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BIOMECHANIC ANALYSIS OF ARCHER ALIGNMENT

2.6 THE VERTICAL ANGLE AT THE DRAW HAND - ANGLE G

Now that we have looked at the archer, from above, and studied alignment laterally, or horizontally, let’s look at the critical angles from the front. This is the vertical alignment, and angles. Let’s start with Angle G, the vertical angle between the draw arm and the line of force. Figure 2.6-1 shows this angle in close up.

Here, just as with the horizontal angle C, the vertical angle between the line of force and the draw arm requires a displacement force. Depending upon how this force is applied, the response and the result is different.

If the archer holds this angle by letting the hand push up against the chin, the downward force is applied by the chin. In this case, at full draw, the arm is pulling up on the hand and it is held in place by the downward force of the chin (Figure 2.6-2). When the archer releases the string, the hand comes out from under the chin and the restraining force that held the hand down, and in place, is no longer applied. This permits the hand to come up under the pulling force. The result for these archers is that, upon release, the hand comes up to the cheek or the ear. (Figure 2.6-3)

The other method of supporting this angle, is to pull down with the draw arm using a moment about the elbow (Figure 2.6-4).

In this case, at full draw, there is a downward tension on the hand, that is cancelling the upward force by the arm. The hand is held in place by the string tension of the bow. For these archers, upon release, the restraining string tension is removed and the hand is free to move down under the pulling force of the moment about the elbow. The result for these archers is the familiar ‘chest thump’ release (Figure 2.6-5).

2.7 VERTICAL FORCES AT THE BOW HAND - ANGLE H

When an archer lifts the bow, he must support the mass weight of the bow with his bow arm. When the archer draws the bow there is a compressive force on the bow arm and, because of the angle H, there is also a slight lifting force on the bow hand. This supplemental lifting force allows the archer to reduce the lifting force applied by his bow shoulder and yet still support the mass weight of the bow.

The only adverse affect of this angle H is that, upon release, the supplemental lifting force is removed and the bow arm begins to drop. The greater this angle the greater the supplemental lifting force and the more significant the reduction in lifting force, upon release. Thus, the more corrective action must be made, or else, the more pronounced the drop.

TECHNICAL NOTE – Supplemental Lifting Force at the Bow Hand

For most archers, angle H is less than 5 degrees. Typical angles are between 2 and 4 degrees. This may sound like a trivial angle, but it means that for an archer pulling a 40 pound bow the supplemental lifting force will be between 1.5 and 3.5 pounds. This means that with a typical bow and stabilizer system weighing between 5 and 7 pounds, as much as half of the mass weight of the bow may be supported by the draw force of the bow.

3.0 DETERMINING THE OPTIMUM FORM

Now that we know what we want, and why, lets use it to determine an optimum form.

To summarize what we want to accomplish at each angle:

A – Angle at bow hand (horizontal) – Reduce as much as possible

B – Angle at Bow shoulder (horizontal)– reduce to 0 degrees

C – Angle at Draw hand (horizontal) – Reduce to 0 degrees

D – Angle at bow shoulder – Dependent

E – Angle at Bow Elbow – Dependent

G – Angle at draw hand (vertical) – Reduce to 0 degrees

H – Angle at bow hand (vertical) – maintain at 2-4 degrees

Looking at the various forms shown in Figure 3.0-1 we can see which forms accomplish what, and which ones are better than others.

Open Form:

The Open Form is immediately wrong. It is comfortable, but all of the critical angles - the angle at the bow hand, the bow shoulder and the draw hand – are at their worst. It does nothing to bring the archer in line, and, in fact, brings him out of line.

Open Trapezoidal Form:

The Open Trapezoidal Form is a great improvement over the Open Form, because it reduces these critical angles, but it does not eliminate any of the critical angles.

Basic Trapezoidal Form:

The Basic Trapezoidal Form eliminates the most critical angle – the angle at the draw hand. The 2 notable problems are: 1) the angle at the bow shoulder is not addressed, and 2) the angles D and E are relatively small. This gives the archer less power over his draw through the clicker.

Closed Form:

The Closed Form eliminates the critical angle at the draw hand, and it eliminates the angle at the bow shoulder. If well executed, angle A can be minimized also. Finally, the angles D and E are greater than in the Basic Trapezoidal Form. This makes it easier to pull through the clicker.

Figure 3.0-2 shows the archer form from the front. From the front all forms are the same. Angle G, the angle at the draw hand should be eliminated. Angle H, the vertical angle at the bow hand, needs to be kept to less than 4 degrees. If the angle becomes too great, the supplemental lifting force could actually exceed the weight of the bow, and require that the archer to be pulling down with his bow arm at the point of release.

4.0 THE WEDGE

All of this theoretical conversation brings us to the logically Closed Form, shown in Figure 4.0-1, A&B. The distinctive features in this form are that the bow arm and the shoulder line are perfectly in line (angle B = 0). Also, the draw forearm is in line with the line of force both horizontally and vertically (angle C = 0; angle G = 0). This puts the archer in a form that from overhead looks like a wedge.

5.0 SUMMARY

Figure 5.0-1 shows a comparison of the Open Form, the Basic Trapezoidal Form, and the Closed (Wedge) Form. Serious archers should avoid the Open Form. It’s comfortable but it has severe technical flaws in alignment, loading, and release, that work against the archer. In most cases, the more open the form, the more detrimental these flaws.

The Trapezoidal Form reduces many of these flaws. It has the advantage that for some archers, with particular physical dimensions, it can reduce the critical draw arm alignment angle to 0 degrees. However, it is still flawed bacause it leaves an angle between the bow arm and the shoulder line.

The Closed/Wedge Form is superior to the other Forms. It eliminates the critical alignment angles at the draw hand and the bow shoulder. With these angles all reduced, or eliminated, the archer is optimally aligned. Proper alignment eliminates many of the static and release flaws inherent in the standard and open forms.