The pectoralis major I believe
Gastrocnemius and Soleus with leg straight, to isolate gastrocnemius bend knee.
the hamstring is used for flexing the knee
Quadricep
Gastrocnemius
upper back
it works your abs
The muscles used in the leg press exercise are your Quads primarily. Hamstring gets a good work out too.
The antagonists would be those muscles that cause knee flexion. Hamstrings (biceps femoris, semimembranosus, semitendonosis) are the primary knee flexors, and would thus be antagonists to knee extension.
it works your abs
The muscles used to straighten the leg are commonly known as the Quadriceps, a group of four muscles on the front of the thigh. This, however, is only the cast when the knee is isolated. If you were to stand up from a squatted position, you would also be using your gluteal muscles as well as your hamstrings to extend the thigh and stabilize the knee, while your quads and inner thigh muscles (the adductor) help to straighten the the knee. You would also be using your calf muscles to straighten the ankle.
I came to this website to know the answers of my questions not answering the question
Muscles help the movement of your legs, while the bones are attached to your muscles to provide support and structure. Furthermore, the bone joins in your hip and knee have the necessary mobility used to climb stairs.