It is raining outside, the passport is boring or it is AW with the colleagues. There are a thousand reasons not to exercise; it is difficult to get started and even worse to stick to a new exercise routine. At least one in four people who participate in research studies on exercise jumps off.

But there are tricks to take. Sports psychologist and professor Deborah Feltz at Michigan State University in the United States has dedicated her research career to exercise motivation. Her best advice is to make training a couple or group activity.

- It creates structure and friendship and makes it more difficult to set up.

Better with a little more well-trained buddy

The training buddy or friends should be a little better than yourself. Industrial psychologist Otto Köhler's hundred-year-old principle of the weakest link still holds today. He discovered in 1920 that people in pairs or three and three managed to lift more weight per person if they cooperated. When everyone lifted a weight, each one did more than they did when lifting alone. The one who previously performed worst was the one who increased his performance the most.

- The weakest link becomes stronger by someone better to compare with whether they are a man or a woman, says Feltz. Men seem to be triggered to outdo others, women do not want to disappoint the group - but both genders perform better in such situations.

She thinks the same goes for exercise motivation. Anyone who trains with a slightly better training buddy will be embarrassed to put more effort into themselves and will get more out of their training.

Exercise pictures are contagious

Feltz also tips on social media. It's easy to snap at people who post boastful workouts on Facebook, but a study done by one of Feltz's doctoral students shows that it actually leads to higher training activity.

When test subjects were told that their results would be posted on Facebook, they cycled considerably longer than when they only learned that it is good for health to cycle. The longest cycled subjects who were informed that the more kilometers they got together, the more money would go to a charity and that their efforts would later be posted on Facebook.

"Appearing to be well-trained, healthy and altruistic is motivating," says Feltz. It is no coincidence that many amateur sports competitions collect money for charitable purposes at the same time.

In addition, your training images can inspire others to move. Other factors that stimulate training, at least in the US, are living in an area with good local traffic and living near a green area.

You can see more about exercise and how it affects health in the SVT program Best training.