Explanation: Super Sentai was the kids TV show that was re-edited to create MIGHTY MORPHIN POWER RANGERS.
Several episodes of the various series (there were several) involve AR, generally with the 'teen' heroes being regressed into children, sometimes along with some of their supporting cast. One series even had an extended episode arc where the Sentai are children even in superhero form and must fight the villains like that.
The episode I found on DVD, however, is on the SUPER SENTAI: NINPUU SENTAI HURRICANEGER box-set from Shout!. 'Crybaby and Candies' involves the villains regressing various people, apparently at random, into five year olds physically and mentally. One of the heroes is also affected and becomes a clingy, frightened child who must find his courage to help his friends triumph.
The kids are shown in oversized clothes but that's pretty much it.