Australian Yoga Journal - April 2016

When a muscle like the biceps contracts
concentrically, a signal from the central
nervous system prompts the thick myosin
fi laments to catch hold of nearby thinner
actin fi laments, forming linkages called
cross-bridges. If the pull is strong enough
to overcome opposing resistance (usually
from the force of gravity), the actin stra
slide between the myosin fi laments and
muscle shortens—in this case, pulling u
your forearm.
A similar thing happens during an
isometric contraction, except the force
generated by the myosin cross-bridges
exactly matches the opposing resistance
so there is no movement and your arm
stays fi xed.
And, if the resistance is greater than
the force the muscle generates, such as
what happens to the biceps when lower
from a pull-up, the biceps muscle will
be stretched, producing an eccentric
contraction that allows your arm to
lengthen with control. Scientists don’t y
fully understand this process, but it app
that during an eccentric contraction, some
myosin cross-bridges continue to latch onto
actin fi laments, while others are pulled apart.
Perhaps surprisingly, muscles generate
more force eccentrically than concentrically,
meaning you can lower a heavier weight
than you can lift. You can use this principle
to build strength by focusing on lowering
movements. For instance, controlling the
descent from Plank Pose to Chaturanga will
eccentrically contract and strengthen your
triceps, while pushing back up to Plank is a
concentric contraction of your triceps.
Because eccentric contractions produce
more force than concentric ones, they also
put more stress on muscles. If you’re not
used to it, eccentric exercise can damage
muscle proteins, triggering delayed-onset
muscle soreness, or DOMS—usually at
its worst one to two days after a tough
workout. While DOMS may be annoying,
it is rarely serious. Your muscles adapt by
becoming stronger after a bout of DOMS
so the next time you do the same routine,
you’re less likely to be sore.
Another caveat about eccentric exercise:
It may also stress tendons, the connective
tissue that binds muscles to bones.
Repeatedly overloading your tendons in
this way without allowing for recovery
increases your risk of tendon damage, or
tendinopathy, a painful condition that can
interfere with your practice. Due to their
slow metabolic rate, tendons recover
gradually; once tendinopathy develops, it
can take months for full recovery.

But that doesn’t mean you should avoid

eccentric exercise. In fact, strengthening

your muscles eccentrically will help build

stronger, more resilient muscles and

tendons that are less likely to get injured

in the future—as long as you allow them

to adapt slowly. In fact, physical therapists

frequently use eccentric exercises to rehab

injured tendons.

Exploring the entry into Side Crane

Pose (above) will help you understand

how to use eccentric contractions wisely in

your yoga practice.

OUR PROS An NYC–based yoga teacher and

Feldenkrais practitioner, Joe Miller teaches

anatomy and physiology trainings for yoga

teachers and students around the world.

Learn more at joemilleryoga.com. Model

Lindsay Gonzalez (breatheonboard.com)

is a teacher at Kindness Yoga in Denver,

where she helps run their 200-hour yoga

teacher trainings. She also offers SUP

yoga trainings and international retreats.

The transition into an arm balance like Side Crane Pose can be scary. There is a very real

risk of falling onto your head, given that one arm is supporting most of your weight.

Eccentrically engaging your triceps will allow you to come into the pose safely and with

control, avoiding a painful face plant.

Squat with your feet and knees together, then twist your upper body to the right, bringing

your left upper arm against the outside of your right knee. Place your hands on the floor

alongside your right thigh, shoulder-width apart. As you shift your weight forward onto

your hands, lift your feet. Imagine that you are pressing the floor away with your hands.

This will keep your triceps eccentrically engaged as your elbows bend, controlling how far

your head lowers toward the floor.

When you find your balance, your triceps muscles will work isometrically to keep

you there. However, at the sweet spot where your upper and lower body exactly

counterweight each other—like the two arms of a scale—your triceps won’t need to do

much. If you sense yourself falling forward, lightly press the floor away with your fingers,

concentrically contracting your triceps to return to the balance point. Eventually, as you get

even stronger, you can work toward straightening your elbows by further concentrically

engaging your triceps.

Use eccentric contractions in

Parsva Bakasana (Side Crane Pose)

81

april 2016

yogajournal.com.au