If the upper body and arm movement is dialed in it will be much easier to hit the proper positions with the lower body. Remember, the goal of sprinting is to provide maximum vertical force to the ground.
In order to achieve that force, the pelvis or hips should be neutral (not tilting forward or backwards). This will create a stretch across the hip flexor muscles during the stride. Similar to the stretch of the arms, this will allow for an elastic return of the thigh to the front side of the body.
To sprint fast you need to have the foot land directly underneath the center of mass. Think of stepping over the knee and driving the foot straight down into the track.
Longer strides should be the result of applying more force to the ground which will automatically propel you forward.
Many athletes make the mistake of trying to cover more ground by lengthening their stride. This is a mistake and should avoided at all costs.
Over-striding or “reaching” is a killer when it comes to sprinting. The reason is because when you reach out for a longer stride you are going against your inertia. It’s like putting on the brakes every time your foot hits the ground.
Each stride will also be less powerful if it lands in front of the body. You won’t be in a position to fully utilize the strength of the quads and gluteus muscles. Reaching also puts unnecessary stress on the hamstrings.
Instead focus on pushing down to the track or ground with a neutral pelvis. Watch where the foot lands in relation to the body in the video below. Both athletes have a great stride length without reaching.