by Michael Carlston, MD
MANY books have been written dealing with the repercussions of this question. One reason for this is that a little bit of knowledge formerly led us to incorrect conclusions.
Can training little girls this age increase endurance? Yes, but …
As children grow their lung capacity grows (until around age 20). Short term training does not appear to increase endurance, however long term training (years) does seem to have significant effects. This effect may be due to better technique – child athletes develop more economical breathing patterns. By age 16 training effects and difference between athletes and couch veggies is quite marked. While a good training program can increase a child’s aerobic fitness on the order of 10%, apparently adults can make bigger gains more easily.
Can weight training prior to puberty/skeletal maturity damage joints and connective tissue?
Children are very prone to overuse injuries around their joints. Possible explanation are that their bodies aren’t ready for such stresses, they are too eager to please adults (just say no), inadequate stretching and nutritional factors (especially problematic among female athletes). Repeating the same activity is not adjusted. We have a good deal of evidence that lifting weights does not significantly build muscle mass in pre-pubertal children. Certainly lifting weights that feel heavy is risky to the child. So why do it? Well the evidence is that lifting weights, if performed correctly, does lead to strength increases and possibly prevent injuries. Although the muscles aren’t getting bigger the child’s body learn to efficiently coordinate the work of the muscles and perform more effectively. So weight lifting is a good idea but with light weights and close attention to properly controlled technique.