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
I take your point that the velocity graph doesn't tell us the complete story with regard to the magnitude of the propulsive and resistance drag, only what the net difference between the two is.
That said, it still seems to me that if maximum velocity occurs when the hand is straight out front and minimum when it comes even with the shoulder you must be slowing down in the period between these points. That implies that resistance drag is greater than propulsive forces during this period. That means that if this portion of the stroke is the most propulsive it is also the highest drag and that drag is winning out in this phase, thus the deceleration.
Meanwhile going from the slowest point, as the hand enters into the rear quadrant, to the fastest point, where it exits the water, implies that speed is increasing throughout this period, i.e. propulsive forces are greater than resistance forces. It may well be that the upper arm is causing a lot of resistance drag but this is outweighed by the propulsive force generated by the forearm and hand, and possibly the lower part of the upper arm.
It's interesting that good freestyle swimmers have their minimum velocity at the point the hand passes the shoulder because it implies that they aren't achieving net propulsion until this point, despite presumably having an early vertical forearm, thereby giving a clue as to how early EVF occurs. It's only a clue though as we don't know the drag profile.
What would be really interesting would be to see the velocity profile for someone doing catchup drill, then we could separate out the contributions of the two arms.
I take your point that the velocity graph doesn't tell us the complete story with regard to the magnitude of the propulsive and resistance drag, only what the net difference between the two is.
That said, it still seems to me that if maximum velocity occurs when the hand is straight out front and minimum when it comes even with the shoulder you must be slowing down in the period between these points. That implies that resistance drag is greater than propulsive forces during this period. That means that if this portion of the stroke is the most propulsive it is also the highest drag and that drag is winning out in this phase, thus the deceleration.
Meanwhile going from the slowest point, as the hand enters into the rear quadrant, to the fastest point, where it exits the water, implies that speed is increasing throughout this period, i.e. propulsive forces are greater than resistance forces. It may well be that the upper arm is causing a lot of resistance drag but this is outweighed by the propulsive force generated by the forearm and hand, and possibly the lower part of the upper arm.
It's interesting that good freestyle swimmers have their minimum velocity at the point the hand passes the shoulder because it implies that they aren't achieving net propulsion until this point, despite presumably having an early vertical forearm, thereby giving a clue as to how early EVF occurs. It's only a clue though as we don't know the drag profile.
What would be really interesting would be to see the velocity profile for someone doing catchup drill, then we could separate out the contributions of the two arms.
