Any given exercise is performed through an entire range of motion.
For example, the regular flat bench press works the chest and is performed in the range of motion
starting with the barbell (parallel to the floor) touching the
chest, and ending with the arms fully extended. Half reps are like
partial reps in the way that they
focus on only a part of the movement. Specifically, half reps focus
on either the top half or the bottom half of the range of motion.
For example, applying this shock technique to standing barbell
curls, you would either perform the curl only raising the barbell
to your chest, or lowering the barbell from your chest to your
thighs. Half reps are good to apply as it will provide a new
feeling for the exercise being performed, in case the pumps you were receiving were not quite up to the
level you wanted, or you were looking for something a little