there are many muscles in the lower leg including peroneus longus. The peroneus longus is near the kneecap but just about under it
femur
Synergists
jaw
your rectus abdominis is the prime mover in a crunch exercise or spinal flexion
Of all the muscles contracting simulataneously, the one that is mainly responsible for producing a particular movement is called the prime mover for that movement. The other muscles that help in producing the movement are called synergists. As prime movers and synergists muscles at a joint contract, other muscles, called antagonist muscles, relax.When antagonist muscles contract, they produce a movement opposite to that of the prime movers and their synergist muscles. -- I wrote kind of alot so you can under stand it just in case if you don't :)
prime movers : muscle that initiate a particular movement synergism : muscles that have the same action of the prime mover antagonist : muscles that come into play to oppose a certain movement
The atissimus obrsi abdominals is the prime mover in a sit up.
Antagonists are muscles that work in the opposite direction from prime movers and synergists.
The agonist muscle
The agonist muscle
According to Anthony's Textbook of Anatomy and Physiology the origin is that point of attachment that does not move when the muscle contracts, and the point of attachment that does move when the muscle contracts is the insertion. Muscles and muscle groups that that directly perform specific movements are prime movers or agonists.
. The prime movers are the core muscles which include the abdominals (rectus abdominus, the transverse abdominus and the internal and external obliques), the lumbo-pelvic-hip area, and the back (erector spinae, quadratus lumborum, paraspinals and the psoas major). Other muscles used in this movement are the glutes and quadriceps.