Planks

A plank is an exercise, which involves the abdominal muscles, primarily the rectus abdominis. This exercise is performed face-down on a mat, suspending your body weight on your elbows and toes. This exercise is an isometric exercise, which means the muscles are activated but at a constant length as opposed to lengthening and shortening. Therefore, this is no upward/concentric or downward/eccentric phase.

The purpose of planks is to strengthen the abdominal muscles while promoting the hypertrophy (increases in size) and muscular endurance of this muscle group.

Promoting hypertrophy of the abdominal muscles with trunk flexion helps define the “6-pack” of the rectus abdominis. Strengthening the abdominal muscles offers protective effects for the lower back as the abdominals play a role in stabilizing the torso. Increasing the strength and muscular endurance of abdominals also complement exercise and sports performance as they can contribute to biomechanical efficiency during physical activity and exercise.

The abdominal wall is made up of broad, flat sheet-like muscles that are layered. The rectus abdominis 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 oblique muscles assist the rectus abdominis with flexion of the vertebral column. 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 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.

The body’s suspended nature in this exercise also requires stability from the back muscles. The quadratus lumborum forms part of the posterior abdominal wall located in the lumbar region (lower back). The longissimus passes though the transverse processes of the vertebrae from the lumbar region to the skull. The iliocostalis is the most lateral of the erector spinae back muscles. It extends from the pelvis to the neck.

The elbow’s weight bearing places tension on the rotator cuff muscles of the shoulder girdle to stabilize as well as the pectoralis major, anterior deltoid and rhomboids.

Side planks.

The abdominal muscles are working all day, every day, when you are physically active. For example, the rectus abdominis stabilizes the pelvis when you’re walking. Therefore, a greater overload stimulus is required to stimulate growth of the abdominals when isolating them during exercise.

Time the duration of how long can you hold a plank position. Perform three to five planks with rest periods in between. Track the progress of your plank durations over time. Strategically increase the difficulty of the plank in accordance with your overall training protocol. Take shorter rest periods (e.g. 30 seconds) between sets and/or add resistance by having a training partner place a plate on your upper back to increase the intensity of planks.

Upon reaching fatigue, the individual may raise the rear end. This can take the tension off of the abdominal muscles, therefore, it is important to be aware of keeping your torso straight or have a training partner monitor you.

When incorporating abdominal 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 abdominals on the same day as performing deadlifts and squats as those exercises fatigue the abdominals substantially. Training abdominals 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 abdominal exercises with added resistance can improve strength gains, increasing the weight beyond the lifter’s capacity can result in injury to the lower back or abdominal tissue.

Ensure proper weight-bearing technique of this exercise to avoid shoulder injury.