Domestic soreness most often occurs when muscles are subjected to new or unusual stress. This is microdamage to muscle fibers and the body's response to stress. Therefore, it's almost always more severe in beginners, while in those who have been training for a year or longer, it's usually less severe.

But an important point: the absence of DOMS does NOT mean the workout was bad. Conversely, severe pain doesn't mean you had a good workout. This is a common mistake in the gym.

For example, the back and shoulder muscles often don't feel as strongly as the legs or chest. Why is this? Firstly, they have many small stabilizer muscles, and they work more deeply. Secondly, people often have a poorer sense of technique in back exercises than in bench presses or squats. The legs and chest, however, usually experience more noticeable muscle soreness because larger muscle groups are involved and the load is more easily "felt."

Over time, the body adapts, and muscle soreness becomes less noticeable even with normal training. This doesn't mean progress has stopped - on the contrary, it's often a sign of adaptation and strength gains.

The key to training is not chasing pain, but rather monitoring the progression of loads: more weight, better technique, more reps, or movement control.

Soreness is simply one of the effects of training, not the primary indicator of results. Real progress is strength, form, and stability, not constant muscle soreness.