I'm not getting any younger, and though sword play is less hard on the body over the long term than many striking or grappling arts, I certainly pay attention to alignments and how I use my body to prevent injury and retain range of motion, flexibility and 'quickness' (I was going to say speed, but this is better) as I would like to keep playing for many decades yet.
Most of what I know about healthy movement comes from the years I've spent studying the Chinese 'Internals' - Tai Ji, Xing-Yi and Bagua, along with their related Nei Gung exercises.
One of the most important things these systems pay attention to is how the weight is dropped into the ground through the weighted leg - knees and hips are notoriously prone to injury, especially for martial artists, so maintaining accurate lower body alignment is key to keeping injury free. Eskrima, Bagua, Tai Ji and Xing-Yi all emphasize the 100% weight shift thus making the alignments through the weighted leg particularly important.
Add to this Eskrima's emphasis on deception and evasion with it's quick direction changes, angle feints and weight shifts, and you get a recipe for soft tissue damage if you do not pay attention.
VCKE has a set of warm up exercises - The Moro Foundation Set - that work these alignment principles, with an emphasis on improving flexibility in the hip joint, the accuracy of hip and shoulder alignments, and the ability to pivot safely.
Pivoting requires the weight to be distributed mostly on the ball of the foot with the heel kept light so the heel is free to turn (heel pivoting is also possible of course but we focus mostly on the ball of the foot pivot). This ensures that the toes and the knee of the weighted leg are always facing in the same direction, and if there's one alignment advice I pay particular attention to it's this -
TOES AND KNEE, SAME DIRECTION, ONE OVER THE OTHER.
Those of you that practice Chen style Tai Ji or Silat will know that the 'one over the other' thing does not always hold true, and if you have developed the fascia, tendons and ligaments along the leg enough you can do this, but in general these are good principles to keep to, at least that has been my experience.
This then brings me to the importance of warm up sets. Most traditional systems have them, and I am reminded of what Luo De Xiu said - Don't dismiss the warm up sets as trivial and unimportant - Why does the teacher make you do them every time? Not because they are convenient or easy, but because they are the most important movements in the system.