LONDON - A friendly game of soccer works off more fat and builds up more muscle than jogging, new research shows.

Danish scientists, who conducted their research on 37 men, also found the soccer players felt less tired after exercising than the joggers because they were having more fun.

"This is good news for men who prefer to play football (soccer) with their mates," said Dr. Gary O'Donovan, a sports medicine expert at the University of Exeter who was not connected to the study.

To measure how hard the men were working out, the researchers strapped heart monitors to their chests and compared blood samples and muscle tissue before and after matches and jogging sessions.

The researchers selected men with similar health profiles aged 31 to 33 and split them into groups of soccer players, joggers, and couch potatoes — who not surprisingly ended the three-month study in the worst shape.

Each period of exercise lasted about one hour and took place three times a week. After 12 weeks, researchers found that the body fat percentage in the soccer players dropped by 3.7 percent, compared to about 2 percent for the joggers.

The soccer players also increased their muscle mass by almost 4.5 pounds, whereas the joggers didn't have any significant change. Those who did no exercise registered little change in body fat and muscle mass.

"Even though the football (soccer) players were untrained, there were periods in the game that were so intense that their cardiovascular was maximally taxed, just like professional football (soccer) players," said Dr. Peter Krustrup, head of Copenhagen University's department of exercise and sport sciences, who led the study.

The soccer players and the joggers had the same average heart rate, but the soccer players got a better workout because of intense bursts of activity. Krustrup and his colleagues found there were periods during soccer matches when the players' hearts were pumping at 90 percent their full capacity. But the joggers' hearts were never pushed as hard.

Unlike the soccer players, the joggers consistently thought their runs were exhausting.

"The soccer players were having more fun, so they were more focused on scoring goals and helping the team, rather than the feeling of strain and muscle pain," Krustrup said.

Health officials were unsure how much impact the study results might have on the wider population.

Nick Cavill, a research associate at the British Heart Foundation at Oxford University, said it's hard enough convincing people to exercise moderately, let alone engage in a high-intensity sport like soccer.