Athletic propulsion labs are a line of sports footwear designed to increase vertical leap in athletes. The footwear acts through a compressing and releasing action that mirrors the effect of a spring.
The shoes generate springing action through a special mechanism called "Load and Launch." This is a hard spine that runs through the middle of the sole and is connected to a plastic spring mechanism embedded in the toe of the shoe. As the athlete transfers weight from the heel of the foot to the toe, the features of the shoe increase responsiveness and bounce directly under the ball of the foot. The result, APL claims, is up to 3.5 extra inches of vertical elevation on a jump.