|
Here you will find an article on one exercise
(new one every month). With a detailed analysis of the
muscles used during the exercise and a informative description
of how to both perform and assist in the actual performance
of the exercise.
A full library of all previous exercises
can be found at members online under the sub menu
Exercise:
Oblique Crunch
Client Instruction:
Starting Position
1. Lie in a supine position on the floor with your right
ankle crossed and resting on the knee of your bent left
leg
2. Support your head in your hands without interlocking
your fingers
3. Keep your elbows out to the side of your head and avoid
any pull of your arms
Up Phase
4. From this starting position, begin to raise your left
shoulder up and forward towards your right knee
5. Attempt to curl up and rotate gently by the contraction
of the internal and external obliques
Down Phase
6. Pause momentarily and then
slowly lower your body by uncurling your spine, bringing
your left shoulder back to the starting position
7. Repeat the exercise lifting your right shoulder up and
towards your elevated left knee
Muscle Analysis
Chart - Oblique Crunch
| Up Phase |
| Joint |
Action |
Contraction |
Muscle Group |
Specific Muscles |
| Spinal Joint |
Rotation |
Concentric |
Spinal Joint Rotators |
External Oblique
Internal Oblique
Erector Spinae muscle group |
| Down Phase
** |
| Spinal Joint |
Rotation |
Eccentric |
Spinal Joint Rotators |
External Oblique
Internal Oblique
Erector Spinae muscle group |
**Down Phase
In the down phase of the exercise the body is lowered slowly
with gravity. The muscles that concentrically contracted to
lift the body are the same muscles that are eccentrically
contracting to lower the body.
General
Kinesiological Analysis
In an oblique crunch the spinal joint is rotated
by the concentric contraction of the rectus abdominis, external
obliques and the internal obliques.
Advanced Kinesiological
Analysis
The prime movers for the oblique crunch are the external
obliques and the internal obliques. The rectus abdominis is
classified as an assistant mover. The oblique crunch movement
to the right side is caused by the contraction of the right
internal oblique and the left external oblique. Movement to
the left side will recruit the left internal oblique and the
right external oblique. As the obliques contract to cause
rotation of the spine they neutralise any unwanted trunk flexion.
By rotating the spine immediately from the supine position
more emphasis is placed on the obliques. If the movement begins
with some spinal flexion, there is the additional recruitment
of the rectus abdominis.
Exercise Variations
Another variation to recruiting the obliques is in a pendulum
exercise. The client lies in a supine position on the floor
with the hips flexed to 90 degrees and the feet pointing towards
the ceiling. The client then slowly lowers the extended legs
down to one side until the outside leg touches the ground.
At this point, the client raises the extended legs back to
the upright position and slowly lowers them down to the other
side. The rotation of the spine occurs due to the pelvis moving
in transverse pelvic rotation as the hips are drawn into horizontal
adduction and horizontal abduction. If the client is unable
to perform the exercise correctly with their legs extended,
they can bend their knees to reduce the size of the resistance
lever.
Machine Weight Variations
Twisting movements of the spine that recruit the oblique
muscles can also be performed on a trunk-twisting machine.
Cable Pulley Machine Variations
The client sits on a bench with their back facing a high
cable pulley machine. The client reaches over their right
shoulder and grasps the handle of the high cable with their
two hands, while keeping their trunk in extension. From this
starting position the client pulls the handle over the right
shoulder by bending and twisting the trunk and drawing it
towards the left foot. Once in the terminal position, hold
momentarily and then lower the weight back by returning to
the original starting position. A more advanced version of
this exercise can be performed sitting or kneeling on a stability
ball rather than on a flat bench. A more advanced variation
occurs when the client faces a high cable pulley machine.
The client begins by reaching up and grasping the handles
with both hands. From this starting position the client pulls
down on the handle by flexing the spine, hip joint and the
knee joint and then rotates the spine to bring the handle
down by the side of the left ankle. Once in this position
the client can lower the weight by returning back to the starting
position and repeating it to the right side.
Disclaimer: No responsibility is accepted for any loss
or damage suffered as a result of the use of the above
information
or any reliance on it. Users should satisfy themselves
as to their own or clients medical and physical condition
before adopting/using
the information or recommendations made. No responsibility
or liability is accepted for any loss or damage suffered
by any person as a result of adopting the above information
or recommendations.
Further information
1300 136 632 Phone +61 02 9212 7185 or Fax +61 02 9211
0002
Suite 505/410 Elizabeth Street Surry Hills 2010 Sydney
Australia
| |
