Biomechanics of Yoga

Presented by: Chair Person: Mr. Suman Bista Dr. Hemant Bhargav JRF, DST Project Assistant Professor, Department of Integrative Medicine Department of Integrative Medicine NIMHANS, Bangalore, India NIMHANS, Bangalore, India Introduction

• Biomechanics involves:

• study of the structure, function, and motion of the mechanical aspects of biological systems.

• study of the effects of internal and external forces on the human body is called biomechanics.

• Mechanical principles applied to the study of biological functions is called biomechanics.

• Bones, Joints, Muscles, Ligaments, Tendons, Nerves etc. play equally important role in biomechanics of human body.

• The application of mechanical laws to human body while practicing yoga posture is called biomechanics of Yoga. Different types of joint Joint Movements Muscle

• There are about 640 muscles in human body. • There are three types of muscle tissue: cardiac, smooth, and skeletal. • Skeletal muscles are attached to bones, allowing body to move. • Joints move because skeletal muscles contract and move them. • Skeletal muscle is responsible for the movement of joints in asana. Group Action of Muscles

Agonists: Group of muscles which contract to provide the force required to produce the movement.

Antagonists: These muscles oppose the action of agonists and relax progressively for permitting the movement.

Synergists: These groups of muscles work with agonists to provide a suitable activity and facilitates the movements

Fixators: These muscles stabilize the bones of origin of the agonists and increases their efficiency for production of movement. Bones, Joints, Muscles, Ligaments, Tendons, Nerves etc. work together to produce movement in human body. Anatomical Directions and Planes Movement on Frontal plane Movement on Sagittal plane Movement on Transverse plane Stretching

Cyclic stretching: A relatively short-duration stretch force that is repeatedly but gradually applied, released, and then reapplied

Ballistic stretching: A rapid, forceful intermittent stretch, that is, a high speed and high intensity stretch

Mechanical stretching: Using equipment to stretch and increase joint ROM.

Manual stretching: External force applied by therapist to move the involved body segment slightly beyond the point of tissue resistance and available ROM.

Neuromuscular inhibition techniques: these proceduces reflexively relax tension in shortened muscles prior to or during stretching. Postures Posture is the attitude assumed by the body Postures may be either Active or Inactive There are basically three categories of postures in Yoga • Cultural: for physical fitness, specially by stimulating and relaxing different groups of muscle

• Relaxing: for relaxation, specially before and after cultural postures • Meditative: for meditation (mental fitness), generally sitting and stable

Cultural posture Meditative posture Relaxing posture Muscular positions in Yoga Postures

Ekapada Rajakapotasana Biomechanics of Muscles

All movements are shaped by force of gravity. In Padahastasana: • Hamstrings, gluteus muscles and erector spinae are extensors of hip joint not flexors. • They act to create flexion of hip by letting go with gravity to control downward movement. • It’s lengthening contraction of hip extensors and erectors In Virabharadrasana II: • Partially bent but stabilized knee • The antagonist must release at the same rate that the agonist contracts. Padahastasana Virabhadrasana II Biomechanics of Vertebral Column

• Biomechanics call it a kinetic chain (connected chain of moving parts).

• It is designed for both movement and stability.

• Stability is created by tripod stool in each vertebra (Intervertebral disc and two facet joints).

• In vertical pose like Tadasana and siting in Siddhasana, maintaining the natural curve will create most stability.

• Range of movement of each vertebral segment is determined by intervertebral discs.

• Direction of movement is determined by angle of facet joints. Siddhasana Tadasana Biomechanics of Cervical Column

• Joints between skull and C1 allows only flexion and extension (Yes Joint)

• C1-C2 joint allows flexion, extension, & rotation (No Joint)

• 50% of rotation on cervical spine comes from C1-C2 joint.

• Apex of extension is at C4 and apex of flexion is at C5

• Rolling head and neck around in a circle is a non-anatomical movement.

• The cervical joints are not ball and socket joints like the shoulder joints.

Biomechanics of Thoracic Spine & Rib Cage Over-flattening of natural kyphosis (sometimes, happens because of the practice of wrong posture) • Practitioner lift sternum with the intention of opening the chest • After years of practice, the spine loses some of its natural curve Side bending and rotation occur to the opposite side except the movement are begun in flexion. • In Trikonasana performed to right, the thoracic spine & cage rotate to left (toward ceiling) • In Parivrtta Trikonasana, if you rotate first before flexing, the natural side bending will be to opposite side. • Bending forward first then rotate to Parivrtta trikonasana is under the law of movement of thoracic spine. Trikonasana Parivrtta Trikonasana Biomechanics of Lumbar Spine

• Significant movements allowed in this region are flexion and extension.

• 50% of all the movements of flexion allowed in entire vertebral column is created in lumbar spine.

• Out of that, 75% created in L5-S1 joint.

• Abdominal muscles and organs are highly responsible for the limitation of extension in lumbar spine.

• The facets in this region allow for almost complete free range of extension.

• Rotation of the lumber spine is quite limited (10 degrees).

• It may seem like you are rotating from lumber spine in Ardha Matsyendrasana, but it’s not true.

• Here too, side bending and rotation occur to the opposite side (as in Trikonasana). Ardha Matsyendrasana Biomechanics of Sacrum

• Primary function of sacroiliac join is stability.

• Some passive joint movements occur here.

• When you bend your lumber spine back (as in Ustrasana), sacrum passively moves anteriorly.

• When you bend forward (as in Padahastasana), sacrum moves posteriorly.

• These coordinated movements are called lumbo-sacral rhythm. Padahastasana Ustrasana Biomechanics of Hip Joint

• The gluteus maximus is a hip extensor.

• The gluteus maximus has a secondary action of external rotation as well.

• It extends the hip joint and externally rotates it at the same time.

• In back bending poses like Dhanurasana & Chakrasana, feet and knees goes out instead of being straight ahead.

• By pressing the knees toward each other, you can activate adductor muscles.

• This neutralizes the external rotation component of the gluteus maximus Dhanurasana

Chakrasana Biomechanics of Knee Joint and Legs

• One of the misconception about the knee joint is that it acts as a hinge.

• Instead, the knee moves with a rolling and gliding action during flexion and extension.

• During extension, the femur rolls backward on, while tibia glides forward on femur.

• During flexion, the femur rolls forward, while tibia glides backward.

• During flexion, femur rotates slightly externally on the tibia (its healthy unlocking mechanism).

• The rotation happens at front knee joint in Parsvakonasana, Virabhadrasana I & Virabhadrasana II Virabhadrasana I Biomechanics of Ankle and Foot

• In Normal ankle joint, there is approximately 45 degrees of planter flexion.

• Dorsiflexion is limited to approximately 20 degrees.

• Dorsiflexion is also limited by tightness in Achilles tendon, gastrocnemius and soleus muscles.

• The supination movement of ankle is quite free and can be overdone in poses like Padmasana.

• Extreme supination easily can lead to sprain of lateral collateral ligaments of ankle.

• Pronation is much less free than supination in ankle joint.

• Eversion of the foot often accompanies pronation of the ankle. Padmasana Biomechanics of shoulder joint

• Biceps muscle is elbow flexor and also a shoulder flexor.

• The strongest action performed by biceps is supination of forearm.

• Biceps action will be easier in Viparitakarani as biceps will have mechanical advantage (supination of forearm).

• Most significant aspect of movement in shoulder joint is the glenohumeral rhythm.

• The gleno-humeral rhythm involves scapula, humerus & clavicle.

• The gleno-humeral rhythm accompanies shoulder flexion and abduction while performing yoga postures. Viparitakarani Biomechanics of Elbow Joint and Forearm

• Common positional faults of elbow joint in yoga asana practice is hyperextension of elbow.

• The condition refers the relationship between humerus and ulna on extension of the joint.

• Hyperextension occurs when elbow is extended past the angle of 180 degrees.

• Another positional fault at elbow joint is called carrying angle, more common in women.

• When elbows are inside the straight line during full extension with supination, carrying angle is present.

• Increased carrying angle contributes to the instability of elbow joint.

• Over stretch on elbow joint should be avoided while practicing asana. hyperextension of elbow

carrying angle Biomechanics of Wrist and Hand

• Under normal circumstances, the wrist and hand are not weight bearing structure.

• But in asana practice, they sometimes bear weight in poses like Chaturanga Dandasana.

• By strengthening forearm muscles & by paying attention to alignment, they can be kept healthy.

• One should pay attention to the placement of hands on floor in weight bearing.

• One should be careful in the poses like Bakasana and mayurasana. Bakasana Research Studies on Biomechanics of Yoga

Author, Variables Intervention outcome Year (Subjects)

Wang et functional biweekly 60-minute Hatha yoga Improvement in Functional Performance al., 2016 performance, classes for 32 weeks flexibility, • Improved timed chair stands (p < 0.01) muscle 16-week beginning phase (Series I) • 8-foot up and go (p < 0.05) strength, and (Chair, Wall Plank, Tree, Warrior I, • 2-min step test (p < 0.05) balance Warrior II, Downward Facing Dog, • Vertical reach (p = 0.05) performance. Side Stretch, Cobra, Bridge, and (Twenty older Abdominal Cultivation) Improvement in Isometric knee flexor adults aged strength (p < 0.05) and repetitions of the 70.7 ± 3.8 16-week advanced phase (Series II) heel rise test (p < 0.001) years) (Chair, Wall Plank, Tree, Warrior II, Side Stretch, Crescent, One-Legged Balance, Recumbent Leg Stretch, Bridge, and Abdominal Cultivation) Author, Year Variables Intervention outcome (Subjects) Wang et al., The lower- Two 60-minute • There was a significant main effect for pose, at the ankle, 2013 extremity net yoga sessions knee and hip, in the frontal and sagittal planes (p = 0.00 – joint per week, for 32 0.03). moments of weeks. • The Crescent, Chair, Warrior II, and One-legged Balance force (JMOFs) poses generated the greatest average support moments obtained The yoga JMOFs. during the sessions • Side Stretch generated the greatest average hip extensor performance comprise and knee flexor. of poses. following poses: • Crescent placed the highest demands on the hip flexors and Chair, Wall Plank, knee extensors. (20 older Tree, Warrior II, • All of the poses produced ankle plantar-flexor. adults: Side Stretch, • In the frontal plane, the Tree generated the greatest average 70.7 + − Crescent, and hip and knee abductor; whereas Warrior II generated the 3.8 years) One-Legged greatest average hip and knee adductor. Balance. • Warrior II and One-legged Balance induced the largest average ankle evertor and invertor, respectively. Author, Variables Intervention outcome Year (Subjects)

(Brennem Electromyography 1 hour lower extremity • Reduced pain (mean improvement an et al., (EMG), self-reported strengthening yoga 2015 pain and physical program comprising (p<0.001) function, knee quadriceps • Increased knee extensor strength (p = strength, mobility, strengthening, squats, fitness, clinical gait lunges, postures 0.004), Increased flexor strength (p = 0.001) analysis, knee including supine • Improved mobility on the six-minute walk adduction moment bridges and heel raises (KAM) 12-week (3 sessions per (p<0.001) week) • Improved mobility on 30-second chair (Forty-five women over age 50 with stand (p = 0.006) symptomatic knee osteoarthritis) Author, Variables Intervention outcome Year (Subjects) Lee et al., Soft tissue In the soft tissue group 2019 injury, axial ______• 66 patients (74.2%) had mechanical myofascial pain due to overuse. non-bony • Rotator cuff injury was seen in 6 (6.7%). injury, and (Retrospective • Trochanteric bursopathy was observed in 1 (1.1%). bony injury study) In the axial group • Pain in degenerative joint disease (46 patients [51.7%]). (66 patients • Facet arthropathy (n=34 [38.2%]) were observed. with injuries • Radiculopathy was seen in 5 patients (5.6%). that were In the bony injury category primarily • Kyphoscoliosis was seen on imaging in 15 patients (16.9%) and caused by spondylolisthesis was present in 15 patients (16.9%). yoga) • Anterior wedging was seen in 16 (18.0%) • Compression fractures were present in 13 (14.6%).

The poses that were most commonly identified as causing the injuries involved hyperflexion and hyperextension of the spine. Author, Variables Intervention outcome Year Kuntz et al., Pain, self-reported Biomechanically- • YE group demonstrated improvements in pain (p = 2018 physical function based yoga 0.003]), intermittent pain (p = 0.009]) and self- and mobility exercises (YE) or reported physical function (p = 0.003]) compared performance, knee traditional exercise to NE. strength, (TE) or no-exercise • Improvements in above outcomes were similar depression, and attention- between YE and TE. health-related equivalent control • TE demonstrated a greater improvement in knee quality of life (NE) for 12 weeks, flexor strength compared to YE. three 1-hour • Improvements from baseline to follow-up were (31 women with sessions each week present in quality of life score for YE and knee symptomatic knee flexor strength for TE, osteoarthritis) • YE and TE demonstrated improvements in mobility Author, Variables Intervention outcome Year

Greendale Health-related Yoga intervention, 2 days • Development of a safe, effective and portable et al., 2012 quality of life, per week, one hour per anthropometri session, for 32 weeks yoga program for seniors: Yoga Empowers cs; and Seniors Study (YESS) asana series biomechanical Series I: Chair, Wall Plank, measures and Tree, Warrior II, Warrior I, • The developmentis based on biomechanical physical Downward Facing Dog, characteristics and physical performance. performance Side Stretch, Chair Twist, tests Cobra, Bridge and • Modifications of postures are required for Abdominal Cultivation. seniors by the support of wall, chair, block etc. (Women and men aged Series II: Chair, Wall Plank, • Yoga series should be in progressive module more than 65 Tree, Warrior II, Crescent, (comparatively easy to difficult) with the time years) One-Legged Balance, Side Stretch, Chair Twist, line of practice. Recumbent Leg Stretch, Bridge and Abdominal Cultivation Author, Variables Intervention outcome Year

Pandit et Retrovesical angle fast yogic • Complicated labor and practice of power yoga al., 2020 (RVA), posterior breathing displacement (PD) maneuver (FYBM): appeared to reinforce the impact of FYBM. and inferior • The values of RVA as well as PD and ID significantly displacement (ID) of Bhastrika and urethra by Kapalabhati, dropped when FYBM was performed with Diagnostic performed with Moolabandha. ultrasound (DUS) and without applying • Aging factor, uneventful vaginal labor, or obesity (15 female yoga Moolabandha at a could not confirm as prevailing risk factors. teachers having speed of 20 and average age & years 120 strokes per • Moolbandha proved its protective behavior while of yoga practice as cycle practicing Bhastrika and Kapalabhati by vulnerable 42.7 years & 7.33 years) women Courtesy for Images: • Ann Swanson, 2019 • Judith Hanson Lasater, 2009 • Leslie Kaminoff, 2007

References • Brenneman, E. C., Kuntz, A. B., Wiebenga, E. G., & Maly, M. R. (2015). A yoga strengthening program designed to minimize the knee adduction moment for women with knee osteoarthritis: A proof-of-principle cohort study. PLoS ONE. https://doi.org/10.1371/journal.pone.0136854 • Greendale, G. A., Kazadi, L., & Mazdyasni BS, S. (2012). The Yoga Empowers Seniors Study (YESS): Design and Asana Series. Journal of Yoga & Physical Therapy. https://doi.org/10.4172/2157-7595.1000107 • Kuntz, A. B., Chopp-Hurley, J. N., Brenneman, E. C., Karampatos, S., Wiebenga, E. G., Adachi, J. D., … Maly, M. R. (2018). Efficacy of a biomechanically-based yoga exercise program in knee osteoarthritis: A randomized controlled trial. PLoS ONE. https://doi.org/10.1371/journal.pone.0195653 • Lee, M., Huntoon, E. A., & Sinaki, M. (2019). Soft Tissue and Bony Injuries Attributed to the Practice of Yoga: A Biomechanical Analysis and Implications for Management. Mayo Clinic Proceedings. https://doi.org/10.1016/j.mayocp.2018.09.024 • Pandit, U. N., Pakhale, H., & Bellare, B. (2020). Protective Role of Moolabandha While Practicing Bhastrika and Kapalabhati by Women Vulnerable to Bladder Dysfunction: A Preliminary Ultrasound Study. International Journal of Yoga. • Wang, M. Y., Greendale, G. A., Yu, S. S. Y., & Salem, G. J. (2016). Physical-Performance Outcomes and Biomechanical Correlates from the 32- Week Yoga Empowers Seniors Study. Evidence-Based Complementary and Alternative Medicine. https://doi.org/10.1155/2016/6921689 • Wang, M. Y., Yu, S. S. Y., Hashish, R., Samarawickrame, S. D., Kazadi, L., Greendale, G. A., & Salem, G. (2013). The biomechanical demands of standing yoga poses in seniors: The Yoga empowers seniors study (YESS). BMC Complementary and Alternative Medicine. https://doi.org/10.1186/1472-6882-13-8 Knowledge of biomechanics is essential to perform postures correctly & to avoid injuries.

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