There’s a conundrum with forced reps, and it’s the key to their effectiveness. By assisting, a spotter makes reps easier, but by making them easier, he makes the set harder. It’s all a matter of perspective. When you’re under the iron and you can’t eke out another rep on your own, continuing onward with forced reps will feel anything but easy, even as helping hands lessen the resistance. Forced reps are one of the most effective methods for blowing through stop signs and barreling into the pain (and growth) zone.
“Assisted reps” would be a more accurate name than “forced reps,” but the latter captures the feeling you might get when just enough resistance is removed for your set to continue beyond your normal limits. You’re forced to keep going. Failure is not an option. And that brings us to the first and most important thing to know about this technique: It’s exercise overtime. A spotter should assist you only when you’re on the verge of failing, and he should apply only enough pressure so you can continue to move the weight at the same pace as before.
The key to effective forced reps is the transfer of resistance from your muscles to his so the reps are not too hard or too easy, progressing at the same pace as all preceding reps