Strother SX-1

Strother SX-1

Using the Above Table:

Kinetic Energy:  (in foot-pounds) This is the energy that actually goes into propelling the arrow. Basically it is the energy that is left over from the stored energy after all of the bow system friction is accounted for.
 
Stored Energy:  (in foot-pounds) When you draw the bow you supply power/energy into the limbs. The amount of energy that the limbs can hold is known as the stored energy.
 
Efficiency Rating:  (in %) This is the amount of the stored energy (in %) that can be successfully transferred into propelling the arrow upon release. The bow design, including limbs, limb pockets, cam systems, and axle types play into the bow’s efficiency. An example would be a sealed ball bearing in the idler wheel verses a simple unsealed rod bearing. It takes more energy to rotate the unsealed rod bearing (more friction) verses the sealed ball bearing (less friction) so more of the bow’s potential energy is used. The end result is a lower efficiency rating because less stored energy is left over to propel the arrow.
 
Power Stroke: This is the actual distance that the archer moves the string from its resting position to full draw

Using The Above Graph:

The area under the graph signifies the amount of energy stored by the system from brace height to full draw (power stroke). The shape of the curve is generated by a plot of draw weight in pounds against draw length in inches and gives an indication of how the bow will feel when drawn. The more rounded the curve the more "smooth" the feel of the draw cycle, however, if the curve is "squared-off" it will likely feel more aggressive. The trade off comes in performance, as the more aggressive curve is generally indicative of more stored energy and more speed.