Edited by Dr. Francesca Fanolla
The two most common abdominal exercises compared.
There are small details that often, as in all the exercises for trophism, "make the difference" and that, if they do not receive due attention, they risk incurring unpleasant problems such as lumbar pain, cervical pain, etc. or not to achieve the set objectives for incorrect technical execution of the exercises.
The two "classic" movements we have all experienced at least once in our "sporting" life are:
1 - THE BENDING OF LOWER LIMBS TO THE BUST or REVERSE CRUNCH
2- MUTUAL FLEXING OF LOWER LIMBS AND BUST OR V-UP
But let's see more closely ...
Lower limb bending towards the trunk or "Reverse crunch"
In these movements the pelvis supports the action of the legs; to contract the abdominals concentrically, the neck and shoulders must be kept to the ground. The first phase of the movement is essentially due to the contraction of the ilio-psoas which, taking a fixed point on the internal iliac fossa and on the last lumbar vertebrae, flexes the femur towards the pelvis. In order for this movement to occur only in a centripetal direction, the point of origin of the ileum-psoas, ie the lumbar segment, must remain immobile. This is done by the large abdominal rectum which is mostly involved in the second phase of the movement, that is when the pelvis is raised with a "push" upwards and towards the head (vertebral rolling), this muscle that originates from the last ribs entering on the pubis, it enters tension to keep the pelvis in retroversion.For further information: anatomy of the abdomen.
1 a- VERSION WITH EXTENDED LEGS:
placing the legs in extension and thus extending the lever arm, the exercise is much more intense and if the load is excessive for abdominal straight not very toned, it happens that they are unable to contract concentrically and attract the pubis towards the coasts, but they are eccentrically 'stretched' and move the pubis away from the ribs, bringing the pelvis into an anteversion.
Then the femoral rectum comes into action which is also the thigh flexor on the pelvis and vice versa.
1-if the abdominal rectum is strong enough, it allows the ileum-psoas to raise the femur and the rectus femoris acts synergistically with it, without an anti-version of the pelvis occurring with consequent lumbar lordosis.
2- if, on the other hand, the abdominal rectum is not sufficiently trophic, the rectus femoris, charging itself with all the "responsibility" of the movement, attracts the pelvis towards the femur and the psoas, becoming an antivaver, lifts the lumbar area from the ground with consequent lordosis.
From this we deduce therefore that the EXTENDED LEGS variant is not only not recommended for beginners and in a preventive-compensatory program, but it is also not very effective for the abdominals, exercising more the psoas, as also shown by electromyographic studies.
1 b- FLEXE LEGS VARIANT
With the departure with legs flexed on the thighs and the thighs flexed on the pelvis, the latter goes into retroversion with consequent shortening and state of tension of the abdominal rectum.
In all this, therefore, the psoas-iliacus is able to flex the thigh without difficulty on the pelvis indirectly favoring the action of retroversion of the pelvis of the abdominal rectum.
This starting variant with bent legs therefore allows:
- not to contract the rectus femoris
- to reduce the load
- to decrease the starting angle of the ileo-psoas
Mutual bending of the lower limbs and torso or "V-UP"
This is one of my favorite abdominal exercises. In it the pelvis acts as a pivot and the action is due to the ilio-psoas and the abdominal rectum which, taking origin from the pelvis and crossing each other, act as fixators.
Due to the intensity of this movement, which can be reduced by bending the legs, it is not recommended to propose it to beginners or in a preventive and compensatory motor education program.
