What makes a natural jumper? Sprinter? How can you be good at both? Every track and field coach during the first week is surveying their team and asking these questions. A lot of times simply watching them walk onto the track can give you all the information you need. I'm going to attempt to explain how I answer these questions in my program.
Athletes with a bias towards vertical jumping ability tend to walk with a bounce in their step. They toe-off vertically and you can see larger oscillations of their center of mass. When the athlete runs, their shin angles are usually more acute. The consequence of a toe-off movement and smaller shin angles is well developed calves coupled with elongated and stretchy tendons---especially the achilles. Often these athletes run with high back-side mechanics. Tight and/or weak hip flexors might have a big influence on their running mechanics. Most of their speed and spring is a result of the stretch shorting cycle.
In the weight room, jumpers can be picked out when they squat. Usually they have a tendency to squat or lunge with their knees more over their toes than ankles. Often they show instability and/or struggle with the hip hinge exercises. When these athletes perform lifts like straight leg deadlifts, dynamic hip bridges, etc. you'll notice them having trouble getting and/or holding full hip extension. They are still very strong and show good performances on lifts that focus on the quads.
Power sprinters tend to walk onto the track with less bounce. They don't exhibit much toe-off so you shouldn't see much bounce in their step. Don't let that fool you. When they get on the track their shin angles are usually a little more vertical and put more force into the ground producing The greater ground contact force along with better back-side mechanics makes them fast and usually faster than a jumper as their athletic careers develop.
Sprinters have rock solid squats. They sit back and are comfortable squatting with their knees over their ankles. Their power comes from their hips so they excel at big power movements like the deadlift and clean. Usually they have no trouble snapping off kettle bell swings, holding dynamic bridges, or stabilizing single leg SLDL's.
In my mind, the ideal track and field athlete is right in the middle of this continuum of quad or hip dominant. They exhibit both quad and hip dominate traits and excel at both jumping and sprinting. Ashton Eaton?