The biggest feature of the ER (External Rotation) type is that the knee caps face outwards as the thigh bones are rotated outwards. Also, since the thigh bones and knee caps look outward, the toes slightly point out in that direction too.

Sitting can feel more comfortable when the legs are crossed rather than W-sitting. Standing with the knees fully extended may not be possible for people with this type.

Compared to the IR (Internal Rotation) type often seen with anterior pelvic tilts, the ER type tends to occur in conjunction with posterior pelvic tilts. However, it can vary depending on an individual's lifestyle/exercise habits, posture, and other factors.

To sum up, all the other characteristics may appear slightly differently for each individual, but the biggest feature mentioned above is almost always seen. Hence, it is the most reliable factor to consider when deciding between the IR or ER type.