we use our quadriceps and our hamtrings
There is no such position in baseball. The running back position is used in American football.
They are used to make a path for the Running Back.
The muscles that are used when snapping a football are all in the arm. More specifically, the forearm muscles are heavily used.
THe legs are the most used in football, especially the calf and thigh muscles. Naturally, the amount of kicking and running associated with football leads to the bulging of calf muscles. But this only after long amounts of practice.
Mostly your Quad muscles
Tricept
Yes fullbacks, halfbacks (this term is no longer often used), and tailbacks are all running backs. The fullback is usually the bigger running back in a two back formation, and although he does carry the football or catch passes on ocassion, the fullback is usually used as a lead blocker or to help protect the quarterback on a passing play.
quads calfs
Most of the muscles of the body are exercised when running. Of course the foot and leg muscles are needed the most but the muscles of the torso and upper body are used as well.
Running and walking does use the same muscles in the body. Three of the main muscles used in the legs are hamstrings, quadriceps and gluteal muscles.
quads,calf,groin,
The muscles used in a squat jump are the quads, and the hamstrings. The lower back muscles and the abdominals are used also