well.blogs.nytimes.com/.../
The better choice for human propulsion, he says, was the paddlelike deep-catch stroke, which actually produced more lift than sculling, along with a hefty dose of drag.
“All things being equal, our data show that the deep-catch stroke is far more effective,” Dr. Mittal says.
Exert from July Swimming Science Research Review on the article:
"This study suggests in freestyle and backstroke lift plays an integral part in propulsion, supporting the 'lift-based' theory. The findings in the study bring to light the importance of a straight line catch, to maximize force production. However, this limited study only analyzed a few swimmers, without indicating the event analyzed, questioning the validity of this study across all swimmers and distances (Mullen 2012)."
It's nice that the New York Times included a link to the original article but there are lots of questions in it.
First of all it isn't clear to me in the article that the thrust number they give is thrust in the direction of travel of the center of gravity of the swimmer.
Second, the thrust numbers for the sculling swimmers were lower but in one case the swimmers were the same speed, so the sculling swimmer had lower thrust but the same speed in the other case te sculling swimmer was MUCH faster.
Third, the introduction says that the movements of several swimmers were analyzed but the data table only shows one speed, one thrust etc, what happened to the data from the other swimmers.
Fourth, the swim speeds of the freestyle examples were VASTLY different, 1.2 vs 1.8 meters per second, 50% difference in speeds. For this application I don't think those are valid examples.
Fifth, was the thrust number average? peak? average for the length of the pull? Were the pulls different lengths?
There are so many questions there, I don't think anything can be made of the study one way or the other.
Exert from July Swimming Science Research Review on the article:
"This study suggests in freestyle and backstroke lift plays an integral part in propulsion, supporting the 'lift-based' theory. The findings in the study bring to light the importance of a straight line catch, to maximize force production. However, this limited study only analyzed a few swimmers, without indicating the event analyzed, questioning the validity of this study across all swimmers and distances (Mullen 2012)."
It's nice that the New York Times included a link to the original article but there are lots of questions in it.
First of all it isn't clear to me in the article that the thrust number they give is thrust in the direction of travel of the center of gravity of the swimmer.
Second, the thrust numbers for the sculling swimmers were lower but in one case the swimmers were the same speed, so the sculling swimmer had lower thrust but the same speed in the other case te sculling swimmer was MUCH faster.
Third, the introduction says that the movements of several swimmers were analyzed but the data table only shows one speed, one thrust etc, what happened to the data from the other swimmers.
Fourth, the swim speeds of the freestyle examples were VASTLY different, 1.2 vs 1.8 meters per second, 50% difference in speeds. For this application I don't think those are valid examples.
Fifth, was the thrust number average? peak? average for the length of the pull? Were the pulls different lengths?
There are so many questions there, I don't think anything can be made of the study one way or the other.
