Not ever having boxed, I learned to hit the speed/punching bag by watching other Karate-kas. The people I learned from would hit the bag with almost unmodified Karate punches, thrown from a guard covering the head down to the rib cage. The only differences was that these would be "lighter", with no all- out muscle contraction and force, as well as somewhat shortened. This made sense to me, in that if the purpose of the exercise is to speed up a particular movement, one needs to practice that very same movement repeatedly and at speed.
Now, watching footage of boxers in training, the way they "punch" the bag leaves me scratching my head. What I've repeatedly seen boxers do is raise their elbows to where they're practically level with their fists, then stike the bag in what I can only describe as a sort of horizontal hammer fist (tetsui). Also, the striking point seems to the edge of the fist closer to the pinky knuckle, instead of the knuckles themselves.
So here's my question: Is there some counter-intuitive reason why the way boxers do it is more effective in developing hand speed for real world strikes than just hitting the darn bag the way you'd hit an opponent in the first place? confused
Just when you think something is foolproof, they come out with a new and improved type of fool.