Physical strain creates a stimulus. The body then needs time to adapt. If there is a good balance between physical load and recovery, performance can improve. If load levels increase too quickly or recovery is too short, the risk of injuries and overload problems increases. Current studies emphasise that overload is usually caused by repeated, insufficiently compensated strain and not by a single moment. (Orejel Bustos et al., 2021)
For adults, the World Health Organization recommends 150 to 300 minutes of moderate-intensity endurance activity per week or 75 to 150 minutes of intensive activity, supplemented by muscle strengthening on at least two days per week.
The starting position is important: someone who has been inactive for a long time should start well below this level and gradually increase. Age, everyday life, sleep, stress and previous illnesses also influence how well load is tolerated.
Warning signals are often unspectacular, but show up repeatedly. These include, for example: discomfort that increases during activity, pain that is clearly worse than usual the next day, stiffness that lasts longer than expected, significantly heavier legs, persistent fatigue, a drop in performance despite the same effort, irritable mood or poor sleep. A single sign is rarely conclusive, the pattern over the course of a few days is more important.
Overload can manifest as irritation of tendons, muscles, bones or structures close to the joint. Literature often makes a distinction between acute injuries (e.g. falls) and overuse injuries, which develop gradually. Typical examples are pain from exertion, inflammatory irritations or stress responses in the bones. (Orejel Bustos et al., 2021)
A common problem is the jump from a little to a lot, for example after holidays, after illness or at the beginning of the year. It is helpful to increase the scope, intensity or frequency individually and to deliberately set lighter days between demanding days. (Qin et al., 2025)
Variation distributes the load to different structures. If you always run the same way, you put repeated strain on similar tissues. Variety through other forms of exercise, different surfaces or additional strength exercises can help to distribute the load more widely.
Plans are useful, but the body’s reaction is crucial. A simple recommendation is to give yourself short daily feedback: How is your sleep? How do muscles and joints feel? How are motivation levels?
Regeneration is more than just doing nothing. It includes sleep, nutrition, sufficient energy intake, stress management and breaks. Even light movement can be beneficial if it does not cause additional strain.
A pragmatic approach is to reduce the load in the short term and observe whether the pattern calms down within a few days. Instead of stopping completely, it may make sense to reduce the intensity or volume and maintain pain-free movements. If symptoms persist, worsen or alarm signals appear, it is important to seek medical assessment.
These include: sudden severe pain, marked swelling or redness, overheating, fever, pain after a fall or twisting, inability to bear weight, numbness or muscle weakness.
Sore muscles after unaccustomed exertion are common and can occur as an adaptation reaction. The decisive factor is whether you recover within days and whether the load is built up sensibly.
Many people choose according to feeling: cold is often perceived as pleasant when something feels warm or swollen, while warmth is more likely to be perceived as beneficial when there is a feeling of stiffness. Studies and reviews show different effects depending on the context, so individual tolerance and safety rules are important. (Klemm et al., 2024; Yao et al., 2024)
In-depth knowledge about muscles, joints, regeneration and stress – explained in a compact, factual and practical way.
