Getting to the Core Helen Crewe Biokineticist, CSCS Linksfield Orthopaedic Sports & Rehabilitation Centre (011) 485 1882 Helen Crewe is a former high-performance gymnast with over 5 years of coaching and judging experience. She completed her qualification as a biokineticist through UCT at the Sports Science Institute of South Africa. She now works in private practice at the Linksfield Orthopaedic and Sports Rehabilitation Centre, and is involved in injury prevention and rehabilitation of athletes of all levels in a wide variety of sports. “Core stability” has been a buzz concept in fitness circles over the past few years, but what is it really all about? Images of exercising on stability balls probably spring to mind immediately with the mention of core stability, and most people know that lower back pain is related to a weak core. But how does balancing on a ball and strengthening your core benefit the gymnast? Firstly, we need to know what the core is. The system that stabilizes the lower back consists of passive restraints, the active muscular system, and neural controls. Passive restraints are the bones and ligaments that allow support of a limited load (only about 10 kg). The muscles of the spine and trunk are divided into “global” and “local” stabilizers. The global group consists of large, superficial muscles that generate movement of the trunk and act as stabilizers during exercises with high external loads. The local group consists of small, deep muscles that control movements of each individual vertebra. The neural system performs the complex task of coordinating which muscles work when and how hard. Lower back pain is common in non-athletic populations, as well as in athletes. However, athletes who perform repeated or forceful loading of the spine may find themselves more prone to lower back instability and other back injuries such as spondylolysis (stress fracture of the vertebra). Add to this that most athletes, gymnasts included, tend to train through pain and it becomes clear as to why many gymnasts suffer from recurrent episodes of lower back pain. Core stability training focuses on improving the strength and endurance of the muscles of the core. Traditional gymnastics conditioning exercises such as jack-knives and back extensions strengthen rectus abdominus and the erector spinae, respectively. However, these are global muscles, and the local stabilizers are often overlooked in conditioning programs. In the healthy spine, the local stabilizers contract automatically before movement of the limbs or the trunk, but in injured spines, the activation of these muscles is delayed. This means that when powerful movements are performed, the core is unstable. Compare the body to a building crane – if the base is unstable when it lifts heavy objects there can be destructive consequences (lower back injury) and the maximum weight that it can lift will be reduced (less power produced at the extremities). The key local stabilizers are multifidus, a deep spinal muscle that maintains posture and extends and rotates the spine, and transversus abdominus, a deep abdominal muscle that flattens the abdominal wall. It is advised that a core stability program begins with simple exercises to isolate these muscles, and is gradually progressed to incorporate the global stabilizers as well. Beginner core stability exercises: 1) Abdominal activation. The gymnast should lie on their back with the knees bent and a neutral lumbar curve (not too arched but not completely flat on the floor). The gymnast must then draw the lower abdomen in and up, maintaining normal lumbar lordosis. Contraction of the transversus abdominus can be felt by placing the finger tips just next to the hip bones. The gymnast must breathe normally and keep the upper abdominals relaxed. To start with hold for 10 sec and repeat 10 times, increasing the duration of contraction up to 60 sec. 2) Marches. The gymnast first performs abdominal activation as described above and then lifts one foot 20-30 cm off the floor, maintaining the position of the lower back and pelvis (no pelvic tilting forwards and backwards, or side to side). Alternate legs for 1 minute, performing 2-3 sets. The quicker the marches, the more difficult the exercise. Another progression is to add lifting the opposite arm at the same time as the foot is lifted off the floor. 3) Quadruped arm or leg lift. The gymnast assumes the quadruped position and activates the abdominals as described above. Then the gymnast must lift one arm forwards and upwards off the floor, without losing neutral lumbar curve or tilting the pelvis to either side. Once this has been mastered, the gymnast can perform the exercise by sliding one leg backwards and lifting the foot off the floor. A more advanced version is to combine the movement of the arm and the opposite leg. 4) Plank. This is a more advanced core stability exercise, and one that already forms part of many gymnastics conditioning programs. The key to the exercise, however, is to focus on maintaining transversus abdominus activation so that the local and global stabilizers are recruited simultaneously.
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