Quote Originally Posted by Sharla
I can see you are well read on the subject but to be honest I'm not and I'm not completely sure I understand. I would have thought that if you did decide to aim to hit with your middle knuckle you could do that regardless of whether or not your fist is vertical or horizontal?

The only person I know who jabs with their palm not finishing facing down had a bad shoulder injury from rugby and modified his punch to avoid turning his shoulder and bodyweight into it. Poor guy is still unable to get back into it the way he'd like to.
THE POWER LINE RUNS FROM EITHER SHOULDER-STRAIGHT DOWN THE LENGTH OF THE ARM TO THE FIST KNUCKLE OF THE LITTLE FINGER, when the fist is doubled. Remember: The power line ends in the fist knuckle of the little finger on either hand. Gaze upon your "pinky" with new respect. You might call that pinky knuckle the exit of your power line- the muzzle of your cannon.

You'll understand the power line if you feel it out.

Stand up. Walk toward a wall until you're at arm's length from the wall when facing it. Put your heels together. You should be standing just far enough from the wall so that you can barely touch it with the tip of the middle finger of your right hand-at a point directly opposite your chin. Touch that chin-high point with your middle-finger tip.

Now, move back three or four inches, but keep the heels together.

Double your right fist firmly. In making a fist, close the fingers into the palm of the hand, and then close the thumb down over the outside of the fingers (Figure 5).

Extend the fist at arm's length toward the spot on the wall-only toward it. The fist should be upright, as if you were holding a stick running from ceiling to floor. The little knuckle is down, toward the floor.

With your arm stiffly extended, let your body sway slowly forward-without moving the feet-until your fist (still upright) is pressed so firmly against the chin-high spot on the wall that your fist and stiff arm are supporting the weight of your leaning body (Figure 6).

Note that the lower part of your fist (still upright)- particularly the little knuckle-provides the natural, solid end of the firm, straight line-from shoulder to fist-that is supporting your weight. Note particularly that this line runs unswervingly through your wrist to the little knuckle (Figure 7).

Now, with your upright fist still supporting your weight at the chin-high spot, try to shift your pressure from the little knuckle to the upper knuckles. Then turn your fist so that the palm of your hand is down. When you attempt those changes, you should feel immediately that both new pressure position of your fist "lack" the "solidity" of the first position. And you should feel and see that a change in position "swerved" the "power line" at the wrist - putting your wrist in a hazardous landing position.

Keeping your feet in the same position, go through the same procedure with your left fist. You'll find the "power line" in the same location - straight from the shoulder through the little knuckle. But, where would the power line be if you wished to lower your fist and punch at a man's stomach?

You can answer that by testing a spot on the wall just opposite of your own solar plexus - the vital body target just below the end of the breast bone. In making the lower test, sway forward from the same standing position - with either fist - toward the solar-plexus spot. But, before you sway, turn your fist palmdown so that the knuckles will be parallel to the ceiling when you press your fist against the wall. The power line still runs solidly through the little knuckle. Now that you have felt out the power line, you can appreciate that the greatest possible solidity would be achieved if you landed every punch with the little knuckle first.

Unfortunately, however, the hand-bone behind the little knuckle is the most fragile of the five backbones. It can be broken the most easily. You must not attempt to land first with the little knuckle. Instead you must try to land first with the knuckle next to your pinky (the ring finger). We'll call that the 2nd knuckle. Aiming with the 2nd knuckle usually brings about a three-knuckle landing. Those three-knuckles are: middle, second (ring) and pinky. If you aim with the second knuckle, those three knuckles usually will land together because the average fist slopes slightly from the middle knuckle to the pinky. Such a three-knuckle landing not only prevents the hand-bone behind any one knuckle from bearing all the punch-shock, but it also permits punching almost exactly along the power line. Rarely will one of those knuckles make a solo landing. But if you aim with the little knuckle, you risk a dangerous solo landing on forehead or blocking elbow.

Always aim with the second knuckle-the one next to your pinky-and LET THE OTHER KNUCKLES TAKE CARE OF THEMSELVES. They'll take care of themselves all right; for the shape of the fist makes it impossible for them to do otherwise.

Clench your right fist and inspect its knuckles. Your thumb knuckle is "out of the way"-completely separated from your row of four knuckles on the striking edge of your fist. More than that, your thumb knuckle is farthest away from your pinky knuckle-farthest away from the end of the power line. Nature took care of that. Never double-cross nature by trying to hit with that thumb knuckle, under any circumstance. It breaks easily. Keep it out of the way.

The knuckle of your index finger (the one next to the thumb) is fairly prominent, but not as prominent as the knuckle of your middle finger. In some face-punches and in most body-blows, that index knuckle will land with the other three, for a four-knuckle landing. That's okay, let the index knuckle come along for the ride. Under no circumstances, however, try to land first with that index knuckle. If you do, you'll not only break your power line, but you may also break your wrist.

Beware likewise of trying to land first with the prominent middle knuckle-the source of most hand injuries. Such aiming will slant your hand off the power line and, at the same time, endanger the middle knuckle and its hand-bone. When that middle knuckle makes a solo landing, its prominence prevents the other knuckles from helping to absorb some of the punch-shock. That shock or pressure is terrific in any full-fledged punch, particularly when you nail an opponent with a head blow just as he is stepping into you. In that split-second, your fist must withstand the shock-pressure of an explosive collision between two hurtling body-weights.

Let me repeat: If your punch is landed correctly, in power-line fashion, the three knuckles-pinky, second and middle-will share the pressure and distribute it over the three hand-bones behind the knuckles. That lessens the chance of bruising or crushing any one knuckle, or of fracturing any one hand-bone.[/size][/size]