Swimming Anatomy

2. When you are in the starting position, focus on holding your legs and body in a straight line from your ankles to the top of your head.

3. Initiate a curling motion with your abdominal muscles and pull your knees up to your chest.

4. Pause at the ending position and then reverse the leg movement.

Muscles Involved

Primary:Rectus abdominis, rectus femoris, iliopsoas

Secondary:Serratus anterior, external oblique, internal oblique, gluteus maximus, biceps femoris, semitendinosus, semimembranosus

Swimming Focus

For many swimmers, simply attaining the starting position for this exercise will be a challenge. The initial emphasis should be on holding the body in a straight line from the feet to the tip of the head for a 60-second duration. Developing the strength to hold this position will greatly enhance your ability to hold a tight streamlined position in the water. Incorporating the trunk-curling motion with hip flexion shifts the focus of this exercise from a general stabilizing exercise to one that targets the rectus abdominis and the hip flexors (rectus femoris and iliopsoas). As a result of this combined strengthening, this exercise strengthens the relationship between the core musculature and the hip flexors, which enhances the hip-rolling movements that take place in breaststroke and butterfly.

VARIATION

Physioball Jackknife With Twist

The addition of the twisting motion shifts the focus from the rectus abdominis to the internal and external obliques. This alteration broadens the benefits of the exercise, making it useful to freestyle and backstroke swimmers.

CHAPTER 6

BACK

The latissimus dorsi and the erector spinae muscle group are the two primary targets of the exercises in this chapter (figure 6.1 on page 114). The latissimus dorsi, a humeral propeller, is the primary workhorse of the upper extremity, responsible for generating most of the forces that propel a swimmer through the water. The latissimus dorsi works in unison with the shoulder girdle (chapter 3) and arm muscles (chapter 2) to transmit forces to the hand and forearm, which allows the swimmer to guide the body through the water with each stroke. As the name implies, the erector spinae muscle group is responsible for extension of the spine, which holds the body erect and, in swimming, maintains proper horizontal body positioning in the water.

The latissimus dorsi is a triangular flat muscle that arises from the lower thoracic vertebra, the thoracolumbar fascia, and the posterior iliac crest (back part of the hip bone). Recall from chapter 5 that several of the core muscles also attach to the thoracolumbar fascia, thus dynamically linking the latissimus dorsi to the core stabilizers. From the attachments that form the base triangle, the muscle tapers to a tendon at the tip of the triangle, which attaches to the upper humerus. Through its attachment on the humerus, the latissimus dorsi contracts to generate the following movements at the shoulder: extension, adduction, and internal rotation. Extension is the movement of bringing the hand and arm down from a forward raised position or, if the arm is already at the side of the body, the movement of reaching the hand behind the body—think of a runner in a relay race reaching behind to grab the baton. Adduction is the movement of bringing the arm down to the side from an overhead position, as when performing a jumping jack. Internal rotation involves rotating the hand inward toward the midline of the body. As you read through the exercises, you will find that several muscles are commonly activated in conjunction with activation of the latissimus dorsi. The lower and middle fibers of the trapezius and the rhomboid major and minor often assist by aiding in retraction of the shoulder blade. The teres major aids with shoulder extension, and the biceps brachii and brachialis flex the elbow joint.