- Mechanical damage (to the protein structure of the muscle fiber),
- Damage to the membrane encasing the muscle fiber,
- Damage to the connective tissue surrounding the muscle fibers,
- The body's inflammatory response, causing further muscle protein breakdown and stimulating certain nerves, causing pain.
Here’s why you don’t need to feel sore after a workout to know it’s worked
"No pain, no gain" is a commonly used expression when it comes to getting in shape. It may also be why many of us think that you need to feel sore after a workout to know that you've done enough.
There are many reasons why your muscles might get sore after a workout. But, contrary to popular belief, you don't necessarily need to feel sore in the hours or days after exercise to know you've had a good workout.
Delayed onset muscle soreness (DOMS) is the scientific term to describe the sore and tender feeling our muscles have after a workout. Typically, it happens after we've done particularly strenuous exercise, or if we do exercise we aren't used to. It can happen after any type of exercise, though it's more common after eccentric exercise.
These are movements where the muscles resist a load as they're stretched (such as when you're running downhill or descending stairs). The smaller upper-limb muscles (such as your biceps and shoulders) can be more susceptible to DOMS as they may not be accustomed to eccentric exercise.
While DOMS can happen even hours after a workout, it usually peaks about two days later, depending on the intensity and volume of exercise. But though DOMS is common, the reason it happens remains poorly understood – though researchers do have a few theories about what's going on.
The current scientific theory is that DOMS is linked to a combination of: