People tend to go through a few distinct phases when it comes to this question.
First there’s the “I want to get into shape but I’m afraid of feeling sore afterward” phase. People who just start working out frequently half-ass it out of an aversion to fatigue. Ironically, this doesn’t always help them avoid soreness, since it can prevent them from fully adapting to the workouts.
Some people skip right past this phase and are really serious about exercise from day one. Or so I’m told.
Then there’s the “Fuck this shit, I’m going balls to the wall, no pain no gain!” phase, typified by an over-reliance on training to failure. People who have this mentality typically view a training session as “successful” if they feel exhausted afterward and can barely walk the next day.
I remember when I went through this phase, after one session of training to failure on every set I bragged on Facebook that I didn’t even have the strength to take my shirt off afterward. Ah, the follies of youth.
So, two extremes, two bad answers to these questions. But what’s the correct attitude towards soreness and fatigue? They’re two different things so I’ll tackle them one at a time.
How Sore You Should Feel After A Workout
Contrary to what you would intuitively assume, soreness does not correlate very well at all with how productive a workout was.
If you’re new to working out, or to doing a specific set of exercises, you’ll probably get very sore unless you’re not pushing yourself very hard at all. This soreness can last for up to 3-4 days in some cases.
Once you have a few years of training experience and/or a couple months of experience with the specific exercises you’re doing, you may feel only a tiny bit or soreness during the workout, and no delayed onset muscle soreness the day after.
It varies by muscle group too– quads, hamstrings and back extensors get sore very easily, pecs, calves and biceps get somewhat sore, and shoulders rarely if ever get sore.
Nowadays I hardly ever get DOMS, aside from a little bit in my lower back after doing deadlift variants followed by squats or leg presses. I usually feel just slightly sore immediately after the workout, but it rarely lasts. I’m still making gainz.
Soreness is simply not a reliable indicator of how well a training session went. It shouldn’t be viewed as the goal of a training session, but neither should you go very far out of your way to avoid it. It’s often a necessary evil, particularly for novices, but that’s entirely different from saying it’s desirable.
How Tired You Should Feel After A Workout
Unlike soreness, fatigue doesn’t change too much with your training age, and it actually is a somewhat reliable gauge for training productivity.
After each set, you should feel like you could use a bit of a rest, but you should be able to get up and move. Some people do stuff like calisthenics or jumprope between sets, and there’s evidence now that this is good for you. You don’t need to do stuff like that, but you should be able to at least– you shouldn’t feel like you need to sit down and rest after every set.
After the whole workout is done, you should feel slightly tired, and noticeably weaker in the specific muscles you trained. You should have no trouble changing clothes, walking home from the gym, or whatever– if you’re too tired to move normally, you overdid it.
You should however feel a decrease in energy and motivation to exercise– if you want to train even more, you should probably have pushed yourself a little harder.
3-4 hours after your workout, you should feel like you could do another workout. Your level of readiness to exercise should still be lower than it was before the workout, but not so low that you feel like you absolutely can’t work out again.
Ignore that last paragraph if you trained in the evening, of course– you should feel tired if it’s bedtime.
All of this assumes you’re well-rested and well-fed. If you’re having an off day, you’ll feel more tired after your workout, but that should be taken as a sign that you need more sleep rather than that you trained too hard.
Got all that? You should be able to move around between sets, feel tired but not wiped out after your workout, mostly back to normal 3 hours later, and soreness doesn’t mater that much either way.