The shape of your muscle can't not really be altered, what change is their size, making them bigger or making them smaller, but you can't make them longer.
What will make a leg look long and lean is first genetic, then body fat % and how much a muscle is developed . Too many squats, dead lifts and the like will make your legs bigger (as will spinning, given the peloton craze)
You can try to give a visual definition by NOT working the front of the leg ( the quats) and over working the hamstrings.
Sprints workout require a lot of force and might actually increase the size of the muscle, so anyone wishing for leaner legs, shouldn't do too many sprint (unless we are talking about 3 or 4 minutes sprints and not a 45 min workout). Having longer, even if less intense runs, is also good for the lymphatic system as with every step, you pump it.
To have smaller legs, you need less fat and less muscle ( and I say this as a weightlifter) .
No PP has mentioned diet, and what you eat will reflect in water retention and circulation. You are what you eat and drink.