Biomechanics of Yoga

Chair Person:Dr. Hemant BhargavAssistant Professor, Department of Integrative MedicineNIMHANS, Bangalore, India

Presented by:Mr. Suman BistaJRF, DST Project

Department of Integrative MedicineNIMHANS, Bangalore, India

• 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.

Introduction

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.

PosturesPosture 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.

TadasanaSiddhasana

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 CageOver-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.

Parivrtta TrikonasanaTrikonasana

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

Author, Year

Variables(Subjects)

Intervention outcome

Wang et al., 2016

functional performance,

flexibility,muscle

strength, andbalance

(Twenty older adults aged 70.7 ± 3.8

years)

biweekly 60-minute Hatha yoga classes for 32 weeks

16-week beginning phase (Series I) (Chair, Wall Plank, Tree, Warrior I, Warrior II, Downward Facing Dog, Side Stretch, Cobra, Bridge, and

Abdominal Cultivation)

16-week advanced phase (Series II) (Chair, Wall Plank, Tree, Warrior II, Side Stretch, Crescent, One-Legged

Balance, Recumbent Leg Stretch, Bridge, and Abdominal Cultivation)

Improvement in Functional Performance

• Improved timed chair stands (p < 0.01)• 8-foot up and go (p < 0.05)• 2-min step test (p < 0.05)• Vertical reach (p = 0.05) performance.

Improvement in Isometric knee flexor strength (p < 0.05) and repetitions of the heel rise test (p < 0.001)

Research Studies on Biomechanics of Yoga

Author, Year Variables(Subjects)

Intervention outcome

Wang et al., 2013

The lower-extremity net

joint moments of

force (JMOFs)obtained

during the performance

of poses.

(20 older adults:70.7 + −

3.8 years)

Two 60-minute yoga sessions

per week, for 32 weeks.

The yoga sessions comprise

following poses: Chair, Wall Plank, Tree, Warrior II,

Side Stretch, Crescent, and One-Legged

Balance.

• There was a significant main effect for pose, at the ankle, knee and hip, in the frontal and sagittal planes (p = 0.00 –0.03).

• The Crescent, Chair, Warrior II, and One-legged Balance poses generated the greatest average support moments JMOFs.

• Side Stretch generated the greatest average hip extensor and knee flexor.

• Crescent placed the highest demands on the hip flexors and knee extensors.

• All of the poses produced ankle plantar-flexor.• In the frontal plane, the Tree generated the greatest average

hip and knee abductor; whereas Warrior II generated the greatest average hip and knee adductor.

• Warrior II and One-legged Balance induced the largest average ankle evertor and invertor, respectively.

Author, Year

Variables(Subjects)

Intervention outcome

(Brenneman et al.,

2015

Electromyography (EMG), self-reported

pain and physical function, knee

strength, mobility, fitness, clinical gait

analysis, knee adduction moment

(KAM)

(Forty-five women over age 50 with

symptomatic knee osteoarthritis)

1 hour lower extremity strengthening yoga program comprising

quadriceps strengthening, squats,

lunges, postures including supine

bridges and heel raises 12-week (3 sessions per

week)

• Reduced pain (mean improvement

(p<0.001)

• Increased knee extensor strength (p =

0.004), Increased flexor strength (p = 0.001)

• Improved mobility on the six-minute walk

(p<0.001)

• Improved mobility on 30-second chair

stand (p = 0.006)

Author, Year

Variables(Subjects)

Intervention outcome

Lee et al., 2019

Soft tissue injury, axial non-bony injury, and bony injury

(66 patients with injuries

that were primarily caused by

yoga)

___________

(Retrospective study)

In the soft tissue group• 66 patients (74.2%) had mechanical myofascial pain due to overuse. • Rotator cuff injury was seen in 6 (6.7%).• Trochanteric bursopathy was observed in 1 (1.1%). In the axial group• Pain in degenerative joint disease (46 patients [51.7%]).• Facet arthropathy (n=34 [38.2%]) were observed. • Radiculopathy was seen in 5 patients (5.6%). In the bony injury category• Kyphoscoliosis was seen on imaging in 15 patients (16.9%) and

spondylolisthesis was present in 15 patients (16.9%). • 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, Year

Variables Intervention outcome

Kuntz et al., 2018

Pain, self-reported physical function

and mobility performance, knee

strength, depression, and health-related quality of life

(31 women with symptomatic knee

osteoarthritis)

Biomechanically-based yoga

exercises (YE) or traditional exercise (TE) or no-exercise

attention-equivalent control (NE) for 12 weeks,

three 1-hour sessions each week

• YE group demonstrated improvements in pain (p = 0.003]), intermittent pain (p = 0.009]) and self-reported physical function (p = 0.003]) compared to NE.

• Improvements in above outcomes were similar between YE and TE.

• TE demonstrated a greater improvement in knee flexor strength compared to YE.

• Improvements from baseline to follow-up were present in quality of life score for YE and knee flexor strength for TE,

• YE and TE demonstrated improvements in mobility

Author, Year

Variables Intervention outcome

Greendale et al., 2012

Health-related quality of life, anthropometri

cs; and biomechanical measures and

physical performance

tests

(Women and men aged

more than 65 years)

Yoga intervention, 2 days per week, one hour per

session, for 32 weeks

Series I: Chair, Wall Plank, Tree, Warrior II, Warrior I,

Downward Facing Dog, Side Stretch, Chair Twist,

Cobra, Bridge and Abdominal Cultivation.

Series II: Chair, Wall Plank, Tree, Warrior II, Crescent, One-Legged Balance, Side

Stretch, Chair Twist, Recumbent Leg Stretch, Bridge and Abdominal

Cultivation

• Development of a safe, effective and portable

yoga program for seniors: Yoga Empowers

Seniors Study (YESS) asana series

• The development is based on biomechanical

characteristics and physical performance.

• Modifications of postures are required for

seniors by the support of wall, chair, block etc.

• Yoga series should be in progressive module

(comparatively easy to difficult) with the time

line of practice.

Author, Year

Variables Intervention outcome

Pandit et al., 2020

Retrovesical angle (RVA), posterior

displacement (PD) and inferior

displacement (ID) of urethra by Diagnostic

ultrasound (DUS)

(15 female yoga teachers having

average age & years of yoga practice as 42.7 years & 7.33

years)

fast yogic breathing

maneuver (FYBM):

Bhastrika and Kapalabhati,

performed with and without

applying Moolabandha at a

speed of 20 and 120 strokes per

cycle

• Complicated labor and practice of power yoga

appeared to reinforce the impact of FYBM.

• The values of RVA as well as PD and ID significantly

dropped when FYBM was performed with

Moolabandha.

• Aging factor, uneventful vaginal labor, or obesity

could not confirm as prevailing risk factors.

• Moolbandha proved its protective behavior while

practicing Bhastrika and Kapalabhati by vulnerable

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.

Thank You