When accelerated from the rear, the Arrow and the Dart flex and store spring energy. This stored energy is then used to push away from the launching platform, whether the launching platform is the spur of the Atlatl or the string of the Bow. The mass of the projectile point, on either Dart or Arrow, influences the amount and rate at which energy is stored and released. The Atlatl and Dart and the Bow and Arrow are considered to be and defined as spring mass systems. And, related both physically and mathematically in nature and deceptively complex in their interpretation, they are both true weapons systems.
However, the Atlatl and Dart is the first true and natural weapons system of the human race, invented thousands of years before the Bow and Arrow and used longer by humans than any other weapon system yet developed. It was the Atlatl and Dart that first placed humans at the top of the food chain, ranking us above all other predators. It is, in fact, our natural ability to throw a projectile at prey that separates us from all other predators. Predators such as Lions, Tigers, and Bears run faster than humans and have sharp teeth and pointed claws, which we do not. Those are the attributes which make these predators successful. The Atlatl is the supreme expression of our natural ability to throw a projectile at a prey animal and is our advantage over all other predators, which makes us the supreme predator. And when humans used this weapon we did not take more from the environment than the environment could naturally replace itself. Thus, humans and nature, for thousands of years, were in balance with one another.
It can be argued that it was when the Bow and Arrow was developed and subsequently replaced the Atlatl that we humans began to deviate from our natural condition and take more from the environment than the environment could naturally replace itself. The Bow and Arrow was a more efficient technology for what we felt at the time to be a better life, but it in fact turned into the never-ending arms race, which continues today. For thousands of years when humans used the Atlatl we were in harmony with nature; what would our environment be like today if we had never progressed beyond that technology?