LEVERS & The Spine

The SPINE:

Curvatures of the spine (complement each other like inhalation and exhalation. It is therefore important to maintain the curvature of the spine).-otherwise functional imbalance, AGE-increases of decreases curvature due to gravity.

1. Cervical (concave)
2. Thoracic (convex)
3. Lumbar (concave)
4. Sacral (convex)

MAXIMIZING THE BENEFITS OF MOVEMENT AND BREATHING

1. Make the exhalation long emphasizing abdominal muscle contraction (steps)
1. Contraction of the lower abdomen
2. Upper part of the abdomen contracts
3. Chest relaxes only at the end of the exhalation
2. Inhalation is about expansion of the chest then down to the abdomen. Do not push the abdomen outward this will increase the curvature in the spine.

-Twisting and the spine (upward movement)

-Backbending and the spine (No lower back compression)

-Forward bending and the spine (belly lengthening)

-BASE/ROOT/GROUNDING

3. breathing can intensify a movement and get you deeper into a posture
1. holding: move deeper, intensify your breath
2. releasing, moving, relax your breath
3. inhale release a bit, exhale draws you deeper

MENTAL STEADINESS & BREATH (reducing rajas and tamas and increasing sattva)

a.     mental focus (Movement of the body or the flow of the breath, drishti)

b.     start your breath before you begin your motion (don’t move when breath is held) Maximizes the SUPPORT of the posture

c.     breath can exceed the movement in some cases

BIOMECHANICS OF ASANA

v gravity and muscle contraction

v muscle contraction occurs at the origin and insertion of the muscle

v Extension arises from external forces of pulling. Muscles cannot pull themselves, they can only push (contract)

v LEVER SYSTEMS (most movement of the body)

                                               i.     Fulcrum: point around which the rotation takes place

                                             ii.     Force: effort

                                            iii.     Weight: load

First order lever: Fulcrum between the effort and the load (E-F-L)

Second order lever: Load between the effort and the fulcrum (E-L-F)---mechanical advantage is favorable (door with hand away from hinges

Third order lever: Effort between the fulcrum and the load (F-E-L)---most parts of the body. The point of attachment of the muscles to the rigid bones (effort) is relatively close to the joint (fulcrum). The center of gravity determines the degree of load. (distal=larger, proximal=smaller)-load is further away from the fulcrum than the effort (insertion point of muscle). ENABLE GREATEST RANGE OF MOVEMENT

WORK = force exerted + distance of movement

If load is closer to the fulcrum the work to lift it is less, but it will move a smaller distance and visa versa (door example-3^rd order-hand close to hinges)

Muscles usually have to contract with greater force than the weight of the load because of this third order construction of the fulcrum of the body. SACRIFICE OF STRENGTH FOR A GREATER RANGE OF MOVEMENT.---in asana we alter the amount of load  and the distance of the load from the joint to create certain effects in movement (or emphasize them).

TORQUE (movement of force on joints which causes rotation and therefore movement)

How much force is necessary to cause an object to rotate. Body movement are mostly the function of the rotation of joints. For movement to occur torque (exerted effort) must exceed the load which includes the weight of our body and gravity. (and maybe a counterforce).

Torque must be applied in the proper direction: THE ANGLE OF THE APPLICATION OF FORCE IS VERY IMPORTANT.

---the larger the angles in the body (which to a great extent are pre-dertermined by our joint structure, the greater the effort, because the torque in minimal.

ASANA & LEVERS

a.     The further the load is from the joint, the greater the effort (force)

b.     Uttanassan-effort is greatest at 90 degree angle with arms extended and then load arm is longest

CENTER OF GRAVITY & SIZE OF BASE

Wider is less load, more difficult torque

A first-class lever has the axis (fulcrum) located between the weight (resistance) and the force (figure 1.21a). An example of a first-class lever is a pair of pliers or scissors. First-class levers in the human body are rare. One example is the joint between the head and the first vertebra (the atlantooccipital joint) (figure 1.21b). The weight (resistance) is the head, the axis is the joint, and the muscular action (force) come from any of the posterior muscles attaching to the skull, such as the trapezius.

In a second-class lever, the weight (resistance) is located between the axis (fulcrum) and the force (figure 1.22a). The most obvious example is a wheelbarrow, where a weight is placed in the bed of the wheelbarrow between the wheel (axis) and the hands of the person using the wheelbarrow (force). In the human body, an example of a second-class lever is found in the lower leg when someone stands on tiptoes (figure 1.22b). The axis is formed by the metatarsophalangeal joints, the resistance is the weight of the body, and the force is applied to the calcaneus bone (heel) by the gastrocnemius and soleus muscles through the Achilles tendon.

In a third-class lever, the most common in the human body, force is applied between the resistance (weight) and the axis (fulcrum) (figure 1.23a). Picture someone using a shovel to pick up an object. The axis is the end of the handle where the person grips with one hand. The other hand, placed somewhere along the shaft of the handle, applies force. At the other end of the shovel (the bed), a resistance (weight) is present. There are numerous third-class levers in the human body; one example can be illustrated in the elbow joint (figure 1.23b). The joint is the axis (fulcrum). The resistance (weight) is the forearm, wrist, and hand. The force is the biceps muscle when the elbow is flexed.