Neanderthal no more question

[Beginner]

Are hamstrings shortened or lenghtened during lordosis?

NNM suggest everyday hamstring stretch, while exrx.net suggest strengthening them, without stretching:

http://www.exrx.net/Kinesiology/Posture.html" onclick="window.open(this.href);return false;

http://www.t-nation.com/free_online_art ... ore_part_i" onclick="window.open(this.href);return false;
https://www.diigo.com/item/image/4zk1s/qd3p" onclick="window.open(this.href);return false;