The skeletal system in the human body is made up of 206 bones. In the normal children, the bones account for almost twenty percent of their total body weight. Normally we think of the skeleton the framework of the body. For athletics, however, it is better to think of the skeleton as a moveable framework. Since movement is the cornerstone to athletics, we will consider the joints as part of the total skeletal system.

The skeletal system is perhaps the only sub-system of the body that cannot be considered as part of the Ability Development program. The reason for this is that the skeleton cannot be trained to improve. Of course, as you exercise, new, living bone tissue constantly replaces older tissue and as a result bones can grow somewhat stronger. The skeletal system cannot, however, be directly trained to improve. In other words, you cannot through exercise or training make your tibia bone longer or shorter. Even speed of the bone as it moves through air cannot be trained directly. It is the muscles connected to the bone that can be trained to improve limb movement velocity.

This is not to downplay the importance of the skeletal system in sport election. It is of great importance in deciding overall suitability for a sport and performance within some sports. There is a large body of data concerning ideal bone and skeletal system dimensions for the various sports. In fact it is actually a science called Kinanthropometrics.

There are three main areas of consideration for the role that the skeletal system plays in athletic performance. They are as follows:

1. Overall size of the skeleton;
2. The skeleton's proportions;
3. . The size of certain crucial individual bones.

This is not to forget the joints; they will be examined toward the end of this section.

We will briefly examine the difference between these three areas before focusing on them individually.

The overall size of the skeleton refers mainly to the total height of the body. This measure is only important in the most general of ways. For instance, a child whose projected height would be 5'8" tall at full growth would probably want to give up his dream of playing center in the NBA. His lack of height, however, would not necessarily mean that he could not play another position in the NBA, say point guard. Even though his height would still be a disadvantage at this position, it could be overcome with a high degree of corresponding abilities such as wide peripheral vision, great lateral movement, quick reaction time, explosive speed, etc. The child that did not possess height and did not test strong in most of the Abilities that point to success in the sport of Basketball would probably have too many hurdles to overcome to be successful. He would be best advised to consider alternative sports where his lack of height would not be a limiting factor.

The proportion of the skeleton is a more important variable in most sports than it its overall size. Proportion refers to the size of the upper body or trunk relative to the lower body or legs. Proportion is a big factor in determining Center of Gravity. A low Center of Gravity is critical to the performance of a number of sports, especially those requiring upright balance (i.e. skiing) or balance during tumultuous movement (i.e. football offensive backfield). Conversely, a high Center of Gravity is important to Runners. The longer your upper body is in relation to your lower body, the lower your center of gravity is.

The final area of the skeletal importance is the size of individual bones. The importance of this measure depends in full on the sport under consideration. Certain sports are advantageous to individuals with certain length body parts. Boxers, for example, need long arms. This is called "reach". Swimmers definitely benefit from large hands and wide feet. The sport of running favors those with long thighs while sprinters need a narrow pelvis which allows for a more direct line for the legs to follow. In general, the size of the individual body parts are far better determinants for ease of success in a given sport than is the overall height of the skeleton.