Working the same muscle group over and over, and ignoring the opposing muscle group, may lead to a muscle imbalance. This imbalance occurs when a particular muscle group is over worked (i.e. Pectorals) and the opposing muscle group (in this case, the rhomboids located in the upper back) is under worked. This disturbs body symmetry and puts the athlete at greater risk of strain and pain. If these muscle imbalances are not corrected early in an athlete's career, they may lead to poor posture, instability, and a reduction in the ability to produce smooth movement.
As mentioned earlier, osteochondrosis can have many long-term effects on the human body. Initially, it is associated with tenderness, and localized pain and swelling to the area. These symptoms will not persist if treated properly. However, in extreme cases such as Osgood-Schlatter’s disease, a calcification of the tendon and ligament attachments at the tibial tuberosity occurs. This causes an enlargement of the tuberosity which is very painful and limits movement. Some physicians believe that in extreme cases, osteochondrosis may lead to arthritis in old age.
Problems as epiphyseal plate damage and osteochondrosis can have drastic effects on a young child’s body through the adolescent years. If severe enough, they can have a marked effect on the child’s normal development into adulthood and on his or her quality of life in old age. Taekwondo instructors should take careful note of the potential damage which can be caused to young bodies by excessive, repetitive high-energy training.
This leads to the question, "How hard should children train?" and "What adjustments need to be made to our Taekwondo curriculum?" Damage to a young athlete’s bony structure depends on the type of activity, the intensity and duration of the activity, and the suitability of the child to that activity. The following table shows the three main somatotypes (body types) and the activities for which they are best suited.