Sneaky, it is a double-triple joint action reflex, initiated by the gastroc/achilles/ankle (plantarflexion) that moves to knee (flexion) then to the hip (extension). What this amounts to is high knee and a high heel at the same time, to start the swing a slight dorsiflexion of the foot at ankle occurs and then knee extension occurs as does hip flexion. Where this process repeats again and again and again. Stride Length is gained as you increase speed by you plantarflexion and stride rate is maintained by keeping a shorter stroke by having a high knee and high heel at the same time.
uh explain how im supposed to run like that please, in english pardon me if im kinda slow