Tip 4: USE THE PROPER REPETITION PROTOCOLS

 The abdominals are composed primarily of fast-twitch fibers and like the ham- strings that respond better to low reps and heavy weights. The next time you do crunches try putting a weight on your upper chest. As a general guideline do not perform any abdominal exercise for more than 40 seconds. If you can perform an exercise for more than 40 seconds the resistance is too light. 

Another interesting point in regard to reps is that women tend to respond better to slightly higher repetitions.  Due to neurological differences, women often have a harder time recruiting fast-twitch fibers and therefore need to perform more repetitions to get the same training response. This idea was supported in a study that looked at the differences between men and women in a biceps curl exercise. After determining the one reputation maximum, the subjects were asked to perform as many reps as they could with sub-maximal weights. The result was that with sub-maximal weights. the average female subject could perform more reps than the average male subject: In fact, at certain percentages, females could perform twice as many reps as males.

Tip 5:  RELAX YOU NECK BEWEEN REPETITIONS

Neck strain often occurs when you hold your head off the ground throughout all parts of abdominal exercises. The head weighs about 7.5% of your bodyweight, and supporting it for long periods can strain muscles in the neck. By resting your head on the floor momentarily between repetitions you allow the neck muscles to relax, thereby minimizing the stress on the neck. Also, in many exercises, this technique increases the range of motion. Obviously, resting your head between 100-rep sets won't work, but it will work if you’re adding resistance and doing the more effective low-rep sets recommended in Tip 4. 

What about those ab-roller devices seen on TV? The major selling “hook" for this equipment is demonstrating that it prevents neck strain, and the in infomercials dramatize their sales pitch by showing people grasping their necks in pain after performing traditional abdominal exercises. The major problem with these ab-roller devices is that the neck muscles don't get strengthened, thereby disrupting the normal balance between the neck and abdominal muscles. This imbalance increases your susceptibility to neck injury, especially if you participate in contact sports.