In considering the structural development of men and women， it is known that the growth pattern between boys and girls parallel one another until the ninth year. At this age the female enters an adolescent growth spurt and grows taller than the male. Because the male does not begin his growth spurt until approximately fifteen years of age the female skeleton reaches a greater maturity earlier than the male. Bone ossification occurs much sooner in the female with the epiphyseal unions of bones being completely oss ified at age 16 in the female and age 19 in the male. At adolescence there is a large spurt of both bone and muscle gorwth in the male， with a corresponding loss of fat. The female， in contrast shows little gain in muscle or bone and a considerable gain in fat. Growth in general terminates in the female between the ages of fifteen and sixteen and the male achieves full maturation and size between the ages of 20-21.It is believed that these extra years of
physical growth,under the influence of growth hormones， account for the greater size of males.

The mature male and female skeletons present some differences. Themature male skeleton is more rugged than the female. The bones are more massive and of greater density， and the long bones are longer.The joints are relatively larger and a greater articulating surface exists. The male trunk is characterized by wide shoulders and narrow hips， whereas， the female trunk exhibits a wider pelvis with fat pads over the hip region. Thewider pelvis necessitates a greater inclination of the femur shaft with the neck of the femur and diminishes the efficiency of body movements in activities such as running. The knee joint， in terms of its width in proportion to height，appears to be wider in the female and more stable in relation to her size. Because of a females shorter leg length and broader pelvis her center of gravity is lower than a males and， therefore，her balance is enhanced.

The chest，shoulder width， and thoracic cavity is larger in the male， but the female possesses a larger abdominal cavity due to her larger visceral organd additional organs of reproduction. Men usually possess the advantage of greater strength in terms of muscle contraction because of the greater bulk of muscles and the resulting cross sectional size.

Circulatory and respiratory differences between sexes are probably evidences of body adjustments which are necessary for the maintenance of different sized bodies.The heart weight is directly proportional to body weight， therefore the larger male heart is accounted fot by his larger physical size.

Considering the respiratory system the vital capacity， which is the volume of air moved through the lungs from a maximum inspiration to a maximum expiration， bears a direct relationship to body size, surface area and height. Females， therefore， would exhibit less breathing capacity than comparable males.

The1 0% additional adipose， tissue that womem posses as compared to men serves as an insulation to prevent excessive heat loss from internal organs. The total body sweat rate is lower in women than in men. Females do not begin sweating until the internal body heat has risen to a slightly higher degree than is the case with men. There is a lessened ability to react to unfavorable heat and humidity conditions in women than in men. This could present major problems under unfavorable environmental conditions,or heavy work done by those not acclimatized and conditioned.

Woman is definitely competent toparticipate in strenuous activity under all conditions in which man can participate. Hse is capable of server endurance ecents and can reach high levels of performance through the utilization of quality training programs,designed to challenge and place overload demands on the individuals body systems. Only in those events requiring great strength or explosive power are sex difference in performances more marked. Limitations to female performance appear only when the athlete seeks to compete with the male on a common ground in which the areas of size, strength and speed are major factors. In some individual and non-contact sports that do not emphasize the factors of size , strength and speed, particuoatuib between males and females can occur on a very equal basis.

Woman has not come close to reaching her potential in sport nor has she been challenged to a great enough degree. She is capable of attaining great golas and her status and stature in sport will cerainly improve.

，tounfavorable heat and humidity conditions in

!womenthan in men. Thiscould present major problems under unfavorable environmental

conditions， or heavy work done by those not acclimatized and conditioned.