Hold the last repetition up at the centre (picture B) and pulse up for 10 more reps. Swap legs. (womenshealthandfitness.com.au)
I find that it gives you that extra edge over that's crucial when you're trying to squeeze out one last repetition, when you've reached failure. (justinkavanaghfitness.com)
I hesitate to say the word «failure», but you should feel as if the last repetitions in the set are difficult, and to continue on would require taking pressure off your hands. (chrissalvato.com)