A long fin can sometimes reduce the full potential of a workout. The large surface area gives a great amount of forward propulsion, allowing the swimmer to move with little effort. Long fins are useful in many ways during training, but the long blade fin is not always the best option for creating muscular endurance. Zoomers demand a faster kick rate and a higher intensity than the longer fins. The Z2 Zoomers are designed with a shorter blade that allows hyper flexion and encourages even smaller and faster kicks. This movement strengthens the hamstrings and glutes over time. Often swimmers will discount the force of the up-kick and only limit their focus on the force of the down-kick. To develop an efficient kick, a swimmer must give the same force to both directions of the kicking motion. The “flex box” found on the bottom of the Z2 helps to catch the water, in order to work on the up-kick.