"They look at the bulked-up guys and automatically believe what they say," said Caspar Trost, a 24-year-old sports student from Cologne. "They think they know a lot more because they look stronger."
Trost was referring to the countless people who visit fitness centres and harm their body by taking tips from the wrong sources. "I injured a disk working out with people who didn't have a clue and lifted especially heavy weights."
Strength training has become very popular, which is a good thing when done correctly. The greatest risk of injury lies in lifting heavy weights too soon, warned Heinz Kleinoeder, an instructor at the German Sport University in Cologne.
"Your weakest link determines how intensely you can train," Kleinoeder noted. If that link fails to hold, you can pull a muscle, dislocate a shoulder, suffer skeletal damage or injure something else.
White fibre for quick movements
Lifting the right amount of weight is one of the most important factors in healthy strength training, according to Jan Pauls, a German sports physician and author of books on strength training.
"A lot of the positive health effects we see in studies were achieved by intensive muscle-building training," Pauls said. "To say that you're supposed to do just 30 to 40 repetitions with less weight would be totally inconsistent with the studies."
Lifting lighter weights improves muscles' metabolic performance and acts on red muscle fibres, which are also known as slow-twitch fibres and are suited for endurance. However, it takes lifting a heavier weight to have an effect on muscle-building and white muscle fibres, which are also known as fast-twitch fibres and are suited for short bursts of speed and power, Pauls said.
Both kinds of fibre are important. "We need the white fibres for quick movements, for instance to prevent injury," Pauls said.
Proper selection of exercises
The second key factor in strength training, besides the right amount of weight, is the proper selection of exercises. "The most important areas are the back and trunk," said Andreas B. Imhoff, a sports orthopaedist at the Munich University of Technology. Training them improves the body's overall stability, he said, and "when you've got that, you stand upright and ease the load on all of your joints."
All major muscle groups in the body should be trained in accordance with a basic principle: Always work out flexors and extensors equally, for example biceps and triceps. Only then, Imhoff said, will the muscles hold the joint in balance from both sides.
Isolated exercises for a particular muscle are pointless, Imhoff added. "Bench presses strengthen the pectoral muscles. They look good in the mirror but have no function by themselves," he said.
Enough is enough
Kleinoeder advises beginners to use exercise machines for strength training so that they do fewer things wrong. Once they have mastered controlled, coordinated movements, they can try more difficult exercises, such as with their own bodyweight or with barbells and dumbbells.
The third key factor is the right amount of training. To achieve positive health benefits, Pauls recommends two to three sets for each exercise and two to three workouts a week.
"You'll weaken your immune system if you continually work out too soon after your last workout," warned Kleinoeder. "At some point your body will tell you that enough is enough." (Sapa, March 2012)
Fitness, getting started
Myths about weight training