Stimulation of Bone Growth Through Sports A Radiologic Investigation of the Upper Extremities in Professional Tennis Players

This contribution addresses the following questions: Does unilateral sports-specific strain affect the skeletal system of the athlete? Specifically, can any differences be found in longitudinal growth of the bones of the forearm and hand in professional tennis players between the stroke arm and the contralateral arm? An investigation was conducted involving 20 high-ranking professional tennis players (12 male and eight female players) between 13 and 26 years of age as well as 12 controls of the same age range. The radiologic examinations of the bones of the forearm and hand yielded an increase in density of bone substance and bone diameter as well as length in the stroke arm as compared with the contralateral arm. Whereas the first results confirm previous findings, the stimulation of longitudinal growth has never been reported. This change in bone structure and size can be attributed to two factors: mechanical stimulation and hyperemia of the constantly strained extremity. It may thus be regarded as a biopositive adaptation process. Within the last 10 years, the high-ranking professional tennis players have become younger. This tendency applies to men as well as women players. Nowadays, players turn professional at the ages of 15 to 17. They start full-time practice at much earlier ages because of the technical complexity of tennis and the high degree of motor skills required. The best time to acquire these skills has been shown to be between ages 10 and 12 for girls and ages 10 and 13 for boys.26 During this period, the differences between boys and girls in the development of their performance graphs are very small27; therefore, professional practice is begun during childhood. It is the responsibility of the physician specializing in sports medicine to direct the load of training to prevent injuries and overuse reactions. To fulfill this task, the physician has to know exactly how the athlete’s growing body will react to high loads of practice. Functional adaptation of bone, cartilage, and muscles has been described by Feldmeier. 10 He found an increase of bone thickness, bigger bone ledges at the insertion of muscles and tendons, and a concentration of bone structure. Wurster et a1.39 referred to the interdependency of blood estradiol and bone density in female track and field athletes; however, an influence of sports-specific strain on the longitudinal bone growth has not been reported. Growth and development of the skeleton Skeletal growth and development are affected by several factors.26 Any growth is caused by cell division. Reduplication is determined by an intracellular genetic code. Another important factor is nutrition; malnutrition will result in a retardation of growth. Third, the hormone-related factors, especially the feedback regulation of calcitonin and parathormone, play important roles in bone development. Estradiol reduces bone resorption39; somatotrophic hormone supports growth in general, i.e., its effect is not limited to bones. The final body height at the end of growth is determined by the genetic code’ but can be affected by the factors mentioned above. Matthiass26 found systemic as well as local regulatory mechanisms of skeletal growth. Bone growth is characterized by a constant remodeling in which gain and loss are not balanced. Systemic regulations tAddress correspondence and repnnt requests to: Prof Dr. med Hartmut Krahl, Department of Orthopaedic Surgery, Alfned-Krupp-Krankenhaus, Alfned-Krupp-Str. 21, D-45117, Essen, Germany No author or related mstitubon has received any financial benefit from research in this study © 1994 American Orthopaedic Society for Sports Medicine. All rights reserved. Not for commercial use or unauthorized distribution. at LAKEHEAD UNIV on May 5, 2007 http://ajs.sagepub. com Downloaded from