The triple extension emphasized in the rear support phase involves which joints?

The triple extension emphasized in the rear support phase involves which joints?

• A. Hip, knee, and ankle
• B. Shoulder, elbow, and wrist
• C. Ankle, knee, and hip
• D. Knee, ankle, and spine

Answer: (A)

Triple extension in sprinting is the coordinated extension of three lower-limb joints to push off the ground and generate forward propulsion. In the rear support phase, the stance leg is behind the body's center of mass, and propulsion comes from extending the hip, knee, and ankle in a synchronized way. The hip extends to drive the thigh backward, the knee straightens to lengthen the leg, and the ankle plantarflexes to press the ground away as you rise. This combination creates the powerful forward impulse needed to move into the next phase of the sprint. The other joints listed aren’t part of this propulsion sequence. Upper-body joints like the shoulder, elbow, and wrist contribute to balance and arm swing, but the push-off propulsion relies on the hip, knee, and ankle. The spine isn’t the primary driver of this triple extension in the rear support phase.

Triple extension in sprinting is the coordinated extension of three lower-limb joints to push off the ground and generate forward propulsion. In the rear support phase, the stance leg is behind the body's center of mass, and propulsion comes from extending the hip, knee, and ankle in a synchronized way. The hip extends to drive the thigh backward, the knee straightens to lengthen the leg, and the ankle plantarflexes to press the ground away as you rise. This combination creates the powerful forward impulse needed to move into the next phase of the sprint.

The other joints listed aren’t part of this propulsion sequence. Upper-body joints like the shoulder, elbow, and wrist contribute to balance and arm swing, but the push-off propulsion relies on the hip, knee, and ankle. The spine isn’t the primary driver of this triple extension in the rear support phase.