need clarity

[tonester]

I was wondering if someone would please help me understand which leg is in eccentric contraction in the following excerpt. From the following article.

http://elitefts.com/documents/extreme_hamstrings.htm

"You must first understand the function of the hamstring and where the most stress is placed on the hamstring in order to correct and prevent injury. The hamstrings are a group of three posterior thigh muscles responsible for knee flexion and hip extension. During high-speed sprints, the hamstrings’ main role is to rein hip flexion and initiate hip extension.

Most hamstring injuries occur during the powerful eccentric contraction of the late swing phase.

This is when the front thigh is almost parallel to the ground during high speed sprinting. There is tremendous stress on the hamstring at this phase between the eccentric and concentric contraction."

Does he mean the front thigh that is parallel as written? Or is he using that as a mental image but meaning the leg that is in contact with the ground? I'm always a bit confused when it comes to knee flexion and hip extension duties of the hamstrings

Thanks so much.

[OldGuy]

If you look at the tempos I think you'll find your answer. The leg off the ground is at eccentric.

A little more details

[tonester]

A little late but thanks for the response and link.