Which statement is true about the hamstrings in sprinting?

Which statement is true about the hamstrings in sprinting?

• A. It crosses two joints
• B. It crosses three joints
• C. It crosses one joint
• D. It crosses no joints

Answer: (A)

Bi-articular muscles cross two joints, and the hamstrings do exactly that: they cross both the hip and the knee. This arrangement lets them help extend the hip to drive the leg forward while also bending (flexing) the knee, coordinating the rapid movements in a sprint. The hamstrings originate on the pelvis (ischial tuberosity) and insert on the tibia and fibula, so they pass over the hip and knee joints, not the ankle. In sprinting, they work eccentrically in late swing to control knee extension and prepare for foot strike, then contribute to propulsion by their hip-extending action as the leg moves into stance. Because they span two joints, the statement that describes them as crossing two joints is the true one, whereas crossing three joints would require the ankle as well, which they do not.

Bi-articular muscles cross two joints, and the hamstrings do exactly that: they cross both the hip and the knee. This arrangement lets them help extend the hip to drive the leg forward while also bending (flexing) the knee, coordinating the rapid movements in a sprint. The hamstrings originate on the pelvis (ischial tuberosity) and insert on the tibia and fibula, so they pass over the hip and knee joints, not the ankle. In sprinting, they work eccentrically in late swing to control knee extension and prepare for foot strike, then contribute to propulsion by their hip-extending action as the leg moves into stance. Because they span two joints, the statement that describes them as crossing two joints is the true one, whereas crossing three joints would require the ankle as well, which they do not.