When in a rugby scrum what type of contraction is used?

As the muscles in both expand and contract during the exercise of kicking the muscle listed undertake at least one of these functions in the kicking leg. The stand leg also undertakes expansion and contraction but of course to a lesser degree.

gluteus maximus and medius

adductor magnus

semitendinous

gracillis

biceps femoris

semimembranosus

sartorius

plantaris

gastrocnemius

solueus