Nice post!
Without a doubt as we get older we stop doing things like jumping, squatting, lunging, and even moving laterally very often. The results is the muscles involved in those activities begin to weaken and atrophy, which only exacerbates this weak muscle/tight muscle problem which exists already in each of us. When this happens, abs get weaker placing greater stress on the entire pelvic region, glutes get weaker, helping to shorten the stride length, inner thigh muscles get weaker while outer thigh muscles stay the same of get slightly stronger and the legs will rotate outwards.
Strength training and proper stretching can help tremendously.

