Final answer:
Proper alignment in sprinting involves ankle plantar flexion, knee extension, hip extension, and a neutral pelvis. These components work together to facilitate balance, stability, and the transfer of energy for effective sprinting performance.
Step-by-step explanation:
Proper alignment of the rear leg and pelvis during sprinting is essential for optimal performance and injury prevention. This alignment includes ankle plantar flexion, which is the foot movement at the ankle where the heel is lifted off the ground or the toes are pointed downward. Knee extension occurs when the leg straightens, engaging posterior cruciate ligament stabilization. Hip extension involves moving the thigh backward, which is crucial for powerful stride generation. Maintaining a neutral pelvis is important for balance and force transmission throughout the sprinting motion.
For instance, a sprinter maximizes power during the brief time their foot is in contact with the ground. As illustrated in Figure 7.1, pushing back hard on the track generates a reaction force propelling the sprinter forward. The muscles work extensively to balance the body, particularly during high-speed activities like sprinting, where efficient energy transfer and stability are key. Proper alignment ensures the runner remains stable while the foot pushes against the track, allowing for a powerful and effective stride.