Copyright  Goodheart-Willcox  Co.,  Inc.  May  not  be  reproduced  or  posted  to  a  publicly  accessible  website.  82  Anatomy  &  Physiology  Essentials  Lab  Manual  2.  The  quadriceps  and  hamstring  muscles  groups  are  antagonistic  of  each  other.  This  means  that  when  one  muscle  group  is  actively  contracting,  the  other  is  relaxed  to  allow  for  joint  movement.  However,  consider  moving  from  a  seated  to  a  standing  position.  During  this  motion,  the  hamstrings  are  extending  the  hip  while  the  quadriceps  are  extending  the  knee.  Why  do  you  think  these  two  antagonistic  muscles  groups  are  able  to  work  together  in  this  scenario?_  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  __________________________________________________________________________________________________________________  _________________________________________________________________________________________________________________  
