Restless legs in toddlers?

Josephine has done this a few times since she was born.  In the past it has only happened after immunization.  However, this time it was random.  I’m not sure what has caused it this time.  I recorded her movements.  

I tried to do some research to find out what this is, or what is causing it.  I found an article about Pediatric Periodic Limb Movement Disorder (PLMD). 

Periodic limb movement disorder (PLMD) is a condition in which children kick or jerk their legs while sleeping.  Symptoms usually happen every 20 to 40 seconds and can last for a few minutes to several hours.  PLMD is often confused with restless legs syndrome (RLS) but, while the two conditions often occur together, they’re not the same thing. While RLS can happen at any time, PLMD only affects sleeping patients.

This does only happen when Jo is asleep.  So this sounds like it might be the case.