Transition Phase (Drive Phase)

The connection between acceleration and top speed

The transition phase, often called the Drive Phase, is the delicate period where the athlete must negotiate the biomechanical shift from the inclined starting position to the vertical posture of maximum speed.

This phase does not occur in a single step; it is a gradual process that can last between 20 and 40 meters, depending on the athlete's power.

The most common mistake in novices is to "jump" to the upright position immediately after the start (the "pop-up" effect). This cuts off acceleration prematurely.

The coach should teach the athlete to be patient and allow the body to unwind naturally.

The goal is to maintain trunk lean while progressively increasing stride frequency and stride length.

The vertical shin indicator

How do we know when to end the push-off phase and begin the transition to vertical? The key biomechanical indicator is the angle of the shin on impact with the ground.

During the first few steps (0-10 meters), the shin strikes the ground at a positive angle.

However, around the seventh step, the shin begins to land vertically (perpendicular to the ground). This is the inflection point.

When the shinbone becomes vertical, it is no longer biomechanically possible to continue to apply large horizontal forces without falling.

At this point, the athlete must begin to shift his or her focus from "pushing back" to "hitting down," gradually elevating the hips and torso with each subsequent step

Progressive hip elevation

During this transition, the visual instruction to the athlete is not "lift the head", but "lift the hips".

If the athlete lifts the head first, the trunk will suddenly straighten, breaking aerodynamics and the line of force. The head should be kept in line with the spine.

As the speed increases, the vertical forces generated against the ground act to raise the center of mass.

The athlete should feel his hips rise stair by stair with each stride until the maximum height is reached.

Only when the hips are high a