After writing nine leadership books and interviewing hundreds of entrepreneurs, I'm convinced that you cannot inspire others unless you're inspired yourself. And inspiration comes from the one emotion that's the most contagious of all--joy.

By now you've seen or have heard about UCLA gymnast Katelyn Ohashi's perfect 10 floor routine in a recent competition. Although the technical performance was flawless, the 88-second routine didn't go viral solely because of her brilliantly-executed flips, splits and jumps.

In a phone interview with the New York Times, Ohashi summarized it best in seven words: "What you see is how I feel."

When you change the way you feel inside, the performer your audience sees will change.

Ohashi's video spread because unbridled joy is irresistible. The Wall Street Journal sportswriter Jason Gay may have summarized it best in the title to his article: "The Meaning of Joy." He writes that the millions who watched the video are "thrilled by it, enchanted by it, wonderstruck by it, moved by it...It's joyful. It's so, so joyful. It radiates warmth and glee."

Radiate is an appropriate verb to describe Ohashi's performance. It means "to send energy waves from one thing to another."

You can see the energy moving with one look at the expressions on the faces of Ohashi's teammates. Ohashi's teammates are raising their arms in celebration, cheering, clapping, singing along and synchronizing their movements with hers.

Neuroscientists who study emotion wouldn't be surprised. 

The Science of Emotional Contagion

Researchers in human behavior are studying an area called emotional contagion. Simply put, when you hang around happy people, their happiness rubs off.

Psychologist Peter Totterdell does research on contagion and team sports. He sees teams as perfect labs for this type of research because they act as 'small social networks.' Totterdell says that a team's collective mood is often in sync with the mood of its leader. When a leader is upbeat, the positive energy is transferred to individual players--it radiates from the top.

How you feel about your job, product, company or career is what others will see. When you 'perform' on the business stage, say, in the form of a presentation, you are transmitting what you feel on the inside. If you don't have joy for the topic, people will see it and react accordingly. If you have passion, enthusiasm and joy, you'll inspire the people around you.

Ohashi Gets Your Joy Back

Ohashi's background story is well-known by now. One of the best gymnasts in the country, Ohashi stepped down from elite gymnastics after injuries and verbal abuse (from coaches and spectators) had taken their toll on her psyche. She had lost passion for the sport, only to rediscover it after joining UCLA's college team in 2015.

In a moving video for Players' Tribune, Ohashi reflects on the decision. "I haven't been able to feel this type of happiness in a long time. I found my joy, my voice, my self, and my love for the sport."

Ohashi's smile is real. Her exuberance is real. It's not an act. It shows and it spreads.

A leader sets the example on any team--in sports and in business. Since your emotions tend to spread, dig deep to find your passion for your company, field or industry.

Once you do, don't be afraid to share it. Your audience will love you for it.