the exercise can be modified by altering the starting forearm placement on the physioball. If the starting position of the hand and forearms is lower on the ball and closer to the floor, the exercise becomes more difficult because you will be able to roll the ball farther away from the body.
Physioball Upper-Trunk Rotation
Execution
1. Sit on a physioball and slide down into a bridge position with your neck and shoulders balanced on the ball. Point your arms toward the ceiling.
2. While keeping your hips straight and your spine in a neutral position, rotate your upper body to one side.
3. Pause and then rotate to the opposite side.
Muscles Involved
Primary:External oblique, internal oblique, transversus abdominis
Secondary:Serratus anterior, rectus abdominis, rectus femoris, gluteus maximus, biceps femoris, semitendinosus, semimembranosus
Swimming Focus
The rotational movements performed during the exercise are useful for strengthening the oblique muscles, which in turn will help to strengthen the linkage between the legs and arms during freestyle and backstroke. This exercise also improves awareness and control of hip position, which can help a swimmer who is having trouble keeping the hips elevated when swimming backstroke.
The degree of rotational movement performed during the exercise depends on the ability to keep the hips straight, meaning that the shoulders should be rotated until the hip position can no longer be controlled. When just learning how to perform the exercise or for those with weak core musculature, the best approach is to keep the rotational movements small and focus initially on maintaining the bridge position for a 60-second hold. As proficiency with the exercise increases, the focus can be shifted toward increasing the rotational movements of the upper body and performing a set number of repetitions.
Physioball Jackknife
Execution
1. Begin with a physioball positioned under your feet, and then walk your hands out to move into the starting position.
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
