Girls generally grow and mature earlier than boys. Cross sectional height values for girls are around 160cm and begin to plateau at age 14 or 15 years of age while boys grow steadily through this period to around 170cm. Similarly girls weights level off at the same time at 55kg while boys grow to 60kg. The differences in the range of values for both sexes from these studies is significant. There are late developers and early developers.
Late developers grow for longer than early developers and they are generally taller as adults.
Late developers need different rowing preparations, they need more skill based work, constant strengthening programs without heavy weights and medium rather than high intensity in the boat. Early developers can cope with high levels of intensity and strengthening programs based on endurance principles. Boys or girls could begin these programs at 17 or 18 years depending on their development and only under the care of a qualified instructor. The program would be for a short period rather than a sustained term. There is common agreement that pre adolescent weight training will do little to increase the muscle size of a child.