Draw length is that one small vital component of bow set up that many archers, whether beginner or pro alike, are often overlooked and are wrongly done especially by beginners.
What Happens When The Draw length is Too Short or Too Long?
Improper draw length, whether too short or too long, causes the accuracy of shooting to suffer because they make us shoot in flawed stances.
How Changes in The Draw Length Affect Your Accuracy As Well
Shorter draw length affects your body position since our elbow has to bend to compensate for the shorter draw length. And any change in the body position specifically shoulders, arms, or heads will cause our accuracy to suffer.
In the case of draw length that is too long, our bow arm is forced to overextend when we shoot. Overextended bow arm messes up our anchor point and degrades our accuracy.
Should the Elbow Be Bent or Straight?
I’m not saying it is not possible to shoot with a bent elbow and achieve a fantastic result. A few worlds champions like Levi Morgan shoots with a bent elbow. However, generally speaking, the best form to shoot is the straight but unlocked elbow.
Why is that?
Try to put your palm against a wall and lean against it with both of your arms straight — this position makes use of skeletal strength, now bend your elbow — this position makes use of muscular strength, and compare which position feels comfortable the most for you.
The straight position, right?
It is recommended to shoot using skeletal strength (straight joints) than muscular strength (bending joints).
There are at least three problems that entail shooting with joint bents.
The first problem is you have to shoot with the same amount of bend everytime you shoot.
Second, If your elbow is bent, you would have to use biceps and triceps muscles to hold the bow steady.
The prolonged use of these muscles will tire out the muscles and cause inconsistency in the amount of bend in your elbow which further causes the draw length to become inconsistent too and therefore affecting your shooting accuracy.
And third, bad shooting form will make us get fatigue quickly after only a few shots, and after quite a while, your muscles might well sustain injury caused by strained muscles.
How to Determine Your Draw Length?
There are several methods to measure your draw length. The fastest method you can do right away, but not the most accurate, is the wingspan method.
1. The Wingspan Method
The wingspan method requires us our back to the wall and our arms spread out. Then we measure the span of our arms from the longest fingertip to the longest fingertip.
Once you have the number, put that number into these two formulas:
- Draw length = (wingspan-15)/2
- Draw length = wingspan/2.5
For example, let’s say your measurement is 71″, from the first formula you will get 71″ minus 15 = 56. 56/2 = 28″.
From the second formula, you’ll get 71″ divided by 2.5 = 28.4.”
As you can see from both formulas, you get 28″ to 28.4″ draw range.
These numbers are “close enough” for most archers, but not exactly accurate since many factors could affect the exactness of the numbers such as your anchor, the type of release aid that you use, different hand types and the likes.
However, they give you a good starting point.
2. Using a Draw Check Bow
The second method is to visit your local archery store and ask them to measure your draw length. They will use a tool called a draw check bow — by far this is the most accurate method to measure your draw length.
A draw check bow is a fiberglass bow with a very light draw weight that has an arrow attached to the string. The arrow acts as a measurement tool and is marked in quarter-inch increments.
All you have to do just draw the bow back until you reach a full draw. The staff or the owner of the archery store will then read the measurement on the arrow to determine your draw length.
3. Using a Traditional Bow
The third method is to use a traditional bow with very light draw weight. Similar to how we use the draw check bow above, first we need to do full draw and hold at anchor.
Ask someone to put an arrow on the string (preferably blunt arrow) then make a mark on the arrow shaft at the point where it passes the far side of the arrow shelf.
The length from the bottom of the nock groove to the marked point is your draw length.
The Correlation Between Draw Lengths and Arrow Speed
You may remember back in school we learn that speed = distance/time.
The distance in the equation is the distance between the belly of the bow and the string (equaled draw length).
The time is the time it takes for any given bows to travel from draw to brace. The time remains constant no matter how far the draw length is. How is that possible?
The concept of time is related to a frequency of one’s object. Frequency is the time needed for one object to complete a single vibration. The frequency (or the time) it takes to complete one single vibration always remains constant.
In the case of a bow, a vibration is a single movement from any draw length to its unbraced brace point. Take a look at a tuning fork for example.
Taping a tuning fork harder or gentler doesn’t make the frequency higher or lower, the rate of frequency always the same.
In the equation above, distance (or draw length) is the only factor that continually changes. Since the time always stays the same, we can conclude that the higher the distance (draw length), the greater the speed needed that means longer draw length leads to greater arrow speed and faster arrow.
This concept becomes important when you use an adjustable bow; some bows allow you to adjust the draw lengths by removing a few screws or moving a few parts.
For instance, when you compete in a 3D archery tournament, there may be some occasions when you need to increase your arrow speed.
You can do that by adding an extra inch of draw length to your bow. An extra inch of draw length will increase the arrow speed by 5-10fps.