I am shocked — shocked! — to learn that girls do indeed throw like girls:
Janet Hyde, a professor of psychology and women’s studies at the University of Wisconsin at Madison, has studied the gender gap across a broad spectrum of skills. She believes that men and women aren’t as different as they are often portrayed, and she has mined data on social, psychological, communication and physical traits, skills and behaviors to quantify the gap. After looking at 46 meta-analyses, Hyde found what she defined as a “very large” difference in only two skills: throwing velocity and throwing distance.
The throwing gap has been researched for more than half a century, and the results have been consistent. According to Jerry Thomas, dean of the College of Education at the University of North Texas in Denton, who did the throwing research Hyde cites in her paper, “The overhand throwing gap, beginning at 4 years of age, is three times the difference of any other motor task, and it just gets bigger across age. By 18, there’s hardly any overlap in the distribution: Nearly every boy by age 15 throws better than the best girl.”
Around the world, at all ages, boys throw better — a lot better — than girls. Studies of overhand ball throwing across different cultures have found that pre-pubescent girls throw 51 to 69 percent of the distance that boys do, at 51 to 78 percent of the velocity. As they get older, the differences increase; one U.S. study found that girls age 14 to 18 threw only 39 percent as far as boys (an average of about 75 feet vs. about 192 feet). The question is why.
The power in an overhand throw — and in a golf swing, a tennis serve or a baseball swing — comes from the separate turning of hips and shoulders. The hips rotate forward and the body opens, and then the shoulders snap around. Women tend to rotate their hips and shoulders together, and even expert women throwers don’t get the differential that men get. “The one-piece rotation is the biggest difference,” says Thomas. “It keeps women from creating speed at the hand.” Even when women learn to rotate hips and shoulders separately, they don’t do it as fast as men.
There doesn’t appear to be a muscular or structural reason for the difference.
(Hat tip to that notoriously misogynistic jock, Tyler Cowen.)