I recently posted these 10 myths on some triathlon websites and stirred up some good conversation. So here I go again.....
Myth #1 To go faster in swimming one must push out the back of the arm pull.
I believe this myth may have originated with an article that appeared some time in the 90's. The article showed a swimming figure mimicking Alex Popov's freestyle pull. It showed the figure with the left arm in front and the the right arm in back ready to exit the water for the recovery. A graph showed the velocity of Popov's body in the water as a function of the position of the hand. The velocity ranged from nearly 3 meters per second down to about 1.4 meters per second during a single pull cycle. The slowest speed occurred when the hand appeared to be at around the shoulder and the fastest speed occurred in the position shown in the figure. The author erroneously concluded that since the speed was so high as the right hand was about to exit, that this is where the most power must be....hence push out the back.
My study with the velocity meter doing freestyle concurs that it is these two positions that consistently show the highest and lowest velocities of the stroke cycle in freestyle (though I was seeing more like a 30 to 40% drop, not 50%). But it is not because of the power out the back that we see the speed highest in this position. It is because it is by far the position of least drag (most streamlined). The propulsive power in this position actually is derived mostly from the left arm out in front and the kick, with little or no power coming from the end of the arm pull. The propulsive power may be even greater when we see the hand at the shoulder (slowest body speed), but because the arm is jetting straight out, perpendicular to the body, the drag coefficient skyrockets and our speed drops instantly.
The harm that is done by pushing out the back is that it delays the recovery and slows the stroke rate. Most of the arm propulsive power is derived from the entry to the shoulder (called the front quadrant....about 1/2 of the total arm cycle time is spent there). So the sooner one can get the hand back to the front quadrant after leaving the shoulder, the better.
If you happened to be blessed with Mercury motors for legs, like Michael Phelps, Ian Thorpe, Gary Jr, Natalie Coughlin etc, then you can afford to use a slower stroke rate...but hold in front, not in back.
For the rest of us mortals, keep your arms moving faster and in the front quadrant. Think you can't do that for a 1500? Think again. Lot's of distance swimmers use high arm stroke rates. You just have to train that way and get fit.
Regards,
Gary Sr.
The Race Club
Parents
Former Member
That's all well and good, but what I am not so sure I accept is the explanation Gary proposes for those velocity changes in terms of propulsion vs drag.
I don't accept the "no brainer" analogy of pushing off a wall with a perpendicular arm, vs the drag that same arm exerts during swimming. During the arm cycle, is the arm truly moving forward (creating reverse drag) relative to the surrounding water? Put pressure sensors (or some such) on the forearms and check.
Let me be clear that I agree that the front quadrant is where much of the propulsion comes from, and that a higher turnover creates more velocity. That is clear from watching sprinters. What is less clear -- to me at least -- is if a higher turnover is the most energy-efficient way to swim a distance event. This is why the question of drag is important.
The upper arm is truly moving forward during nearly the entire underwater pull and is responsible for most of the frontal drag of the arm/hand combination. You can test this yourself by taping a streamer (like on a bicycle handle) to your upper arm and one to your wrist, then film yourself underwater from the side. You will see the streamer on the upper arm floating to the back while the one on the wrist changes from floating backward to forward once the hand reverses direction. The increase in frontal drag caused by the protruding upper arm moving forward is extremely high.
If you want to test the difference in drag that simply changing the arm position makes, kick 25 meters hard with fins on, one arm in front and the other pointing straight down. Now do the same with the arm bent 90 degrees and to the side. Same arm, same surface area... a lot less drag with the bend. Changing the shape of your arm changes the drag coefficient.
Gary Sr.
That's all well and good, but what I am not so sure I accept is the explanation Gary proposes for those velocity changes in terms of propulsion vs drag.
I don't accept the "no brainer" analogy of pushing off a wall with a perpendicular arm, vs the drag that same arm exerts during swimming. During the arm cycle, is the arm truly moving forward (creating reverse drag) relative to the surrounding water? Put pressure sensors (or some such) on the forearms and check.
Let me be clear that I agree that the front quadrant is where much of the propulsion comes from, and that a higher turnover creates more velocity. That is clear from watching sprinters. What is less clear -- to me at least -- is if a higher turnover is the most energy-efficient way to swim a distance event. This is why the question of drag is important.
The upper arm is truly moving forward during nearly the entire underwater pull and is responsible for most of the frontal drag of the arm/hand combination. You can test this yourself by taping a streamer (like on a bicycle handle) to your upper arm and one to your wrist, then film yourself underwater from the side. You will see the streamer on the upper arm floating to the back while the one on the wrist changes from floating backward to forward once the hand reverses direction. The increase in frontal drag caused by the protruding upper arm moving forward is extremely high.
If you want to test the difference in drag that simply changing the arm position makes, kick 25 meters hard with fins on, one arm in front and the other pointing straight down. Now do the same with the arm bent 90 degrees and to the side. Same arm, same surface area... a lot less drag with the bend. Changing the shape of your arm changes the drag coefficient.
Gary Sr.
