Now, with StrongLifts 5x5 your goal is NEVER to get sore or "pumped" because the only thing that matters for building muscle is gaining strength. That's why you will always try to lift 5 pounds more (that's 2.5kg) than last workout on each exercise. You see, I cannot BS you here, you'll quickly know if StrongLifts 5x5 works or not by just looking at your progress. If you're lifting more and more weight as the workouts go by - which I guarantee you will happen - then you are gaining strength and muscle. It's that simple.