The role of the core abdominal muscles in swimming can be easily broken down according to their roles as trunk flexors, trunk rotators, and trunk stabilizers. Through their ability to flex the trunk, the rectus abdominis, external oblique, and internal oblique all play important roles in the movements that take place during swimming. For example, flexion of the trunk during flip turns is initiated by the upper fibers of the rectus abdominis, sustained by the lower fibers of the rectus abdominis, and helped to completion by both obliques. The trunk flexors are also important contributors to the wavelike, or undulating, body roll that takes place during butterfly, breaststroke, and underwater dolphin kicking. Besides contributing to flexion of the trunk, the obliques are responsible for trunk rotational movements. Strong obliques are vital to enhancing the speed of open turns performed during butterfly and breaststroke. The obliques are active during the body-rolling movements that take place during freestyle and backstroke, functioning to link the movements of the arms with the movements of the hips and legs. As previously mentioned, through their ability to function like a corset, the abdominal muscles are central to stabilizing the trunk. Trunk stability is one of the keys to efficient movement through the water, because it ensures a firm base of support upon which the arms and legs can generate their propulsive forces.
When incorporating abdominal strengthening exercises into the dryland program, you must understand the importance of focusing on correct technique. The focal point of correct technique begins with the conscious recruitment of the abdominal muscles, often referred to as setting, or locking in, the core, as described in the sidebar on page 13 of chapter 2. Setting the core first involves using the abdominal muscles to control the positioning of the hips and low back. This is best done by lying on the back, as pictured in the starting position for the first exercise of this chapter, the hollow hold. In this position, contraction of the abdominal muscles rolls the hips backward, pressing the low back against the floor. Conversely, contraction of the hip flexors rolls the hips forward, causing the low back to arch. After becoming comfortable with rolling the hips forward and backward, attention should be switched to holding the low back and pelvis in a neutral, fixed position. A useful approach to maintaining this neutral position is to visualize all the abdominal muscles as a corset and to focus consciously on contracting the abdominal muscles in this manner. You should perform the process of setting the core at the start of every abdominal exercise, and it should remain the underlying focus while you execute the entire exercise. The most common indicators that you are not setting the core are excessive arching of the low back and, if you are performing an exercise while facing the ground, excessive rounding of the low back and the hips rising toward the ceiling. Either of these compensatory movements is an indication that you are relying on your stronger hip flexors (rectus femoris and iliopsoas) to hold the body position instead of your abdominal musculature.
Hollow Hold
Execution
1. Lie face up on the floor with your arms by your sides, knees bent, and feet on the floor.
2. Tighten the abdominal muscles like a corset to set your core.
3. Lift your shoulders 6 inches (15 cm) off the ground, making sure to keep the low back in a stable and fixed position.
4. While lifting the shoulders, reach your arms toward the tops of your knees.
5. Hold this position for 60 seconds or until you are unable to keep the low back in the set position.
Muscles Involved
Primary:Rectus abdominis (upper fibers)
Secondary:External oblique, internal oblique, transversus abdominis, serratus anterior
Swimming Focus
This exercise is a good way to learn how to use your abdominal musculature to position the hips for correct technique and to stabilize the low back. In the starting position, you can experiment with contracting and relaxing your abdominal musculature to roll your hips forward and backward. Practicing these movements will help you gain a feel for the positioning of your hips. Gaining this feel will help you detect when you haven fallen out of the proper positioning for the exercise. A partner can monitor your positioning by testing whether he or she can slide a hand under your low back. If your partner can slide a whole hand under your low back, then you have fallen out of the proper position. When you lift your shoulders off the ground, look down your arms and past your knees to increase recruitment of the upper fibers of the rectus abdominis.
Direct benefits include strengthening of the core musculature, which will carry over to a tighter streamline and a reduction in the risk of injury. By targeting the upper fibers of the rectus abdominis, this exercise helps with the initiation of trunk flexion during freestyle and backstroke flip turns.
VARIATION
Hollow Hold With Feet Elevated
Incorporation of the legs will make the exercise significantly more challenging. Again, the key to performing the exercise properly is maintaining contact between the low back and the ground.
Watch TV
Execution
1. Facedown, support your body weight on your toes and forearms.
2. After holding the starting position for 15 seconds, rotate your body so that it is perpendicular to the floor and supported by one arm.
3. Hold this position for 15 seconds and then rotate back to the starting position.
4. Next, rotate your body so that it is again perpendicular to the floor but now facing the opposite direction. Hold for 15 seconds.
Muscles Involved
Primary:Rectus abdominis, external oblique, internal oblique, transversus abdominis
Secondary:Serratus anterior, rectus femoris, gluteus maximus, gluteus medius, biceps femoris, semitendinosus, semimembranosus
Swimming Focus
This exercise is a good way to transition from the hollow hold to a more challenging exercise when the primary focus is engaging the abdominal musculature to stabilize the low back. Again, monitoring the positioning of the hips and low back is important when performing the exercise. In both the starting and the ending position, the body should be held in a straight line from the ankles all the way to the tip of the head. If the hips begin to drop, the swimmer should be cued to focus on tightening the abdominal musculature. Monitoring the position of the head is also important because its position will indirectly affect the positioning of the low back. If the head is out of alignment with the rest of the body, holding proper body positioning will be much more challenging. As you become more proficient at performing the exercise, gradually increase the amount of time that you spend in each position. The goal is to reach 30 to 45 seconds.