Let's take the bench press as an example — try doing one or two
high repetition sets of barbell rows before you hit your work sets on bench press.
However, when you
do high repetition sets of crunches and sit ups they are being asked to also perform the role of slow twitch stabilisers and this is why it is quite common for high rep abdominal exercises to lead to lower back pain.
Doing
high repetition sets of isolation abs exercises in the hope of building strong muscular abs is fundamentally flawed as this type of training can only build endurance regardless of the muscle being exercised.
Strength and endurance workout routines utilize a combination of low repetition sets and
high repetition sets.
The result of this is you use only a small percentage of your bodyweight, the exercises soon become too easy and you end up doing
the high repetition sets that we know should be avoided.
Perfecting your timing and technique allows for safe,
high repetition sets that will improve work capacity, functional explosiveness, and muscular endurance.