The female body tends to more flexibility, the male body to more muscle power.
Flexibility in one joint does not necessarily imply flexibility in others.
More muscles means less flexibility. Bodybuilders have the most limited range of movement for all the joints, first because they don't stretch, second because the bulging muscles get in the way (remember Zangief in Street Fighter II?). Only athletes and performers who follow power workouts as well as stretching routines (Wushu athletes, gymnasts) can have both muscle strength and flexibility, and their muscles are fine and sinewy, not bulging (think Bruce Lee). In daily life, something like cycling will also decrease leg flexibility if not balanced by just as much stretching. So it's very common for people not to even have the range shown below – look for the parts of their body they use most, and you'll know where they are most stiff.
The reverse is also true: more flexibility means less muscle, and those muscles are often very fragile because they are stretched so thin. For instance, some yoga practitioners who do extensive stretching but do not build the muscle, are extra vulnerable to muscle tear. Muscle power is actually essential for the active and dynamic types of flexibility, explained below.
Some people who are exceptionally flexible, or double-jointed, or have undergone intensive flexibility training from a young age, and they can move beyond the range shown here. This in no way means it's OK to ignore flexibility rules, as we all instinctively know what's "normal" for a body and what's exceptional. If you draw someone with limbs at an impossible angle, outside of a context that would allow suspension of disbelief (circus, gymnastics, the Exorcist), you risk coming across as a poor artist.