Studying is actually hard when the you’re unable to concentrate on what you’re doing.
Reading is likely to be difficult when you have a poor concentration. And sometimes, even if you manage to concentrate during the first hour of your studies, Your concentration can diminish over time.
And fading concentration is very possible if you have been sitting for several hours. Our steady sitting position affects our blood flow and poor blood flow badly affects our concentration. So the best thing to do to revive your diminishing concentration is to stand-up and shake your legs! Shaking your legs will get the blood flow back to normal.
So the next time you feel that you can not concentrate anymore to what you are reading, give your leg a shake!