Even if you have little or no fat covering your mid-section performing crunches
alone is not going to give you complete abdominal development. In order to
develop your mid section musculature you need to not only work your rectus
abdominis but also your core (transverse abdominis) and obliques. Twisting toe
raises are a great abdominal exercise because they work both abdominals and
obliques.
There are 2 primary ways to perform this exercise. The easier method is
starting with your feet on the ground in front of you and performing a
repetition then returning your feet from the floor. The more difficult
method is keeping your legs as vertical as possible and feet in the air
throughout the entire set. The twisting toe raises are not challenging
enough for you, you can either add resistance via ankle weights, a medicine
ball between your legs or even resistance bands. You can also try to perform
the
twisting hanging leg raises which are even more challenging.