Distance divided by time equals speed. How fast something, or in this case, someone, moves across distance is based on speed. When we train athletes to increase speed, we're looking to increase stride frequency then stride length. The goal is to cover more distance on each stride, while increasing how often the athletes strides.
Often, during youth sports, the fastest players have the most success. They're the first ones to the ball. They're the best offensive threat. They're the greatest defensive helper. It can be difficult for a young athlete with decent skills to out perform the faster player. Even if the faster player has lesser skills, they often shine due to pure speed.
What kills speed?
Long distance, slow, plodding, jogging will absolutely destroy a young athlete's speed. Train slow, be slow. Train fast, be fast. We all have fast twitch and slow twitch muscle fibers, but most fibers are intermediate muscle fibers. The intermediate muscle fibers can be coarsened to act like fast twitch or slow twitch fibers based on training.
Another issue is that mechanics for sprinting and reacting quickly are very different than long slow distance. Hips flex and extend to greater ranges of motion. Arms drive. Foot contacts are powerful from the ball of the foot. We can't improve speed through jogging. There is little to no correlation.