Someone who "throws like a girl" probably just has bad
footwork.
As
Lord Brawl noted previously in this node, in the act of throwing an object, one generates
power from the
shoulder,
abdominal and
leg muscles; one uses the
elbow and the
wrist for
accuracy.
This is all understandably
counter-intuitive for a
novice; throwing seems like something one does with the arm, but if you don't use the rest of your body, your throw will have little
distance.
In a proper throwing motion, one should step forward with the opposite foot just after
cocking the arm. While doing this, the thrower should twist
his/her torso a bit toward the throwing arm. Then, in the process of throwing the object, the person will naturally transfer his/her weight to the forward (opposite) foot during the forward throwing
motion and twist his/her body from right to left (for a
right-hander) during the follow-through. All this will add power.
Unfortunately, many people who haven't been taught how to throw properly try copying their peers and end up stepping forward with the
incorrect foot i.e., the right foot for a right-handed person. This will
definitely make you throw poorly and will look like a total
dork as well. I'd guess this is the real
genesis of the "throws like a girl" insult.