The average female Army recruit is 4.8 inches shorter, 31.7 pounds lighter, has 37.4 fewer pounds of muscle, and 5.7 more pounds of fat than the average male recruit. She has only 55 percent of the upper-body strength and 72 percent of the lower-body strength... An Army study of 124 men and 186 women done in 1988 found that women are more than twice as likely to suffer leg injuries and nearly five times as likely to suffer fractures as men.

The Commission heard an abundance of expert testimony about the physical differences between men and women that can be summarized as follows:

Women's aerobic capacity is significantly lower, meaning they cannot carry as much as far as fast as men, and they are more susceptible to fatigue.

In terms of physical capability, the upper five percent of women are at the level of the male median. The average 20-to-30 year-old woman has the same aerobic capacity as a 50 year-old man.

The same report also cited a West Point study from the early 90s which discovered that, in terms of fitness, the upper quintile of female cadets achieved scores equal to the lowest quintile of their male counterparts.

via In From the Cold: Too Many White Guys.