My abs are switching off!!!

[Sergei82]

Hi everyone. I am experiencing the following phenomenon...

I am doing a heavy weighted abdominal isolation workout (no flexion in hips, pulling my ribcage to pelvis to reduce spinal muscles involvement). First 10-15 minutes of the workout my abs feel pumped as hell, but then all pump disappears. Even is I add more weight, I do not any burn in my abs. Obviously, they are working, but pump is not there anymore! Feels more like a massage, not workout.
I have an impression that all synergists "steal" the work from abs without letting my brain know about it... Needless to say, there is no soreness in my abs the next day, even though I trained them for 1 hour.

What a hell do I do wrong? Is it normal for the brain to switch off abs once they get tired?

For example, during squats I always feel pump in my legs. The feeling will never get blunted even if I squat for an hour!

[Singularity7]

The exercise you mention sounds like a crunch or similar correct? If you do the exercise correctly the mechanics of a crunch will always have the abs contracting.
This is true for all exercises. Bench, squat etc. All muscles involved in the lift will be called into play.
My guess is that your form is breaking due to fatigue and allowing the synergist muscles to take more of the workload.

Your brain does not turn off muscles during a lift. Never. I repeat never.

Just my 2 pesos on your problem.

[Sergei82]

Looks like that's response for the way I started training recently in every muscle.

I started training for volume, but not in high reps: I start with weight that allows me to lift 10 times to failure, and complete 100 (sometimes 200) repetitions in as many sets as it takes. All sets are to failure or close to failure (last sets may be 3 to 1 reps only).
Somewhere after maybe 8 sets my target muscle group becomes numb and less sensitive. I do not know about the physiology of the phenomenon, but I think it has to do something with endorphines organism produces to "fight off" the burn in muscle. Muscle is still working, it just doesn't feel the way it felt in the beginning of the session (squats I mentioned above are different, cuz nobody will go until failure with free weight squats for obvious reason).

[Canadienbakon]

Why so much ab work? Honest question.

[jo_el]

try and lower the reps ad focus on sucking your bellybutton to your spine

[Sergei82]

Why so much ab work? Honest question.

I'm doing everything like that now, not only abs.

[Stinnon]

I echo "try and lower the reps ad focus on sucking your bellybutton to your spine"

[Sergei82]

There is difference between burn in rectus abdominis and pain in abdominal area in general. Sucking anything is not necessary during ab exercises.

[mkcookin]

A great way to get more of a burn (a better workout) is do your ab exercises at the very end of your workout routine. They will already have gotten a good workout from your previous exercises I assume -- so by training them at the end it makes it much more difficult.

As someone mentioned earlier you really don't need to spend an hour doing ab exercises -- unless you want to that is. You can pick three exercises like..

1. ab wheel
2. planks
3. hanging leg raises

Then simply do 20 reps for each exercise back to back, rest for 1 minute, then repeat 3 more times. This really is all the exercise you need for a good ab workout.

Rest depends on your diet and how low your body fat % is.