Jefferson Curls question

For Jefferson Curls, should I be keeping my legs stiff until I'm fully stretched out and then bend them to go past my feet?  Or should I just keep my legs stiff the whole time even if I can't touch my toes all the way?  After I've warmed up and gone through the front split series, I'm able to touch and go past my toes.  However, my cold flexibility is still not that good so I'm not able to touch my toes when doing J-Curls?  FYI - I'm just doing bodyweight and with 5-lb dumbbell in each hand right now for the J-curls.

Hi Sam,

Keep your knees locked when doing Jefferson curls. Don't worry about going past your toes to begin with, as your flexibility improves you will get there. Feel free to submit a form check. This is definitely the best way to get feedback on your form