Principle of Horizontal and Vertical Force

Before we examine how this principle applies to archery, let us examine some of the other sports to get a good idea of the principles involved.

For instance, let us study a basketball player. To be able to create the maximum horizontal distance for a shot, a certain amount of vertical force has to be generated.

Based on data taken from Miller, S. and Bartlett, R, Journal of Sports Sciences, approximately 81% of the speed is generated by the upper body and 19% comes from extending the knee, hip and ankle. Even though only 19% of the ball speed is generated by using the legs, it will mean that less effort is required from the muscles of the shooting arm. If a shooter has to put less effort into the shot, it is more likely to be successful.

Similarly, in shot-put, most of the world top shot-putters now use a spinning motion coupled with a strong vertical force, generated by the rapid flexing of the legs, to generate maximum power. The more vertical force the shot-putter can generate, the more horizontal force is feasible, increasing the release angle closer to the optimum angle.

To illustrate the effect of vertical force and horizontal force, try running on soft sand. As the legs push against the sand to generate vertical force, the sand will give way and less horizontal force can be developed, resulting in less forward speed.

Basketball, shot-put, running and any other movement sports require a more dynamic balance in which the stability can easily be altered, while archery demands a more static balance, which has to be maintained throughout the shot. However, in archery too, being best biomechanically balanced will assist in establishing a sound technique with less muscular effort. Proper body positioning will create less tension in the body, allowing a steadier hold and aim, thereby producing a flowing shot.

It must therefore be recognized, that the pressure distribution of 60-70% on the balls of the feet and 40-30% on the heels is a very important component of the horizontal and vertical force distribution. Unfortunately, many Western archers are standing more on their heels and as such cannot achieve optimum stability.

A direct proportional relationship between horizontal and vertical forces in archery cannot be shown using force plates; however, with the right posture and balance, we can be stronger, develop forces more beneficially, thereby achieving greater stability.

Nevertheless, force plate analysis has shown that the movement of the center of gravity is much greater in lower level archers when compared to elite archers. This especially becomes evident on release. The elite archers were also shown to improve their stability during the last few seconds preceding the release, while in contrast, the lower level archers showed a significant difference in balance parameters already 4-6 seconds prior to and up to release.

Дата добавления: 2015-05-09