In this post, I put up a very interesting article by Geoff Fong from http://sfldbt.wordpress.comon Body lean. Although quintessential, is it necessary? Read the article to find out.
Body Lean
How
far does a paddler need to lean forward with their trunk to get a
long pull? How much lean is needed for a strong pull? Probably
not as much as you’d think.
What
propels the boat? The paddlers.
How
do paddlers propel the boat? They use their paddles.
Like
I’ve mentioned in previous posts, the paddle blade is the business
end. Skillful paddlers can impart both great work and control
to their paddle blade as it moves through the water. Remember
that work is defined as
force over a distance. Pulling the paddle faster through the
water requires greater force. The limits of human
arthrokinematics and equipment leverage along with a paddlers
physical strength determine some max value for work. It
probably looks like a bell-curve. A paddler is only as strong
as they are at that moment, but paddling technique has everything to
do with paddling efficiency to reach the peak of that bell curve.
If
you’re thinking of paddling from the perspective of how a paddle
interacts with the water, the goal becomes how to move your body in a
way that applies max leverage to the paddle through some optimum
amount of paddle travel/displacement. Several things happen
when a paddler leans all the way down to the gunnel:
-
They
lose reach at the paddle blade resulting in a shorter pull. While
it’s true that full lean to the gunnel may put the outside/bottom
hand at its farthest forward distance from the bench, it doesn’t
mean the same for the paddle blade (the business end). Full
lean takes away from our spinal mobility. When your joints are
taken to a maximum range in one direction, it becomes more and more
difficult to move in other directions. In this case, full trunk
flexion takes away from rotation. Try sitting in a chair,
leaning forward and rotating your trunk to either side (don’t hurt
yourself). Now sit up straight and rotate in place. You
can probably rotate farther sitting up than curled over. Decreased
trunk rotation during the reach puts both hands at a similar distance
from the bench, making a more vertical paddle angle on the entry,
cutting actual reach at the paddle blade.
-
They
have less strength.
Leaning forward fully during the reach puts most muscles used in
paddling on full or very stretched position. Glut max,
hamstrings, lumbar extensors, lat dorsi, teres major, deltoids,
rhomboids/mid and lower trapezei are out of their optimum zone for
force production. Your muscles are happiest and strongest in
their mid-range. For a simple example, think of curling a heavy
weight. It’s tough to start the lift from elbow fully
extended and, when you’re fatigued, most folks struggle to get the
weight all the way up to finish the rep (elbow fully flexed). This
is because 90 deg of elbow bend is about the middle of the elbow
flexor muscle length (and coincidentally the joint angle of about the
most mechanically efficient line of pull).
- They are slower paddlers. Sitting up from a fully reached position on a pull requires bringing up your whole trunk. This takes a lot of time and energy because your trunk is a long lever arm. Think of a long pendulum and how it swings slower than a short one (or takes much more force to swing faster than a short pendulum). Slower movement sets paddling rate limitations. When you’re racing fast, the water moves fast and you need to be able to move your paddle faster than the water to exert force on it. Using a slow body movement like trunk flexion and extension will cap your ability to hold a faster rate to meet fast hull speeds.
The
short answer is it depends. The long answer is that there is no
one answer and it depends. (ha)
I
am an advocate for a paddle stroke that has minimal trunk
flexion/extension during the stroke and relatively more degrees of
rotation. My reason is that rotation allows for the paddle
blade to get more positive on the catch and set the blade more
forward than a negative/neutral angle, which increases the length of
pull (possibly allowing more work to be performed). Rotation is
also mechanically more efficient for generating force to the paddle
because the distance of your shoulders to your spine is less than the
distance of your shoulders to your hips (shorter torque arm for
rotation means less of a mechanical disadvantage compared to hip
hinging alone). One thing I am not a
proponent of is sitting straight up and paddling. It sets your
shoulders way above the water line and, with it, your paddle
resulting in less water contact and a shorter pull. It also
makes you work harder to resist the forces against the paddle (trunk
as a long lever arm resisting paddle force at 90 degrees is the most
mechanical disadvantage you can face).
I’ve
never really paddled OC, but the stroke generally seems much more
constrained than the typical dragon boat technique being used by
local rec teams. Part of the reason for less body excursion and
more paddle movement is for energy conservation, which makes sense to
me with OC’s racing for many miles. I can see how allowing
*some* increased trunk excursion may be desired in DB because the
power gains may outweigh the need for energy conservation when you’re
racing for sub 2 minutes or a 100-500 meter race.
On
a side note, I think this is one of the reasons why senior/masters
level teams can do as well/better than some youth teams is because
masters paddlers may have 1) better water “feel” 2) physically
less ability to flex their hips/spines so default to more rotation 3)
better strength from a longer history of resistance training.
Credit to http://sfldbt.wordpress.com
