Using only a lifting (concentric) phase for strength training exercises could also be more effective for improving vertical jump height than traditional, stretch-shortening cycle exercises under load, for two reasons. Firstly, using only a lifting phase involves faster rate of force development through higher rate coding, and this may increase high-velocity strength more over the long-term. Secondly, doing stretch-shortening cycle exercises under load *might* cause the tendons to increase stiffness to a greater extent. This would make the muscle lengthen more in the countermovement phase of a jump, and thereby reduce muscle force for a given countermovement depth.
“There aren’t many people in the world who can [dunk], that’s why it has this allure, I guess,” Carter told me last fall, during his first training camp with the Grizzlies. “As far as trying to do it, there are so many ways people can go about it. The approach you’re taking is the right approach. When I was younger, that’s how I started. Tennis ball, to the point that it became easy. Then a volleyball. Then a girls’ ball. Finally I took—it was like a dodgeball. I dunked that and said, ‘You know what, I’m gonna try it.’ Next thing you know. . . .” He shrugged and smiled, the gray whiskers on his jaw sinking into a dimple.
The simplest method to measure an athlete's vertical jump is to get the athlete to reach up against a flat wall, with a flat surface under his/her feet (such as a gym floor or concrete) and record the highest point he/she can reach flat-footed (the height of this point from the ground is referred to as "standing reach"); fingertips powdered with chalk can facilitate the determination of points touched on the wall. The athlete then makes an effort to jump up with the goal of touching the highest point on the wall that he or she can reach; the athlete can perform these jumps as many times as needed. The height of the highest point the athlete touches is recorded. The difference between this height and the standing reach is the athlete's vertical jump.