The running back is fundamental to the offense. They have many different jobs to do so they have to be flexible. The moment the quarterback calls a running play, it’s the running back they will turn to. Then it’s up to the running back to see a gap in the opposition defense and make as much progress downfield as possible.
But a running back is more than just a runner. When a quarterback calls a passing play they may have to act as a blocker to help protect the quarterback, or they may be sent downfield to act as an additional receiver.
A running back can come in different shapes and sizes. The “straight-ahead” style of running back relies on power to bulldoze through the opposition defense, well as the “cutback runner” will be fast and nimble, always looking to change direction to outpace and outwit the defense. And you have some running backs who are just all-round footballers who may make as many yards as a receiver than as a runner.
The constant theme with running backs is that they get hit. A lot. A running back really needs to be tough to survive. In a close game it’s the running back who the coach will turn to time and again. There is basically an expectation that running backs will play injured and do pretty much whatever is asked of them so this is not a position for the faint hearted.
The running back will need a strong and durable running back uniform in order to stand up to all the hits.