"You’ve likely gained less from that workout because so much muscle damage has to be repaired. Even though the body’s response is strong, most of it goes toward fixing what you broke down. You don’t gain anything from a session like that," he says.
He is a researcher at Stockholm University and surveyed people at fitness centres about their attitudes toward exercise-related pain. Results were published in the journal BMC Public Health in 2024.
"Soreness is associated with progress. In some contexts, recreational exercisers can almost compete over who has become the most sore. It carries such positive connotations," says Pelters.
Repeated overload
Is it true that soreness is important for progress?
Marcus Moberg is a researcher at the Swedish School of Sport and Health Sciences. He tells Dagens Nyheter that muscles become bigger and stronger through repeated overload.
"When following a training programme, measurable results usually appear after 8 to 12 weeks. What you've done in one or two sessions matters less than completing, say, 30 sessions over a longer period," he says.
"Development lies in repetition. In other words, you can get just as good an effect from working out even without becoming sore," he says.
So repetition is more important than giving everything in a single workout.
The muscles need to be repaired
Pushing your body too far can lead to a condition called rhabdomyolysis.
"That means that some muscle cells die and have to be rebuilt from scratch. Recovery from this can take anywhere from six to eight weeks. Rhabdomyolysis can also cause problems for your kidneys," says Truls Raastad.
Annonse
Truls Raastad is a professor at the Norwegian School of Sport Sciences.(Photo: Gjermund Erikstein-Midtbø / Norwegian School of Sport Sciences)
A more balanced outcome is feeling some tenderness the day after a workout without it limiting you very much. According to Truls Raastad, that kind of soreness is usually fine.
"It means you've had a good session and that your muscles were challenged enough," he says.
This tenderness signals small amounts of muscle damage, a sign that you've pushed them a bit harder than they're usually worked.
"When the load is moderate, muscles adapt over time, becoming stronger and better able to handle the same load," he says.
Adjusting the load and avoiding soreness
People who regularly exercise don't need to feel sore to have an effective workout.
"If you've matched the load to what your muscles can handle, you can still get results without soreness," says Raastad.
"Do athletes rarely get sore?"
"It varies, but if you load the muscles sensibly and increase with gradual progression, you should generally have relatively little soreness after training sessions," he says, adding:
"In a competitive setting, you may get some more soreness, because maximum effort is required. Some workouts are intentionally designed to mimic competition intensity. In those cases, accepting a bit more soreness can help prepare the body for the demands of competition."
Pressure on the connective tissue
So why do muscles become sore in the first place? The dominant theory is that it's caused by tiny injuries in the muscle fibres. But the pain doesn't come directly from these injuries.
"It's really the after-effects of tiny injuries to the muscle fibres that cause soreness," Marcus Moberg tells Dagens Nyheter.
"The muscle itself has no pain sensors. Those are instead located in the connective tissue, the fascia, which surrounds the muscle. The microscopic damage sets off an inflammatory process in the muscle. This process releases substances that trigger pain. At the same time, the muscle becomes slightly swollen, and with that swelling comes fluid that presses against the connective tissue. It's probably the combination of all this that causes the soreness we feel," he says.
When do we get sore?
We typically get sore when we're out of shape. If you don't regularly exercise and jump straight into strength workouts taken to exhaustion, severe soreness is almost guaranteed, says Truls Raastad.
He says this is something commonly seen after the new year, when many start exercising.
"Another case is when you usually train consistently but take a break of two or three weeks or longer. When that happens, your muscles lose the protection they’d built up for the exercises you normally do," he says.
If you work out at the same intensity as before the break, you will easily get muscle damage and severe soreness, says Raastad. That’s why easing back in for the first session after a break is recommended.
We also often become sore from new exercises.
"Even if the exercise targets the same muscle groups you've trained before, you should take it a little easier the first time you do a completely new exercise," he says.
Workouts that emphasise a heavy eccentric phase – when you use a lot of force to slow a movement – make us sore.
This happens, for instance, during downhill running or exercises like lunges with a barbell on your back, where you step forward, control the descent, and then push yourself back up.
"There’s extra strain on the muscles every time they have to slow down a movement like this with great force. You’re producing force even while the muscle fibres are still being stretched. In that phase, we’re particularly vulnerable to these small injuries if we’re not well accustomed to it," says Raastad.
