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
Again, Gary, thanks for the very helpful discussion. I got back in the water just over two years ago and basically had to relearn freestyle. I found just what you said, that pulling straight back from the initial entry with a high elbow, trying to "anchor" the forearm into the water, then keeping the elbow away from the side in the back half of the stroke is more efficient for me. However the upper arm needs to move during the stroke, mechanically there is no other way. To minimize drag, I could see keeping your upper arm pointed ahead might help, but to accelerate your "anchor" you need to move your upper arm in a way that will maximize the force you can exert. Ian Thorpe does this beautifully, as does Grant Hackett -- both are very efficient and delay moving their upper arms to the side during their pull.
Your statement about the release is what I suspected, that you should sweep your hand out (have it act like a wing again) and slide it out of the water.
From a fluid mechanics standpoint, it is the difference in velocity that causes drag forces that both allow and inhibit your movement through the water. In a solid, the force is proportional to displacement, in a fluid the force is proportional to velocity. So generating hand speed (and, mechanically, arm speed) while minimizing form drag by good body position should provide the highest peak speed. Great! Now I need to figure out how to swim more than 50 yards ...
I'll look forward to further myth-busting!
Right you are. People tend to get the propulsive drag force confused with the frontal drag, both acting at the same time. Hand/forearm speed and surface area are what generate the propulsive drag force (propulsive power). Like in many cases in swimming, reaching the optimal position of the arm underwater involves compromise between power and frontal drag. More on this to come. Thanks for your input.
Gary
Again, Gary, thanks for the very helpful discussion. I got back in the water just over two years ago and basically had to relearn freestyle. I found just what you said, that pulling straight back from the initial entry with a high elbow, trying to "anchor" the forearm into the water, then keeping the elbow away from the side in the back half of the stroke is more efficient for me. However the upper arm needs to move during the stroke, mechanically there is no other way. To minimize drag, I could see keeping your upper arm pointed ahead might help, but to accelerate your "anchor" you need to move your upper arm in a way that will maximize the force you can exert. Ian Thorpe does this beautifully, as does Grant Hackett -- both are very efficient and delay moving their upper arms to the side during their pull.
Your statement about the release is what I suspected, that you should sweep your hand out (have it act like a wing again) and slide it out of the water.
From a fluid mechanics standpoint, it is the difference in velocity that causes drag forces that both allow and inhibit your movement through the water. In a solid, the force is proportional to displacement, in a fluid the force is proportional to velocity. So generating hand speed (and, mechanically, arm speed) while minimizing form drag by good body position should provide the highest peak speed. Great! Now I need to figure out how to swim more than 50 yards ...
I'll look forward to further myth-busting!
Right you are. People tend to get the propulsive drag force confused with the frontal drag, both acting at the same time. Hand/forearm speed and surface area are what generate the propulsive drag force (propulsive power). Like in many cases in swimming, reaching the optimal position of the arm underwater involves compromise between power and frontal drag. More on this to come. Thanks for your input.
Gary
