Cable Crunch

A cable oblique crunch is an exercise, which involves the oblique muscles, primarily the external and internal oblique. This exercise can be performed standing or kneeling next to a cable crossover station with a D-handle attachment. The concentric portion of the exercise is flexion of the vertebral column, flexing the trunk to one side. The eccentric portion is extension of the vertebral column, which involves the body returning to the upward position.

The purpose of cable oblique crunches is to strengthen the oblique muscles while promoting the hypertrophy (increases in size) of this muscle group.

Promoting hypertrophy of the oblique muscles with trunk flexion to one side helps define the surrounding area adjacent to the “6-pack” of the rectus abdominis. Training the obliques is essential to abdominal muscle aesthetics.

Strengthening the oblique muscles offers protective effects for the lower back as the obliques aid the lower back when bending over and bending sideways. Stronger obliques also complement exercise and sports performance as they can contribute to biomechanical efficiency (e.g. rotation) during physical activity and exercise. Performing this exercise with a cable provides constant resistance throughout the entire range of motion.

The abdominal wall is made up of broad, flat sheet-like muscles that are layered. The oblique muscles are essential to trunk rotation and lateral flexion of the vertebral column (as with oblique crunches). They surround the rectus abdominis on both sides. The external oblique muscle runs downward and medially and forms the inguinal ligament of the groin area. Its origin is at the outer surfaces of the lower eight ribs and it inserts into the linea alba via a broad aponeurosis. Some of the fibers of the external oblique insert into the pubic crest and iliac crest.

The internal oblique, as its name suggests, is located below the superficial external oblique. Its fibers run in an upward and medial direction. Its origin is located at lumbar fascia, iliac crest and inguinal ligament. Its insertion is located at the linea alba, the pubic crest and the last three or four ribs.

The rectus abdominis aids the oblique crunch by rotating the lumbar region of the vertebral column. It is a vertical muscle that extends from the pubic crest and symphysis (at the pelvis) to the rib cage (xiphoid process and costal cartilages of ribs 5-7). The rectus abdominis is segmented by three tendinous intersections that run horizontally across the rectus abdominis. This tendon outlines the “6-pack” of the rectus abdominis along with the linea alba, a tendinous seam that runs down vertically, dividing the “6-pack” in half.

The transverse abdominis is the deepest muscle of the abdominal wall with fibers running horizontally. This stabilizing muscle compresses the abdominal contents. Its origin is located at the inguinal ligament, lumbar fascia, iliac crest and the cartilage of the last six ribs. It inserts at the linea alba and the pubic crest.

As the rope is pulled down, the shoulders must remain in a semi-extended position to accommodate to trunk flexion. The latissimus dorsi is the prime mover of shoulder extension. When well developed, this is the muscle that is credited for giving the body its “V-shape”. Its origin is located at the lower six thoracic vertrebrae, lumber vertebrae, lower 3 to 4 ribs, and iliac crest of the pelvis. Its insertion is located around the teres major at the intertubercular groove of the humerus.

Oblique crunches (on a mat).

The obliques are constantly assisting the lower back and abdominals with physical activity. Therefore, a greater overload stimulus is required to stimulate growth of the obliques when isolating them during exercise. The unilateral nature of cable oblique crunches provides isolation and increased muscle activation of the obliques as each side is targeted. Strategically varying your intensity, rest times and volume (number of repetitions in a set) will optimize oblique development with time.

This exercise can also be performed in a kneeling position.

Focus on each concentric portion of the contraction, concentrating on “squeezing” as elbow reaches the upper thigh.

Emphasis on eccentric contractions, prolonging the return back to the upward starting position, may also be incorporated with an abdominal training program focused on increasing strength of the obliques. This should be implemented accordingly and with adequate muscle recovery as eccentric contractions cause substantial damage to muscle tissue and/or delayed onset muscle soreness (DOMS).

It’s important to note that your repetition and set volume will depend on your goals (e.g. strength, hypertrophy, muscular endurance).

Using momentum to lift the weight minimizes the benefit gained from the exercise. Therefore, it is important to control the concentric and eccentric contractions to optimize activation of the obliques.

When incorporating oblique training into your exercise regimen it is important to evaluate what other exercises you are doing in that training session. For example, it may not be best to train obliques on the same day as performing deadlifts and squats as the obliques work to stabilize the lower back. Training obliques before or after a training session that involves smaller muscle groups (e.g. calves, biceps, triceps) may be suitable, as it will not interfere with the quality of the overall training session.

While performing oblique exercises with added resistance can improve strength gains, increasing the weight beyond the lifter’s capacity can result in injury to the abdominal tissue or lower back.