"You are the average of the five people you spend the most time with."

Whether or not you agree with Jim Rohn, there is one relationship that's essential for career growth. This person doesn't have to be one of the five people you spend the most time with. But you need this person in your life.

Without this relationship, you'll struggle to move on to the next step. You'll be tempted to play small. You may even think you've reached the top of the ladder.

But having this relationship will propel your continuous progress and growth. This person will inspire you, light a fire in your heart, and give you lightbulb moments.

I'm referring to a relationship with someone who's at the next step up from where you are right now.

Why You Need This Relationship

Sure, you can blaze your own trail, push through, and find your own way. But it's much easier when you relate with someone who's already done it, who's already where you want to be. They don't even need to teach you how to do it. After all, your circumstances are probably different, and so are your paths to success.

The value of this relationship lies in showing you what's possible. Some people call this the Roger Bannister effect.

Roger Bannister was the first person to run one mile in under four minutes. Before he accomplished this, everyone thought it was humanly impossible. Australian runner John Landy said the four-minute mile was "like trying to break into a brick wall." But just 47 days after Bannister pushed past that wall, Landy himself broke Bannister's record by 1.4 seconds. More runners followed suit and, today, athletes consider the sub-four-minute mile ordinary.

Analysts say Bannister removed the psychological barrier to the sub-four-minute mile. Until they saw it for themselves, runners didn't believe they could do it without harming their bodies. But once they did, they realized it was a possibility for them, too.

You can harness the Roger Bannister effect to drive you to greater levels of success and achievement. Being exposed to someone who's ahead of you opens your mind to other possibilities. It could change how you approach problems and challenges. You'll find it much easier to take the next step when you deeply believe it can be done, because you've seen someone do it.

Don't Be the Smartest Person in the Room

The problem is, sometimes we forget to develop relationships with people who are at least one rung ahead of us.

When you've achieved some success, you may find yourself frequently surrounded by others who are either your peers or subordinates. You're always the smartest, most successful person in the room. If this is the extent of your connections and networks, then your growth will be stunted.

Whose example will smash your psychological barriers? Look within your circles, not just at work, but also among your family and friends. It could be your boss, a parent, or an uncle. Maybe it's your competitor, a former classmate, or a complete stranger.

The point is to always seek and reach out to those who have achieved your next milestone.

Find Your Roger Bannister

Where do you find people to look up to, and how do you build relationships with them?

Reading websites and books can be a great start. But don't stop there, because the more personal your exposure is, the better.

Attending conferences and networking events could be another way to find them, as long as the other attendees aren't all at the same level as you.

My favorite way to meet and nurture relationships with those who are ahead of me is through business masterminding. Find a mastermind whose members are a good mix of those who can inspire you and those who might be inspired by you. Masterminds meet regularly, so you will benefit from the constant interaction and support of those you look up to.

Put yourself in the same environment as people who have reached the next level you're aiming for. Seeing someone has already done it will energize you to do the same.