'Burning calories easier with a team mate'

Kansas State University researcher Brandon Irwin tested whether individuals engage in more intense physical activity when alone, with a virtual partner or competing against a teammate.

"People like to exercise with others and make it a social activity," Irwin said.

"We found that when you're performing with someone who you perceive as a little better than you, you tend to give more effort than you normally would alone," Irwin said.

For the first part of the study, college-age females exercise on a stationary bike six sessions in a four-week period. They told participants to ride the bike as long as they could. On average, each participant rode for 10 minutes.

Next, the same group of participants returned to the lab for more exercise sessions, but was told they were working out with a partner in another lab whom they could see on a screen.

In reality, this was only a looped video. Participants also were told that their virtual partner was part of the first study and had ridden the bike approximately 40 percent longer than them.

"We created the impression that the virtual partner was a little better than the participant," Irwin said.

"That's all they knew about their partner. In this group, participants rode an average of nine minutes longer than simply exercising alone."

While this 90 per cent increase was promising, Irwin said he and his team had a hunch that the motivation could go even further. The participants were invited back to the lab for more exercise sessions with a virtual partner. This time, though, they were told they were on a team with their partner.

"We told them they were working together to achieve a team score," Irwin said.

Participants exercised approximately two minutes longer than simply working out alongside someone.

"This was an average, but over time the difference got much bigger. In the beginning, the participants were exercising about a minute longer than the partner group," he said.

By the last session, participants in the team group were exercising almost 160 per cent longer than those in the partner group, and nearly 200 per cent longer than those exercising as individuals.