82). Intention-to-treat analysis showed that median AUC for post-intervention cortisol (263.69) was significantly higher (p < 0.05) than median AUC for pre-intervention levels (189.46). Mediation analysis revealed that mid-intervention mindfulness scores significantly (p < 0.05) mediated the relationship between pre- and post-intervention pain catastrophizing scores.
Discussion
The results suggest that a yoga intervention may reduce pain and catastrophizing, increase acceptance and mindfulness, and alter total cortisol levels in women with FM. The changes in mindfulness and cortisol levels may provide preliminary evidence for mechanisms of a yoga program for women with FM. Future studies should use an RCT design with a larger sample size.
To assess the effect of yoga on anthropometry, blood pressure, glycemic control, and oxidative stress in type 2 diabetic patients on standard care in comparison with standard care alone.
The study involved 123 patients stratified according to groups with microvascular complications, macrovascular complications, and peripheral neuropathy and without complications and assigned to receive either standard care or standard care along with additional yoga for 3 months.
In comparison with standard care alone, yoga resulted in significant reduction in BMI, glycemic control, and malondialdehyde and increase in glutathione and vitamin C. There were no differences in waist circumference, waist-to-hip ratio, blood pressure, vitamin E, or superoxide dismutase in the yoga group at follow-up.
Yoga can be used as an effective therapy in reducing oxidative stress in type 2 diabetes. Yoga in addition to standard care helps reduce BMI and improve glycemic control in type 2 diabetic patients.
Japan has a large number of senior citizens. Yoga can be wisely applied in old age care. There is no any age restriction to practice yoga. The effect may differ by age. There is a need to study the mechanism of action of yoga with respect to age.
This study was conducted in Japan to find the effect of yoga on mental health between young and senior people.
Twenty-five normal healthy volunteers of both sexes were divided into two groups according to age. Fifteen participants of the age group between 65 to 75 years and 10 participants of the age group between 20 to 30 years were selected. This study was approved by the ethical committee of Kawasaki University of Medical Welfare. Selected individuals were subjected to 90 min of yoga classes once or twice a week for a month. Salivary amylase activity was assessed before and after yoga practice. State Trait Anxiety Inventory (STAI) was given before yoga on the first day and after one month of practice to assess the change in State anxiety and Trait anxiety.
Senior group - Salivary amylase activity decreased from 111.2±42.7 to 83.48±39.5 kU/L [average±standard deviation]. Younger group - Salivary amylase activity reduced from 60.74±31.8 to 42.39±24 kU/L. Senior group - State anxiety score decreased from 41.13 ±8.43 to 30.8±6.49, Trait anxiety score reduced from 45.66±7.5 to 40.73±8.3. Younger group - State anxiety score reduced from 38.7±4.8 to 30.8±4.1,Trait anxiety score reduced from 46.2±7.9 to 42.9±9.1. Changes were statistically significant with P<0.05.
Decrease in Salivary amylase activity may be due to reduction in sympathetic response. Reduction in State and Trait anxiety score signifies that yoga has both immediate as well as long-term effect on anxiety reduction. Thus yoga helps to improve the mental health in both the groups.
Yoga has been practiced for thousands of years to improve physical and emotional well-being. Empirical research on yoga has been ongoing for several decades, including several recent studies conducted with cancer patients and survivors.
This review provides a general introduction to yoga and a detailed review of yoga research in cancer.
Nine studies conducted with cancer patients and survivors yielded modest improvements in sleep quality, mood, stress, cancer-related distress, cancer-related symptoms, and overall quality of life. Studies conducted in other patient populations and healthy individuals have shown beneficial effects on psychological and somatic symptoms, as well as other aspects of physical function.
Results from the emerging literature on yoga and cancer provide preliminary support for the feasibility and efficacy of yoga interventions for cancer patients, although controlled trials are lacking. Further research is required to determine the reliability of these effects and to identify their underlying mechanisms.
Cervical spine injury resulting from compressive impact loading is a particularly devastating musculoskeletal injury due to the frequency of neurologic involvement. The objective of this research was to investigate the effect of axial eccentricity on the tolerance of the cervical spine. Two functional spinal unit segments (3 adjacent vertebra and their intervening discs and soft-tissues) were dissected from the lower cervical spine of twenty-four human cadaver cervical spines and randomly assigned to one of three loading groups. The eight specimens were tested to failure in compression, compression-flexion, and compression-extension under displacement control on a high-rate MTS load frame. The resulting six-axis loads were measured and evaluated by injury mechanism (group). Statistically distinct (p < 0.01) injury mechanisms, in terms of measured axial eccentricity, were produced by each of the eccentric axial compression inputs (compression-flexion, compression-extension, and compression). The axial force at failure for the compression and compression-extension loading environments were nearly equal and significantly (p < 0.01) larger (4-times) than their counterpart in the compression-flexion group. Failure data were compared with the neck injury criteria (Nij) recently proposed by the NHTSA using the 50th percentile male and 5th percentile female injury reference values. The compression and compression-extension mechanisms produced Nij values near 1.0. The compression-flexion series resulted in significantly lower Nij values at failure (approx. 0.3, p < 0.01). The results of this study provide tolerance data for the cervical spine subjected to different compressive loading environments and may be used to enhance injury reference computations facilitating neck injury prevention.
From a mechanical and structural point of view, the cervical spine is a very complex mechanism. The human neck contains vital neurologic, vascular, and respiratory structures as well as the cervical vertebrae and spinal cord. Although injury statistics generally attribute only 2% to 4% of serious trauma to the neck, any neck injury can have debilitating if not life-threatening consequences. Permanent paralysis is a particularly devastating and costly injury. When it is a consequence of accidental trauma, frequently a young productive member of society is transformed into a totally dependent member. The advent of high-speed land and air transportation has made us increasingly aware of the serious consequences that can result from a structural failure of the neck. Also, as more people pursue leisure-time activities, the potential for serious neck injuries increases. Football, diving, gymnastics, skiing, hang gliding, mountain climbing, and amusement rides are but a few activities that expose the neck to a risk of serious injury. As a result, a variety of devices have evolved that offer a measure of protection to the neck from mechanical trauma. Head and seat restraints, motorcycle and football helmets, energy-absorbing pads and collars, and gymnastic mats are but a few examples of head and neck protective devices. Unfortunately, the design of many of these has proceeded with insufficient biomechanical input because of the lack of relevant data.
BACKGROUND
Research suggests that stress-reduction programs tailored to the cancer setting help patients cope with the effects of treatment and improve their quality of life. Yoga, an ancient Eastern science, incorporates stress-reduction techniques that include regulated breathing, visual imagery, and meditation as well as various postures. The authors examined the effects of the Tibetan yoga (TY) practices of Tsa lung and Trul khor, which incorporate controlled breathing and visualization, mindfulness techniques, and low-impact postures in patients with lymphoma.METHODS
Thirty-nine patients with lymphoma who were undergoing treatment or who had concluded treatment within the past 12 months were assigned to a TY group or to a wait-list control group. Patients in the TY group participated in 7 weekly yoga sessions, and patients in the wait-list control group were free to participate in the TY program after the 3-month follow-up assessment.RESULTSEighty nine percent of TY participants completed at least 2–3 three yoga sessions, and 58% completed at least 5 sessions. Patients in the TY group reported significantly lower sleep disturbance scores during follow-up compared with patients in the wait-list control group (5.8 vs. 8.1; P < 0.004). This included better subjective sleep quality (P < 0.02), faster sleep latency (P < 0.01), longer sleep duration (P < 0.03), and less use of sleep medications (P < 0.02). There were no significant differences between groups in terms of intrusion or avoidance, state anxiety, depression, or fatigue.CONCLUSIONS
The participation rates suggested that a TY program is feasible for patients with cancer and that such a program significantly improves sleep-related outcomes. However, there were no significant differences between groups for the other outcomes. Cancer 2004. © 2004 American Cancer Society.
Complex loading develops in multiple spinal motions and in the case of hyperflexion is known to cause intervertebral disc (IVD) injury. Few studies have examined the interacting biologic and structural alterations associated with potentially injurious complex loading, which may be an important contributor to chronic progressive degeneration.
This study tested the hypothesis that low magnitudes of axial compression loading applied asymmetrically can induce IVD injury affecting cellular and structural responses in a large animal IVD ex-vivo model.
Bovine caudal IVDs were assigned to either a control or wedge group (15°) and placed in organ culture for 7 days under static 0.2MPa load. IVD tissue and cellular responses were assessed through confined compression, qRT-PCR, histology and structural and compositional measurements, including Western blot for aggrecan degradation products.
Complex loading via asymmetric compression induced cell death, an increase in caspase-3 staining (apoptosis), a loss of aggrecan and an increase in aggregate modulus in the concave annulus fibrosis. While an up-regulation of MMP-1, ADAMTS4, IL-1β, and IL-6 mRNA, and a reduced aggregate modulus were induced in the convex annulus.
Asymmetric compression had direct deleterious effects on both tissue and cells, suggesting an injurious loading regime that could lead to a degenerative cascade, including cell death, the production of inflammatory mediators, and a shift towards catabolism. This explant model is useful to assess how injurious mechanical loading affects the cellular response which may contribute to the progression of degenerative changes in large animal IVDs, and results suggest that interventions should address inflammation, apoptosis, and lamellar integrity.
Magnetic resonance imaging (MRI) study on degeneration of the thoracic spine in asymptomatic subjects.
To investigate the incidence of degenerative MRI findings of the thoracic spine in asymptomatic subjects and to identify factors related to the degeneration of the thoracic discs.
Studies on age-related degenerative changes of the thoracic spine are scarce.
Ninety-four asymptomatic Japanese volunteers (48 men and 46 women, mean age of 48.0 +/- 13.4 years) underwent MRI of the thoracic and cervical spine and filled the questionnaire regarding life styles. The items evaluated on MRI using a numerical grading system were (1) decrease in the signal intensity of the intervertebral discs (DSI), (2) posterior disc protrusion (PDP), (3) anterior compression of the dural sac (ACD), and (4) disc space narrowing. Association between each degenerative MRI finding and several factors, including age, sex, smoking, sports, body mass index, and degeneration of cervical spine was investigated.
Forty-four (46.8%) patients demonstrated positive degenerative MRI findings at 1 or more thoracic intervertebral levels. The percentage of the subjects with positive MRI findings was 37.2% in DSI, 30.9% in PDP, 29.8% in ACD, and 4.3% in disc space narrowing. The percentages of all MRI findings increased with aging. In 85 (90.4%) patients, degenerative MRI findings were positive in the cervical spine. DSI was significantly associated with age (odds ratio, 11.21, 95% confidence interval, 2.70-46.5), PDP with age (3.44, 1.02-16.61), smoking (4.94, 1.55-15.71) and presence of PDP in the cervical spine (4.25, 1.01-17.92), and ACD was associated with smoking (3.99, 1.28-12.44).
Degenerative changes in the thoracic spine on MRI was observed in approximately half of the asymptomatic subjects, whereas their incidences were less frequent than those in the cervical spine. Factors significantly associated with degenerative changes in the thoracic spine included age, smoking, and degeneration in the cervical spine.
In this study, the authors have developed a technique to replicate clinically relevant traumatic cervical spine injuries and determined the injury biomechanics. Because of the importance of compressive forces in neck injuries, this research was conducted using compression as the primary load vector. Six fresh human cadaveric head-neck complexes were prepared by fixing the distal end in methylmethacrylate. Tests were done with varying loading rates to include quasistatic and dynamic conditions. For quasistatic experiments, the proximal end was fixed to the piston of the testing device. In dynamic tests, the cranium was unconstrained, and to maintain stability, the effects of the spinal musculature were simulated by means of pulleys, deadweights, and springs in the anterior and posterior parts of the head-neck complex. Quasistatic tests conducted at a rate of 2.0 mm/sec produced cervical spine trauma at forces ranging from 1.7 to 2.3 kN, with deformations ranging from 2.2 to 3.7 cm. The specimens were deep-frozen at the level of injury, preserving the local deformation of the tissues to enable a detailed evaluation immediately after the injury. Dynamic tests conducted at velocities of 3.2 to 5.7 m/sec resulted in impact injuries at one level of the head-neck complex. The applied forces at the vertex were considerably higher than those recorded at the distal end. The failure deformations for both the quasistatic (2.2-3.7 cm) and dynamic (1.7-3.2 cm) tests, however, were found to be similar, suggesting that the human head-neck complex is a deformation-sensitive structure.
Fifteen fresh, intact, human male cadavers suspended head down were dropped vertically from a height of 0.9-1.5 meters. In eight specimens the heads were restrained to simulate muscle forces. The head-neck complex was oriented for maximal axial loading of the cervical and upper thoracic spine. In several cadavers, load cells were placed in cervical bodies. Head impact forces of 3,000-7,000 N in the unrestrained, and 9,800-14,600 N in the restrained, cadavers were recorded. There were more cervical and upper thoracic fractures in the restrained cadavers than in the nonrestrained subjects. The biomechanic and pathologic findings, including results of cryomicrotomography and computed tomography (CT), are discussed.
Carrying loads on the head is a common practice in rural Zimbabwe. Headloading imposes a considerable amount of strain to the axial skeleton. The cervical spine, being the most cranial and mobile part of the vertebral column, may be susceptible to spondylosis or disc degeneration in headloading. Age as well as the effects of intrinsic factors on cervical spondylosis have been well documented. However, studies on the effect of extrinsic weight bearing to spondylosis on the cervical spine are lacking. In this study, the effect of headloading on the pattern of spondylosis attributed to aging was examined. Results indicated that age led to significant degeneration of the fifth intervertebral disc space (P < 0.05) as well as significant straightening of the lordotic curve (P < 0.01). Load carrying seems to accentuate the straightening of the curve (P < 0.001). The results also suggest that headloading creates a shift in the degeneration from the fifth intervertebral disc space to higher levels. It is concluded that carrying heavy loads on the head alters the pattern of degenerative changes of the cervical spine.
To evaluate the relationship between load-carrying on the head and the development of degenerative change in the cervical spine.
A case-control study was performed with 35 individuals who had carried loads on their head (carriers) and 35 persons who never had carrier loads on their head (non-carriers). A scoring system was utilized for the assessment of the degenerative change in the cervical spine at the C3/C4, C4/C5, C5/C6 and C6/C7 levels on lateral cervical spine radiography. A total score was calculated by summing the scores for the single segments.
In 31 of the 35 (88.6%) carriers degenerative change was found in the cervical spine, but only in 8 of the 35 (22.9%) non-carriers (P < 0.01). The total score and the scores for segments C4/5, C5/C6 anc C6/C7 were significantly higher for the carriers than the non-carriers. It is concluded that the axial strain of load-carrying on the head exacerbates degenerative change in the cervical spine.
The vertebral column is a complicated anatomical structure which is composed of the intervertebral discs and the vertebrae. Both components develop special degenerative changes and morphologic features during life. This paper first reviews the anatomical fundamentals and then describes the morphological features of the aging intervertebral disc and the subsequent osseous changes of the vertebral bodies and the zygapophyseal joints. The aging intervertebral disc is characterised by processes which are labeled as intervertebral chondrosis and intervertebral osteochondrosis. Often these processes are combined with typical dislocations of intervertebral disc tissue in an anterior or dorsolateral direction. The well known Schmorl's nodules must also be mentioned in this context. Furthermore calcification and ossification of the intervertebral disc tissue can take place. More severe processes lead to osseous changes of the vertebral bodies. In particular, an osteophytosis of the vertebral bodies can be established. These sturdy osteophytes are able to stiffen the vertebral column. Furthermore the arthrotic changes of the zygapophyseal joints are delineated in this paper. The special appearances of these changes are discussed according to the different and specialised regions of the vertebral column. The advanced degenerative changes of the zygapophyseal and uncovertebral joints of the cervical spine are of essential clinical interest because the compression of the vertebral artery or the narrowing of the intervertebral foramina by these processes may cause severe neurological symptoms. The arthrotic changes of the medial atlantoaxial joint, which lead to the crowned odontoid, and the pseudospondylolisthesis (so called M. Junghanns) of the lumbar spine must also be mentioned. It is the aim of this paper, not only to explain and review the degenerative changes, but to illustrate the anatomy and pathology of the aging spine on the basis of macerated osseous specimens in order to make radiological investigations and pictures more understandable and clear.
Statistical analysis of human cadaver cervical spine compression experiments.
To quantify the cervical spine compressive injury threshold as a function of the person's age, gender, and external loading rate.
Results of epidemiologic studies have indicated that most survivors of cervical spinal cord injury have spinal column fractures and dislocations that result from a compression or compression-flexion force vector. Cervical spinal column injury thresholds are dependent on many factors. Delineation of the injury thresholds according to age, gender, and loading rate is necessary to improve clinical assessments and prevention strategies.
Twenty-five human cadaver head-neck compression tests were included in the analysis. Two statistical models were used to quantify the effects of age, gender, and loading rate on the force required to induce failure in the cervical spine. A multiple linear regression model provided a direct equation that quantified the effects of the variables, and a proportional hazards model was used to quantify probability of injury with each factor.
The regression model had a correlation coefficient of 0.87. There was an interactive effect between age and loading rate: Increasing age reduced the effect of loading rate and at approximately 82 years, loading rate had no effect. Men were consistently 600 N stronger than women. The 50% probability of failure for a 50-year-old man at a 4.5-m/sec loading rate was approximately 3.9 kN. Differences in probability curves followed the same trends as seen in the regression model.
The effects of age on cervical spine injury threshold are coupled with the rate of loading experienced through the external force vector that causes the trauma. Assessment of injury mechanisms and thresholds should be based on the person's age, gender, and loading rate to determine treatment and prevent injuries.
A study using a validated viscoelastic finite-element model of a L2-L3 motion segment to identify the load sharing among the passive elements at different loading rates.
To enhance understanding concerning the role of the loading rate (i.e., speed of lifting and lowering during manual material handling tasks) on the load sharing and safety margin of spinal structures.
Industrial epidemiologic studies have shown that jobs requiring a higher speed of trunk motion contribute to a higher risk of industrial low back disorders. Consideration of the dynamic loading characteristics, such as lifting at different speeds, requires modeling of the viscoelastic behavior of passive tissues. Detailed systematic analysis of loading rate effects has been lacking in the literature.
Complex flexion movement was simulated by applying compression and shear loads at the top of the upper vertebra while its sagittal flexion angle was prescribed without constraining any translations. The lower vertebra was fixed at the bottom. The load reached its maximum values of 2000 N compression and 200 N anterior shear while L2 was flexed to 10 degrees of flexion in the three different durations of 0.3, 1, and 3 seconds to represent fast, medium, and slow movements, respectively. The resisted bending moment, gross load-displacement response of the motion segment, forces in facet joints and ligaments, stresses and strains in anulus fibrosus, and intradiscal pressure were compared across different rates.
The distribution of stress and strain was markedly affected by the loading rate. The higher loading rate increased the peak intradiscal pressure (12.4%), bending moment (20.7%), total ligament forces (11.4%), posterior longitudinal ligament stress (15.7%), and anulus fiber stress at the posterolateral innermost region (17.9%), despite the 15.4% reduction in their strain.
Consideration of the time-dependent material properties of passive elements is essential to improving understanding of motion segment responses to dynamic loading conditions. Higher loading rate markedly reduces the safety margin of passive spinal elements. When the dynamic tolerance limits of tissues are available, the results provide bases for the guidelines of safe dynamic activities in clinics or industry.
An in vivo study of the toxic consequences of static compressive stress on the intervertebral disc.
To determine whether disc cell death is correlated with the magnitude and duration of spinal compressive loading.
Static compression in vivo has been demonstrated to induce cell death. Cell death, in turn, has been associated with disc degeneration in humans. There are currently no tolerance criteria for the intervertebral disc that combine both biomechanical and biologic factors, although both have been implicated in cases of accelerated degeneration.
Mouse tail discs were loaded in vivo with an external compression device. Compressive stress was applied at one of two magnitudes (0.4 and 0.8 MPa) for 7 days, and at one additional magnitude (1.3 MPa) for 1, 3, and 7 days. Midsagittal sections of the discs were stained for apoptosis using the TdT-dUTP terminal nick-end labeling (TUNEL) reaction. Quantal analysis was used to correlate the extent of cell death to the magnitude and duration of loading.
The probit transformation of the percentage of dying cells was proportional to the sum of the logarithmic transformations of the compressive stress and the time of loading.
The results of this study demonstrate the feasibility of developing a quantitative correlation between spinal loading and disc degeneration. Such a correlation may be coupled in the future to existing engineering models that predict spinal loading in response to physical exposures and lead to improved definition of the bounds of healthy and unhealthy spinal loading, and ultimately, refined guidelines for low back safety.
Mechanical testing of cadaveric lumbar motion segments.
To test the hypothesis that minor damage to a vertebral body can lead to progressive disruption of the adjacent intervertebral disc.
Disc degeneration involves gross structural disruption as well as cell-mediated changes in matrix composition, but there is little evidence concerning which comes first. Comparatively minor damage to a vertebral body is known to decompress the adjacent discs, and this may adversely affect both structure and cell function in the disc.
In this study, 38 cadaveric lumbar motion segments (mean age, 51 years) were subjected to complex mechanical loading to simulate typical activities in vivo while the distribution of compressive stress in the disc matrix was measured using a pressure transducer mounted in a needle 1.3 mm in diameter. "Stress profiles" were repeated after a controlled compressive overload injury had reduced motion segment height by approximately 1%. Moderate repetitive loading, appropriate for the simulation of light manual labor, then was applied to the damaged specimens for approximately 4 hours, and stress profilometry was repeated a third time. Discs then were sectioned and photographed.
Endplate damage reduced pressure in the adjacent nucleus pulposus by 25% +/- 27% and generated peaks of compressive stress in the anulus, usually posteriorly to the nucleus. Discs 50 to 70 years of age were affected the most. Repetitive loading further decompressed the nucleus and intensified stress concentrations in the anulus, especially in simulated lordotic postures. Sagittal plane sections of 15 of the discs showed an inwardly collapsing anulus in 9 discs, extreme outward bulging of the anulus in 11 discs, and complete radial fissures in 2 discs, 1 of which allowed posterior migration of nucleus pulposus. Comparisons with the results from tissue culture experiments indicated that the observed changes in matrix compressive stress would inhibit disc cell metabolism throughout the disc, and could lead to progressive deterioration of the matrix.
Minor damage to a vertebral body endplate leads to progressive structural changes in the adjacent intervertebral discs.
This review presents considerations regarding major cervical spine injury, including some concepts that are presently undergoing evaluation and clarification. Correlation of certain biomechanical parameters and clinical factors associated with the causation and occurrence of traumatic cervical spine injuries assists in clarifying the pathogenesis and treatment of this diverse group of injuries. Instability of the cervical column based on clinical and mechanistic perspectives as well as the role of ligaments in determining instability is discussed. Patient variables such as pre-existing conditions (degenerative disease) and age that can influence the susceptibility or resistance to injury are reviewed. Radiological considerations of major injuries including dynamic films, CT and MRI are presented in the diagnosis and treatment of cervical trauma. Specific injury patterns of the cervical vertebral column are described including attention to the relative mechanisms of trauma. From a biomechanical perspective, quantification of injury tolerance is discussed in terms of external and human-related variables using laboratory-driven experimental models. This includes force vectors (type, magnitude, direction) responsible for injury causation, as well as potential influences of loading rate, gender, age, and type of injury.
The present study had two aims: (1) To assess heart rate variability (HRV) along with non-specific autonomic measures (used in earlier studies), before and after two minutes of the head stand. (2) To compare changes in two categories of subjects, i.e., those who practiced the headstand in a traditional way (without any support) and those who used the support of the wall (a present day adaptation). The subjects were forty male volunteers (age range 19 to 36 years), with twenty subjects under each category. The following changes were significant after the practice, compared to values at baseline. (i) Both categories had an increase in the power of the low frequency component (LF) and a decrease in the high frequency component (HF) of the HRV spectrum, increased LF/HF ratio, and decreased heart rate. (ii) Subjects who practiced the head stand with the support of a wall showed reduced finger plethysmogram amplitude suggesting increased sympathetic vasomotor tone. (iii) Practicing the headstand without support was associated with an increase in the skin conductance level, suggestive of increased sympathetic sudomotor tone. Hence, both categories showed similar changes in the HRV components though changes in sympathetic vasomotor and sudomotor activity were different. These changes suggest sympathetic activation, irrespective of the method of practice.
Reports of cardiovascular responses to head-stand posture are lacking in literature. The results of the various responses, respectively, to the supine, erect, and head-stand posture, are as follows: heart rate/min 67, 84, and 69; brachial arterial pressure mm Hg 92, 90, and 108; posterior tibial arterial pressure mm Hg 98, 196, and 10; finger blood flow ml/100 ml min 4.5, 4.4, and 5.2; toe blood flow ml/100 ml min 7.1, 8.1, and 3.4; forehead skin temperature C 34.4, 34.0 and 34.3; dorsum foot skin temperature C 28.6, 28.2, and 28.2. It is inferred that the high-pressure-capacity vessels between the heart level and posterior tibial artery have little nervous control. The high-pressure baroreceptors take active part in postural adjustments of circulation. The blood pressure equating mechanism is not as efficient when vital tissues are pooled with blood as when blood supply to them is reduced.
man; heart rate; blood flow; skin temperature
Submitted on January 3, 1963
Metabolic cost to the human body of various postures has been assessed by many workers. The cost with the body in the topsy-turvy posture, or while “standing on the head,” has not been reported so far. Energy expenditure was calculated indirectly by estimating the amount of oxygen consumed while in a particular posture. A Benedict-type recording spirometer was used for this purpose. The subjects were six healthy medical students. The mean cost of standing on the head was determined to be 336 ml, or 1.62 kcal/min, and that of “suspension by the feet” to be 300 ml, or 1.44 kcal/min. The possible causes of increased consumption in relation to the “standing erect” posture are discussed.
Submitted on May 26, 1961
Yoga teachers and students often report that yoga has an uplifting effect on their moods, but scientific research on yoga and depression is limited.
To examine the effects of a short-term Iyengar yoga course on mood in mildly depressed young adults.
Young adults pre-screened for mild levels of depression were randomly assigned to a yoga course or wait-list control group.
College campus recreation center.
Twenty-eight volunteers ages 18 to 29. At intake, all participants were experiencing mild levels of depression, but had received no current psychiatric diagnoses or treatments. None had significant yoga experience.
Subjects in the yoga group attended two 1-hour Iyengar yoga classes each week for 5 consecutive weeks. The classes emphasized yoga postures thought to alleviate depression, particularly back bends, standing poses, and inversions.
Beck Depression Inventory, State-Trait Anxiety Inventory, Profile of Mood States, morning cortisol levels.
Subjects who participated in the yoga course demonstrated significant decreases in self-reported symptoms of depression and trait anxiety. These effects emerged by the middle of the yoga course and were maintained by the end. Changes also were observed in acute mood, with subjects reporting decreased levels of negative mood and fatigue following yoga classes. Finally, there was a trend for higher morning cortisol levels in the yoga group by the end of the yoga course, compared to controls. These findings provide suggestive evidence of the utility of yoga asanas in improving mood and support the need for future studies with larger samples and more complex study designs to more fully evaluate the effects of yoga on mood disturbances.
Injury biome-chanics of the human cervical column. Spine 15, 1031e1039 Jensen + MODEL Please cite this article in press as Sirsasana (headstand) technique alters head/neck loading: Considerations for safety
- N Yoganandan
- A Jr
- F Pintar
- R Hector
- J L Hector
- R Jensen
Yoganandan, N., Sances Jr., A., Pintar, F., 1990. Injury biome-chanics of the human cervical column. Spine 15, 1031e1039. 8 R. Hector, J.L. Jensen + MODEL Please cite this article in press as: Hector, R., Jensen, J.L., Sirsasana (headstand) technique alters head/neck loading: Considerations for safety, Journal of Bodywork & Movement Therapies (2014), http://dx.doi.org/10.1016/j.jbmt.2014.10.002
Yoga-m ım aṅs a (Lonavla
- Kuvalayananda
Kuvalayananda, 1924. Yoga-m ım aṅs a (Lonavla, Bombay).
Preliminary findings on the effect of load-carrying to the structural integrity of the cervical spine.
- Josaab M.
- Torode M.
- Rao P.V.